Enhancing biosecurity along Uganda’s pig value chains to control and prevent African swine fever

Irish AidInternational Fund for Agricultural Developmen

Mapping the risk of Rift Valley fever in Uganda using national seroprevalence data from cattle, sheep and goats

Uganda has had repeated outbreaks of Rift Valley fever (RVF) since March 2016 when human and livestock cases were reported in Kabale after a long interval. The disease has a complex and poorly described transmission patterns which involves several mosquito vectors and mammalian hosts (including humans). We conducted a national serosurvey in livestock to determine RVF virus (RVFV) seroprevalence, risk factors, and to develop a risk map that could be used to guide risk-based surveillance and control measures. A total of 3,253 animals from 175 herds were sampled. Serum samples collected were screened at the National Animal Disease Diagnostics and Epidemiology Centre (NADDEC) using a competition multispecies anti-RVF IgG ELISA kit. Data obtained were analyzed using a Bayesian model that utilizes integrated nested Laplace approximation (INLA) and stochastic partial differential equation (SPDE) approaches to estimate posterior distributions of model parameters, and account for spatial autocorrelation. Variables considered included animal level factors (age, sex, species) and multiple environmental data including meteorological factors, soil types, and altitude. A risk map was generated by projecting fitted (mean) values, from a final model that had environmental factors onto a spatial grid that covered the entire domain. The overall RVFV seroprevalence was 11.3% (95% confidence interval: 10.2–12.3%). Higher RVFV seroprevalences were observed in older animals compared to the young, and cattle compared to sheep and goats. RVFV seroprevalence was also higher in areas that had (i) lower precipitation seasonality, (ii) haplic planosols, and (iii) lower cattle density. The risk map generated demonstrated that RVF virus was endemic in several regions including those that have not reported clinical outbreaks in the northeastern part of the country. This work has improved our understanding on spatial distribution of RVFV risk in the country as well as the expected burden of the disease in livestock

Identifying target areas for risk-based surveillance and control of Transboundary Animal Diseases: A seasonal analysis of slaughter and live-trade cattle movements in Uganda

Abstract Animal movements are a major driver for the spread of Transboundary Animal Diseases (TADs). These movements link populations that would otherwise be isolated and hence create opportunities for susceptible and infected individuals to meet. We used social network analysis to describe the seasonal network structure of cattle movements in Uganda and unravel critical network features that identify districts or sub-regions for targeted risk-based surveillance and intervention. We constructed weighted, directed networks based on 2019 between-district cattle movements using official livestock mobility data; the purpose of the movement (‘slaughter’ vs. ‘live trade’) was used to subset the network and capture the risks more reliably. Our results show that cattle trade can result in local and long-distance disease spread in Uganda. Seasonal variability appears to impact the structure of the network, with high heterogeneity of node and edge activity identified throughout the seasons. These observations mean that the structure of the live trade network can be exploited to target influential district hubs within the cattle corridor and peripheral areas in the south and west, which would result in rapid network fragmentation, reducing the contact structure-related trade risks. Similar exploitable features were observed for the slaughter network, where cattle traffic serves mainly slaughter hubs close to urban centres along the cattle corridor. Critically, analyses that target the complex livestock supply value chain offer a unique framework for understanding and quantifying risks for TADs such as Foot-and-Mouth disease in a land-locked country like Uganda. These findings can be used to inform the development of risk-based surveillance strategies and decision making on resource allocation. For instance, vaccine deployment, biosecurity enforcement and capacity building for stakeholders at the local community and across animal health services with the potential to limit the socio-economic impact of outbreaks, or indeed reduce their frequency

Quantitative Outcomes of a One Health Approach to Investigate the First Outbreak of African Swine Fever in the Republic of Sierra Leone

African swine fever (ASF) outbreaks have been reported in Sub-Saharan countries, including West Africa states, but has never been notified in the Republic of Sierra Leone. This is the first report describing field epidemiological and laboratory investigations into the outbreak of fatal pig disease in western rural and urban districts, Freetown. A preliminary finding indicated that pigs exhibited clinical and necropsy signs suggestive of ASF. Serological (ELISA) and molecular (qRT-PCR) methods used to confirm and investigate the outbreak yielded three positive results for the ASF antibody and all negative for Swine flu; thus, confirming ASF as the etiology agent

An Update on the Surveillance of Livestock Diseases and Antimicrobial Use in Sierra Leone in 2021-An Operational Research Study.

In Sierra Leone, in 2020, a study by the Livestock and Veterinary Services Division (Ministry of Agriculture and Forestry) on the surveillance system of animal diseases and antimicrobial use found poor reporting. Of the expected weekly districts reports, <1% were received and only three of the 15 districts had submitted reports occasionally between 2016 and 2019. Following this, staff-capacity-building on reporting was undertaken. In 2021, we reassessed the improvement in reporting and used the reports to describe livestock diseases and antimicrobials utilized in their treatment. Between March and October 2021, 88% of expected weekly reports from all 15 districts were received. There were minor deficiencies in completeness and consistency in the terminology used for reporting animal disease and antimicrobials. Available reports showed that 25% of the livestock had an infectious disease, and a quarter of the sick animals had received an antimicrobial drug. Most animals received antimicrobials belonging to World Organization for Animal Health's "veterinary critically important" category (77%) and World Health Organization's "critically" (17%) and "highly important" (60%) categories for human health. These indicate a significant improvement in the animal health surveillance system and highlight the need for enhanced antimicrobial stewardship to prevent misuse of antimicrobials that are significant in animal and human health