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Tropical theileriosis has long been recognized as a hindrance to the development of sound dairy industry in the Sudan and is a cause of major economic losses. Serological surveys indicated that Theileria annulata infection is widespread in the country but the disease mostly affects exotic dairy breeds and their crosses with indigenous breeds. The disease has recently been identified in Darfur and southern parts of Blue Nile State in dairy farms around large urban areas where it has never been detected before. These new introductions were accompanied by the establishment of Hyalomma anatolicum tick which is the main vector of the parasite in the Sudan. The disease is routinely diagnosed using microscopic examination of stained blood and lymph node biopsy smears. More advanced techniques are mainly used for research purposes. Tropical theileriosis in the Sudan is mainly controlled by using anti-theilerial drugs and acaricide application. It is recommended that live attenuated schizont vaccines developed from locally isolated T. annulata strains be used to control the disease. In addition, every care should be taken to prevent introduction of the disease into new areas.

Theileria-free Hyalomma anatolicum larvae were fed on a naturally infected sheep with Theileria lestoquardi. Resulting flat nymphs of the tick were able to transmit T. lestoquardi infection upon feeding to 3/3 susceptible sheep. Adults emerging from the same batch of larvae were also infective to 3/3 susceptible sheep when they had the infection during their larval feeding. Transmission of T. lestoquardi to sheep was confirmed through clinical monitoring, examination of blood and lymph node biopsy smears, serology using indirect immunoflourescent test, and molecular using polymerase chain reaction technique.

A loop-mediated isothermal amplification (LAMP) assay was developed for the diagnosis of Theileria lestoquardi infection. The primers were designed based on the clone-5 sequence of T. lestoquardi. The specificity and sensitivity of the assay were established. Analysis of the specificity showed that the selected LAMP primers amplified the target sequence from T. lestoquardi DNA successfully, while no amplification was seen with DNA from Theileria annulata, Theileria ovis, Babesia ovis, Anaplasma ovis, or ovine genomic DNA. The specificity of the LAMP product was further confirmed by restriction digestion and sequencing. The sensitivity of the LAMP assay was analyzed in comparison to PCR resulting in a detection limit of 10 fg/μl of plasmid DNA containing the clone-5 sequence. The suitability for utilizing the LAMP assay in the field for the diagnosis of T. lestoquardi infection was tested on 100 field samples collected in Sudan and compared with results obtained by PCR. The relative specificity and sensitivity of the established LAMP assay was determined to be 92.1% and 87.5%, respectively, indicating that it may be regarded as an alternative molecular diagnostic tool to PCR which could be used for epidemiological surveys on T. lestoquardi infection.

An outbreak of malignant ovine theileriosis among goats was confirmed and documented. In this outbreak, 16 out of 22 (72.7%) goats died within 4 days showing clinical signs of malignant ovine theileriosis as well as in the postmortem findings. The goats were reared in a mixed flock with sheep in Atbara Town, Northern Sudan. The infection was detected microscopically and confirmed serologically by IFA test and molecularly by PCR technique using specific primer for Theileria lestoquardi. Hyalomma anatolicum was the most prevalent (dominant) tick species found in the farm. It is recommended to undertake future research on the role of goats on the epidemiology of malignant ovine theileriosis.

An ELISA based on a recombinant Theileria annulata surface protein (TaSP) was evaluated for detection of antibodies in sera from cattle exposed to tropical theileriosis in Sudan. The reference positive samples, used in this study, were from Theileria-infected populations and consisted of 80 cattle from an endemic area in Khartoum State, with high antibody titers in the indirect fluorescent antibody test (IFAT). The reference negative samples were taken from non-exposed populations and consisted of 120 cattle maintained under strict tick control at a commercial farm in Sudan. The cut-off value determined by Two-Graph Receiver-Operating Characteristic (TG-ROC) curves was set at 31.6%, based on the positive reference samples. Further diagnostic validation was performed, which consisted of the measurement of the area under the ROC (AUC) and by valid range proportion (VRP), which was 0.97 and 0.98 for the cut-off, respectively. There were no cross-reactions with antibodies raised against Babesia spp. It is concluded that the TaSP ELISA is a useful test for the diagnosis of T. annulata infection in cattle under field conditions.