An abattoir survey of contagious bovine pleuropneumonia lesions in slaughtered cattle in selected districts in Northern Tanzania.

OBJECTIVE: To establish and estimate incidence of contagious bovine pleuropneumonia (CBPP), using abattoir survey as a diagnostic tool in slaughtered cattle in Northern Tanzania. METHODS: A total of 4 460 cattle were slaughtered in five abattoirs in 3 northern zone regions (Arusha, Kilimanjaro and Tanga) during the period of January to May 2004. They were examined ante-mortem for 'pneumonia signs', and 'characteristic contagious bovine pleuropneumonia (CBPP) lung lesions'. RESULTS: Forty-one (0.91%) of the slaughtered cattle, the majority of which were Tanzania short horn zebu, had gross lung lesions suggestive of CBPP. The prevalence of lesions was significantly (P<0.05) higher in Karatu abattoir compared to others. No animal was detected to have lesion in Bomang' ombe abattoir. The most observed pneumonic signs included labored breathing (90%), dry cough (57%) and mucopurulent nasal discharge (47%). The gross characteristic CBPP pathological lesion, frequently encountered was left lung lesion (47%), pinkish lung (71%) and pleural adhesion (98%). Epidemiological reports show that the CBPP reported outbreaks increased from 19 in 2002, 65 in 2003 and 18 in 2004 (January-March). The corresponding number of reported deaths increased from 137 in 2002, 269 in 2003 and 77 in 2004 (January-March). CONCLUSIONS: It's concluded from this study that CBPP is a problem in spite of the extensive awareness and vaccination campaigns. Nevertheless, a continued surveillance programme including routine checks of all cattle carcasses at the abattoir and subsequent epidemiological investigation of suspected cases are recommended.

The incursion, persistence and spread of peste des petits ruminants in Tanzania: epidemiological patterns and predictions.

Peste des petits ruminants virus, which causes a severe disease in sheep and goats, has only recently been officially declared to be present in Tanzania. An epidemiological study was carried out between September 2008 and October 2010 to investigate the incursion, persistence and spread of the virus in Tanzania. The investigation involved serosurveillance, outbreak investigation and computation of epidemiological indices such as the effective reproductive number, persistence and the threshold level for vaccination. Field and molecular epidemiological techniques were applied to isolate, characterise and trace the origin of the virus in Tanzania. A total of 2182 serum samples from goats and 1296 from sheep from 79 villages across 12 districts were investigated. Village-level prevalence of infection was variable (0.00% ­ 88.00%) and was higher in pastoral than in agro-pastoral villages. The overall antibody response to the virus was 22.10% (CI95% = 20.72% ­ 23.48%). About 68.00% and 73.00% of seropositive goats and sheep, respectively, did not show clinical signs. The proportion of seropositive animals differed significantly (p ≤ 0.001) between age groups, sex and farming practices. Real-time polymerase chain reaction results showed that the isolated strains belong to lineage III, whose origin is in East Africa and the Middle East. This indicates that one of the northern neighbouring countries is most likely the source of infection. The computed overall effective reproductive number, the threshold level of vaccination necessary to eradicate the disease and persistence were 4.75% and 98.00%, respectively. These estimates indicate that achieving elimination of the peste des petits ruminants virus from pastoral flocks will require significant effort and development of highly effective intervention tools.

A longitudinal study on morbidity and mortality in youngstock smallholder dairy cattle with special reference to tick borne infections in Tanga region, Tanzania.

The incidence and potential determinants of tick borne diseases (TBDs) were estimated in a longitudinal study that was conducted in cohorts of youngstock animals of less than 3 years kept in smallholder dairy farms in Tanga region, Tanzania. A combination of serological tests, blood and lymph node smears were used as diagnostic tests for TBDs during the study. A total number of 549 youngstock were followed for a total of 532.2 animal years from August 1999 to July 2001. Overall morbidity and mortality rates (due to all causes) were 8.26 and 12.0 per 100 animals year at risk, respectively. Of the total deaths, 56% were attributed to TBDs (37.5%-East Coast fever (ECF) and 18%-anaplasmosis). Specific morbidity and mortality rates for ECF were estimated to be 3.57 and 4.51 per 100 animals year risk, respectively, and for anaplasmosis 2.21 and 2.25 per 100 animals year risk, respectively. Analysis of survival times to death indicated that calves < 6 months of age and those out on pasture had higher death rates than older calves and those kept under zero-grazing systems (relative risk [RR] 3.80, P = 0.001 for pasture-grazed calves). There was no mortality or morbidity arising specifically from cowdriosis (heartwater) or babesiosis during the whole period of monitoring. The study revealed that most farms were applying under strength acaricide and using acaricides at irregular intervals. It is concluded that TBDs namely ECF and anaplasmosis are important diseases in this farming system and reducing morbidity and mortality in smallholder dairy farms in Tanga region is an achievable goal. Both farmers and extension services should target at risk calves with the provision of both strict tick control and optimal husbandry management practices.

A comparison of seroprevalence and risk factors for Theileria parva and T. mutans in smallholder dairy cattle in the Tanga and Iringa regions of Tanzania.

A cross sectional serological survey was carried out in two geographical small-scale dairying areas of Tanzania to determine the distribution and prevalence and to quantify risk factors for Theileria parva and T. mutans during the period January to April 1999. The prevalence of serum antibodies to these two Theileria parasites was determined using an indirect enzyme-linked immunosorbent assay (ELISA) technique. The results suggest that the parasites are widely distributed through out the two study sites and seroprevalence of 23% and 48% for T. parva were obtained for Tanga and Iringa regions, respectively. Seroprevalence of T. mutans ranged from 17% in the Tanga region to 40% in the Iringa region. Farm and animal data were collected and analysed by multiple logistic regression models to explore the risk factors associated with seroprevalence to T. parva and T. mutans pathogens. In both regions, seroprevalence for the two Theileria spp. pathogens increased significantly with age. Pasture grazed animals were more likely to be seropositive than those that were zero-grazed. Among individual animal characteristics, seropositivity was higher in cash-bought and charity gifted animals compared to cattle obtained using a formal credit agreement. Further studies on the relative role of risk factors for theileriosis found in this study may assist in the development of an effective control package.