A Note on the Survival of Unfed Adult Rhipicephalus Simus Simus Koch,1844

Abstract

One-third of a batch of unfed adults of Rhipicephalus simus simus Koch survived for 32 months in the laboratory in Kenya and a few subsequently produced normal progeny after they had engorged on a rabbit. The probable importance of the species in the transmission of various human and animal diseases is briefly discussed in relation to the apparent preference of the immature stages for small animals as hosts. This is thought to make it unlikely that R. s. simus is an important field vector of either East Coast fever or anaplasmosis, although its ability to transmit the causal agents (Theileria parva and Ana plasma marginale) is well established [cf. RAE B 26 26; 46 121; 57 262]. On the other hand, it has been suggested that small mammals are important in the maintenance of rickettsial infections [cf. 51 150], and the production of a syndrome typical of tick typhus {caused by Rickettsia conori] following inoculation into a human volunteer of a strain of rickettsiae isolated from Rhipicephalus s. simus has been recorded [48 130]. It is considered that this tick may be a more important vector of rickettsial infections than has hitherto been realised.