A mathematical model that describes the transmission dynamics of Theileria annulata is proposed that consists of 2 host components: the Hyalomma tick population and a compartmental model of T. annulata infection in the cattle population. The model was parameterized using data describing tick infestation and the infection status of cattle in Turkey from 2006 to 2008. The tick attachment rates are highly seasonal and because of the temporal separation of infectious and susceptible ticks virtually all ticks are infected by carrier cattle, so that annual peaks of disease in cattle do not impact on infection in the Hyalomma tick population. The impact of intervention measures that target the tick population both on the host and in the environment and their impact on the transmission of T. annulata were investigated. Interventions that have a limited ‘one-off’ impact and interventions that have a more permanent impact were both considered. The results from the model show the importance of targeting ticks during the period when they have left their first host as nymphs but have yet to feed on their second host.

Descriptions of Babesia occultans have previously been restricted to sub-Saharan Africa. Here, we report the finding, for the first time, of this low or non-pathogenic bovine Babesia species in Tunisia, northern Africa. B. occultans DNA was detected by molecular methods in Hyalomma marginatum unfed ticks collected in 3 bioclimatic regions of Tunisia. The near-full-length 18S rRNA gene was sequenced and compared with related sequences retrieved from GenBank. Phylogenetic analysis indicated that other sequences deposited as Babesia sp. could also correspond to B. occultans, suggesting that this species may have a wide distribution in Mediterranean and Asiatic regions, and not only in sub-Saharan Africa as previously described. A B. occultans-specific Reverse Line Blot (RLB) oligonucleotide probe was designed for future epidemiological studies that would help to clarify this possibility.

Immature stages of Amblyomma lepidum were fed on rabbit ears and the adult ones on calf ear. There was a three-host type of development during an average period of 160.5 days. The mean larval feeding period was 5 days, 7 days for nymphs and 14.5 for females. At 27 ± 1°C and 100% r.h. the engorged larvae required 21 days for moulting and nymphs took 22 days to develop to adults. The pre-oviposition period was 14.2 days and the oviposition period was 21.4 days during which a mean number of 7564.6 eggs were laid. Hyalomma anatolicum anatolicum and Rhipicephalus evertsi evertsi were fed on rabbit ears. The larvae, nymphs and adults of Hyalomma ticks fed for 4.6 and 8.5 days, respectively. The larvae and nymphs of R. e. evertsi fed sequentially on the same host for 14 days while the females took 7.5 days to engorge. At 27 ± 1°C and 75–80% r.h. the engorged larvae and nymphs H. a. anatolicum moulted after a further 8.5 and 13 days respectively. The engorged nymphs of R. e. evertsi at 27 ± 1°C and 75–80% r.h. moulted 14.5 days after dropping off the host. At 27 ± 1°C and 75–80% r.h. the preoviposition and oviposition periods of H. a. anatolicum were 4.6 and 20.8 days, while those of R. e. evertsi were 5.4 and 14 days. The average number of eggs laid per female under the same conditions (27 ± 1°C and 75–80% r.h.), was 4684.6 for H. a. anatolicum and 3392 for R. e. evertsi.

A brief description is given of the tick species, their distribution, the diseases they transmit and the control methods used in Botswana. Most of the country is unsuitable for the permanent establishment of the more important ticks so that the diseases they transmit are confined mainly to the eastern part of the country. Among the tick-borne diseases, cowdriosis is the most important although sporadic cases of anaplasmosis and babesiosis also occur. Canine erhlichiosis is established in the urban areas. The presence of theileriosis as a clinical disease has yet to confirmed in Botswana.