Tropical theileriosis caused by the apicomplexan hemoparasite Theileria annulata is a tick‐borne disease that constraints livestock production in parts of Europe, Asia and Africa. Four Hyalomma tick species transmit T. annulata in at least eight Africa countries (Mauritania, Morocco, Algeria, Tunisia, Egypt, Sudan, South Sudan and Ethiopia). The two dominant T. annulata vector ticks present in Africa, H. scupense and H. anatolicum, underlie two different patterns of transmission, which in turn greatly influence the epidemiology of tropical theileriosis. H. dromedarii and H. lusitanicum are also capable of transmitting T. annulata in North Africa, but their roles are associated with specific production systems and agro‐ecological contexts. The emergence of resistance to the most widely used theilericidal compound, buparvaquone, continues to limit the effectiveness of chemotherapy. In addition, acaricide use is increasingly becoming unsustainable. Deployable T. annulata attenuated live vaccines established from local strains in Tunisia, Sudan and Egypt are available, and recent work has indicated that these vaccines can be protective under conditions of natural transmission. However, vaccination programmes may vary over space and time due to differences in the prevalence of disease amongst cattle populations, as well seasonal variation in vector activity. We review recent descriptive and analytical surveys on the epidemiology of T. annulata infection with reference to (a) demographic aspects such as breeds and ages of cattle herds previously exposed to distinct T. annulata infection pressures and (b) seasonal dynamics of tick activity and disease transmission. We then discuss how the wider endemic patterns that we delineate can underpin the development and execution of future vaccination programmes. We also outline options for integrated control measures targeting tick vectors and husbandry practices.
The purpose of this study was to estimate the prevalence of equine piroplasmosis in Sudan. The presence of antibodies against Babesia caballi and Theileria equi was determined in serum samples obtained from 158 horses raised in different locations in Sudan by enzyme-linked immunosorbent assay (ELISA). The B. caballi 48-kDa and the T. equi EMA-2 purified recombinant proteins were used as antigens in the ELISA test. Results showed that seven (4.4%) were positive for B. caballi and 80 (63.5%) were positive for T. equi. Polymerase chain reaction (PCR) assays have been applied using primers targeting the B. caballi 48-kDa merozoite antigen, the T. equi SSUrRNA and the T. equi EMA-1 genes. PCR performed on 131 blood spots in filter paper revealed that 33 (25.2%) samples were positive for T. equi but no positives were found for B. caballi. It is concluded that equine piroplasmosis is endemic in the country. This is the first study on serological and molecular epidemiological diagnosis on equine piroplasmosis in Sudan.
Monthly total body tick collections from 13-20 camels were conducted for 2 consecutive years (2000-2001) in Northern Sudan. Tick populations were correlated with locality, season, predeliction site, sex and coat colour. Hyalomma dromedarii was found to be the predominant (89 %) tick species infesting the camels. Other tick species found in very low numbers were Hyalomma impeltatum (7.7 %), Hy alomma anatolicum anatolicum (3.3 %), Hyalomma truncatum (0.29 %), Hyalomma marginatum rufipes (0.25 %), Rhipicephalus praetextatus (0.30 %) and Rhipicephalus sanguineus group (0.09 %). Nymphs of the genus Hyalomma were collected in significant numbers. Adult ticks significantly preferred to attach to the lower parts of the camel's body for feeding while the nymphs preferred the back of the animal.
, the geographical distribution of ticks on cattle in the Sudan was determined. Seventeen locations were surveyed from Northern, Central, Eastern, Western, Blue Nile and White Nile Provinces. Total body collections of ticks were made from 20 cattle at each location. Four tick genera and 11 species were identified. The tick species collected included Amblyomma lepidum, Amblyomma variegatum, Boophilus decoloratus, Hyalomma anatolicum anatolicum, Hyalomma dromedarii, Hyalomma impeltatum, Hyalomma marginatum rufipes, Hyalomma truncatum, Rhipicephalus evertsi evertsi, Rhipicephalus sanguineus group and Rhipicephalus simus simus. Major ecological changes have occurred due to extensive animal movement, deforestation, desertification and establishment of large mechanized agricultural schemes. These factors have certainly affected the distribution of ticks and tick-borne diseases in the Sudan. The absence of A. variegatum and A. lepidum in northern Sudan was not surprising, since these tick species are known to survive in humid areas and not in the desert and semi-desert areas of northern Sudan. The absence of B. annulatus in northern and central Sudan is in accordance with the finding that this tick species is restricted to the southern parts of the central Sudan. The presence of H. anatolicum anatolicum in Um Benin in relatively high abundance is an interesting finding. The present finding may indicate that the southern limit of this species has changed and moved southwards to latitude 13° N. It is concluded that major changes in tick distribution have taken place in the Sudan.
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