The dermacentor variabilis, more commonly known as the American dog tick, is most prevalent in the eastern part of the United States. It is so-named because its preferred host is the domestic dog and it is mostly found in North America. The American dog tick likes environments with tall grass and is a vector for Rocky Mountain Spotted Fever and tularemia.

 

 

 

 

 

 

 

 

 

Habits

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American dog ticks like to sit in high-grass areas and shrubs. They’re also found along roads and walkways. Since these ticks are so commonly found in areas close to human activity, humans are often attacked.

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American dog ticks are considered particularly troublesome because they can easily be brought into your home, via your dog. You should always check yourself and your dog for ticks after walking through a high-grass area.

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Furthermore, the amount of time an American dog tick spends engorging on its host depends on what phase of the lifecycle it’s in. For larvae it’s 3-5 days, for nymphs 3-11 days and full adults spend between 5-13 days feeding on their host. It’s most likely to attack a dog or human in the adult phase, so you could have a tick attached to your pet or yourself for several days before you notice it.

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Catching and removing a tick early is ideal, because it may not have been attached long enough for harmful pathogens to be transmitted. If you notice any symptoms of common diseases carried by American dog ticks (see below) then get yourself or your pet check checked immediately.

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Lifecycle

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The American dog tick, like most ticks, passes through 3 life phases after it hatches – larva, nymph, and adult. They also must feed off of a host at each stage in the lifecycle to move to the next. This tick can, however, live up to two years without feeding on a host. As larvae, these ticks will look for small mammals like voles, raccoons, or mice to feed on. In New England, larvae are typically active in late spring and summer.

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When winter comes, the larva will overwinter and molt into a nymph, the next life phase. Larvae and nymphs won’t typically seek out human hosts, preferring either small or medium-sized animals like skunks and rabbits.

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When American dog ticks become adults, however, they are more likely to seek human hosts. This is due partially to humans’ proximity to the ticks’ favorite host animal, domestic dogs. In addition, adult ticks are active between April and early August. Male American dog ticks will seek a female to mate once they’ve finished feeding. Once the female American dog tick is fully engorged, she’ll drop off of the host to lay eggs. She dies soon after, the end of the lifecycle for this tick.

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Identification

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American dog ticks are brown with white or gray markings. Like all arachnids, they have 8 legs – except their larvae, which only have 6. They expand in size when engorged, after having fed on their host. But they are generally still recognizable in their engorged state.

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In addition, these ticks like to crawl through dog fur or human hair, which are the likeliest places you’ll find them if you or your pet has one. If you have tall grass or an outdoor pet, you have higher chances to attract American dog ticks as well. Keeping grass cut short is one way to stave off an infestation since ticks don’t like this sort of low-humidity environment.

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If you spot an American dog tick in your garden or a potted plant, it might be cause for concern. These are areas where female ticks like to lay eggs, so you may have an infestation.

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Associated Diseases

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American dog ticks are most commonly associated with Rocky Mountain Spotted Fever and tularemia. These ticks are vectors for the bacterium Rickettsia rickettsii, the causative agent of Rocky Mountain Spotted Fever. Tularemia is caused by the bacterium Fracisella tularensis, which these ticks are exposed to when feeding on small animals like rabbits, mice, and squirrels.

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Another disease linked to American dog ticks is tick paralysis. Tick paralysis can result in rapid-onset muscle weakness and respiratory distress.

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Final Thoughts

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As a major vector for diseases that threaten humans and domestic dogs, the American dog tick is a dangerous pest indeed. The best way to protect yourself is to be knowledgeable and take precautions. Always cover up your arms, legs, and feet when walking or hiking through areas dense with tick populations. And check your body for ticks upon returning home.