Parasites – Flea/Tick Season

Now that spring has arrived on the west coast, so too has the return of flea and tick season. Fleas and ticks are awakening in our outdoor environments and are in need of finding a host to feed. Our pets are among the ones at greatest risk.

Fleas lay thousands of eggs a day after feeding, contaminating the environment in which their host lives or wanders. Local wildlife populations, along with all of our unprotected furry friends, spread these eggs around our communities. As the eggs hatch and the larval stages of the flea develop, the flea matures and looks for a new host. When your pet walks through an area with fleas they become a target for the continuation of the flea life cycle. The adult flea will jump on our cat or dog while it is out exploring, and once attached it remains feeding and laying eggs until it is killed or falls off from scratching or bathing.

Fleas can also carry and spread other illnesses to our pets. For instance, tapeworm infestations, Mycoplasma infection (a red blood cell parasite causing anemia in cats), and allergic dermatitis in response to flea saliva can all cause illness.

Ticks live in wooded or brushy locations, and can be found here in our neighbourhoods within the surrounding parks and along the pathways. Ticks can also carry and spread diseases to our pets and even to us. The bacterial organism Borrelia which causes Lyme disease is spread through the saliva when a tick bites and feeds from its host. Ticks can spread other bacterial agents that can cause fever, blood cell derangements, and lameness to even paralysis.

Lyme disease risk is low in BC. According to the BC Centres for Disease Control (CDC), there were twelve reported human cases in 2012, nine of which were thought to have originated from exposure during travel elsewhere. Positive cases have been reported from the North Shore, southern Vancouver Island, and from the Okanagan and Kootenay regions. The biggest risk for Lyme disease exposure comes from travel. The highest incidence rates are found within Eastern Canada, and within the US Midwest and along the US Eastern Seaboard.

Prevention of flea and tick exposure and/or infestation is a key preventative health measure for our pets. There are many products available that claim to do this, some are considered a more natural approach, and others claim to be safe for your pet. Not all, however, are considered equal in effectiveness or in their relative safety after application.

What about the ‘natural’ options?

  • Garlic has long been reported to help prevent flea infestations. There is no clinical evidence however to substantiate the claims of those that believe this. Garlic is also toxic to some of our pets, especially to cats, as it can lead to anemia (red blood cell breakdown).
  • Research has disproven the belief by some that brewer’s yeast can be effective at controlling fleas.
  • Not only do ultrasonic devices not work, they are a nuisance to our pets. The high frequency sounds emitted from them are audible to our pets and are known to cause behavioural changes when used on or around animals.
  • Tea tree oil is toxic! Given in the right amounts, it can kill your pet. As little as seven drops of 100% oil has resulted in severe poisonings.
  • Diatomaceous earth dehydrates flea larvae in the environment; however, it does nothing to control the adult population. So yes, it could be used, but only in conjunction with other adequate flea control.
  • Cedar is a natural flea repellent and can be used as mulch. However, most flea infestations occur from exposure outside of our yards and then propagate within our homes.
  • Keeping your pet indoors will lower the risk of flea infestations, but we ourselves can carry fleas into our home environment. Once inside, fleas thrive and multiply exponentially within a couple of weeks.
  • What about ‘pet store’ brands?

Far to often we as veterinarians see pets exposed to a flea and/or tick adulticide purchased over the counter from our neighbourhood pet stores. These products come with extreme risk to our pets, as they are composed of pyrethrins and pyrethroids. These are parasiticides that can be extremely toxic, especially to cats. NEVER use a product labelled for a dog on a cat!

What do we recommend for flea control?

  • There are many safe and effective alternatives to the control of flea infestations. Your veterinarian can prescribe a number of options.
  • Environmental control is important. Regular vacuuming, washing of bedding, manual flea removal through brushing and bathing, as well as keeping grass cut and vegetation pruned can help minimize exposure.

For dogs:

  • Sentinel, a monthly oral flea insect growth regulator (prevents the development of early flea stages to adults), and heartworm and intestinal worm preventative.
  • Revolution, a monthly topical parasiticide that kills adult fleas and prevents the development of earlier flea stages, it is also a heartworm preventative, and kills mites and lice.
  • Advantage, a monthly topical parasiticide that kills fleas.

For cats:

  • Program, an injectable insect growth regulator that remains effective for six months.
  • Revolution, a monthly topical parasiticide that kills adult fleas and prevents the development of earlier flea stages, it is also a heartworm preventative, intestinal worm preventative, and kills mites and lice.
  • Advantage, a monthly topical parasiticide that kills fleas.

What do we recommend for tick control?

  • Daily manual inspection and removal of ticks during high-risk times. In some cases, depending on the length of and degree of tick attachment we may prescribe a course of antibiotics in case of bacterial transmission. The live tick can also be sent to the BC CDC for Borrelia testing for a minimal cost.
  • Tick collars can be used as needed, and then removed and safely stored for up to 90 days once opened.
  • K9 Advantix is a parasiticide for fleas and ticks that is available for dogs only.
    Revolution has some efficacy against ticks. The tick has to bite and feed; therefore, the risk for bacterial transmission to the host remains.
  • If you are seeing ticks on your cat, please do not apply any product without first discussing with your veterinarian!


B.C. Centres for Disease Control

Government of Canada

American Animal Hospital Association

Pet Poison Helpline

Natural Resources Defense Council

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