Ticks (Acarina, Ixodoidea) of the northern regions of the Somali Democratic Republic

Abstract

In this survey of distribution and prevalence of adult ticks (Acarina, Ixodoidea) parasitising domestic animals in the northern regions of the Somali Democratic Republic, 26 species were identified. The ten most common species were widely distributed with Hyalomma anatolicum anatolicum Koch, H. dromedarii Koch, H. erythraeum Tonelli-Rondelli, H. impeltatum Schulze & Schlottke and Rhipicephalus sanguineus group more common in the drier vegetation zones, and H. marginatum rufipes Koch, H. truncatum Koch, R. e. evertsi Neum., R. pravus Dön. and R. pulchellus (Gerst.) more common in the wetter woodland, evergreen and forested zones. Four species, Amblyomma gemma Dön., A. variegatum (F.), Boophilus decoloratus Koch and R. simus Koch, were confined to the wooded zones above 1200 m altitude. Species collected less frequently were Argas persicus (Oken), Amblyomma falsomarmoreum Tonelli-Rondelli, H. anatolicum excavatum Koch, H. m. marginatum Koch, H. m. turanicum Pom., H. punt Hoogst., Kaiser & Pedersen, Ornithodoros savignyi (Aud.), R. armatus Pocock and R. longicoxatus Neum. Ambylomma lepidum Dön. was represented only by a few specimens introduced on nomadic livestock.Nearly 60% of the total number of ticks collected were R. pulchellus. This species is considered to be the main vector of Nairobi sheep disease (NSD) virus in northern Somalia. NSD is the most important tickborne disease in sheep and goats and causes considerable economic losses to the Somali livestock industry. A. gemma and A. variegatum are probably the vectors of Cowdria ruminantium (heartwater) in sheep and goats in the western highlands. These two ticks are also incriminated in the spread of Dermatophilus congolensis infection (streptothricosis). R. e. evertsi may be the vector of Babesia motasi in sheep and goats. Boophilus decoloratus is probably the vector of Babesia bigemina in cattle in the western highlands. Various tick species may be associated with bacterial abscesses of feet and lymph nodes in sheep and goats.