The persistence of sleeping sickness (human African trypanosomiasis) in some areas of south-eastern Uganda has necessitated further investigations, focusing mainly on domestic animals as reservoirs of this disease in three agro-ecological zones. The inter-zone differences in the prevalences of trypanosome infection among cattle (P < 0.001) and pigs (P < 0.001) were significant. Overall, 5.0% of the cattle, 13.9% of the pigs and 0.4% of the small ruminants investigated were found to be infected with parasites of the Trypanosoma brucei subgroup. The results of blood incubation infectivity tests (BIIT) indicated that all of the T. brucei-subgroup isolates from cattle in Kamuli district (zone I) were human-serum-sensitive. Of the zone-I pigs found infected, however, almost all (82.5%) were considered to be infected with T. brucei and many (30.2%) carried human-serum-resistant T. brucei. Pig-tsetse-human appears to be a major transmission cycle in zone I. In Mukono district (zone II), 10.5% and 26.1% of the T. brucei isolates from cattle and pigs, respectively, were human-serum-resistant, indicating that cattle-tsetse-human and pig-tsetse-human are major transmission cycles in zone II. In Tororo district (zone III), 47.3% of the T. brucei isolates from cattle were human-serum-resistant but there were no T. brucei isolates from pigs, indicating that cattle-tsetse-human is the major transmission cycle. Interestingly, as the only T. brucei isolate from sheep in zone III was human-serum-resistant, there may also be a sheep-tsetse-human cycle. In south-eastern Uganda, control efforts must be designed to eliminate the parasites not only from cattle but also from pigs and small ruminants.

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Tick abundance and seroconversion rates of 640 indigenous cattle in a mixed crop-livestock system in Uganda were investigated in a 14 months longitudinal study. Up to 100% of the cattle in Buyimini, Kubo, Nanjeho, Ojilai and Sitengo villages (high tick challenge zone) were consistently infested with Rhipicephalus appendiculatus, whereas on average 50% of the cattle in Bunghaji, Hitunga and Magoje villages (low tick challenge zone) were inconsistently infested. Likewise, up to 50% of the cattle in Buyimini, Kubo, Nanjeho, Ojilai and Sitengo villages were consistently infested with R. (Boophilus) decoloratus ticks, while on average 30% of the cattle in Bunghaji, Hitunga and Magoje were inconsistently infested. Seroconversion rates of cattle to Anaplasma marginale infection under low tick challenge were higher than those under high tick challenge, but the reverse was true for Babesia bigemina infection. For Theileria parva infection, seroconversion rates of cattle older than 6 months under low tick challenge were significantly higher than those under high tick challenge (P < 0.05). However, the likelihood of occurrence of theileriosis cases among calves (0-6 m) under high tick challenge was 6 times (Odds ratio = 5.82 [1.30-36.37]) higher than under low tick challenge. The high density of anti-tick plants Lantana camara and Ocimum suave that were widespread in villages with low tick challenge, among other factors, was probably the cause for unfavourable tick survival.

Uganda had an unusually large number of foot-and-mouth disease (FMD) outbreaks in 2006, and all clinical reports were in cattle. A serological investigation was carried out to confirm circulating antibodies against foot-and-mouth disease virus (FMDV) by ELISA for antibodies against non-structural proteins and structural proteins. Three hundred and forty-nine cattle sera were collected from seven districts in Uganda, and 65% of these were found positive for antibodies against the non-structural proteins of FMDV. A subset of these samples were analysed for serotype specificity of the identified antibodies. High prevalences of antibodies against non-structural proteins and structural proteins of FMDV serotype O were demonstrated in herds with typical visible clinical signs of FMD, while prevalences were low in herds without clinical signs of FMD. Antibody titres were higher against serotype O than against serotypes SAT 1, SAT 2 and SAT 3 in the sera investigated for serotype-specific antibodies. Only FMDV serotype O virus was isolated from one probang sample. This study shows that the majority of the FMD outbreaks in 2006 in the region studied were caused by FMDV serotype O; however, there was also evidence of antibodies to both SAT 1 and SAT 3 in one outbreak in a herd inside Queen Elizabeth national park area.