Ticks

Description and Geographic Distribution

Ticks are small parasites that feed off the blood of birds and mammals, including humans, and are vectors for several diseases :  Anaplasmosis, tick-born paralysis, Erhlichiosis, Lyme, and many others. In North America, the most commonly transmissible disease from ticks is borreliosis or Lyme disease. Given the different species of ticks present in Quebec, the only type that can transmit Lyme disease to an animal or a human is Ixodes scapularis also known as the black-legged tick or deer tick. This arachnid is becoming more and more common in the Montérégie possibly due to climatic changes and the rise in population of Virginia deer and wild turkeys in our geographic area. The white-footed mouse is a host for the bacteria responsible for Lyme disease and the deer plays a role as the breeding ground for ticks without actually being a carrier of the bacteria. Also, migrating birds drop between 50 and 175 million ticks on their journey across the United States every year according to a 2008 study.

Ixodes scapularis is found mainly on the East Coast of the United States and in Eastern Canada, (regions include Southern Manitoba, Southern Ontario, South Western Quebec, and Nova Scotia), generally in regions that experience warmer climates. The Montérégie appears as a risk zone, possibly because of its proximity to areas in the United States where the bacteria is more prevalent.

Ticks are found in wooded areas and long grasses. Beginning in the month of May, once the snow has melted, ticks climb to a high perch and wait for a human or animal to pass so it can attach itself and feed. Another popular time for ticks is in October and November.

What does a tick look like?

Ixodes scapularis has an oval body with four pairs of legs. It develops in three stages from larva to nymphe to adult. In the first two stages, a tick measures 0.5mm to 1mm and an adult measures 1 to 3mm. Once engorged with blood after feeding, the tick may measure 5-6mm or more. The males are dark brown in colour and the females are brown/orange. The body colour changes to grey when filled with blood. The tick`s mouth is constructed with barbs that sink into the body of its host, allowing it to remain firmly attached while it feeds for 3 to 14 days. Once fed, the tick will simply let go and drop away. Common areas to find ticks on a dog are on the head, the neck and the back.

Studies have shown that approximately 10% of Ixodes scapularis found in Quebec are carriers of the bacteria Borrelia burgdorferi which is the bacteria that causes Lyme disease. In Montérégie, it is actually 18% that are carrier of the bacteria while in certain areas of the United States, that number climbs to as much as 50%.

The transmission of the disease usually occurs several hours after the beginning  of feeding (48 hours or more), which means that it is very important to remove the tick as soon as it is discovered to avoid the risk of being infected by dangerous pathogens.

A dog that has been bitten by a tick carrying Borrelia burgdorferi may contract the infection and be a carrier for the antibodies of the disease without showing any clinical signs of infection such as fever, limping on alternating legs, polyarthritis, swollen joints, and loss of appetite. This is true of 95% of cases of infected dogs. Only 5% of dogs infected with Lyme disease will show any clinical signs of the disease. It is vitally important to treat dogs who have tested positive for Lyme disease and who show clinical signs of the disease with antibiotics (oral doxycycline for one month) as soon as possible in order to avoid complications with the kidneys or other internal organs. As opposed to dogs, most people infected with Borrelia burgdorferi will develop symptoms. Cats are naturally resistant to Lyme disease but can suffer by other  tick born diseases.

What to do if my pet has a tick:

 

1. Ideally, while wearing gloves, remove the tick as soon as possible using fine tweezers. Grasp the front part of the  tick as close to the animal’s skin as possible and pull slowly without twisting. Do not apply alcohol or Vaseline to the tick in an attempt to kill it. Always clean the bite area and wash hands well after the procedure is complete. If you are not comfortable removing the tick yourself, contact your veterinarian as soon as possible.
2. Avoid crushing the tick in order to reduce the risk of contaminants. If a small piece of the tick remains embedded under the skin, it is important to try to remove it. Contact your veterinarian if necessary. Surgical instruments and a magnifying glass may be required to excise the small piece of tick.
3. Conserve the intact body of the tick in a clean, dry container for future analysis. L’Hôpital Vétérinaire de L’Île-Perrot regularly receives specimens of ticks which are sent to a lab to be identified and analyzed. Tests will determine if the tick is the type known to be a vector for Lyme disease and if it is a carrier for Borrelia Burgdorferi (test PCR). A fee is charged for the analysis of all ticks in the Montérégie since 2012 when the period of free testing in public health Laboratories in Quebec ended in our territory.
4. If the bite of the tick causes inflammation or a significant wound, an antibiotic ointment may be prescribed. We suggest to our clients to watch for signs of Lyme disease in the following weeks after a tick has been discovered and removed. It can take 2 to 6 months for signs of the disease to show. If ever a tick tests positive for Borrelia burdorgferi, tests for your dog (a search for specific immunoglobulines 6-8 weeks after infection, quantitative titre of C6 if necessary) are recommended to see if the bacteria was transmitted.  If the results confirm an infection by Borrelia burgdorferi, further tests will be recommended (hematology and biochemistry) and a urine analysis is often suggested to determine if the dog will require antibiotics. Several factors influence the decision of the veterinarian in whether to treat the dog who is asymptomatic but seropositive for Borrelia burgdorferi (blood tests, urinalysis, the breed of dog, and medical history).

Ticks and Lyme disease prevention in dogs

With our awareness of ticks in the environment it is prudent to protect your dog against these parasites with a product such as K-9 Advantix from Bayer, a topical product applied once per month from April to December. The product acts as a tick repulsive on dogs (permethrines), preventing ticks from biting the pet. K-9 Advantix also prevents fleas (imidaclopride) and repulses mosquitoes. If a dog has several ticks on its body, an application of the medication will help to rid the dog of undetected ticks as well.

CATS MAY NEVER BE TREATED WITH K-9 ADVANTIX AND SHOULD NOT BE IN CONTACT WITH DOGS THAT HAVE BEEN RECENTLY TREATED, since the permethrines are toxic to cats. Separate your dog and cat for 48 hours after the application of the product. If your cat has a habit of licking the dog, or likes to be very close to the dog (they frequently play and sleep together, groom each other, etc), check with your veterinarian about prevention options other than the topical treatment K9 Advantix which is hazardous to cats.

The product Nexgard from Boehringer Ingelheim is an excellent option for dogs in preventing ticks and fleas. It comes in the form of a flavoured cube and is administered by mouth monthly from April to December.

You may prefer Bravecto from Merck, which is administered orally once every 3 months during the flea and tick season. Other oral preventive medications now available include Simparica from Zoetis and Credelio from Elanco.

Oral products are a very good alternative for dogs who are regularly bathed with medicated shampoos for skin problems during the summer months,  (regular bathing can diminish the effectiveness of topical products such as K9 Advantix), for dogs who live in close quarters with cats, or for families who do not want their children exposed to a topical product while it is drying on the skin.

A vaccine against Lyme disease is available. However, the experts agree that prevention of ticks remains the best solution, with or without the use of vaccines. Cats and other domesticated animals may be infested by ticks. However, cats are  resistant to Lyme disease; in spite of being seropositive, they do not develop clinical signs. The same procedure applies for removing the tick, should you find one on your cat.

Ticks prevention in cats and tick born diseases prevention

Excellent preventive treatments are now available for cats (Bravecto and Revolution Plus).

Protection for Humans

1. Avoid areas where ticks are known to be present.
2. Wear long sleeves and long pants for excursions into the forest. Stay on the paths and avoid going off the trails into long grass. Keep your pants tucked into tall boots and shirts tucked into pants, which can help to prevent tick bites.
3. Use a mosquito repellent containing DEET.
4. Wear light-coloured clothing and take a moment to inspect everything after returning home. Check the pets as well.
5. Keep bushes and shrubs trimmed, cut the grass regularly and always keep the areas around sandboxes and play areas trimmed back.

Conclusion

Ticks are a presence in our environment, given the statistics and our observations here at Hôpital Vétérinaire de L’Île-Perrot.  As a pet owner you should be aware of this parasite and take the appropriate measures if a tick is identified on your pet, you or a family member. Lyme disease can cause serious health problems therefore ticks found on humans or dogs should be analyzed. Contact your doctor or veterinarian  should this occur.

Preventive measures should be taken. With the increase in tick population, Lyme disease cases may become more and more prevalent in the years to come for us and our pets.

References:

1. La tique, mieux la connaître, mieux s’en protéger
   Dr Alain Villeneuve, DMV, parasitologiste , Faculté de médecine vétérinaire,Université de Montréal
2. Feuillet d’information sur la maladie de Lyme (Ministère de la santé et des services sociaux)
3. La progression de la maladie de lyme au Québec
   Dre Cécile Aenishaenslin, Ph.D. en épidémiologie à la faculté de médecine vétérinaire , Université de Montréal, Le Vétérinarius, mai 2013
4. Que faire avec un patient asymptomatique qui a une sérologie positive pour la maladie de Lyme?
   Dre Manon Lécuyer, DMV, DACVIM,  Le Vétérinarius, mai 2013