Lyme Disease and Tick Prevention
Posted by Dr. Susan O'Dell DVM on 02/04/2015
Lyme disease is caused by infection with the bacteria Borrelia burgdorferi. The bacteria are transmitted to animals and humans by ticks. Lyme disease can cause a variety of signs, but the most common are fever, joint swelling with lameness, lethargy and loss of appetite. Less often, some dogs may develop a very serious and life-threatening complication affecting the kidneys called Lyme nephritis.
Lyme disease is very prevalent in the United States, but particularly through the Northeast. According to the Companion Animal Parasite Council, about 6% of dogs nationwide test positive for Lyme disease. This percentage leaps to somewhere near 50% in the Northeast, where 1 out of 2 dogs may test positive for this condition. In certain counties, the prevalence approaches a frightening 75% infection rate.
This begs the question, how do we prevent Lyme disease? To answer that question, we must examine several different topics: tick removal, vaccination, parasiticides and yard treatments.
An infected tick cannot transmit the Borrelia bacterium immediately. It takes time for the bacteria to leave the tick and move into the host, usually this happens no sooner than 24 hours from attachment. The longer the tick is attached and feeding, the more likely your pet can become infected. This makes daily tick checks (especially after high risk of exposure) very important. Feel along your dog’s body, paying careful attention to areas such as the ears and between the toes. If you find a tick attached to your pet's skin, you do not need to panic. Simply remove the tick using a commercial tick removal device, or you can use a pair of tweezers with a fine point. Do not wait for the tick to detach on its own; this increases the possibility of infection.
How to remove a tick
1. Grasp the tick as close to the surface of the skin as possible using the tweezers.
2. With a firm grip, pull upward slowly and steadily to prevent the mouth parts from breaking off and remaining in the skin.
3. Dispose of the live tick by sealing it in a bag, wrapping it in sticky tape, or flushing it down the toilet. Do not try to crush the tick, as this could cause unnecessary exposure to tick borne diseases.
4. After removing the tick, clean the skin at the site of the wound with rubbing alcohol or mild soap and water. Don't forget to wash your own hands thoroughly also.
There are a variety of vaccines available to protect dogs against Lyme disease. Each one requires an initial vaccination followed by at least one booster, and annual boosters are also needed to continue protection. There are many factors that play a role in deciding to vaccinate a dog for Lyme. These are points that should be discussed with your veterinarian when contemplating a vaccine for your pet:
1. How common is Borrelia burgdorferi in my area? If you live in an endemic region like the Northeast US, your dog is at high risk of contacting infected ticks. Unless he has a history of reactions to vaccines, it may be a good idea to protect your pet with the Lyme vaccine.
2. How common is Lyme disease? In endemic regions, nearly 10% of dogs may not only test positive, but also show clinical signs of illness from infection.
3. Is Lyme disease treatable? Most dogs respond rapidly to antibiotic treatment and clinical signs often resolve within the first 1-2 days. However, based on many studies, we also know that some dogs never completely clear the bacteria from their bodies even after proper treatment. Also, some dogs can develop a more severe condition called Lyme nephritis, which can be deadly.
4. How expensive and how reliable is the vaccine? They are relatively inexpensive. The reliability of the vaccines is unknown, but ranges anywhere from 50% to 100% protection.
5. Is the vaccine safe for my pet? Of course, each dog is an individual and no rules apply across the board. Overall, the risk for a reaction to the Lyme vaccine appears to be very small (<2% of dogs have an adverse reaction).
Although we have vaccines to protect against infection by Borrelia and Lyme disease, there are no vaccines to protect against other tick borne diseases such as Anaplasma phagocytophilum, Rocky Mountain Spotted Fever, and Ehrlichia canis. To expand the protection that we give to our pets, we should also consider products designed to repel and kill ticks before they can transmit disease. We are fortunate to have a plethora of outstanding antiparasitic agents.
Traditionally, we have recommended and used topical tick control products containing chemicals like fipronil and permethrin. These products, by brands like Frontline and K9 Advantix, come in liquid form and must be applied to the pets skin, typically once monthly. They have been commercially available for many years and are familiar to most pet owners. Newcomers to the topical tick control market include Certifect, Activyl Tick Plus, and Vectra 3D.
More recently, newer insecticides and acaricides (products that kill ticks) have joined our arsenal against ticks. These newer compounds include flumethrin, deltamethrin, cyphenothrin, afoxalaner and fluralaner. Not only are these novel chemicals, they are also administered to dogs by alternate methods – some orally and some by treated collar. Tick collars like Preventic, Seresto, and Scalibor appear to be effective and safe. The two oral products for tick protection, Nexgard and Bravecto, also appear to be quite effective and safe. Many owners are turning to these new options for longer lasting protection, especially for those dogs that dislike the topical applications or had adverse reactions.
We can also lessen the risk of disease for pets and humans by reducing the overall exposure to ticks. Premise pesticides for ticks are easy to apply, relatively inexpensive, and can reduce the number of ticks in your yard when applied at the proper times of year. If applied according to the label instructions, they should also be safe.
To control the population of deer ticks, it is best to spray the yard once in May or early June to target the nymphal stage of the deer tick life cycle. The spray can be repeated in October to control adult deer ticks, but these do not transmit disease as commonly as the nymphs. If there are any concerns about applying a pesticide to the yard, a professional can be contracted for this purpose.
Here are some simple landscaping techniques that can help reduce tick populations:
1. Mow the lawn often
2. Remove leaf litter, which is a favourite spot for ticks
3. Spread a barrier of wood chips or gravel 3 feet wide at the edge of the lawn to prevent ticks from migrating into the yard
4. Stack wood neatly in a dry area
5. Discourage wildlife from entering the yard, and never feed these visitors
6. Remove trash or large items which may serve as hiding places for ticks
7. Keep decks, patios, and play structures away from the edges of the yard
Preventing tick borne diseases is not always possible. The best thing you can do is use a combination of these methods to reduce the risk of your pet becoming sick with Lyme disease or another one of the tick borne illnesses.