The brown dog tick, Rhipicephalus sanguineus, is a parasitic arachnid. They feed on blood, usually from dogs, although they have been known to bite people. Unlike most other ticks, brown dog ticks can live their entire lives indoors as long as they have a warm and dry environment. Their ability to live indoors means these ticks can be found in homes anywhere in the world.
Both male and female brown dog ticks feed on blood from their hosts. Before feeding, the ticks are about the size of poppy seeds. After feeding, the female swells to the size of a raisin. The male does not enlarge after feeding. These ticks are distinguished from others by their hexagonal basis capituli, a body part located behind the mouthpart that resembles an angled collar.
Another identifying characteristic of the brown dog tick is its color. Behind the basis capituli is an area called the shield. The shields, basis bapituli, mouthparts, and legs of brown dog ticks are reddish brown. After the female tick feeds, the engorged portion of her body becomes a grayish-blue color. The rest of her body remains reddish brown.
The female brown dog tick can lay as many as 5,000 eggs on the ground, on carpet, or in cracks and crevices. After hatching, the larvae find hosts and feed for about three days before dropping off. They molt into nymphs after about a week and then find another host. After feeding for about four days, the nymphs drop off and molt into adults. The adult ticks find hosts and feed until the females are ready to lay their eggs, at which point they drop off, and the cycle repeats.
Control of brown dog tick infestations can be difficult due to their behavior between life cycles. Tick species that remain attached to their hosts are easier to eradicate. A brown dog tick not only needs to be removed from the host, but the living quarters will usually need to be treated as well. These ticks are susceptible to several insecticides including fibronil, amitraz, permethrin, and deltamethrin.
Ticks are responsible for several canine diseases. The brown dog tick carries both canine babesia and canine ehrlichiosis. These ticks rarely feed on people unless there is a heavy infestation or if their main food source is removed. In the United States, brown dog ticks can carry Rocky Mountain spotted fever. In other parts of the world, the ticks are known to spread Mediterranean spotted fever and tick typhus.