Brent Wagner poses while examining ticks in a microbiology laboratory at the Western College of Veterinary Medicine. Photo by Rigel Smith.

Panel updates guidelines for managing parasites in pets

As more problems related to ticks, worms and other parasites emerge in veterinary clinics across Canada, practitioners now have access to the latest guidelines on managing and treating these organisms in their patients.

By Rigel Smith

A new edition of Canadian Parasitology Expert Panel Guidelines for the Management of Parasites in Dogs and Cats, published in May, replaces the first set of guidelines developed in 2009.

“It was either leave [the old edition] and let it turn into dust, or re-invigorate things,” says Brent Wagner, a parasitologist in the Western College of Veterinary Medicine’s Department of Veterinary Microbiology who was part of the expert panel that created the new guidelines. “I just thought it would be a worthwhile update to do based on new data and best practices.”

Wagner says the guidelines for managing parasites need to reflect the change in the parasites themselves – and one of the major changes is species expansion.

“Ticks have expanded their range significantly across much of Canada and there’s good data to show where and how that has happened,” says Wagner.

“Another parasite that’s becoming more widespread is the Echinococcus multilocularis – a very, very small tapeworm in dogs that seems to be expanding its range and infecting in ways that we didn’t expect to see.”

He adds that there’s been an increase in research on different lungworms that affect pets, and the new guidelines include latest findings from these studies.

In addition to Wagner, the expert panel included veterinary parasitologists from across Canada and the United States: Dr. Gary Conboy (University of Prince Edward Island), Dr. Christopher Fernandez Prada (Université de Montréal), Dr. John Gilleard (University of Calgary), Dr. Emily Jenkins (University of Saskatchewan), Dr. Alice Lee (University of Florida) and Dr. Andrew Peregrine (University of Guelph).

Two small animal practitioners — Dr. Ken Langelier of VCA Canada Island Animal Hospital in Nanaimo, B.C., and Dr. Scott Stevenson of Thousand Islands Veterinary Services in Ganonoque, Ont. — were also panellists.  

The panel’s work received financial support from companies involved in North America’s animal health industry: Bayer, Boehringer Ingelheim, Merck, Vétoquinol, Zoetis and Elanco.

Wagner hopes the guidelines are accessible for everyone because parasite management doesn’t just pertain to animals; much of the information can also be used to improve human health.

“A number of the parasites that pets will get can be transferred to people. And so, if we keep them out of our pet population, we can keep those parasites out of the human population as well,” says Wagner.

For example, two species of roundworms – Toxocara canis in dogs and Toxocara cati in cats — are zoonotic parasites (parasites that can be transferred between animals and people).

 “­If we somehow ingest eggs from these parasites … we can be infected with those parasites ourselves,” says Wagner. 

Wagner adds that another example is E. multilocularis, which has recently caused concern for pet owners in Ontario and Western Canada: “If dogs have this parasite in their intestines, eggs come out in the feces. If we incidentally ingest some of these eggs, we can get quite large cysts on our liver or in our lungs or other places. It’s really quite a nasty parasite for people to acquire.”

Wagner says people can do simple things such as washing their hands after playing with pets to decrease the spread of parasites between humans and animals. Regular and thorough veterinary diagnostic testing is also important “to have a handle on what’s really out there,” says Wagner.

“We recommend different treatment and diagnostic protocols depending on the risk – where that animal falls in acquiring levels of parasites,” says Wagner. “A local, indoor dog that really gets leash-walked, or indoor cats – [are] pretty low risk for many of these parasites.”

He adds that diagnostic testing and treatment would be reduced in cases involving household pets compared to dogs and cats living outdoors that have potential contact with wildlife as well as dead animals.

Wagner says it was “illuminating” to see how parasites and the range of their environments have changed in recent years.  

“When I started in parasitology in Canada almost 30 years ago now, Ixodes scapularis … [the] deer tick that’s able to spread Lyme disease, was found only in Point Pelee National Park [in southwestern Ontario],” says Wagner. “Now, we see reproducing populations in Manitoba and up into central Ontario and central Québec and into New Brunswick and Nova Scotia.”

“It’s a problem — it’s really a problem.”

Find the guidelines and more information at the CPEP web site.

Rigel Smith is a fourth-year student at the University of Regina’s School of Journalism and the 2019 summer research communications intern at the WCVM.