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Monday: 8:30 a.m.-7 p.m.
Tuesday: 8:30 a.m.-7 p.m.
Wednesday: 8:30 a.m.-5 p.m.
Thursday: 8:30 a.m.-7 p.m.
Friday: 8:30 a.m.-7 p.m.
Saturday: 8:30 a.m.-2 p.m.
Sunday: 9:00 a.m-12 p.m.

The deer tick life cycle and Lyme disease, pt. 2

In our first article we discussed the general life cycle of Ixodes scapularis, or the deer tick (May 12, 2011 Leisure, www.northshoreoflongisland.com for article). This second article will focus more on what are known as the transmission time of Lyme disease and other tick-borne diseases, as well as prevention techniques.

As discussed in the first article, ticks do not feed directly from blood vessels. Rather, they insert their mouthparts through the skin and into the underlying tissues and suck up as much as possible. This mixture that is ingested by the tick includes red blood cells and protein, but also comes with a lot of fluid. A female tick's body weight can increase more than 100-fold during a single feeding period. Ticks need to take in large amounts of nutrition to reproduce and lay eggs so they don't have time to stop and "go to the bathroom." Therefore, they are forced to regurgitate some of the fluid they take in when eating and with this they will transmit certain bacteria that live in their gut.

How long does it take for an attached tick to transmit bacteria that cause disease (eg., Lyme disease, Rocky Mountain Spotted Fever, Ehrlichiosis, Anaplasmosis, etc.)? The time it takes for a tick to spread disease after it attaches its mouthparts to the skin (what is known in veterinary medicine as transmission time) varies. Understanding transmission time is important because it informs us of what precautions we need to take. The "winner" for the quickest transmission time of disease is none other than our friend Borrelia burgdorferi, or the bacteria that causes Lyme disease and it is 24 hours.

So how do we prevent it?

1. Environmental Control. We know that every stage of a tick life cycle needs brush to survive before finding a host. Therefore, keeping a barrier between our backyards and potential tick breeding areas is imperative. We can do this by removing leaf litter, clearing (and frequent mowing) tall grasses and brush, and placing wood chips or gravel between lawns and wooded areas to restrict tick migration to recreational areas. If you frequently hike or mountain bike with your dog, check them daily for ticks to remove the tick before it attaches to feed.

2. Tick Preventatives. These are medications that are applied topically (directly to the skin) to prevent ticks from living long enough to spread disease. Many of the topical tick preventatives can now be found over the counter, but be wary. In some products the active ingredient may act as what is referred to as a "slow kill." A slow kill means that it can take up to 72 hours from when the tick is exposed to when it is completely dead.

We already know that it only takes approximately 24 hours for the deer tick to pass the Lyme bacteria along so, as tempting as it is to go with what is more readily available, I recommend always consulting with your veterinarian as to what he or she thinks is the best product based on your dog's risk of exposure.

3. Vaccination. The vaccine has gotten a bit of a bad rap because of the problems associated with the development of a human vaccine against Lyme disease and side effects. Fortunately, the vaccine for dogs has been around for decades and we do not see any long term problems from this vaccine. The vaccine is also very effective in preventing Lyme disease — up to 100 percent effective in some studies. The idea is to introduce the Lyme bacteria in a killed state or to present certain proteins to our dog's immune system before they are exposed naturally. This is a nice fall-back plan to use in conjunction with a topical tick preventative.

I hope this accurately describes the deer tick life cycle and how it can also transmit Lyme disease. This way we can all have a fun-filled, tick-free summer.

Dr. Kearns has been in practice for 13 years and is pictured with his son Matthew, as well as the newest member of the family, Jasmine, a Labrador retriever.

Author: 
Matthew Kearns, DVM