Molecular survey for spotted fever group rickettsiae in ticks from Morocco

Abstract

The number of representatives of the genus Rickettsia and the number of newly described rickettsioses have increased in recent decades as a result of improved cell culture isolation techniques and of the extensive use of bacterial detection and identification based on molecular biology techniques [1]. Comparison of the sequences of PCR-amplified fragments of rickettsial genes has become a reliable method for the identification of rickettsiae in arthropods, including ticks. As a consequence, from 1984 to 2008, more than a dozen rickettsial species or subspecies were identified as emerging agents of tickborne rickettsioses throughout the world. As an illustration, in Morocco five rickettsial species, all human pathogens, have been identified from ticks in the Taza region, including: Rickettsia massiliae in Rhipicephalus sanguineus, R. slovaca and R. raoultii in Dermacentor marginatus, R. aeschlimannii in Hyalomma marginatum, and finally R. monacensis and R. helvetica in Ixodes ricinus [2]. We present here the detection and characterisation of rickettsiae in more ticks collected in different areas of Morocco using PCR and sequence analysis of amplified products.