Abstract:
BACKGROUND : Rhipicephalus microplus, an invasive tick species of Asian origin and the main vector of Babesia species,
is considered one of the most widespread ectoparasites of livestock. The tick has spread from its native habitats
on translocated livestock to large parts of the tropical world, where it has replaced some of the local populations of
Rhipicephalus decoloratus ticks. Although the tick was reported in Uganda 70 years ago, it has not been found in any
subsequent surveys. This study was carried out to update the national tick species distribution on livestock in Uganda
as a basis for tick and tick-borne disease control, with particular reference to R. microplus.
METHODS : The study was carried out in Kadungulu, Serere district, south-eastern Uganda, which is dominated by
small scale livestock producers. All the ticks collected from 240 cattle from six villages were identified microscopically.
Five R. microplus specimens were further processed for phylogenetic analysis and species confirmation.
RESULTS : The predominant tick species found on cattle was Rhipicephalus appendiculatus (86.9 %; n = 16,509). Other
species found were Amblyomma variegatum (7.2 %; n = 1377), Rhipicephalus evertsi (2.3 %; n = 434) and R. microplus
(3.6 %; n = 687). Phylogenetic analysis of the 12S rRNA, 16S rRNA and ITS2 gene sequences of R. microplus confirmed
the morphological identification.
CONCLUSIONS : It is concluded that R. microplus has replaced R. decoloratus in the sampled villages in Kadungulu subcounty,
since the latter was not any longer found in this area. There is currently no livestock movement policy in force
in Uganda, which could possibly limit the further spread of R. microplus ticks. Future surveys, but also retrospective
surveys of museum specimens, will reveal the extent of distribution of R. microplus in Uganda and also for how long
this tick has been present on livestock without being noticed.
