Prevalence of vectors of the spotted fever group Rickettsiae and murine typhus in a Bedouin town in Israel

A survey of the vectors of spotted fever group Rickettsiae and of murine ty phus was carried out in Rahat, a Bedouin town in the Negev Desert, where th e diseases are endemic. Houses with known cases of spotted fever group Rick ettsiae or murine typhus were compared with those without reported clinical cases. A neighboring Jewish community, Lehavim, where no cases of spotted fever group Rickettsiae and murine typhus were reported in recent years, wa s used as a control. In the houses of patients with spotted fever group Ric kettsiae in Rahat, an average of 7.4 times more ticks were found than in co ntrol houses. Out of 190 ticks isolated from sheep and goats or caught by n agging in Rahat, 90% were Rhipicephalus sanguineus (Latreille), 7.9% Rhipic ephalus turanicus Pomerantzev, and 2.1% were Hyalomma sp. In the houses of patients with murine typhus, three times more rats were caught and, on the average, each rat was infested with 2.2 times more fleas than rats in the c ontrol houses. Out of 323 fleas collected from 35 Norwegian rats (Rattus no rvegicus Berkenhout), 191 were Xenopsylla cheopis Rothschild and 132 Echidn ophaga murina Tiraboschi. Thus, there was a six to seven times higher proba bility of encountering a tick or nea vector where infections had occurred t han in control houses in Rahat. The percentage of rats seropositive to Rick ettsia typhi was similar in study and control households (78.3 and 76.2, re spectively). In the control settlement. Lehavim, only three Mus musculus L. were caught, which were not infested with ectoparasites and their sera wer e negative for murine typhus. Out of 10 dogs examined in this settlement, 1 5 R. sanguineus and eight specimens of the cat flea ((Ctenocephalides felis felis Bouche) were isolated. No rats were caught in this settlement. These data indicate that there is a correlation among the density of domestic an imals, their ectoparasites, and the incidence of spotted fever group Ricket tsiae and murine typhus in Rahat.