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

Review of current problems and shortcomings in the Tanzanian animal health information system with suggestions on improvement

Livestock diseases have always been the focus of the Tanzanian Veterinary Authorities. However, they have become more important since the formation of the World Trade Organisation and subsequent implementation of the various multilateral agreements on trade. There is also a strong political desire to improve the animal health status as part of poverty alleviation strategies. As a result there is a need to develop better systems for investigating and reporting of animal diseases. In order to follow the OIE pathway and to obtain a disease free status, reliable evidence of freedom from particular diseases is becoming an issue of major interest. Assessment of the Tanzanian animal health information system revealed two major problems; firstly, the absence of disease information that accurately reflects the health status of the source population, and secondly, an inefficient information management system which is unable to provide useful information on the spatial component of animal health. A strategic approach is proposed that involves the collection of animal health information using active surveillance techniques and the introduction of a geographic information system. This approach should improve the management and reporting of animal health information.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Participatory epidemiological study on the burden of rabies in animals and humans in three districts of Buno Bedele Zone, West Ethiopia

Rabies is one of the priority zoonotic diseases and a major public health challenge in Ethiopia. Dog plays an important role in the transmission of the disease to humans. With this point in mind, this study was conducted in selected districts of Buno Bedele Zone namely Bedele, Gechi, and Dabo Hana districts, Western Oromia regional state from December 2019 to April 2020. The objective of the study was to know the status and burden of rabies in the community using the participatory approach and retrospective record assessment from animal and human health facilities. Twelve interview meetings were conducted in 12 Kebeles, which involved 156 informants. In this survey authors learned that dogs were the species most affected by rabies followed by cattle, human, cat, equine, and shoats. Accordingly, rabies in dog had an average score of 64 out of 100 with a range of 50-80. Besides, rabies outbreak was frequently noted between June to October in the study areas. Slaughter and sharing of the meat for household consumption was the most common practice taken to salvage bitten cattle. As per the available record in the study area, the estimated rabies cases incidence was 1.75 bovines, 18 dogs, 2.37 equines, 2.28 cats, and 0.37 shoats per 10,000 animals annually. The annual average post-exposure rabies vaccinations records were 75, 39, and 63 in Bedele, Dabo Hana, and Gechi districts, respectively. On the other hand, the average annual rabies death in humans was 2.2, 1.4, and 1.8 in Bedele, Dabo Hana, and Gechi districts, respectively. In general, this study shows that rabies is a disease that worth serious attention in the study 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

Peste des Petits Ruminants infection among cattle and wildlife in Northern Tanzania

We investigated peste des petits ruminants (PPR) infection in cattle and wildlife in northern Tanzania. No wildlife from protected ecosystems were seropositive. However, cattle from villages where an outbreak had occurred among small ruminants showed high PPR seropositivity, indicating that spillover infection affects cattle. Thus, cattle could be of value for PPR serosurveillance

One hundred years of African swine fever : a tribute to R. Eustace Montgomery

One hundred years ago, the first scientific publication on “a form of swine fever” that occurred in East Africa was published by R. Eustace Montgomery in the Journal of Comparative Pathology and Therapeutics (Montgomery, 1921). Now known as African swine fever (ASF), this disease has, over the last century, been reported from all five continents and is dreaded by pig industries worldwide (Liang et al., 2020; Penrith, 2020 ). It is hoped that this tribute will contribute to ensuring that the great legacy of Montgomery's research is not forgotten.https://wileyonlinelibrary.com/journal/tbedhj2022Veterinary Tropical Disease

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% (CI 95% = 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

Are we prepared for emerging and re-emerging diseases? Experience and lessons from epidemics occurred in Tanzania during the last five decades

This paper reviews preparedness for containing and controlling emerging and re-emerging diseases drawing lessons from disease events that occurred in animal and human populations in the last five decades (1961-2011). A comprehensive analysis based on retrieval and analysis of grey and published literature as well as reported cases was carried out to document type and trend of occurrence of emerging and re-emerging infectious diseases in different parts of Tanzania. Overall, the majority of diseases reported in the country were viral in nature followed by bacterial diseases. The trend for the occurrence shows a number of new emerging diseases as well as re-occurrence of old diseases in both animal (domestic and wild) and human populations. In humans, the major disease epidemics reported in the last five decades include cholera, influenza A H1N1, plague and rubella. In animals, the major epidemic diseases reported were Contagious Bovine Pleuropneumonia, Contagious Caprine Pleuropneumonia, Peste des petits ruminants and Giraffe Ear and Skin Diseases. Some epidemics have been reported in both human and animal populations including Rift Valley fever and anthrax.  The emergence of the ‘fit-for purpose’ approaches and technologies such as the discipline of One Health, use of participatory epidemiology and disease surveillance and mobile technologies offers opportunity for optimal use of limited resources to improve early detection, diagnosis and response to disease events and consequently reduced impact of such diseases in animal and human populations

A dynamic model of transmission and elimination of peste des petits ruminants in Ethiopia

Peste des petits ruminants (PPR), a devastating viral disease of sheep and goats, has been targeted by the global community for eradication within the next 15 years. Although an efficacious attenuated live vaccine is available, the lack of knowledge about the transmission potential of PPR virus (PPRV) may compromise eradication efforts. By fitting a metapopulation model simulating PPRV spread to the results of a nationwide serological survey in Ethiopia, we estimated the level of viral transmission in an endemic setting and the vaccination coverage required for elimination. Results suggest that the pastoral production system as a whole acts as a viral reservoir, from which PPRV spills over into the sedentary production system, where viral persistence is uncertain. Estimated levels of PPRV transmission indicate that viral spread could be prevented if the proportion of immune small ruminants is kept permanently above 37% in at least 71% of pastoral village populations. However, due to the high turnover of these populations, maintaining the fraction of immune animals above this threshold would require high vaccine coverage within villages, and vaccination campaigns to be conducted annually. Adapting vaccination strategies to the specific characteristics of the local epidemiological context and small ruminant population dynamics would result in optimized allocation of limited resources and increase the likelihood of PPR eradication

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