An epidemiological study of epizootic ulcerative syndrome (EUS) was conducted in Zimbabwe within Kavango Zambezi (KAZA) and Great Limpopo (GL) Transfrontier Conservation Areas (TFCAs), during the period between May 2016 and September 2018. The study aimed at understanding factors associated with EUS spread, biosecurity risk factors, pathological features, fish species affected and establishment of disease prevalence. During the three-year study period, and within the prescribed study area, twenty-seven randomly selected study sites from wild (artisanal) capture fisheries on Lake Kariba and impoundments on inland rivers were surveyed. These emanated from four respective provinces in Zimbabwe, namely Mashonaland West, Midlands and Matabeleland North & South provinces, eleven (11) fish farms were also sampled.
Out of the 2569 fish sampled in wild fisheries 246 were found with typical gross pathological skin lesions of EUS disease, derived from 15 positive locations indicating a prevalence rate of 9.58%. The most important observations of highest infection rates and most severe skin lesions were found on inland water bodies as opposed to Lake Kariba, signifying the state of water quality. Clinical observations highlighted Clarias species as the most severely affected, followed by Barbus and Oreochromis species respectively, similar findings were made during a retrospective study by Sibanda et al., 2018. The Epidemiological and a Socio-economic studies involving detailed interviews with key stakeholders and fishermen established an initial rise and steady decline, in disease outbreaks from 2008, when EUS was first suspected and later confirmed on Darwendale impoundment in 2012
. No outbreaks were recorded during the peak winter EUS disease season of 2018.
The disease spread from endemic Zambezi River Basin (ZRB) in KAZA TFCA to the Great Limpopo TFCA drainage system was attributed to flood events experienced subsequently following the establishment of the disease in several Southern African countries sharing the ZRB, including Zimbabwe. No EUS disease outbreaks were confirmed on 11 randomly selected aquaculture farms surveyed during the study. The Epidemiological study was envisaged to contribute towards formulation of policy frameworks and strategy guidance in aquatic animal health which currently are inadequate in view of the recently fast-growing production of particularly the aquaculture sub- sector of Zimbabwe.