On the Forefront of Veterinary Medicine

Infectious Disease 

Did you know that according to the World Health Organization, antibiotic resistance is one of the biggest threats to global health? 

Resistance makes it more difficult to treat a growing number of infections as the drugs used to treat them become less effective; resistance can affect all species and anyone, of any age, in any country. While resistance to drugs occurs naturally, a lack of understanding or the misuse of antibiotics in humans and animals is accelerating the process. 

Photo: 3-D illustration of a Clostridium difficile bacteria. 


With the speed of climate change and the rapid growth in urbanization, globalization, overpopulation and current trends in pet ownership, the study and understanding of infectious disease is of increasing importance. 

“If you think about it, it is obvious: disease spreads around the world because humans and animals move,” says Dr. Scott Weese, professor at the University of Guelph’s Ontario Veterinary College (OVC). 

Weese is an international leader in the field of infectious disease or infectiology, a medical specialty dealing with the diagnosis, control and treatment of infections. His specific interests lie in managing the risks associated with diseases that can be transferred between animals and humans, or vice versa, commonly called zoonotic diseases. 



As people and animals travel, the chances of coming in contact with or in bringing foreign viruses home is greater than ever before. Furthermore, the rising threat of drug resistant superbugs – disease strains that are not or are no longer affected by certain medications due to liberal use of antibiotics that are normally reserved for serious infections – there is an urgent and growing need for more knowledge and awareness of infectious disease amongst the general population. How are infectious diseases controlled, how do they spread and how does our behaviour magnify their impact on our overall health? 

Weese explains that everything is interconnected: infections, antibiotics and resistance are all intertwined. The better we can isolate and control infections, the better we can optimize our health and well-being. The more we can prevent or control diseases, the more we can limit antibiotic use and ultimately drug resistance. 

He points out that the strategy for reducing unnecessary antibiotic use is directly linked to reducing disease in general. For example, Weese’s research that investigates methods to control Clostridium difficile (C.difficile) within human hospitals, a potentially deadly bacteria that infects people and animals, indicates that we need to control flu in the community. If we can control seasonal flu, we have a lot less people who are sick, resulting in fewer hospital stays, decreased use or need for antibiotics and a reduced number of hospital-acquired infections. The same applies with animals. Preventing disease reduces secondary bacterial diseases and the need for antibiotics to treat or prevent those diseases in the first place. 

Weese has coordinated and published international guidelines for antibiotic use that are influencing veterinary care around the world and wants to address a pressing issue: how can we support veterinarians in providing excellent patient care and using antibiotics most appropriately and effectively in each case? 

“In order to decrease the burden of disease (the impact of a health problem on a given population, measured using a variety of indicators such as mortality, morbidity or financial cost), we must improve antibiotic use across the board in both human and veterinary medicine,” Weese says. 



Weese is one of only a handful of prominent experts worldwide who has dedicated their career to the study of infectious disease, and is regularly called upon to develop tactics to manage and mitigate emergent diseases and outbreaks in Canada. 

Often dealing with the unknown, he tackles issues as if he were a detective. He spends his days working with veterinarians, physicians, public health agencies, researchers and provincial, federal and international government agencies who seek his expertise. 

“OVC has invested time and effort in developing our expertise in this area,” Weese says. “Research support for various studies, including funding from OVC Pet Trust, has allowed us to invest in this field.” 

According to Weese, the scientific exploration and increased knowledge of infectious diseases can save the lives of pets in three major ways. First, there are clinical benefits: research and progress make it possible to treat animals with rare or emerging infections. Second, preventive medicine benefits pets by helping to prevent and control infectious disease. Third, lack of owner education and awareness may lead to euthanasia or rehoming of pets; people often lose their pets because of fear, worry and anxiety about infections. He says the more we can communicate with pet owners, work with physician groups and veterinarians, the more we can help owners reduce risks associated with pet ownership when they are going through a health problem so they don’t have to give up or surrender their animal. 



For Weese, there is always something new on the horizon, whether it is studying West Nile, Lyme disease, Echinococcus multilocularis, canine flu or leptospirosis. He says when we start to understand one infection, we have to figure out how to apply it to the next emerging infectious disease. His future work will examine infection control at large international dog shows, the use of antibiotics in animal cancer patients and the implications of importing pets from other countries into Canada. 

He emphasizes the important role veterinarians play in controlling emerging infectious diseases; pet owners who have questions about how to protect their own pet should always consult with their family veterinarian. 

“The goal is to improve the use of antibiotics across the board to improve the outcomes of patients we are treating today, and to reduce the risk that future patients, human or animal, contract a drug resistant infection,” Weese says. 



Dr. Scott Weese is a Canada Research Chair in Zoonotic Diseases and professor at OVC. He is also the newly appointed Director of the Centre for Public Health and Zoonoses at U of G. Dr. Weese has offered his expertise to help manage disease outbreaks such as: 

  • Developing protocols for containing and eradicating canine influenza from Canada. 

  • Identifying new species of ticks and tracking tick behaviour in Ontario

  • Investigating and containing Brucella canis, a bacterium that can cause disease in dogs and people, in kennels and puppies in Ontario. 

  • Partnering in a Lyme disease lifetime study to help understand how this disease is emerging in dogs in Canada. 

  • Developing provincial isolation protocols for potentially exposed animals as part of dealing with the worldwide 2015 Ebola virus outbreak. 

  • Maintaining a blog to inform on the status of infectious diseases in Canada (www.wormsandgermsblog.com). 


Read more in the spring / summer issue of Best Friends Magazine