Rhipicephalus is a genus of ticks in the family Ixodidae, the hard ticks, consisting of about 74 or 75 species. Most are native to tropical Africa. Rhipicephalus ticks are commonly called 'the brown tick' as they are mostly brown in colour. Most adult ticks in this genus do not have colour patterns on their scutum (inornate). This makes the species difficult to distinguish from one another because most are quite similar, but individuals of one particular species can be quite variable. Ticks have traditionally been identified by examination of distinctive morphological features. Most of the characteristics used to identify species pertain to male specimens. The immature and female specimens are sometimes simply impossible to identify due to the lack of differential morphological features. Many Rhipicephalus spp. are of economic, medical, and veterinary importance because of their blood feeding lifestyle. They are possible vectors of many pathogens in humans and animals. They can transmit pathogens that cause animal and human diseases, such as East Coast fever, anaplasmosis, babesiosis, rickettsiosis, Boutonneuse fever, Lyme disease, Q fever, Rocky Mountain spotted fever, and Crimean–Congo hemorrhagic fever. In addition to the infectious agents spread by ticks, tick bites can lead to allergic and toxic reactions. A toxic reaction occur when they inject a neurotoxin with their bite that leads to tick-caused paralysis. Boophilus was once considered a separate genus, but studies in the early 2000s resulted in Boophilus being made a subgenus of Rhipicephalus. Although Boophilus has been included in the Rhipicephalus genus, their morphology is different from the typical Rhipicephalus species. Species familiar in the domestic environment include the brown dog tick (R. sanguineus).

Sex pheromone studies

A number of Rhipicephalus spp. females produce phenol and p-cresol after being fed for six days. These compounds may act as sex pheromones since these compounds were shown to be the sex pheromone of Rhipicephalus appendiculatus.

Etymology

The name Rhipicephalus is derived from the Greek word rhiphis, meaning "fan-like", and κεφαλή, kephalē, meaning "head". The two terms are related to the hexagonal basis capituli of Rhipicephalus.

Epidemiology

Rhipicephalus bursa is a carrier of babesiosis, theileriosis and anaplasmosis in domestic animals, of the Nairobi sheep disease, and an aggressive vector of the agents of the Crimean–Congo hemorrhagic fever and of the Q fever.

Species

Subgenus Boophilus