Common Parasites

It’s Finally Here!

It’s so great to get out into the warmth and sunshine, and our pets love it too, but as every pet owner knows, this is also the time of year that parasite problems gear up. In Toronto the most common parasites that we see are fleas, ticks, roundworms, tapeworms, and giardia.

Pulex irritans isolated on a white background.

Pulex irritans isolated on a white background.

Fleas are extremely common and almost every pet owner has encountered them at some point. Their bites not only cause itching but some pets get a severe skin reaction called flea allergy dermatitis or FAD for short. Fleas can also carry the infectious phase of tapeworm and, in fact, these two parasites are so closely associated with each other, that when we treat a pet for fleas, we also treat them for tapeworm.

Fleas2 Annex
Ticks are becoming increasingly common even in downtown Toronto and every year we see dogs who have never left the downtown core with live ticks on them. Ticks, like fleas, also survive on blood, but they’re different in many ways. First, they bury their heads in the pet’s skin and feed for days while fleas stay on a pet and take frequent meals. Second, ticks’ bodies expand as they feed so while they start as a brownish, flea-sized insect they grow to be almost dime-sized while fleas never get bigger than a few millimetres. Third, ticks carry different health risks than fleas including Lyme disease and several other blood-borne diseases. Ticks are also active earlier in the spring than fleas – as soon as the temperature is 4 degrees or higher

Four life stages of a black-legged tick

Female black-legged ticks at various phases of feeding

Fleas tick 2
Giardia is a protozoa that is most commonly picked up by pets when they drink infected water or eat feces from an infected animal. This is a nasty parasite that can be difficult to get rid of and which causes flatulence, watery diarrhea, and lethargy. The symptoms may come and go as the parasite goes through it’s life cycle.

Roundworms, hookworms, and whipworms can all be passed on to your pet through the environment (ringworm isn’t actually a worm; it’s a fungus), and of the three, roundworm is the most common in Toronto; we regularly see pets, mainly dogs, for roundworm infections.

Heart worms are in a league of their own. The adult worms lodge in the blood vessels around the heart and in the heart itself causing inflammation and blockages. If left untreated they cause permanent damage and death. Unlike other types of worms, heart worms are not transmitted through feces, but by infected mosquitoes so even indoor pets are at risk. Luckily, the risk in Ontario is much lower than in the south-eastern U.S., and up the Mississippi river, but thanks to climate change, heart worm infected mosquitoes are here, and have been for decades, and every year dogs are diagnosed with heart worm disease right here in Ontario. The procedure to kill adult heart worms is expensive and dangerous so as we do for all parasites, we recommend using safe medications to prevent infection in the first place. Check out this video http://youtu.be/P6F9KApqkII for a great overview of heart worms.

Today’s preventives are generations better than what used to be available. Gone are the days of stressful flea baths and messy flea powders; prevention can be as easy as putting drops on your pet’s skin or giving a delicious chew. Veterinarians will tailor parasite prevention programs to each pet’s needs and an important part of every program are blood and stool tests to see what parasites, if any, your pet already has.