VIDO research and researchers in the media

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Project Looks At Link Between Stress And Disease Severity In Cattle
A research project completed by scientists at the University of Saskatchewan's Vaccine and Infectious Disease Organization (VIDO) is breaking new ground in identifying the relationship between stress and disease susceptibility in cattle.

The research sought to identify biomarkers associated with stress, as stress makes animals more susceptible to a number of diseases, such as bovine respiratory disease.

"We tried to address a very old question with a new insight," said Dr. Palok Aich, the project leader of the VIDO team which undertook the research. "We knew that stress plays an important role in the mortality of cattle."

The team investigated how changes in certain blood compounds, called metabolites, can be used as "biomarkers," to predict the dangerous combination of stress and disease.

"We already knew there were certain elements that could actually be measured that correlate with stress. We found that the most common marker was not very reliable because it fluctuates," Aich said.

"If we could find something better, we would be able to identify whether the animal is going through stress - and, if so, how much stress and will it increase the animal's susceptibility to disease?"

What puzzles scientists is that exposure to viruses or bacteria cause disease in some individual animals, but not in others. Bovine respiratory disease involves an interaction of viral and bacterial infections, and is a disease most likely associated with stress-susceptible animals.

"We found a group of markers using various types of new technologies on any fluid sample, like blood," explained Aich. "These markers are at the levels of proteins, or metabolites, or even minerals present in blood. Then, we can determine whether or not the particular group of markers is associated with a particular type of stressor, and, if we can change the trend of these markers, how that will affect the outcome for the animals."

The refinement of biomarker tracking could result in identifying disease-susceptible animals at the feedlot or the ranch, allowing for earlier intervention and handling methods that will minimize stress.

An important aspect of this project was to help producers understand the effect of handling-related stress and disease susceptibility, and to help in the identification of susceptible animals.

"The problem is the difficulty in identifying exactly when animals become infected," said Aich. "What we have to do is understand how long these markers are stable in the animal's system. We can then tell which markers are a predictor of what will happen to a particular animal if it becomes infected, before the disease is present."

The VIDO study was funded by the Saskatchewan Ministry of Agriculture's Agriculture Development Fund, the Ontario Cattlemen's Association, Genome Prairie, Genome British Columbia, and Inimex Pharmaceuticals Inc. The results of the study have now been published in the scientific journal Omics.

VIDO scientists will be pursuing future funding to move their experimental results into a clinical setting as a diagnostic tool.

A copy of the ADF report, Proteomic Investigation of Molecular Basis of Stress and Disease Resistance in Cattle, project number 20020145, can be obtained by phoning Saskatchewan Agriculture at (306) 787-5929, or downloaded from the Saskatchewan Agriculture website at http://www.agriculture.gov.sk.ca/.

For more information, contact:
Dr. Palok Aich, Project Leader
Vaccine and Infectious Disease Organization, University of Saskatchewan
Phone: (306) 966-1541
E-mail: palok.aich@usask.ca

New VIDO director daunted but excited

By Karen Morrison
The Western Producer
(This article was originally published in the June 7, 2007 issue of The Western Producer. It is posted here with permission.)

Replacing Lorne Babiuk is a little like curling against the skip that beat the best team in the league, says the incoming director of the University of Saskatchewan’s Vaccine and Infectious Disease Organization.

Andy Potter is the long-time curling enthusiast and vaccine researcher who will tackle that challenge in July when Babiuk moves to a new job at the University of Alberta.

“It’s extremely daunting,” he said.

Within years, VIDO will add the International Vaccine Centre, or InterVac, and within weeks it will begin to collaborate with the university’s new school of public health.

The son of an RCMP officer, Potter lived in a number of Canadian communities before attending Carleton University in Ottawa. He completed his PhD in New Zealand, where he met his Philippine born wife. They have two children, both students at the U of S.

Potter worked in plant and animal biotechnology in the Philippines and for Health Canada before Babiuk recruited him for VIDO in 1985.

He began working in respiratory vaccines for cattle, the first time he had been involved with livestock. Those experiences shaped his current work and helped him to learn to work as a team.

“You get more bang for your buck when working together,” he said. “You share in the work and in the rewards that come of the work.”

Potter said VIDO had embraced that concept to help it develop vaccines. Thirty percent of its work is devoted to human vaccines, with the rest created for livestock.

He plans to largely stay the course Babiuk set.

“VIDO will continue to work on what we’re good at,” he said.

The role vaccines play in public health hits home for Potter, who suffered through measles and mumps and had a neighbour afflicted with polio.

“People don’t go through that today,” he said.

The introduction of InterVac, which is expected to be complete by 2010, will allow the organization “to move on to the tough ones.”

“Without InterVac we couldn’t take it to the logical conclusion,” he said. “We can only take it part way.”

He said VIDO can work with the proteins that it thinks would be good vaccine components and can make prototype vaccines, but has no way to test whether they work until InterVac is completed.

VIDO has developed seven vaccines for livestock, which have made a $500 million impact in the Western Canada economy, he added.

“It’s incredible to get a return like that.”

VIDO is also involved in humanitarian work with Microsoft founder Bill Gates’ foundation by improving vaccines for newborns in the developing world.

In the future, it will link up with the new school of public health, providing high level training for graduate students in human and animal health.

Potter said VIDO receives valuable input, support and direction from the VIDO advisory board, chaired by Saskatoon livestock producer Brian Perkins.

Perkins said Potter’s history with the organization and international reputation in vaccine research bodes well for the new director and the institution.

“There will be challenges but he has the opportunity to really add his flair to the whole situation.”

Perkins called Potter a brilliant scientist who works well with others in research.

“He brings out the best in them.”

Beef, bacteria, and food safety: Study investigates potential link to human disease

With “mad cow disease” and “bird flu” now household terms, the question of food safety is on every Canadian’s mind. More than ever, we are becoming more cautious—and more informed—about the food we eat and the potential hazards our food may pose.

This concern has led the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO) to initiate a new food safety study, funded by Advancing Canadian Agriculture and Agri-Food Saskatchewan (ACAAFS), the Manitoba Rural Adaptation Council, and the Agriculture and Food Council of Alberta. The study will determine if there is a genetic similarity between the Campylobacter organism found in cattle feedlot droppings and ground beef, and the common human bacterial infection it causes (Campylobacteriosis).

Poultry is usually considered the source of Campylobacteriosis, but other sources, including beef, are also suspected of causing this infection. Europe and Australia have initiated studies to this end, but there is no published data on the prevalence of Campylobacter in ground beef, nor is it known if there is a link between the bacteria found in feedlot cattle feces and those from human cases of the disease.

“Cattle are common carriers of the organism. Ultimately, we want to know if cattle and beef products are leading to an increased risk of disease in people,” says Dr. Hugh Townsend, the project leader.

“This research will build on past research by filling in several gaps in knowledge,” he says. “Determining the prevalence of Campylobacter in ground beef would be new knowledge that is essential public health information for risk assessment and food safety. Alternatively, drainage from feedlots or cattle operations into water supplies could be another source of Campylobacter, which is why we are trying to establish prevalence of these bacteria in feedlot cattle feces.”

Seven Alberta feedlots will participate in the study, providing 2,800 fecal samples. Fresh ground beef samples (1,200) will be sourced from 60 supermarkets in Alberta throughout the course of a year. The study will also include 100 Campylobacter samples from confirmed human cases. VIDO will then process each sample to determine potential links between the Campylobacter bacteria found in each.

“A big problem with Campylobacter is being able to classify these organisms with sufficient discrimination. The results of this study will look at the entire bacterial genome, and compare genetic similarity or differences between samples from the three sources: cattle feces, ground beef and humans. This study is not set up to show that the bacteria from the cattle or meat are causing disease in people, but is a first step in deciding whether this is an important possibility that we should continue to pursue. The molecular genomotyping results will be useful both to us and to colleagues elsewhere.”

Campylobacteriosis is the number one bacterial enteric disease in Canada and worldwide. Dr. Townsend says that further knowledge of Campylobacter epidemiology in people, animals and meat products is critical in identifying prevention and control points in the farm-to-fork process. Ultimately, consumers will benefit from this research as the safety of the food and water supply is improved.

The study began in January 2005 and will likely be completed by January 2007.

Evolving diseases call for new approaches to treatment: Dr. Lorne Babiuk

By Tess Laidlaw
VIDO Communications Officer

For a time, antibiotics appeared to have defeated infectious disease, leading the U.S. Surgeon General in 1969 to declare the war against infectious disease over – and then 30 new diseases emerged.

Lorne Babiuk, director of the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO), described just how ill-fated that prediction was to a crowd of more than 100 people at the Royal University Hospital on Jan. 27.

Many of the new diseases, which have developed over the last 30 years, infect both animals and humans.

Antibiotics won’t be the answer this time around. “There have been no blockbuster antibiotics for 20 years,” Babiuk said. The rapid increase in antibiotic resistance shows that even new antibiotics won’t stop micro-organisms for long.

At breakneck speed, Babiuk covered the origin of vaccination 200 years ago to the new technologies available today, from comparative genomics to novel vaccine additives that increase the effectiveness of existing vaccines with stunning results.

From the statistics, it seems that new technologies cannot be developed fast enough. Babiuk pointed out that according to the World Health Organization, more than 16.5 million people die from infectious disease each year. Diseases which have seemed to be under control are returning. Tuberculosis, for example, killed more people last year than had ever been reported.

Babiuk oversees an arsenal of research programs aimed at controlling infectious disease.
One promising direction at VIDO is the focus on innate immunity. “The innate immune response is key to determining whether an infection starts or not,” he said.

The strength of the response can differ from one person to the next. Babiuk pointed out that some people who are exposed to a bacteria or virus never seem to get sick. “The body has a number of receptors that recognize something foreign, and they respond within minutes or hours to overcome the infection,” he said.

If this powerful response could be managed, it would be a valuable tool against disease. Cationic peptides, one aspect of this response, are a type of protein present naturally in humans and animals. When VIDO researchers tested the peptides in animals against pneumonia, the peptides protected animals as well as antibiotics did. More importantly, the proteins carry limited potential for resistance to develop.

Another compound that stimulates the innate immune response is called polyphosphazene. In one study, VIDO researchers added the compound to a vaccine against hepatitis B that is currently on the market. Normally, protection against hepatitis B wanes by 12 weeks after vaccination, requiring two more booster shots. However, the vaccine with the polyphosphazene added provided protection right up until the study ended at 48 weeks.

Pharmaceutical companies are already paying attention to innate immunity. Coley Pharmaceutical Group sold the rights of use of an immune-stimulating compound in a single area of application (cancer therapy) for $510 million.

Babiuk said that VIDO thrives through being competitive and being fast. “Research is like the Olympics,” he said. “You have to lead the pack. If you’re not going to get the gold medal, you shouldn’t even play.”

Remaining competitive in an era when most new diseases fall into the Biosafety Level 3 category led to the creation of the $110 million International Vaccine Centre (InterVac). VIDO currently possesses only Level 2 facilities. The anticipated construction start for the new centre in early 2007 will encourage a number of researchers across the University of Saskatchewan campus and around the world who are eager to extend their work in an accessible large-animal facility.

The new lab has been given the go-ahead by the U of S board of governors to move to the next stage of finalizing the design, financial support and governance structure.

Babiuk emphasized that success for any research endeavour can only occur through extensive partnership and collaboration. “Collaboration is important, because no one individual, or institute, or university can do everything,” he said.

Through his tenure at VIDO, Babiuk has illustrated a great deal of creativity in vaccine development. Yet, he says, “one of our greatest challenges is that we do not actually dream big enough. Lack of imagination is our biggest albatross.” TOP

Articles published in Alberta Beef Magazine

Beef InfoNet offers rapid online access to beef industry information

Curious about why some cattle handling systems work better than others? Do you want to lower the risk of dystocia, or find out which livestock diseases pose a health risk to you and your staff? Try Beef InfoNet (www.vido.org/beefinfonet ).

The web-based Beef InfoNet is a database and Internet portal providing producers with rapid access to quality information on a broad range of topics.

“Agriculture is a knowledge-intensive industry, and it’s becoming increasingly technical,” says Dr. Philip Griebel, a scientist at the Vaccine and Infectious Disease Organization (VIDO), and facilitator of the VIDO Beef Technical Group (VBTG).

He says that beef producers must deal with a broad range of issues that impact animal health and production, including economic, environmental and social factors that affect daily decisions.

“Having rapid access to online resources is very important since producers don’t have a lot of time to search the Internet,” says Dr. Griebel, who manages his own cow-calf operation.

Because the sources of information are rapidly expanding beyond the traditional trade journals and government extension services to include a variety of specialized web sites, the main objective of the VBTG in creating Beef InfoNet was to provide producers with a well-organized, easy-to-navigate portal.

He points out that resources for Beef InfoNet are carefully chosen based on scientific data or research that has provided conclusive, quality results. Principles demonstrated by the research should work effectively when applied in field conditions. Members of the industry are encouraged to suggest resources and provide feedback.

VBTG members include cattle producers, industry representatives, and academics from across Canada. “Members of the VBTG identified the range of topics that would be included in the Beef InfoNet. These topics were selected on the basis of their relevance to decisions affecting all aspects of the beef industry, including the cow-calf producer, feedlot operators, and the seedstock industry,” says Dr. Griebel.

“We’re not interested in duplicating the many excellent electronic resources that are out there, but rather in providing rapid links to existing sites. Part of our responsibility is to also identify topics for which adequate information is not available.”

For example, the emergence of the biofuels industry will create a number of challenges and opportunities for the beef industry. The VBTG is preparing a Question and Answer with Dr. John McKinnon, University of Saskatchewan professor and Saskatchewan Beef Industry Chair, to provide insight into how the beef industry may respond to this situation.

Beef InfoNet is updated weekly with information from academic, government and beef industry sources based across North America. Content ranges from livestock handling fact sheets and video developed by Dr. Temple Grandin, to vaccination guidelines and economic forecasts for the beef industry. Formats range from pdfs to web pages to videos. A News and Events section tracks happenings in the industry such as conferences, workshop and seminars.

Demonstrations of Beef InfoNet by VBTG members are taking place at industry events across the country, including the Alberta Beef Industry Conference and the Termuende Field Day in the spring.

The VIDO Beef Technical Group is a volunteer industry resource group operated by the Vaccine and Infectious Disease Organization. Funders and supporters of the VIDO Beef Technical Group include:
Alberta Beef Producers, Alberta Livestock Industry Development Fund (ALIDF), the British Columbia Cattlemen’s Association, La Fédération des producteurs de bovins du Québec, InterVet Canada Inc., Manitoba Cattle Producers, Novartis Animal Health, Ontario Cattlemen’s Association, Pfizer Animal Health, Saskatchewan Agriculture and Food, Saskatchewan Cattle Marketing Deductions Fund, Saskatchewan Horned Cattle Trust Fund, and Schering-Plough Animal Health.

VIDO closer to tackling BVDV

Bovine viral diarrhea virus (BVDV) is a headache for beef producers in terms of both its impact on the health of their animals and on their livelihood. Not only does BVDV cause fever and diarrhea and increase respiratory rate, it also causes a decrease in the number of white blood cells and thus weakens the immune system. This predisposes animals to secondary infections. These secondary infections are most often those of the bovine respiratory disease (BRD) complex, commonly known as shipping fever—also a significant problem for beef producers.

Vaccines are available against BVDV, but some (modified live) cannot be delivered to highly stressed or pregnant cattle. Also, the virus is careless when reproducing itself, so there are many versions of each of the type 1 and type 2 strains in circulation.

In a perfect world, a needle-free vaccine would be available to protect against both type 1 and type 2 BVDV viruses in all cattle. Over the past few years, the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO) has been working to develop such a vaccine.

The first step in vaccine development is to isolate which part of a pathogen can be used in a vaccine to launch an immune response that will protect against the real pathogen. It was found that the E2 protein of BVDV was most effective at generating a protective immune response, so we developed vaccines containing either the BVDV type 1 version of this protein or the BVDV type 2 version. We chose to develop DNA vaccines because they are suitable for all ages of animals, and can be delivered through the skin with a needle-free device. They are also straightforward and economical to manufacture.

First, we tested the BVDV type 1 vaccine in calves. We vaccinated animals with the E2 DNA vaccine, then boosted with the E2 protein together with an immune-stimulating compound. We found that this led to excellent immunity and protection from BVDV-1 challenge.

Since we need to be able to protect against both BVDV-1 and BVDV-2, we tried the same strategy to induce protection from BVDV-2 challenge and found that the BVDV-1 vaccine offered very little protection. However, the BVDV-2 vaccine, or a mixture of BVDV-1 and BVDV-2 vaccines, fully protected the calves from BVDV-2 challenge.

Since we now know that the mixture of BVDV type 1 and type 2 DNA-based vaccines offers excellent protection from BVDV, our next goal is to establish protection in animals of all ages—including newborn calves—against both type 1 and type 2 BVDV, and to induce long-term immunity and protection. We seek to do this by further optimizing the formulation and delivery of these vaccines.

As part of a VIDO project on immune modulation led by Dr. George Mutwiri, we are also applying an immune-stimulating compound to improve existing commercial vaccines against BVDV. As an approach to improve protection, in this case the compound is added to a family of bovine respiratory disease vaccines that are already on the market. Preliminary results indicate that the immune-stimulating compound delivered in combination with the vaccine might improve the performance of these vaccines. The next step for this project is now to induce long-term protection.

This work is supported by the Beef Cattle Industry Development Fund (BCIDF), the Beef Cattle Research Council (BCRC), and the Ontario Cattlemen’s Association (OCA), the Advancing Canadian Agriculture and Agri-Food Saskatchewan (ACAAFS) program and Merial.

By Dr. Sylvia van den Hurk, head of VIDO’s Nucleic Acid Technologies program.
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Past, present and future: VIDO and cattle health

2007 has barely begun, yet it has already been an exciting year for the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO).

In January, the federal government announced up to $25 million for a new International Vaccine Centre to be built adjacent to VIDO. Most emerging and re-emerging diseases are classified such that specialized equipment and facilities are needed in order to study them, and such facilities are scarce internationally. With nearly all funding now secured, this support makes InterVac a reality. Construction is expected to begin in 2007.

As well, VIDO’s food safety program saw its first vaccine graduate to the marketplace. A groundbreaking vaccine for cattle that will protect water and food supplies from the toxic E. coli O157:H7 bacteria has been approved for release in Canada and should be available by early summer.

Improving vaccine delivery and effectiveness
VIDO remains active in addressing the livestock disease challenges that let to its creation. Conceived in 1975 by Dr. Chris Bigland, VIDO’s mandate was to address the need for research focused on animal health problems prevalent in western Canada. The new organization produced the first vaccines to prevent both bacterial and viral scours in newborn calves, and revolutionized vaccines for respiratory disease in feedlot cattle.

More recently, VIDO has focused on improving vaccine delivery and effectiveness—a challenging task. The cattle industry agreed that vaccines were a great tool, but there was increasing concern that vaccinations were adversely affecting meat quality and possibly food safety. Our challenge was to attempt to eliminate these adverse reactions without compromising vaccine efficacy.

New concepts and technologies were emerging that gave us a better understanding of what would induce a strong response to a vaccine. There were, however, many variables to be tested; and each success would need to pass the final tests of cost and ease of manufacture.

The search to improve vaccine delivery has yielded remarkable successes. We identified a potent immune system stimulant that can be incorporated into vaccines to improve protective immunity. This immune stimulant does not damage muscle at the site of injection—a unique property. It is also effective when injected either under the skin (subcutaneously) or within the skin (intradermal).

Needle-free vaccination
These observations were exciting, since they meant the immune stimulant could be used in vaccines delivered with needle-free technologies. VIDO scientists explored the use of needle-free vaccine technologies in cattle, and one technology that was both practical and cost-effective was the delivery of a stream of high-pressure fluid directly through the skin. This technology was optimized for use in cattle, and disease challenge trials confirmed that needle-free vaccination was as effective as traditional vaccination.

Other advantages were also noted when using needle-free vaccination. The dose of vaccine needed to induce protective immunity was much less with needle-free vaccination, and animals did not react during vaccination, indicating there would likely be fewer vaccine failures when processing large numbers of animals.

Other vaccine development programs at VIDO, such as the Vectored Vaccine program aimed at developing oral vaccines based on adenovirus vectors, are long-term in scope but will revolutionize vaccine delivery in the future. By eliminating the need to handle each animal, oral vaccination will allow more timely immunization relative to the period of greatest disease risk. For example, vaccines for respiratory diseases can be delivered in the pasture before calves are weaned, and booster vaccinations could be delivered with feed in the feedlot.

Collectively, these vaccine research programs will change not only how vaccines are delivered, but also when and how often vaccination must be done to maximize disease prevention.

Taking aim at M. bovis, BSE, and Johne’s disease
We continue our work to address infectious diseases threatening the beef industry with the recent establishment of a Mycoplasma bovis research program. It has been estimated that M. bovis infections result in losses of more than $32 million per year in North American feedlots. Treatment of M. bovis infections is costly and frequently fails.

VIDO also established a BSE research program in 2006 to investigate the mechanisms underlying this unusual disease and aiming to develop vaccine prototypes against BSE. This year, we will establish a Johne’s disease research program to address this important animal health problem and possible food safety issue. This chronic disease has been very difficult to study, but with the advent of new molecular biology tools, it is possible to begin identifying disease mechanisms that will provide a basis for vaccine development.

Part of the solution to animal health problems includes translation of new knowledge into improved management procedures. The VIDO Beef Technical Group (VBTG) reflects our commitment to knowledge transfer to the beef industry. Our interaction with individuals within the beef industry helps us maintain an awareness of emerging problems and continue to respond to industry priorities. Information resources developed by the VBTG are available online at www.vido.org.

By VIDO staff
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A new vaccine against E. coli O157:H7 is approved for release in Canada

A vaccine for cattle that limits levels of E. coli O157:H7 is expected to be available to Canadian veterinarians by early summer. Co-developed by the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO), the vaccine is great news for cattle producers uncomfortably familiar with the strain, which caused the 2000 outbreak in Walkerton, Ontario that caused the deaths of several people and made hundreds ill.

Studies show that the new vaccine greatly reduces the amount of E. coli O157:H7 bacteria shed by cattle into their environment. “This makes Canada the first country in the world to have access to a vaccine for control of E. coli O157:H7,” said VIDO Director Lorne Babiuk. This vaccine is the first intended for use in animals in order to protect humans.

These bacteria do not cause illness in cattle, but the vaccine will protect human health by decreasing the chance of contamination of water supplies and beef products destined for grocery shelves. E. coli O157:H7 is also making an appearance in many food products in addition to beef. Food-borne illness caused by E. coli and other pathogens is estimated by the World Health Organization to affect up to 30 per cent of the population of developed countries.

The vaccine is based on the discovery by Brett Finlay of the University of British Columbia (UBC) of how E. coli bacteria attach to the intestinal surface. Andrew Potter, Associate Director (Research) at VIDO, spearheaded the transformation of the discovery into a vaccine candidate.

“The vaccine prevents the bacteria from attaching to the intestine. This in turn prevents its ability to remain—and reproduce—in the body,” Potter said.

In the early years of the research, before the events in Walkerton, Potter says the scientists had a tough time finding a commercial partner to ramp up production and market the vaccine. However, Bioniche Life Sciences Inc. of Belleville, Ont. was interested and took on the task of commercialization.

In December 2006, Bioniche announced that the Canadian Food Inspection Agency had authorized the vaccine for distribution. As further data is required for full licensing of the vaccine, it will be distributed by request to individual veterinarians.

The vaccine must be delivered via three doses for cattle heading to slaughter, and is expected to be cost-effective. Non-beef cattle can also be vaccinated.

VIDO spent $2 million to $3 million over five years developing the vaccine, and is continuing its food safety research with programs to extend the technology behind the O157 vaccine to additional strains of E. coli and Salmonella, which the Centers for Disease Control estimates causes illness in 1.4 million people in the U.S. each year.

Led by Potter and Wolfgang Koester, the team is also working to develop a vaccine against Campylobacter, which causes five per cent of food-related deaths in the U.S. annually.

In addition to Bioniche and UBC, the Alberta Research Council collaborated on the development of the vaccine. Many funders supported the work, including the Alberta Livestock Industry Development Fund, the Canadian Institutes of Health Research (CIHR), the Canada Beef Industry Development Fund and the Canadian Bacterial Diseases Network of Centres of Excellence. The scientists leading the VIDO work, Potter and Koester, are Bioniche/NSERC Industrial Research Chairs.

VIDO’s capacity to respond to emerging pathogens will be profoundly enhanced by the $110 million International Vaccine Centre, a Biosafety Level 3 facility slated to begin construction in 2007. The facility will be equipped to study diseases such as BSE and avian influenza.

By VIDO staff
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New BSE research program begins at VIDO

With the launch of its bovine spongiform encephalopathy (BSE) vaccine and prion research program this summer, VIDO hopes not only to be testing vaccines for cattle within three years, but also to shed light on the mysterious mechanisms behind prion diseases.

Prion diseases affect a range of mammals, from sheep to cattle to humans. A 1960s theory about the cause of these unusual diseases coined the term “prion,” from “proteinaceous infectious particle.”

The widely-held belief about the cause of prion diseases is that a natural protein becomes malformed and then goes on to “infect” other, normal, proteins of the same type – causing them to take on this unnatural shape. This theory was confirmed in 1982 by Dr. Stanley Prusiner, who received a Nobel Prize for the work. When the abnormal proteins accumulate, they cause the breakdown in brain matter that gives the tissue the “spongy” appearance seen in post-mortem examinations.

It is believed that prion diseases can spread in some cases through environmental contamination by infected bodily fluids or via the recycling of animal proteins within the food chain. Therefore, a vaccine against BSE would be valuable in controlling the disease, with the added benefit of strengthening perceptions in the export market.

We hope that the vaccine candidates we develop could also function as therapy against BSE in the early stages of infection. Our program may also generate technologies to support the development of diagnostic tests.

Although prion diseases have been around for at least two centuries, very little is known about the natural prion protein’s function or about how infectious prions cause disease. We also need to learn how different versions of the disease compare – chronic wasting disease versus BSE for example. Therefore, in addition to vaccine development, we will try to reveal the mechanisms of how natural prions develop into disease-causing forms and how those infectious prions cause disease.

In most cases, disease is caused by an agent foreign to the body – a virus or a bacteria, for example. Vaccines specifically targeting these foreign substances can be developed. However, the challenge of vaccinating against BSE and other prion diseases is that the disease-causing protein has a natural origin in the host animal’s body. Therefore, vaccines targeting infectious prions could also target healthy proteins, triggering effects such as autoimmune disease.

Our program was sparked by discoveries made by Dr. Neil Cashman, Canada Research Chair in Neurodegeneration and Protein Misfolding Diseases at the University of British Columbia. Dr. Cashman’s team discovered a unique characteristic of abnormal, disease-causing prions – a protein-binding site – which provided a target for vaccine development. As several mammal species share the site, we expect our vaccine research to be applicable to species in addition to cattle.

We also realized that VIDO had an existing technology that could be used in vaccines against BSE. We had already developed a patented vaccine system for vaccinating against naturally occurring proteins. Based on Dr. Cashman’s discovery, our system could provide the basis for vaccines against prion diseases – targeting the diseased prions but leaving the healthy ones alone.

Within three years, we hope to be testing vaccine candidates to control BSE in cattle; and with another University of Saskatchewan team led by Dr. Trent Bollinger at the Western College of Veterinary Medicine, to control chronic wasting disease in domestic or wild deer and elk. Knowledge about the disease in cervids is crucial to understanding potential risks posted to cattle herds by wild animals.

While VIDO brings its expertise in vaccine design, formulation and delivery to the project, Dr. Cashman, who is scientific director of PrioNet Canada, will provide expertise in prion protein structure and the disease itself. The VIDO team also includes members based in the Norwegian Veterinary College in Oslo, Norway, who contribute expertise with scrapie and its diagnosis.

Funding for this work is provided by Saskatchewan Agriculture and Food; and PrioNet Canada, a federal Network of Centres of Excellence.

By Dr. Andrew Potter, Associate Director (Research), VIDO; and Dr. Scott Napper, manager of VIDO’s Emerging Diseases and Microbial Virulence program.

A new vaccination program at VIDO targets Mycoplasma

Dr. Jose Perez-Casal is one of several researchers from VIDO who are working to develop vaccines against M. bovis to protect animals against all strains of the bacteria.

Mycoplasma bacteria cause a range of illnesses in cattle of all ages – pneumonia, arthritis, mastitis – and are difficult to eradicate. M. bovis is one of the more serious pathogens, yet it may be overlooked as a causative agent of these conditions because of the presence of other, more familiar bacteria. Difficult to treat, M. bovis is suspected of being a main predisposing factor in disease development, particularly with respect to respiratory disease.

First seen in the U.S. in 1961, M. bovis is now thought to be circulating worldwide. In the U.S., the impact of this pathogen on weight gain and carcass value as part of the bovine respiratory disease complex was estimated at $32 million per year (1999 study). Over the past decade, M. bovis has been responsible for a chronic pneumonia-polyarthritis syndrome plaguing the beef industries of Canada and the United States. It can also cause abortion and sterility.

Antibiotic treatment and isolation of affected animals are currently the only ways to manage Mycoplasma infection. This route is expensive and often ineffective. Many antibiotics interfere with the synthesis of the bacterial cell wall and since Mycoplasmas do not possess a cell wall, these antibiotics are not effective to treat the disease.

In addition, Mycoplasmas are equipped with mechanisms to escape the immune surveillance of the host. This characteristic is common to other types of difficult-to-treat disease agents such as influenza, and occurs because the bacteria or virus is able to keep changing its surface proteins, swapping combinations like a mask. These masks make it more difficult for an infected animal to “recognize” the bacteria and develop an effective immune response. While vaccines do exist, this variation has been an obstacle to the development of effective vaccines to date.

Given these issues, we began in late 2005 to develop vaccines against M. bovis to protect animals against all strains of the bacteria. In a novel approach, we will test both conventional (needle-and-syringe) and needle-free versions of vaccine candidates, and test the vaccines in combination with a novel adjuvant – a compound added to the vaccine to boost the immune response.

To address the issue of the changing protein “masks” of M. bovis, our vaccine development program will focus on proteins that we know remain consistent. At VIDO, we identified a unique group of proteins located on the cell surface of the bacteria that remains very similar within a species. We have found comparable proteins in other bacterial species and believe a similar protein is located on the M. bovis cell surface.

An additional group of Mycoplasma proteins appears to be similar from one strain to the next, so these will provide a further target in vaccine development. We will be able to test vaccines made with either protein alone, and it may be that the best candidate contains both proteins.

The vaccines will be tested with a conventional adjuvant, Emulsigen, and a novel immune system stimulant that we have found in other studies to be not only effective against some diseases on its own, but also capable of stimulating long-lasting immunity when formulated with a vaccine.

Currently, we are on track to test vaccine candidates in late 2007.

This work is supported by the Beef Cattle Research Council, the Alberta Livestock Industry Development Fund, and the Alberta Agriculture Research Institute.

By Dr. Jose Perez-Casal, Project leader
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Improved vaccines to prevent BHV-1

Infectious bovine rhinotracheitis (IBR) is a highly contagious disease caused by bovine herpesvirus-1 (BHV-1). The University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO) is developing better ways to protect herds from BHV-1, part of the bovine respiratory disease complex. Bovine respiratory disease costs cattle producers millions of dollars annually.

Calves are most susceptible to this disease, so VIDO is working to develop better vaccines for very young animals. Although there are vaccines for BHV-1, they work less efficiently in newborn calves. Part of the reason for this is that the immune systems of young animals do not respond as well to vaccination as those of older animals.

VIDO is taking three approaches to the development of these vaccines. To date, we have developed potential vaccines that protected not only older calves but also newborn calves from BHV-1, and we have shown that needle-free vaccination against BHV-1 is effective.

CpG
Common in disease-causing organisms, “CpG” is a short genetic sequence that functions as a “danger” signal in mammals. In vaccines, it creates a stronger immune response to the vaccine.

We found that vaccination of calves with a vaccine against BHV-1 containing CpG induced a high-quality overall immune response, a strong antibody response, and protection after exposure to BHV-1. We also found that this approach is very effective in newborn animals. This technology is at the stage where it could be licensed and marketed by a commercial partner.

Another benefit of CpG is that the type of immunity that is important in suppressing BHV-1 and many other infectious agents is difficult to generate in young animals. CpG shows promise in adjusting this immune response.

DNA vaccines
A DNA “vaccine” is manufactured in the animal’s body by the animal’s own cells. The vaccine antigen – protein of the disease-causing organism – is made in the animal from the DNA vaccine and causes antibodies to be formed and an immune response to be stimulated.

Like CpG, DNA vaccines also show promise in restoring a balanced immune response.
Our group was the first to show that DNA vaccination could be effective in cattle. We have found that animals vaccinated against BHV-1 with a DNA vaccine develop levels of protection that are similar or better than animals vaccinated with conventional vaccines containing killed BHV-1. DNA vaccines also induce immune responses in newborns, as we proved by successfully immunizing three-day-old lambs and calves against BHV-1.

One reason for a superior immune response is that because DNA vaccines function by creating the vaccine inside the animal, the antigen concentration is maintained over an extended period of time in the animal.

DNA vaccines have many advantages. They can be produced relatively quickly and easily and their quality can be precisely controlled. The immune response they create is long-lived and broad, and they can possibly be used to immunize against several disease-causing organisms with a single vaccine.

The challenges of DNA vaccines lie in their delivery. Techniques must be further refined, but a heterologous prime-boost method (priming with a DNA vaccine and boosting with a conventional vaccine) is a likely model and one that is already being used in trials with human diseases.

Vectored vaccines
In addition, VIDO operates a “vectored vaccine” program that is developing a vaccine against BHV-1. Harmless, live viruses can be used to “carry” a vaccine. Vectored vaccines are created when part of the virus’s genome is replaced with genes representing the disease or diseases to be targeted by the vaccine.

This team, headed by Dr. Suresh Tikoo, has successfully created a vector expressing the BHV-1 protein gD that led to development of immunity when tested in animals.

Such vaccines have many advantages – they can be delivered through needle-free methods; they induce a broad and long-lasting immune response; they do not require strong adjuvants; and they are economical to produce.

Needle-free delivery
To circumvent the inconveniences of traditional needle-and-syringe vaccine delivery, we have also tested needle-free vaccine delivery against BHV-1. We used a device called Biojector 2000®, which delivers vaccine by high-pressure gas as a fine mist that penetrates the skin. Compared to needle-and-syringe delivery, animals vaccinated with the Biojector had stronger immune responses as well as overall better health. This model was developed for human use, but we are looking forward to testing a recently developed model that is more applicable and practical for use in cattle.

Vaccination alone cannot prevent the BHV-1 virus from entering a latent state only to be re-activated to infect other animals. For there to be any chance of eliminating this virus, control needs to be based on a strict vaccination schedule combined with careful management.

This work is supported by the Agriculture Development Fund, the Alberta Livestock Industry Development Fund, the Beef Cattle Industry Development Fund, the Beef Cattle Research Council, the Ontario Cattlemen’s Association and the Natural Sciences and Engineering Research Council.

By Dr. Sylvia van den Hurk, head of VIDO’s DNA Immunization program.

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VIDO explained: A perspective on vaccine development

In the 1970s, a fledgling organization devoted its entire staff and resources to development of an urgently-needed vaccine against E. coli calf scours. Within four years, the University of Saskatchewan’s Veterinary Infectious Disease Organization (VIDO) had developed Vicogen™. The world’s first effective vaccine against calf scours, Vicogen™ improved survival of young calves and decreased industry costs.

VIDO came into being in 1975 as the brainchild of Dr. Chris Bigland in order to focus on preventing the livestock diseases unique to western Canada. The organization went on to run programs studying cattle health threats such as E. coli and viral scours, shipping fever, infectious bovine rhinotracheitis and respiratory syncytial virus. Many diseases of swine and poultry were also studied, and six additional vaccines were marketed including Ecolan™ and Pneumostar™.

The motto “serving the livestock industry through research” led VIDO for nearly 30 years. However, a trend in new infectious diseases became apparent. Seventy-five per cent of new human diseases have a link to animals. BSE is an example of the impact of this link on the beef industry.

Although the number of livestock-specific projects VIDO operates has not decreased in 15 years, the organization changed its name in 2003 to become the Vaccine and Infectious Disease Organization in order to acknowledge the benefits of studying human health alongside animal health. Controlling these issues at the animal level is much more effective than developing treatments for both animals and humans.

Today, the organization consists of 130 researchers and students running 18 major research programs in one of the best-equipped animal and human health research laboratories in the country. With a recent expansion, there are more than 40 new staff members, and many of these researchers are focusing on livestock diseases.

VIDO scientists continue to study infections and issues posing headaches to the industry; for example bovine respiratory syncytial virus, bovine herpesvirus and bovine viral diarrhea virus. The organization is also working on the development of needle-free vaccines – which according to surveys could save cattle producers up to $9.58 per head.

Vaccine development begins with protein
Vaccine development and commercialization can be a lengthy process, taking up to 20 years for a human vaccine, and up to 15 years for livestock vaccines.

The key to a vaccine is protein. Only a few of the proteins that make up bacteria or viruses are important in inducing protective immune responses following vaccination. One of the bacteria that causes respiratory disease in cattle, Mannheimia haemolytica, is made up of approximately 3,000 proteins, but only a couple of them are important in inducing protective immunity. For each of the viral or bacterial pathogens VIDO studies, researchers must identify the specific proteins that will produce a strong immune response.

Following identification of proteins that can be used as antigens, researchers identify the genes that code for the proteins so the protein can be manufactured in the lab, and then vaccines are developed and tested. VIDO must provide evidence that the vaccine is effective in animal models and suitable for large-scale production before it can be submitted to the Canadian Food Inspection Agency for approval of conducting clinical trials and eventual marketing.

VIDO does not manufacture vaccines, but passes the technology to a commercial partner, usually one that has entered into partnership with VIDO during the vaccine development process. In order to make the technology attractive to a commercial partner so that it will eventually become a product, VIDO patents the technology so that the company can have a competitive position in the marketplace. VIDO scientists also provide development support throughout the process. The partner oversees clinical testing, scales up the production process for manufacturing and obtains regulatory approval for the product.

As a financially self-reliant, non-profit research organization, VIDO’s projects are chosen according to the needs of the end-user and by the resources that are available. The funds needed to do research come from provincial and federal government provisions and grants, from livestock industry councils, from contract research and from licensing fees and royalties. Once the organization has done its part and a product has been commercialized by an industry partner, VIDO receives royalties from product sales. These funds are directed back into research programs.

The funding received from producer organizations is crucial to VIDO’s continued operation. Certain grants would not have been awarded at all had VIDO not been able to show the support of the livestock industry, either through funding or word-of-mouth advocacy.

Future
Plans are underway to construct an International Vaccine Centre (InterVac) – a $110 million Biosafety Level 3 lab. Level 3 diseases include avian influenza, BSE, tuberculosis and West Nile virus. VIDO currently has Level 2 facilities, but most emerging animal pathogens are Level 3.

The new centre will provide more resources in Canada for large-animal research toward disease prevention. Research activities to take place at InterVac include studies of the ways in which infectious agents cause disease, responses to infection, development of novel diagnostic methods, and development of vaccines and novel vaccine delivery systems.

By Lorne Babiuk,
VIDO Director

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A technology that holds great promise in the treatment of human diseases is being investigated at the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO) for use in improving vaccines for cattle.

The technology, called “CpG,” can be a vaccine additive and can also function as a stand-alone medicine. CpG is a short DNA sequence that is found naturally in almost every living thing. It occurs in much greater frequency and in a slightly different form in bacterial and viral DNA. When the immune system of a mammal encounters the CpG sequence, it recognizes it as a “danger signal” and responds with a strong immune response that protects the mammal from bacteria and viruses.

The CpG technology led to the creation of Coley Pharmaceutical Group, Inc., which today has offices in the U.S., Germany, and Ottawa. A synthetic form of CpG (CpG ODN) is currently being developed by Coley as a vaccine adjuvant and therapy in humans for diseases such as cancer and asthma. It is also of great interest to researchers studying ways to protect the health of livestock, in this case to improve vaccines for shipping fever, a bovine respiratory disease. Losses due to shipping fever are estimated at $100 million annually in Canada.

Making existing vaccines better
Dr. George Mutwiri co-ordinates CpG research at VIDO. “The idea is that the vaccines out there, they do help, but they are not as good as they could be. We hope that by using CpG, we can make the existing vaccines protect animals better.”

VIDO senior scientist Dr. Sylvia van den Hurk is the lead scientist testing CpG for its ability to stimulate the immune system of cattle and thus improve immune responses to a family of shipping fever vaccines that are already on the market. More importantly, CpG is intended to broaden the degree of protection to shipping fever. The researchers are comparing the efficiency of both killed and live viral vaccines with CpG added, because both types of vaccines are currently in use in the livestock industry.

“CpG is going to stimulate the body’s immune system and that’s how it’s going to help the vaccine. It’s going to stimulate a better response not only just by magnitude, but the quality of the response is going to improve,” says Mutwiri. Currently in Canadian feedlots, most animals are treated with long-acting antibiotics as they enter the feedlots. Producers don’t wait for the animals to get sick – they treat all the animals to make sure they are protected, says Mutwiri. If global pressures continue to eliminate non-therapeutic use of antibiotics, feedlots will suffer tremendous economic losses due to infectious diseases. Yet, says Mutwiri, “if you have a vaccine that works much better, it negates the need for either the frequency of the antibiotics or the amount.” In addition, feed conversion efficiencies are increased with more effective vaccination.

Instant disease protection
A vaccine is not normally immediately effective, so the CpG offers some protection until the vaccine kicks in. Mutwiri says that CpG added to a vaccine causes an immediate, broad immune response that helps the animal manage most of the disease-causing organisms it encounters, and it sets the stage for the vaccine to achieve full efficacy. Although the effect drops off over time, it buys time for vaccine-induced immunity. “That is what is going to make a big impact,” says Mutwiri. This protection has been proven in studies at VIDO in mice and sheep against a broad range of viruses, bacteria and protozoa. The presence of CpG in the vaccine also leads to stronger protection by the vaccine once it gains full efficiency.

This type of research will place better products in the hands of producers, faster. Some existing vaccines can be made more effective through addition of compounds like CpG or through different modes of delivery (e.g., nasal or oral). This approach to vaccine development is attractive because the regulatory process is not as extensive for the addition of CpG, for example, to a commercial vaccine. “The existing product has had a lot of toxicity studies done already,” says Mutwiri. “And, you’re adding a very defined molecule – CpG – we know a lot about its toxicity and effects and there are clinical trials using similar molecules in humans for cancer…so you’re adding a new compound that seems to be pretty safe.” If results are favourable, enhanced livestock vaccines containing CpG could be on the market in a few years.

These efforts at VIDO to improve shipping fever vaccines are funded in part by the Advancing Canadian Agriculture and Agri-Food Saskatchewan (ACAAFS) Program of the Saskatchewan Council for Community Development (SCCD). Funding for the ACAAFS program is provided by Agriculture and Agri-Food Canada.

By Tess Laidlaw
VIDO Communications Officer

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The Vaccine and Infectious Disease Organization (VIDO) at the University of Saskatchewan is carrying out a number of research programs to improve and protect the health of cattle.

One major project area is the development of DNA vaccines. These hold a great deal of promise against diseases for which effective vaccines have remained elusive. DNA vaccines are especially good at creating “cell-mediated” immunity, which helps to defeat most viruses and bacteria. This response isn’t usually created by conventional vaccines.

DNA vaccines consist of small pieces of DNA called plasmids that deliver genes from a disease-causing virus or bacteria to an animal. When the DNA is introduced into the cells of the animal to be protected, the information is read by the cell’s protein-making machinery and the viral or bacterial protein is made. The resulting protein is recognized by the animal’s immune system. Thus, the “vaccine” is essentially produced right inside the animal’s body. There are no tissue reactions or other side effects, and once the protein has been made, the DNA itself eventually disintegrates completely.

VIDO was the first to demonstrate that immunization with DNA vaccines could be effective in cattle. We are now working to develop DNA vaccines against a number of pathogens affecting cattle, including bovine herpesvirus-1 (BHV-1), bovine parainfluenzavirus-3, bovine respiratory syncytial virus, bovine viral diarrhea virus, Manheimia haemolytica and Haemophilus somnus.

VIDO is looking at several aspects of DNA vaccine production and delivery. We are studying ways of formulating DNA vaccines; for example, we have tested delivery in tiny vesicles and by coating gold beads with DNA. We are testing compounds, called adjuvants, which we deliver along with the DNA in order to achieve an even greater immune response.

DNA vaccines offer several choices for delivery beyond conventional (needle-and-syringe) methods. New routes of delivery are a focus as we seek to reduce needle-stick injuries and animal discomfort as well as meat damage through needle use. These vaccines are compatible with needle-free jet injection, gene gun, skin patches, spray (i.e. nasal or oral), or use with small vesicles or particles. DNA vaccines can be delivered via intramuscular, intradermal, intravenous, oral, intranasal, intravaginal, rectal or transdermal routes, or in utero.

In addition to the range of delivery methods, DNA vaccines offer a number of advantages. A strong and broad immune response is created, because the vaccine mimics a natural infection. Yet because only one or two viral or bacterial proteins are created, there is no chance that an infection can result. As well, we can create vaccines with this technology that are protective against multiple diseases.

Much of this work is relevant to infectious agents that also affect humans. Certain viruses show similarities in how the disease manifests in both cattle and humans, and similar proteins can be used to achieve protection. For example, respiratory syncytial virus, rotavirus and herpesvirus in calves, and parainfluenzavirus-3 in sheep and calves, all mirror infections of humans.

In the practical sense, DNA vaccines are stable over variations in temperature, whereas most vaccines have an optimum temperature and must be kept within a strict temperature range. From a manufacturing perspective, they are quick and relatively easy to make, as well as being economical.

In practice, VIDO studies have shown in the case of BHV-1 that animals vaccinated with a DNA vaccine are well-protected from viral challenge, and the quality of protection is similar or better than that achieved with conventional killed vaccines. DNA vaccines appear promising against many of the diseases mentioned here, as well as for use in conjunction with other vaccines. These vaccines can also induce immune responses in newborns, one of the most difficult targets for vaccination. We have recently confirmed the ability of neonatal lambs to respond to vaccination at this age.

However, despite the promise of this technology, several issues, especially those regarding delivery, economy and safety, remain to be examined before this technology can find widespread use in animals and humans. Candidates have already been tested in human trials, but still await approval.

With respect to the technical aspects of DNA vaccination, the DNA itself is targeted for degradation by the host animal’s body. Obviously a large enough amount of DNA must escape degradation in order to produce a protective immune response, so this is one challenge facing us. As well, it has generally been more difficult to induce immune responses in large animals than in mice, and so we are working to optimize DNA vaccines for large animals both at the molecular level and through formulation and delivery methods.

Funding support for this work is provided by: the Alberta Agricultural Research Institute (AARI); the Beef Cattle Industry Development Fund (BCIDF); the Canadian Institutes of Health Research (CIHR); the Ontario Cattlemen’s Association (OCA); Saskatchewan Agriculture and Food’s Agriculture Development Fund; the Saskatchewan Health Research Foundation (SHRF); and Science and Engineering Research Canada (NSERC).

by Dr. Sylvia van den Hurk, head of VIDO’s DNA Immunization program.
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A report on vaccination guidelines

In addition to vaccine development, a parallel focus at VIDO has been the operation of its two technical groups, which bring producers together with VIDO scientists and staff to develop and distribute information for the beef and swine production communities.

The VIDO Beef Technical Group (VBTG), formed in 2001 after consultation with representatives of the beef industry, brings together individuals with expertise in the beef industry from across Canada. Members are mandated to provide relevant and current information to benefit beef producers. The VBTG is also tasked with bringing the animal health concerns of cattle producers to VIDO for research consideration.

As there are a number of factors that can influence effectiveness of disease control through vaccination, the first project of the VBTG was a report to outline the safe and appropriate use of vaccines and illustrate the strength of this approach. The report, titled Vaccination Guidelines, also suggests additional management procedures to prevent or reduce disease.

The report touches on aspects of the vaccination process that can affect the efficacy of vaccines, beginning with transport of the vaccine to the livestock operation. Transport of vaccines must be carried out appropriately to ensure the vaccine is not inactivated through exposure to extremes of temperature or light. It is also important to recognize the varying handling and preparation requirements of different types of vaccines (i.e. killed versus modified-live-virus (MLV) vaccines), as for example, killed vaccine remains effective for up to a day while MLV vaccines should be used within one hour.

Given the potential for broken needles and tissue damage due to vaccination, the report describes a number of aspects affecting choice of needles, such as the age and weight of the animal, the route of administration and viscosity of the vaccine. Only sharp and straight needles should be used - dull, bent or burred needles should be discarded.

The report describes appropriate locations and routes of injection, as well as how to monitor for and deal with adverse reactions. Proper waste disposal and sanitation habits are key steps of the vaccination process and will prevent needle-stick injuries or cuts due to sharps (needles and scalpel blades) not being handled or disposed of properly.

The report also provides background information on vaccines; for example, the licensing process and definitions of common terms relating to vaccination.

Vaccination Guidelines has appeared in a variety of provincial beef organization newsletters and magazines and has been widely distributed to producers, representatives from pharmaceutical companies, regional Quality Starts Here representatives, and provincial and national veterinary medical associations. It can also be accessed from the VIDO website.

Currently, the VBTG is focusing on the development of an evidence based decision-making process aimed at identifying optimal use of vaccines in disease control. Initially, the group will focus on the use of clostridial vaccines and strategies to maximize vaccine effectiveness. Future projects will explore the use of respiratory and enteric vaccines.

Funding for the VBTG is provided by the British Columbia Cattlemen’s Association, Alberta Beef Producers, Saskatchewan Horned Cattle Trust Fund, Saskatchewan Cattle Marketing Deductions Fund, Manitoba Cattle Producers and the Ontario Cattlemen’s Association.

Dr. Philip Griebel, Dr. Hugh Townsend and Dr. Don Wilson are VIDO scientists and members of the VBTG.

To contact members of the VBTG with questions or comments, please email info@vido.org or phone (306) 966-7465.
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Needle-free vaccine against BVDV

It’s considered one of the greatest disease challenges in the Canadian cattle industry, and as such the bovine viral diarrhea virus (BVDV) is the focus of a research effort at the Vaccine and Infectious Disease Organization (VIDO) to develop a needle-free vaccine for use in calves.

As many know who deal with this virus, it is tremendously complicated to manage. BVDV is a problem around the world and occurs in most cattle populations. Effects of the virus depend on the immunity and age of the animal infected and the strain or “biotype” of the infecting virus. There are seemingly endless combinations of these factors, and outcomes range from no effect at all in protected animals, to fever, depression, diarrhea and death. Depending upon timing, infection of a pregnant cow can lead to malformation or abortion of the fetus, or “persistently infected” calves. Another effect of BVD is the suppression of infected animals’ immune systems, making them susceptible to other infections, most notably those in the bovine respiratory disease/shipping fever complex.

It is estimated that one to two per cent of cattle are persistently infected (PI). Because these cattle are infected in the womb when their immune systems are immature, the virus is not recognized as foreign and the cattle test negative for antibodies to the disease. PI cattle serve as a reservoir for the virus, constantly shedding it into the environment. The introduction of PI cattle into a susceptible feedlot can double calf morbidity and mortality and can be disastrous in a naïve, BVDV-free herd.

When replicating, the virus is prone to mutation, so there are many versions of the virus circulating, divided broadly into type 1 and type 2 viruses. An effective vaccine must protect animals from both types. Current vaccines often require annual re-vaccination, and do not stop all virus shedding. Most modified live virus vaccines should not be used in or near naïve pregnant dams, and killed virus vaccines require repeated administration. In addition, current vaccines are often thought to be ineffective in very young animals due to interference from maternal antibodies and to the immaturity of the animal’s immune system.

Our project aims to develop a needle-free vaccine against type 1 and type 2 BVDV that can be given to young calves at the time of branding. We will combine two technologies under development at VIDO that can be applied to different species and diseases: DNA vaccines and “CpG” technologies.

A DNA vaccine consists of a plasmid, which is a circular DNA segment with a gene coding for a protective protein and short sequences that control the production of the protein in the cells of vaccinated animals. We have found that in comparison to protein vaccines, DNA vaccines are easy to administer, although much still depends on which delivery technology proves most cost-effective in commercialization. DNA vaccines are also easier and cheaper to produce than many conventional vaccines. They are effective when delivered through the skin with needle-free devices, eliminating the threat of broken needles and injection-site damage.

Secondly, “CpG motifs” are a type of bacterial DNA that elevates the body's normal disease resistance. Synthetic CpG oligodeoxynucleotides (ODN), when added to a protein vaccine as an adjuvant, can drastically improve the immune response to the vaccine.

Two of the greatest advantages of DNA vaccines and protein vaccines formulated with synthetic CpG ODN are the induction not only of high antibody, but also of strong cellular immune responses, which target cells infected with micro-organisms such as viruses, fungi and certain bacteria. Secondly, these types of vaccines are effective in adult as well as newborn animals.

We are designing DNA-based vaccines to be protective against type 1 and type 2 BVDV; we are also evaluating methods of delivery and optimal age of vaccination for newborn and young calves. However, these vaccines will also be effective in older cattle and safe in pregnant cows. Effective vaccination against BVDV is expected to lower the risk of PI calves. The vaccines are intended to be suited for needle-free delivery, and previous research has shown that the vaccine components do not cause tissue reactions, eliminating the need for meat trimming.

The major protective protein of BVDV is the E2 protein. We have constructed DNA vaccines that produce both cell-associated and secreted forms of the E2 protein (sE2) of type 1 and type 2 strains, and demonstrated that the DNA vaccines encoding sE2 induced the strongest and most balanced immune responses. Furthermore, vaccination of calves with the E2 protein formulated with CpG ODN also elicited strong antibody production and cellular immune responses. We are currently further evaluating BVDV type 2 E2 DNA and protein vaccines. In addition, we are testing various combinations of BVDV DNA vaccines and protein vaccines delivered with CpG ODN adjuvants.

Although the template disease for this project is BVD, the technology developed for inducing broad immune protection in young calves will be applicable to a variety of organisms that cause disease in cattle.

Funding support for this work is provided by the Beef Cattle Industry Development Fund (BCIDF) and the Ontario Cattlemen’s Association (OCA).

by Dr. Sylvia van den Hurk, head of VIDO’s Nucleic Acid Technologies program.
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Charting disease development
Imagine being able to see, at the molecular level, what happens when a bacteria or virus infects an animal. One could zero in on the events that allow the infection to progress, and on the features of the animal's immune response that strive to fight the infection. VIDO's Functional Pathogenomics program is focused on exploring the genetic responses of humans and animals, specifically cattle and poultry, following exposure to infectious agents. We are particularly interested in immune responses at the mucosal surfaces of the digestive and respiratory tracts, which is where more than 90 per cent of pathogens invade. These distinctive responses contribute either to the progression of disease or to protection from infection.

We are investigating these responses from the perspectives of both the invading organism and the infected animal. The microarray technology we are using allows us to identify specific genes in bacteria that are activated when the organism enters an animal. The genes of interest are those involved in assisting the bacteria to stage a successful infection.

These genes also represent the organism's "Achilles heel" in terms of disease treatment and prevention. Once we have identified the genes, we can use the information to develop better vaccine adjuvants and facilitate the screening and development of therapeutic compounds to enhance protective immune responses.

Of the number of infectious agents to which humans and animals are exposed daily, only a small proportion successfully causes disease. This is because when a human or animal is infected with a pathogen, a cascade of events occurs comprising the "innate" immune response. This powerful response often subdues the pathogen, so knowing how to boost or guide this response would lead to valuable advances in disease treatment, with consequences for more effective antibiotic usage. In addition, a long-term objective of the project is to use functional genomics to identify genetic markers for disease resistance which may then be used in livestock breeding programs. Of the program's four main project areas, two are dedicated to respiratory and intestinal diseases of cattle. Within these two, specific objectives are to identify the molecular mechanisms occurring in a number of situations; for example, the viral-bacterial synergy that leads to fatal pneumonia in cattle; the contribution of stress to disease susceptibility; and rotavirus and coronavirus pathogenesis in the small intestine of newborn calves.

We are also studying mucosal responses to Salmonella typhimurium and enterohemorrhagic E. coli, and carrying out comparative analyses of mucosal responses to identify both common and unique responses to each pathogen.

Microarrays, which have made these studies possible, are small glass slides that can each contain upwards of 20,000 different genes. The slide provides a visual representation of gene expression changes at the level of individual cells and tissues. The focus to date has been to apply this technology to human health and diseases, and there have been few studies focusing on the responses of cattle to infectious agents. Current studies have identified specific genes that are critical for recognition of an invading pathogen and have begun to characterize the cascade of events that occurs within hours of infection.

This technology is already generating results that will impact livestock management. For example, the epidemiology of bovine respiratory disease in North America has been linked to changes in the animals' environment and nutrition, as well as husbandry procedures. Weaning is particularly significant in terms of association with respiratory disease.

These observations have implicated stress as a significant factor that can compromise the animal's immune system and increase disease susceptibility. To date, it has been difficult to quantify stress responses and determine what adaptation period is required to eliminate the effects of stress when altering animals' environments. Microarray analyses, however, are providing a more global view of the physiological response induced by stress, and how these responses alter disease susceptibility.

VIDO's Pathogenomics program is one facet of a larger Functional Pathogenomics of Mucosal Immunity project supported by Genome Prairie, Genome B.C. and Inimex Pharmaceuticals Inc, a corporate partner. The Canadian Institutes of Health Research (CIHR) and the Ontario Cattlemen's Association (OCA) also contribute funding to this work. The project includes internationally recognized investigators at the University of Saskatchewan, the University of British Columbia and Simon Fraser University.

Dr. Philip Griebel is head of VIDO's bovine respiratory disease pathogenomics program.

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It is well-known that stress can cause disease susceptibility in livestock. One outcome of the stress studies underway at VIDO, led by Drs. Philip Griebel, Paul Hodgson and myself, is that calves exposed to the environmental stress of weaning have been shown to be twice as likely to die from respiratory infection as un-stressed calves.

However, the molecular basis of the link between stress and disease has yet to be discovered. Knowledge about this link would pinpoint the cause of stress-induced disease and therefore, its remedy.

Bovine respiratory disease (BRD) is a major killer of newly weaned cattle and costs North American producers millions of dollars every year. A common pattern in the development of BRD is an initial viral infection that opens the door to a deadly bacterial respiratory infection (called viral-bacterial synergy). Also implicated as key factors in BRD are stressors of various types (environmental, nutritional and management).

The effects of stressors on any organism and the relation of stress to disease susceptibility are revealed through the organism’s gene and protein expression. Our studies are one of the few in vivo investigations being attempted to correlate stress-dependent disease susceptibility with molecular events. These investigations will help in understanding the disease process with the goal of developing effective intervention.

We are studying stress-dependent disease susceptibility at the level of gene expression and beyond that, to the additional level of information contained in protein expression. Using proteomics methodologies – the large-scale study of the structure and function of proteins – we can isolate information to relate physiological processes to disease outcome. For example, we will be looking at disease resistance to see whether certain animals have a natural resistance or susceptibility to stress.

BRD provides an effective and relevant model in cattle for these studies. The disease model developed at VIDO for BRD supports studies of the molecular mechanisms underlying the viral-bacterial synergy which results in fatal respiratory infections. We plan to concentrate on understanding the role of the environmental stressors of weaning, transportation and nutrition in young calves (which are more susceptible to infection through this synergy), and would like to understand the molecular basis of survival or death of infected animals.

This analysis would identify protein biomarkers – “signal” proteins that indicate the presence of a stress response and assist in predicting disease outcome. The project also has the potential to discover the regulatory mechanisms for the immune system of cattle following stress and infection. We will use the results of these studies to identify the susceptibility of animals to stress-associated disease, and to develop novel interventions and therapeutics to control stress-associated respiratory disease.

These stress studies fall within a larger area of focus at VIDO which is the use of genomics and proteomics to see what is happening in animals at the molecular level when they are exposed to disease-causing organisms. A number of laboratory techniques have been invaluable for identifying the biological activities associated with specific molecules. However, testing the relevance of these activities remains a challenge unless the question is addressed at the level of the genes, as it is at this level that physiological effects appear following stress and infection, or treatment with drugs or vaccines.

Progress to date
Bovine herpesvirus-1 is a major viral component of BRD, and Mannheimia haemolytica is a member of the normal flora of the respiratory tract and the major bacterial pathogen in BRD. Preliminary results are being analyzed from our experiments with these pathogens to investigate the effects of stress in combination with the common feedlot situation of primary viral infection and secondary bacterial infection in stressed cattle.

Through studies to determine the effects of weaning, transportation and nutrition changes as stressors on cattle, we are creating protein databases as resources for identifying bovine serum proteins that appear to play significant roles in stress-related disease. This information, as well as efforts to locate proteins (biomarkers) that offer information about a disease state, will lead to new diagnostic tools and drug targets.

Funding support for this work is provided by Genome Prairie and the Agriculture Development Fund.

By Dr. Palok Aich, member of the Functional Pathogenomics of Mucosal Immunity (FPMI) program and Project Leader, Bovine Enteric Disease program. VIDO, University of Saskatchewan.
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