How Toronto’s raccoons could threaten your health

WATCH: Raccoons can be more than just a nuisance. They can pose a real health risk. Dr. Samir Gupta has the details.

TORONTO – With Toronto’s new green bin regulations, there has been a lot of talk about raccoons lately. We all know about the nuisance and property damage caused by these pests, but it’s also a good time to consider the health hazards.

There are several health risks related to infections that people can catch from raccoons, and these can be acquired in several different ways.

Having a raccoon bite or scratch, or direct contact of any sort is obviously a concern, but the bigger concern is contact with raccoon feces or urine, which people can often have inadvertently.

The most serious infection is raccoon roundworm – known as Baylisascaris procyonis. This is a parasite that lives inside raccoon intestines, has little or no harmful effect on raccoons, and sheds eggs into raccoon feces.  Once these eggs turn into larvae, they’re extremely resistant to physical or chemical cleaning, and can remain in the environment for long periods of time.

If these larvae are then accidentally consumed by a pet dog or cat, or even a human, they travel through the body and often end up in the brain, causing multiple organ damage, severe neurological impairment, and even death.

There is no effective cure for this condition.  We have seen about 30 cases reported worldwide, almost exclusively in kids, including a case in Toronto in 2005.  A 2014 study by Claire M. Jardine and colleagues in the Journal of Wildlife Diseases detected these roundworms in 38 per cent of raccoons in Ontario.

There are also other infections to keep in mind. Raccoon bites can cause rabies, which accounts for a share of human cases reported each year in the U.S.  Another infection reported from raccoons is leptospirosis, which is a bacterial infection that can be acquired when broken skin contacts raccoon urine or droppings, and can sometimes cause severe infections in humans, including meningitis. Even salmonella infections have been reported as a result of incidental ingestion of raccoon feces.

How can you protect yourself?

It goes without saying that people should avoid direct contact with raccoons (as tempting as it seems, do not engage!).  If you see raccoon feces, the sooner you clean it the better, because the eggs don’t form larvae until after about 21 days.

Also, wear gloves and a mask, because those roundworm eggs can be inhaled.  If you have a garden, wear shoes and gardening gloves, and wash all of your vegetables thoroughly before you consume them.

However, the biggest risk is with young kids, partly because they’re more prone to some of these infections, and partly because they’re more likely to be playing outside on the ground and usually don’t wash they’re hands.  Keep kids away from surfaces that may have had raccoon contact, and keep any sand boxes covered when not in use.

What about other animals?

We know that over half of Canadian households now have a pet of some sort, and the number of exotic pets (i.e. not just cats and dogs) is also increasing. As a result, not only are we are seeing more and more of what is known as “zoonotic” diseases, which are infections contracted through animals, but we are also encountering other health effects from animals.

Top 5 diseases your pet can cause

1. Dog heartworm

Dogs can cause all sorts of bacterial, fungal, and other infections through bites, licking, or human contact with dog excrement. A parasite in dogs called Dirofilaria immitis (dog heartworm) which lives near the dog’s heart, but doesn’t cause symptoms in most dogs.  This parasite can be transmitted by mosquitoes from a dog to a human, after which it can sometimes find its way into human lungs, leaving a scar that can look a lot like lung cancer.

2. Cat scratch fever

Cats can also cause a variety of different infections, but one of the best known is cat scratch fever – caused by a bacterium called Bartonella henselae.  This usually causes a fever, skin infection and lymph node swelling near the site of the scratch, but can sometimes cause a more severe infection.

3. Salmonella from pet turtles

People are familiar with salmonella outbreaks from contaminated food, but there have also been several salmonella outbreaks linked to contact with pet turtles, affecting several hundreds of people in the last few years.  Similar outbreaks have been seen from pet lizards and frogs as well.

4. Bird-fancier’s lung

This is an unusual reaction that I see in the respirology clinic sometimes, whereby long-term exposure to the feathers and/or excrement of certain birds, like budgies, can cause a type of scarring in the lungs called hypersensitivity pneumonitis.

5. Allergies and asthma

This is just a reminder that the most common consequence of household pets is simply worsening of allergic symptoms and allergic asthma.  Although this is usually related to dogs or cats, I have even seen it from pet rabbits and pet mice.