Unveiling the tick-borne pathogens from domestic ruminant ticks in Malawi and the emergence of the brown ear tick in the southern region: implications for East Coast fever control

Ticks transmit a wide range of protozoan, bacterial, and viral pathogens to humans and animals globally. However, data on ticks infesting domestic ruminants and the pathogens they carry are scarce in Malawi. In this study, we examined ticks collected from domestic ruminants and screened them for selected veterinary and medically important protozoan and bacterial pathogens. A total of 964 ticks were collected from 202 cattle, 63 goats, and 16 sheep across eleven districts in Malawi. Ticks were morphologically identified to species level using taxonomical keys, with molecular confirmation by PCR amplification and sequencing of the 12S ribosomal RNA (12S rDNA) and cytochrome c oxidase subunit I (COI) genes. Tick DNA was further screened for tick-borne pathogens using species-specific PCR assays. Identified tick species included Rhipicephalus microplus (30.5%), Rhipicephalus appendiculatus (23.3%), Rhipicephalus decoloratus (13.2%), Rhipicephalus evertsi (9.8%), Hyalomma rufipes (7.5%), Amblyomma variegatum (6.3%), Rhipicephalus sanguineus sensu lato (tropical lineage) (3.6%), Hyalomma truncatum (2.8%), Rhipicephalus simus (2.0%), Rhipicephalus pravus (0.6%), and Rhipicephalus annulatus (0.4%). Overall, 37.0% of ticks carried at least one tick-borne pathogen, with Theileria parva being the most prevalent (34.7%), followed by Anaplasma marginale (17.4%), Babesia bigemina (14.9%), Anaplasma ovis (11.2%), Ehrlichia ruminantium (9.2%), Theileria mutans (8.4%), Babesia bovis (2.2%), and Anaplasma bovis (2.0%). This study provides the first molecular identification of ticks infesting domestic ruminants in Malawi and documents associated tick-borne pathogens. Notably, Rhipicephalus appendiculatus was identified for the first time in southern Malawi, refining current understanding of East Coast fever epidemiology and highlighting the need for updated surveillance approaches.