Climate change and animal infectious diseases: a systematic review of emerging evidence

Climate change is increasingly recognised as a major driver of infectious disease dynamics, yet its impact on animal health remains understudied compared with its impact on human populations. This systematic review aimed to assess the effects of climate variability and change on the epidemiology of animal infectious diseases, focusing on measurable changes in disease incidence, prevalence, mortality, and geographical distribution. We searched PubMed and CAB Abstracts for studies published between Jan 1, 1970, and Dec 31, 2024, and identified 33 eligible studies that that assessed associations between climatic factors and observed disease outcomes in animal populations. The evidence base has grown over the past decade but remains geographically and taxonomically imbalanced. Most (24 [73%] of 33) studies reported positive associations between climatic variables and increased disease risk, expanded geographical ranges, or higher prevalence. Vector-mediated mechanisms were consistently proposed as underlying drivers (25 [76%] of 33). Domestic species were the most frequently studied hosts (18 [55%] of 33), whereas wildlife hosts were under-represented (11 [33%] of 33). Four studies (12%) included mixed host populations. 6200 studies identified by our search were excluded because they relied solely on environmental suitability indices, vector abundance models, or synthetic epidemiological outcomes, highlighting a persistent scarcity of longitudinal empirical disease data linked to long-term changes in weather and climate. Although modelling approaches are valuable for risk projection, the poor availability of longitudinal epidemiological data constrains validation and attribution. Overall, the available evidence suggests that climate variability and change are reshaping animal infectious disease epidemiology, with important implications for animal health, food security, and zoonotic risk. However, important gaps in our understanding of these dynamics remain. Bridging these gaps, strengthening climate-aware surveillance, expanding data accessibility, and integrating animal health into One Health strategies will be essential to address emerging health risks.