Ticks and tick-borne haemoparasites from domestic animals in Lesotho
Ticks are amongst groups of ecto-parasites that feed on blood and transmit pathogens including protozoan parasites, bacteria, viruses which are disease causing agents in animals and humans. Lesotho is a landlocked country surrounded by the Republic of South Africa and lacks documented scientific information on ticks infesting domestic animals and the tick-borne haemoprotozoa that they harbour. The aim of this study was therefore to document information of ticks infesting domestic animals in Lesotho as well as detecting haemoparasites they are harbouring. A total of 1654 tick specimens were collected from cattle, sheep, goats, horses and dogs in five districts of Lesotho, namely Leribe, Maseru, Qacha’s Neck, Mafeteng and Butha-Buthe. Ticks were identified on the basis of their morphology using microscopy and tick guides. The tick specimens were submitted to the tick museum of the ARC-Ondersterpoort Veterinary Research - where species identification was verified and voucher specimens were issued. Successfully extracted tick DNA samples were used for amplification of cytochrome oxidase1 (COI) and the internal transcribed spacer 2 (ITS2) genes whereby PCR positive amplicons were purified, sequenced and analysed for genetic diversity and phylogenetics using MEGA 6.0 software. Out of 1654 specimens, 132 (8%) tick samples were obtained from Leribe district with 53 from cattle, 51 from sheep and 28 from unrecorded hosts. In Maseru district 322 (19%) tick specimens were collected, with 268 from cattle and 54 from unrecorded hosts. In Qacha’s Neck district 641 (39%) tick samples were collected, with 290 from cattle, 36 from dogs, 87 from horses, 2 from sheep and 226 from unrecorded hosts. In Mafeteng district all 75 (5%) tick samples were collected from cattle. Whilst in Butha-Buthe district a total of 484 (29%) tick samples were collected, with 422 from cattle, 30 from sheep, 28 from goats and 4 from unrecorded hosts. Four Ixodidae ticks were identified namely; Rhipicephalus evertsi evertsi, R. microplus, Hyalomma rufipes and H. truncatum, and one Argasidae tick, Otobius megnini. In Leribe district, there was a total of 93 (70%) of R. e. evertsi and 39 (30%) of R. microplus, in Maseru district, 181 (56%) of R. microplus,138 (43%) of R. e. evertsi and 3 (1%) of O. megnini; in Qacha’s Neck district, 351 (55%) of R. e. evertsi, 215 (34%) of O. megnini, 39 (6%) of R. microplus, 26 (4%) of H. rufipes and 10 (2%) of H. truncatum; and in Mafeteng district, 28 (37%) of O. megnini, 24 (32%) of R. e. evertsi and 13 (17%) of R. microplus. From the COI multiple alignment of soft tick sequences, the average p distance (pairwise distance) value for the intraspecific divergence of soft ticks was 0.4% with an average number of nucleotide differences (nt) of 3 and an average p distance of 15.2% (95nt) the for the interspecific divergence. Both COI gene maximum likelihood (ML) and neighbour-joining (NJ) phylogenetic trees of soft ticks correctly clustered Lesotho O. megnini in its respective species specific O. megnini cluster together with other O. megnini species from Madagascar and South Africa. Multiple alignments of COI sequences of hard ticks, showed an average p distance of 2.5% with an average number of nucleotide differences of 11 for intraspecific divergence of R. e. evertsi and 0.2% (1nt) for intraspecific divergence of H. rufipes. Multiple alignments of ITS2 for hard ticks showed an average p-distance of 0.8% (5 nt) for intraspecific divergence of R. microplus, 0.1% (9nt) for intraspecific divergence of R. e. evertsi A and D and 6.3% (42 nt) for interspecific divergence of R. microplus and R. e. evertsi. The COI ML and NJ phylogenetic trees grouped R. e. evertsi A and D from Lesotho in the R. e. evertsi species sub-cluster within the genus Rhipicephalus cluster. The Lesotho H. rufipes tick species also appeared in the genus Hyalomma cluster. The ITS2 gene ML and NJ phylogenetic trees showed that both R. microplus and R. e. evertsi belonged in their respective species specific clusters. In a nutshell, both COI and ITS2 gene sequence analyses have supplemented the morphological identification of Lesotho tick species collected in this study. A total of 164 tick DNA pools from cattle were screened for the presence of B. bigemina and B. bovis DNA by PCR. None of the tested samples were positive for the presence B. bigemina. A total of 13 (7.9%) samples were PCR positive for the presence of B. bovis DNA for which 5 samples were represented by R. microplus species and the other eight were R. e. evertsi from various villages in Butha-Buthe district. Four horse DNA samples collected from Maseru district tested negative for both B. caballi and T. equi. Twenty two samples from goats (n = 6) and sheep (n = 16) which were screened for the presence of Babesia ovis, B. motasi, Theileria ovis and T. lestoquardi tested negative for T. ovis and T. lestoquardi. One R. e. evertsi DNA sample from a goat and two R. e. evertsi samples from sheep of Qalo village tested positive (13.6%) for B. ovis. This study has documented tick species infesting domestic animals in four Lesotho districts using both morphological and molecular techniques. Furthermore, the study has also documented the haemoparasites harboured by these ticks. This study is the first of it’s kind in Lesotho and will hopefully contribute in formulation of control methods for both vectors and tick-borne parasitic diseases as well as open doors for detailed epidemiological studies of ticks and tick-borne diseases in domestic animals in Lesotho.