Basic tick biology
The common ticks on dogs and cats in North America are all three host ticks. Accordingly, the larvae, nymphs, and adults
of each species must each quest, attach to a host, and feed before leaving the host to molt or deposit eggs in the environment.
Most of the common ticks of dogs take as long as 2 to 3 years to complete this developmental cycle, becoming dormant and sheltering
during adverse environmental conditions and emerging again to actively seek a host when conditions become favorable. One
notable exception is Rhipicephalus sanguineus, the brown dog tick or kennel tick, which can survive inside homes and may complete development from egg to egg laying adult
in as little as two months. Effective control of ticks and prevention of tick-borne diseases requires (1) recognition of
the tick species active in a given area at a particular time of year, (2) understanding of the habitat and reservoir hosts
required to support that species, (3) awareness of the reproductive capacity and strategies of ticks, and (4) consistent use
of effective acaricide control products on the dog and, when necessary, in the environment.
Identification of common tick species
Although not often pursued, adult ticks can be easily identified by veterinarians and veterinary technicians with minimal
effort. Several excellent pictoral keys are available to aid in identification. Knowing the tick species infesting a given
dog or active in an area at a particular time of the year enhances our ability to recommend effective control measures, allowing
adjustments to be made when necessary. For example, persistent R. sanguineus infestations on a dog suggests a home or kennel
infestation may present, whereas A. americanum ticks are more likely acquired from wooded areas around the home where the
dog spends its time. Identification of ticks on dogs can also provide valuable information about tick-borne diseases of concern
in the area because different ticks transmit different pathogens to dogs.
The brown dog tick or kennel tick, Rhipicephalus sanguineus, is the most widely distributed tick on dogs worldwide (Dantas-Torres,
2008), and dogs infested with this tick can be found in every state in the USA although infestations are more commonly reported
in the South. Brown dog ticks are unique among the ticks of dogs in that they use dogs as a strongly preferred, almost exclusive
host in all life stages. Although individual ticks occasionally feed on another species, such as people or cats, populations
of R. sanguineus are supported almost entirely on dogs. In addition, they can tolerate the low humidity inside homes and
kennels and can complete their life cycle in as little as 2 months, thus this tick can establish in large numbers and thrive
indoors so long as adequate dogs are available for feeding (Dantas-Torres et al., 2006). Home infestations with R. sanguineus,
which may be found in climate controlled environments at any time of the year, are particularly troubling because they increase
the risk of transmission of zoonotic disease agents, such as R. rickettsii and E. canis (Goddard et al., 1989; Demma et al.,
2005). This tick can also thrive outdoors in warmer areas, usually in an area immediately surrounding a home, with peaks
of activity occurring late spring to early fall (Goddard 1989; Louly et al., 2007).