Trends and geographic distribution of bacterial zoonoses in veterinary cases in the Eastern Cape: A ten-year retrospective analysis

Diseases affecting livestock can have ripple effects on surrounding ecosystems, especially by contaminating water sources. Their occurrence poses significant public health issues, especially in areas such as the Eastern Cape province in South Africa, susceptible to climatic variations and where people and animals often share water sources, increasing the risk of transmission of waterborne zoonoses. Waterborne zoonoses are infectious diseases caused by zoonotic pathogens, including bacteria, viruses, protozoa, and parasitic helminths transmitted from animals through the aquatic environment to humans and vice versa. Tracking zoonoses in livestock is an early indicator of potential contamination of water sources used by animals and humans. This study analysed trends in prevalence of water-transmissible bacterial zoonoses over ten years, identifying the most frequently recorded zoonoses, their geographical distribution, and determining the animal species most commonly associated with these diseases. Bacterial zoonoses remain a global threat due to their potential for re-emergence, antimicrobial resistance, and economic impact. This study employed monthly reports on livestock disease from the Ruminant Veterinary Association of South Africa (RuVASA) website. The data was aggregated by month and scale of importance to summarise the trend in scale of importance over time. Following this, the specific diseases frequently, with more than 10 cases reported monthly, were explored. The findings from this study reveal a notable rise in cases of zoonoses in animals, particularly colibacillosis, across several regions in Eastern Cape, South Africa, such as Alexandria, Graaff-Reinet, and Jeffreys Bay. Cattle had the highest prevalence of all three diseases—brucellosis, colibacillosis, and salmonellosis—emphasising their role as key reservoirs, compared to sheep, cattle and goats. The findings of this study provide critical understanding, such as zoonoses posing the highest risk, local hotspots for disease transmission, and the animal's reservoirs that will potentially and significantly contaminate shared water sources by their presence near water. Analysing trends in animal diseases that can impact water quality and pose risks for zoonosis transmission, spread and outbreak is the needed holistic outlook recognising that regress in animal health can have broader environmental and public health implications, which is in line with the One Health principle that considers the interconnectedness between human, animal, and environmental health systems.