The high burden of adult ticks on cattle in Serere district, south-eastern Uganda confirms that ticks and associated diseases (anaplasmosis, babesiosis, theileriosis and heartwater) constitute a major constraint to livestock production in this region [23, 24]. It has been reported previously that R. appendiculatus, vector of Theileria parva, is the predominant tick species in Serere district [24–27]. Besides the discovery of R. microplus and the complete absence of R. decoloratus, the other tick species were the same as reported before in south-eastern Uganda [24–27]. However, the Ugandan tick population structure varies greatly between the different regions of the country, due to variation in microclimatic conditions [23, 24, 28]. For example, Amblyomma lepidum, Hyalomma truncatum, Amblyomma gemma and Rhipicephalus pulchellus thrive under the arid conditions of north-eastern Uganda [28, 29], and were therefore not found in this less arid study area.
In “The Ixodid Ticks of Uganda”,by Matthysse and Colbo published in 1987  the authors report a systematic survey of ticks on livestock conducted between 1965 and 1966, wherein not a single R.microplus tick was found. Interestingly, before this survey, R.microplus was reported from Uganda by S. G.Wilson, who conducted a limited survey on cattle along the borders of Karamoja district, closer to the border with Kenya . It is unlikely that R.microplus would have been missed during the nation-wide extensive survey conducted by Matthysse and Colbo, now more than 50 years ago. Interestingly, our results clearly indicate that R.microplus has been overlooked for years, since it takes years to replace an indigenous population of R.decoloratus ticks.
R. microplus was introduced into West, South and East Africa on cattle imported from Asia and Latin America, where R. microplus is well established [2–4, 11]. Within the East-African region, R. microplus has been confirmed in Tanzania and more recently in South-Sudan [13, 14]. Given the invasiveness of this tick species, exacerbated by poor animal movement control and communal grazing practices within the East African region, it is likely that populations of R. microplus are now well established in Uganda.
Molecular phylogenetic analysis may be a useful tool to discern possible relationships between isolates collected from different geographical regions. In this study, the 12S rRNA and ITS2 regions of the tick isolates from Uganda were identical to those previously isolated from Taiwan, Mozambique, Nigeria, USA and South Africa. It is therefore plausible that the R. microplus ticks collected from cattle in south-eastern Uganda were introduced on livestock imported from the southern parts of Africa. In the past 10 - 15 years, there have been significant importations of dairy cattle into Uganda from South Africa to improve the Ugandan dairy herd through cross-breeding . This requires more extensive genotyping of ticks collected from different geographical areas [25, 31].
Unprecedented levels ofacaricide resistant tick populations have recently been reported in Uganda . The cause of this problem is due to farmer-related factors [acaricide overuse and misuse] potentiated by lack of national acaricide and animal movement control policies [31–33]. Under such favourable conditions, R. microplus tick populations are known to rapidly become acaricide resistant as a result of target specific mutations and metabolic adaptations . The introduction of R. microplus into Uganda is likely to exacerbate the already existing problem of ticks and tick-borne diseases in three ways. These include; (i) complete replacement of R.decoloratus by R. microplus, resulting ina national and probably regional upsurge of R. microplus populations, (ii) emergence of acaricide resistant R. microplus populations, and (iii) a proportional increase of bovine babesiosis given that R. microplus is an efficient vector of B. bovis [11, 25, 30]. Unless effective national acaricide and animal movement control policies are instituted, the Ugandan livestock sector will suffer severe losses due to the direct effects of R. microplus infestation and bovine babesiosis.