Jan 17 2017

A Guide To Ticks In Maryland

Worldwide, there are nearly a thousand species of ticks and nearly 100 of those are found within the continental United States. Of these, a handful are capable of transmitting disease to humans and dogs.  (While tick-borne disease in cats is possible, incidence is rare. Look for another blog post on this topic soon.) The range of each species of tick varies with season, availability of hosts and the timing of activity of each species will vary. In general, larvae and nymphal forms are difficult to identify due to their small size.  Tick populations are dynamic and ever evolving, and should be considered a source of emerging disease.  It should also be noted that dogs are sentinels for human disease and since most species that bite both humans and pets can transmit disease to both, there is value in testing dogs regularly for tick-borne disease. In addition, consistent year round tick prevention and control is vital to protect your pet, and yourself, from the various tick species that are found in Maryland.

Here are the tick species seen in Maryland, including Baltimore City.

Lone Star Tick
Widely found in the southeastern and eastern US, this aggressive tick is expanding its range westward and northward. Six legged larvae actively seek out hosts by climbing plants or objects and waiting for a potential host to pass by. Larvae are active July through late September.  After molting into nymphs, which are active May through early August, the Lone Star tick actively seeks out larger mammals, including humans, dogs and cats, as well as birds and smaller mammals such as squirrels. After feeding, nymphs drop off and molt again, emerging as adults. Adults are active April through late August and search out humans, dogs, deer and other large mammals by waiting on tall grass or the tips of low hanging branches and twigs. The female tick is easily recognizable by the single white dot in the center of a brown body. Males have spots or streaks of white around the edges of the body.

This tick is often misidentified as blacklegged ticks. The Lone Star tick tends to be larger than the blacklegged tick.  The Lone Star tick does not transmit Lyme disease, but is capable of spreading the pathogens that cause other tick-borne diseases, including Ehrlichiosis and Rocky Mountain Spotted Fever.

American Dog Tick
This tick is widely found east of the Rocky Mountains and is most common in areas with little to no tree cover, such as grassy fields or along trails. They feed on a variety of hosts, including pets and humans. While both male and female adults feed, male American dog ticks do not become engorged with blood. This species of tick is hardy and can survive up to two years without a host. Larvae are active April through September, nymphs May through July and adults April though early August.

American Dog Ticks are colorful and larger than other species, growing up to 1.5 centimeters when fully engorged. Females are recognizable by the large off white area on the back, shaped like a shield, on a dark brown body. This kind of tick does not transmit Lyme disease but is capable of transmitting other tick-borne disease, such as Rocky Mountain Spotted Fever.

Blacklegged Tick (Deer Tick)
This species takes two years to complete its life cycle and distribution relies heavily on the white-tailed deer, which serve as the reproductive host. The larvae of the deer tick are active July through September, hatch from eggs into leaf litter and remain there until attaching to any available mammal, as well as birds. Larvae have six legs and are about the size of a poppy seed. After feeding, the larvae drop off the host, molt, and emerge as nymphs in the spring. Nymphs are active May through August, have eight legs and are about the size of a pinhead. This life stage of the deer tick will attach to smaller mammals but will also feed on humans, cats and dogs before dropping off, molting, and emerging as adult deer ticks in the fall.  Adults are active October through May and prefer larger hosts, including humans and pets.  Adult males do not feed and are uniformly brown in color and slightly smaller than adult females.  The adult female feeds, drops off into leaf litter to overwinter, then lays a single egg mass before dying. An unfed female deer tick is 3 to 5 millimeters long and red and brown colored with eight legs. An engorged female appears darker and can reach 10 millimeters in length.

This tick species transmits Lyme Disease, Anaplasmosis and Ehrlichiosis.

Brown Dog Tick
This type of tick is found worldwide and occurs predominately around and in settlements with humans and dogs residing. The dog is this tick’s preferred host for all of the life stages but will also bite humans and other mammals. Capable of completing their entire life cycle indoors, in as little as three months, this tick can also survive up to 18 months without feeding. All three stages of the life cycle can be found year round, making this tick an extremely difficult species to control.

Adults are large ticks, growing up to half an inch long when engorged.  Unfed adults are a uniform reddish-brown color and lack any distinctive markings. The brown dog tick does not transmit Lyme disease but can transmit Anaplasmosis and Ehrlichiosis, as well as other tick-borne pathogens.

And One More To Watch For…

Gulf Coast Tick
This tick species is related to the Lone Star Tick and is found in coastal areas on the Atlantic coast and Gulf of Mexico.  This species has been found in Virginia, so Maryland residents should be aware of the potential for this tick to expand its geographic range. This is a small type of tick, similar in marking to the American dog tick, but smaller in size. This tick is considered an emerging threat.

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Tick-borne Disease In Cats

 

 

bsah6244 | Canine Health, parasites, Preventative Medicine, Seasonal Health, Zoonoses

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