Hyalomma (Hyalommina) rhipicephaloides Neumann (Ixodoidea: Ixodidae): its identity, hosts, and ecology, and Rickettsia conori, R. prowazeki, and Coxiella burneti infections in rodent hosts in Egypt.

Abstract

Hyalomma (Hyalommina) rhipicephaloxdes Neumann, 1901, described from 2 ♂♂ collected in Egypt in 1838, has otherwise been known only from a few adults and single cast larval and nymphal skins taken near the Dead Sea. From a relict population of this tick recently found in 2 desert valleys of NE Egypt, we collected 373 immature and 2 adult specimens; 162 adults and 3 nymphs were reared in the laboratory from earlier stages. Several to 30 larvae and nymphs cluster on the lower throat and chest of spiny mice, chiefly on the relatively abundant Acomys dimidiatus megalodus Setzer, also on A. russatus aegyptiacus Bonhote. Immature stages infest these mice from late winter to late summer; none was found during fall. Infestation rate and index were greatest during hot summer months. Ecology of the habitats near the Red Sea is described. Descriptions of the ♂, ♀, nymph, and larva are provided as well as keys to adults of the subgenus Hyalommina of the world. New records of nymphs from Acomys russatus subsp. in Jordan are included. This tick appears to have a relict-type distribution pattern and to be able to survive in few desert situations of the eastern Mediterranean region. Of 92 serum specimens from Acomys near the Red Sea, 29 (32%) were positive for typhus group agglutinins; 5 were positive for Rickettsia conori and 11 for COXIELLA BURNETI agglutinins. The percentage positive for typhus (32%) is almost double that of Acomys sera for Egypt as a whole (17%); however in no case was the individual typhus group antibody titer high enough to permit specific identification of epidemic or murine typhus.