Abstract
Rhipicephalus (Boophilus) microplus (“Cattle tick”) is an important vector of livestockdiseases in (sub)-tropical regions, resistant to common acaricides. In 2013, 234 feeding ticks were collected in Ogun State in south-western Nigeria from cattle herds (121 cows) and the vegetation (n=15). Molecular species identification based on 16S rRNA revealed that 42.3% of feeding ticks were R. microplus (n=99), 41% Amblyomma variegatum (n=96) and less than 1% R. annulatus and R. geigyi. These results were confirmed using Cytochrome C oxidase I sequencing. 15.8% ticks (n=37) that clustered separately (cluster I) could not be identified as a result of missing reference sequences. R. microplus was found (for the first time in Nigeria) in 17 of 21 herds (80.9%). Cluster 1 ticks were found in about half of the herds (47.6%). The majority of ticks collected from the vegetation were R. microplus (46.7%, n=7). Only immature R. microplus were collected from the vegetation (85.7%, larvae; 14% nymphs). Verifiable evidence suggests that R. microplus has successfully present established a viable population in south-western Nigeria probably engendered by uncontrolled trade and movement of livestock across Borders. The discovery of this species in Nigeria must have occurred only recently, as R. microplus was not priorly found the same area in 2009 or in central Nigeria in 2010. The displacement of indigenous tick species with no vector competence for B. bovis (e.g. R. decoloratus, R. evertsi) by the competent vector species R. microplus leads to an increased risk of infection for cattle.

Key words: Nigeria; Rhipicephalus microplus; cattle tick; Amblyomma variegatum, cattle