Foot-and-mouth disease in Tanzania from 2001 to 2006.

Foot-and-mouth disease (FMD) is endemic in Tanzania, with outbreaks occurring almost each year in different parts of the country. There is now a strong political desire to control animal diseases as part of national poverty alleviation strategies. However, FMD control requires improving the current knowledge on the disease dynamics and factors related to FMD occurrence so control measures can be implemented more efficiently. The objectives of this study were to describe the FMD dynamics in Tanzania from 2001 to 2006 and investigate the spatiotemporal patterns of transmission. Extraction maps, the space-time K-function and space-time permutation models based on scan statistics were calculated for each year to evaluate the spatial distribution, the spatiotemporal interaction and the spatiotemporal clustering of FMD-affected villages. From 2001 to 2006, 878 FMD outbreaks were reported in 605 different villages of 5815 populated places included in the database. The spatial distribution of FMD outbreaks was concentrated along the Tanzania-Kenya, Tanzania-Zambia borders, and the Kagera basin bordering Uganda, Rwanda and Tanzania. The spatiotemporal interaction among FMD-affected villages was statistically significant (P≤0.01) and 12 local spatiotemporal clusters were detected; however, the extent and intensity varied across the study period. Dividing the country in zones according to their epidemiological status will allow improving the control of FMD and delimiting potential FMD-free areas

Risk Factors for Foot-and-Mouth Disease in Tanzania, 2001-2006

We developed a model to quantify the effect of factors influencing the spatio-temporal distribution of foot-and-mouth disease (FMD) in Tanzania. The land area of Tanzania was divided into a regular grid of 20 km x 20 km cells and separate grids constructed for each of the 12-month periods between 2001 and 2006. For each year, a cell was classified as either FMD positive or negative dependent on an outbreak being recorded in any settlement within the cell boundaries. A Bayesian mixed-effects spatial model was developed to assess the association between the risk of FMD occurrence and distance to main roads, railway lines, wildlife parks, international borders and cattle density. Increases in the distance to main roads decreased the risk of FMD every year from 2001 to 2006 (ORs ranged from 0.43 to 0.97). Increases in the distance to railway lines and international borders were, in general, associated with a decreased risk of FMD (ORs ranged from 0.85 to 0.99). Increases in the distance from a national park decreased the risk of FMD in 2001 (OR 0.80; 95% CI 0.68-0.93) but had the opposite effect in 2004 (OR 1.06; 95% CI 1.01-1.12). Cattle population density was, in general, positively associated with the risk of FMD (ORs ranged from 1.01 to 1.30). The spatial distribution of high-risk areas was variable and corresponded to endemic (2001, 2002 and 2005) and epidemic (2003, 2004 and 2006) phases. Roads played a dominant role in both epidemiological situations; we hypothesize that roads are the main driver of FMD expansion in Tanzania. Our results suggest that FMD occurrence in Tanzania is more related to animal movement and human activity via communication networks than transboundary movements or contact with wildlife

Spatial and Temporal Pattern of Rift Valley Fever Outbreaks in Tanzania; 1930 to 2007

Rift Valley fever (RVF)-like disease was first reported in Tanzania more than eight decades ago and the last large outbreak of the disease occurred in 2006–07. This study investigates the spatial and temporal pattern of RVF outbreaks in Tanzania over the past 80 years in order to guide prevention and control strategies. A retrospective study was carried out based on disease reporting data from Tanzania at district or village level. The data were sourced from the Ministries responsible for livestock and human health, Tanzania Meteorological Agency and research institutions involved in RVF surveillance and diagnosis. The spatial distribution of outbreaks was mapped using ArcGIS 10. The space-time permutation model was applied to identify clusters of cases, and a multivariable logistic regression model was used to identify risk factors associated with the occurrence of outbreaks in the district. RVF outbreaks were reported between December and June in 1930, 1947, 1957, 1960, 1963, 1968, 1977– 79, 1989, 1997–98 and 2006–07 in 39.2% of the districts in Tanzania. There was statistically significant spatio-temporal clustering of outbreaks. RVF occurrence was associated with the eastern Rift Valley ecosystem (OR = 6.14, CI: 1.96, 19.28), total amount of rainfall of .405.4 mm (OR = 12.36, CI: 3.06, 49.88), soil texture (clay [OR = 8.76, CI: 2.52, 30.50], and loam [OR = 8.79, CI: 2.04, 37.82]). RVF outbreaks were found to be distributed heterogeneously and transmission dynamics appeared to vary between areas. The sequence of outbreak waves, continuously cover more parts of the country. Whenever infection has been introduced into an area, it is likely to be involved in future outbreaks. The cases were more likely to be reported from the eastern Rift Valley than from the western Rift Valley ecosystem and from areas with clay and loam rather than sandy soil texture

Endemic stability for <i>Theileria parva<i/> infections in Ankole calves of the Ankole ranching scheme, Uganda

A population-based study was carried out on the Ankole ranching scheme in south-west Uganda with the aim of determining the endemic status of Theileria parva infections. For this purpose, the age-related sero-prevalence of T. parva and the specific calf mortality associated with the parasite were assessed. Blood samples were collected from 931 Ankole calves of up to 12 months of age from 81 randomly selected herds. The relationship between rainfall pattern and whole-body Rhipicephalus appendiculatus counts was determined. The influence of tick control practices on East Coast fever-related calf mortality, and sero-positivity were also determined. A significant (r2 = 0.76, P = 0.000) association between R. appendiculatus counts and rainfall was observed. There was no significant (P > 0.05) association between theileriosis- related calf mortality, sero-positivity and the different tick control practices. Antibody prevalence based on the PIM ELISA was above 70 % among calves of 6 months of age in 96 % in all the herds. Theileria parva-related calf mortality determined by repeated herd visits and farm records ranged between 0% and 5.4 %. It was concluded that endemic stability for theileriosis, caused by T. parva, existed in the study area, and that the risk of the occurrence of economically important outbreaks of East Coast fever in indigenous cattle was regarded as minimal under the prevailing conditions

Epidemiological perspectives of ticks and tick-borne diseases in South Sudan: Cross-sectional survey results

A cross-sectional study was conducted between September and October 2010 in five states of South Sudan that were selected on the basis of the perceived risk of tick-borne diseases. The purpose was to investigate epidemiological parameters of tick-borne diseases in South Sudan and their uses in future control strategies. A total of 805 calves were assessed by clinical, microscopic and serological examination and tick counts. The indirect Enzyme-Linked Immuno-Sorbent Assay (ELISA) was used to detect antibodies to Theileria parva, Theileria mutans, Anaplasma marginale and Babesian bigemina. Sero-conversion risks for T. parva and T. mutans were 27.3% and 31.3% respectively, whilst the risk was 57.6% and 52.8% for A. marginale and B. bigemina, respectively. Major tick species identified include Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus microplus, Amblyomma variegatum, and Rhipicephalus evertsi. There was great variation (P ≤ 0.001) in the number of all these ticks, both between herds in a state and between calves in an individual herd. The low and intermediate sero-conversion risks observed in the study states suggest that immunisation against East Coast fever (ECF) is justified. Fortunately, three major genotypes that were identified by applying Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCRRFLP) analysis on the p104 to the blood samples and T. parva Muguga, matched very well with T. parva Kiambu 5 and T. parva Muguga; therefore the Muguga cocktail can be used for the immunisation of cattle in South Sudan. However, prospective studies are required to develop optimal control measures for tick-borne diseases under different ecological and husbandry practices in South Sudan

Risk Factors for Foot-and-Mouth Disease in Tanzania, 2001-2006

We developed a model to quantify the effect of factors influencing the spatio-temporal distribution of foot-and-mouth disease (FMD) in Tanzania. The land area of Tanzania was divided into a regular grid of 20 km x 20 km cells and separate grids constructed for each of the 12-month periods between 2001 and 2006. For each year, a cell was classified as either FMD positive or negative dependent on an outbreak being recorded in any settlement within the cell boundaries. A Bayesian mixed-effects spatial model was developed to assess the association between the risk of FMD occurrence and distance to main roads, railway lines, wildlife parks, international borders and cattle density. Increases in the distance to main roads decreased the risk of FMD every year from 2001 to 2006 (ORs ranged from 0.43 to 0.97). Increases in the distance to railway lines and international borders were, in general, associated with a decreased risk of FMD (ORs ranged from 0.85 to 0.99). Increases in the distance from a national park decreased the risk of FMD in 2001 (OR 0.80; 95% CI 0.68-0.93) but had the opposite effect in 2004 (OR 1.06; 95% CI 1.01-1.12). Cattle population density was, in general, positively associated with the risk of FMD (ORs ranged from 1.01 to 1.30). The spatial distribution of high-risk areas was variable and corresponded to endemic (2001, 2002 and 2005) and epidemic (2003, 2004 and 2006) phases. Roads played a dominant role in both epidemiological situations; we hypothesize that roads are the main driver of FMD expansion in Tanzania. Our results suggest that FMD occurrence in Tanzania is more related to animal movement and human activity via communication networks than transboundary movements or contact with wildlife

Constraints Associated With Production In Smallholder Dairy Farms In The Eastern Coastal Zone Of Tanzania

A study involving 105 smallholder dairy farmers was conducted in Kibaha and Morogoro districts, Tanzania to characterise husbandry practices, milk production constraints; and farmers\' knowledge on milk-borne zoonoses. About 50% of the farmers in Kibaha (n=57) and 60% in Morogoro (n=48) were employed in formal public and private sectors, and hired labour while only 16.5% depended entirely on dairy farming. The average milk production was 5.9 litres/cow/day. Seventy-two percent of the farmers in Kibaha and 83.3% in Morogoro practised stall-feeding while others either tethered or herded the animals. Dairy production constraints included animal diseases; shortage of feeds, water and markets for milk; lack of animal breeding services and shortage of capital. The major cattle diseases were trypanosomosis, East Coast fever, anaplasmosis and mastitis. Only 14% of the farmers were aware of subclinical mastitis, and 67% of them were aware of milk-borne zoonoses especially tuberculosis while only 10% farmers knew about brucellosis.On a mené une étude portant sur 105 petites exploitations laitières dans les districts de Kibaha et Morogoro en Tanzanie, en vue de déterminer les modes d\'élevage, la production laitière, les obstacles rencontrés et la connaissance des éleveurs sur les zoonoses d\'origine laitière. Environ 50% des éleveurs à Kibaha (n = 57) et 60% à Morogoro (n = 48) étaient employés dans les secteurs public et privé ; seuls 16,5% dépendaient entièrement de l\'élevage laitier. La production moyenne de lait était de 5,9 litres/vache/jour. 72% des éleveurs à Kibaha et 83,3% à Morogoro avaient recours à l\'alimentation à l\'étable, tandis que les autres attachaient leur bétail au piquet ou gardaient leurs animaux. Les entraves à la production laitière étaient les suivantes : les maladies animales, la pénurie d\'aliments et d\'eau, l\'absence de marchés pour écouler le lait, l\'absence de services de reproduction et le manque de capital. Les principales maladies bovines étaient : la trypanosomose, la fièvre de la côte-Est, l\'anaplasmose et la mammite. Seuls 14% des éleveurs connaissaient la mammite infraclinique, parmi lesquels 67% étaient au courant des zoonoses d\'origine laitière, notamment la tuberculose, et 10% connaissaient la brucellose.Bulletin of Animal Health and Production in Africa Vol. 54 (4) 2006: pp. 286-29