Spatiotemporal epidemiology of Lumpy Skin Disease in Tanzania from 2018 to 2023

Abstract

Lumpy Skin Disease (LSD) is a significant Trans-boundary Animal Disease (TAD) affecting cattle, whose causative agent is Capripoxvirus of family poxviridae. Despite its importance, there is limited information on its epidemiology in Tanzania. This study aimed to describe spatiotemporal epidemiological features of LSD in cattle from all 26 regions of Tanzania mainland from 2018 to 2023. Retrospective data on LSD cases in regions and districts obtained from the Ministry of Livestock and Fisheries were analysed using space-time scan statistics. The data were presented as spatial distribution maps at regional and district levels and temporal patterns as histograms. Between 2018 and 2023, 13,339 LSD cases were reported in the country. All 26 regions (100.0%) reported at least one case during this period. At the district level, LSD was reported in 83.0% (155 out of 185 in the country) of the district councils. The highest number of cases in regions were reported in Dodoma (2,287), Kagera (1,395), Iringa (1,040), and Mbeya (1,012). The lowest number of cases were reported in Shinyanga (109), Mtwara (107), Mwanza (69), Geita (67), Pwani (59), Simiyu (49), Lindi (30), and Dar es Salaam (2). The year with the highest number of LSD cases was 2021 (4,701), while the lowest number was 2018 (415). Although LSD cases were reported throughout the year, the highest number was observed from January to March. Cluster analysis identified six regional- and ten district-level distinct clusters of LSD cases. Arusha, Kilimanjaro, Iringa, and Mbeya regions were identified as the highest-risk clusters at the regional level. These findings suggest that LSD is endemic in Tanzania, occurring in all regions and most districts. The results provide a foundation for further investigation through active surveillance to determine the true prevalence and identify the risk factors contributing to its persistence.