Molecular detection of tick-borne pathogens from ticks infesting domestic ruminants in Malawi

Abstract This study examined ticks infesting ruminants and tick-borne pathogens (TBPs) they are carrying using polymerase chain reaction (PCR) and sequencing analysis. A total of 964 ticks were collected from cattle (n=202), goats (n=63) and sheep (n=16) in 11 districts of Malawi. Stereomicroscope and taxonomical keys were used to morphologically identify the ticks to species level, and PCR by amplifying and sequencing 12S rRNA and cytochrome c oxidase subunit I (COI) genes were used to confirm the species. PCR assays with species-specific primers were used to screen TBPs. The identified tick species were Rhipicephalus microplus (30.5%), R. appendiculatus (23.3%), R. decoloratus (13.2%), R. evertsi(9.8%), Hyalomma rufipes (7.5%), Amblyomma variegatum (6.3%), R. sanguineus (3.6%), H. truncatum (2.8%), R. simus (2.0%), R. pravus (0.6%), and R. annulatus (0.4%). Out of the total ticks, 37.0% were infected with at least one TBP, with Theileria parva making the majority (34.7%), followed by Anaplasma marginale (17.4%), Babesia bigemina (14.9%), A. ovis (11.2%), Ehrlichia ruminantium (9.2%), T. mutans (8.4%), B. bovis (2.2%) and A. bovis (2.0%). The present study reveals critical data on the distribution of tick species infesting ruminants in Malawi and TBPs they are carrying. Moreover, this study has pioneered genetic characterization of ruminant ticks in Malawi and overall data will contribute to formulation of improved ticks and TBPs control approaches.