Aim: This study was conducted in dairy cattle in Nyala, South Darfur State, during the period from June to September 2015, to study the prevalence of bovine tropical theileriosis.

Materials and Methods: Apparently, healthy cattle of different age groups, different breeds, and from both sexes were randomly selected from seven locations. Three age groups of cattle were selected, group one <1 year old, group two 1-3 years old, and group three older than 3 years. These cattle were indigenous and cross (Friesian X zebu). A total of 150 blood samples were collected for blood smears, blood in EDTA tubes, and serum samples as well as ticks infesting cattle. Three diagnostic techniques were used such as blood smear, indirect fluorescent antibody test (IFAT), and polymerase chain reaction (PCR).

Results: Of 150 samples, 11 (7.3%, 95% confidence interval [CI]: 9.1-5.5) were positive for Theileria spp. piroplasms in the blood smears, 70 (46.7%, 95% CI: 35.7-57.7) were positive for Theileria annulata antibodies in the IFAT, and of 100 samples, 39 (39%, 95% CI: 46.6-31.4) were positive for T. annulata using PCR. The prevalence of T. annulata was higher in indigenous breed than cross cattle by the three diagnostic techniques. The highest prevalence of T. annulata was recorded among cattle older than 3 years old. There were three genera and ten species of ticks found feeding on cattle. These were Rhipicephalus evertsi evertsi, Rhipicephalus decoloratus, Rhipicephalus annulatus, Hyalomma dromedrii, Hyalomma impeltatum, Hyalomma rufipes, Hyalomma anatolicum, Hyalomma truncatum, Amblyomma variegatum, and Amblyomma lepidum.

Conclusion: The study concluded that tropical theileriosis is prevalent among dairy cattle in Nyala. H. anatolicum was found in very low numbers, suggesting other ticks may play a role in the transmission of the disease. Molecular characterization of T. annulata is recommended for accurate mapping of the disease and evaluates the magnitude problem of tropical theileriosis in South Darfur region.

Keywords: indirect fluorescent antibody test, polymerase chain reaction, South Darfur, Sudan, Theileria annulata, ticks.

1. FAO. (1983) Ticks and Tick-borne Diseases Control. The Sudan: Studies on Important Tick-borne Diseases of Cattle. Technical Report No. 2. AG: GCP/SUD/024/DEN/Rome.

2. Hassan, S.M. and Salih, D.A. (2013) Factors affecting geographic distribution of livestock ticks in the Sudan. Sokoto J. Vet. Sci., 11(2): 1-9.

3. Uilenberg, G., Estrada-Pe-a, A. and Thal, J. (2013) Ticks of the central African republic. Exp. Appl. Acarol., 60(1): 1-40. [Crossref]

4. Tretina, K., Gotia, H.T., Mann, D.J. and Silva, J.C. (2015) Theileria-transformed bovine leukocytes have cancer hallmarks. Trends Parasitol., 31(7): 306-314. [Crossref] [PubMed]

5. Dolan, T.T. (1989) Theileriosis: A comprehensive review. Rev. Sci. Tech. Off. Int. Epiz., 8: 11-36. [Crossref]

6. Salih, D.A., Hassan, S.M. and El Hussein, A.M. (2007) Comparisons among two serological tests and microscopic examination for the detection of Theileria annulata in cattle in Northern Sudan. Prev. Vet. Med., 18: 323-326. [Crossref] [PubMed]

7. Latif, A.A. (1994) Economic losses in exotic breeds of cattle due to theileriosis in the Sudan. In: Attelmanan, A.M. and Kheir, S.M., editors. Tropical Theileriosis in the Sudan. Proceedings of a workshop held at the Sudan Veterinary Association Residence, Khartoum, Sudan. p4-5.

8. Anon. (2012) Report of Sudan Federal Ministry of Animal Resources and Fisheries. Sudan Government.

9. Anon. (2004) Ministry of animal resources and fisheries. Sudan Government. Statistical Bulletin for Animal Resources, Sudan. Issue No. 14.

10. Jaafer, B.B.M., Hassan, S.M., Limia, M.E.H., Salih, D.A. (2015) Prevalence of tropical theileriosis in Nyala dairy farms in South Darfur State, Sudan. Sudan J. Vet. Res., 30: 7-12.

11. FAO. (1984) Ticks and Tick-borne Diseases Control. A Practical Field Manual. Vol. 1, 2, 11. Food and Agricultural Organization of the United Nations, Rome. p621.

12. d'Oliveira, C., van der Weide, M., Habela, M.A., Jacquiet, P. and Jongejan, F. (1995) Detection of Theileria annulata in the blood samples of carrier cattle by PCR. J. Clin. Microbiol., 13: 2665-2669.

13. Hoogstraal, H. (1956) African Ixodoidea. I. Ticks of the Sudan (With special Reference to Equatoria Province and with Preliminary Reviews of the Genera Boophilus, Margaropus and Hyalomma). Department of the Navy, Bureau of the Medicine and Surgery, Washington, D.C., U.S.A. p1101.

14. Walker, A.R., Bouattour, A., Camicas, J.L., Estrada-Pena, A., Horak, I.G., Latif, A.A., Pegram, R.G. and Preston, P.M. (2003) Ticks of domestic animals in Africa: A guide of identification of species. Biosci. Rep. Edinb., 44: 221.

15. Gamal, A. and EL Hussein, A.M. (2003) Economic impact of theileriosis on a dairy farm in river Nile State. Sudan J. Vet. Sci. Anim. Husb., 42(1,2): 268-273.

16. Abdallah, M.M. and Hassan, S.M. (2010) Current status of distribution and population dynamics of ticks (Acari: Ixodidae) infesting cattle in South Darfur State, Sudan. U. K. J. Vet. Sci. Anim. Prod., 1(2): 76-97.

17. Salih, D.A. (2003) Epidemiological Studies on Tropical Theileriosis (Theileria annulata infection of cattle) in the Sudan. M.V.Sc. Thesis. U. K.

18. Abdallah, M.E.A. (2005) Prevalence of Blood Parasite Commestronglyrs in Domestic Animals in South Darfur State of Sudan. M.V.Sc. Thesis. U. K.

19. Ali, A.M. (2005) Molecular Characterization and Phylogenetic Analysis of Theileria annulata in dairy cattle in Khartoum State, Sudan. M.V.Sc. Thesis U. K.

20. Salih, D.A., Hassan, S.M., Bakheit, M., El Hussein, A.M., Jongejan, F. and Ahmed, J. (2005) Application of the Indirect TaSP Enzyme-linked Immunosorbent Assay for Diagnosis of Theileria annulata Infection in Cattle. Proceedings of the 5th International Conference on Ticks and Tick Borne Diseases (TTP5), 29th August - 2nd September 2005 University of Neuchatel, Switzerland. pp163-166.

21. Ali, A.M., Bakheit, M.A., Mukhtar, M.M., Hassan, S.M., Ahmed, J.S. and Seitzer, U. (2006). Epidemiology of Theileria annulata infection of dairy cattle in Sudan using molecular techniques. Ann. N. Y. Acad. Sci., 1081: 471-472. [Crossref] [PubMed]

22. Osman, A.M. (1976) A review on tick-borne diseases in the Sudan and their control. Bull. Off. Int. Epiz., 86: 81-87.

23. Bakheit, M.A. and Latif, A.A. (2002). The innate resistance of Kenana cattle to tropical theileriosis (Theileria annulata infection) in Sudan. Ann. N. Y. Acad. Sci., 969: 159-163. [Crossref] [PubMed]

24. El Hussein, A.M., Hassan, S.M. and Salih, D.A. (2012) Current situation of tropical theileriosis in the Sudan. Parasitol. Res., 111(2): 503-508. [Crossref] [PubMed]

25. Al-Fahdi, A., Alqamashoui, B., Al-Hamidhi, S., Kose, O., Tageldin, M.H., Bobade, P., Johnson, E.H., Hussain, A.R., Karagenc, T., Tait, A., Shiels, B., Bilgic, H.B. and Babiker, H. (2017) Molecular surveillance of Theileria parasites of livestock in Oman. Ticks Tick Borne Dis., 8(5):741-748. [Crossref] [PubMed]