Increasing dog bites in humans: Indoor and outdoor risk factors and spatiotemporal patterns in Chile

Dog bites pose a serious global public health problem, leading to at least 14,000 annual deaths globally, primarily from rabies, and contributing to physical injuries, psychological trauma, transmission to other zoonotic diseases, and substantial economic costs. This study aimed to estimate the spatiotemporal distribution of dog bite incidents involving humans in Chile and to analyze the risk factors associated with bites in indoor and outdoor environments. We analyzed data from the Registry System of Biting Animals (SIRAM) in Chile between 2019 and 2024. To examine spatiotemporal patterns of dog bites and associated risk factors, we conducted time-series analyses, spatial autocorrelation, and generalized linear mixed-effects models with a negative binomial distribution. The cumulative rate of reported dog bites was 263 (95% CI: 262.5-264.3) per 100,000 inhabitants and increased from 216 (95% CI: 214-218) per 100,000 inhabitants in 2019 to 400 (95% CI: 398-403) per 100,000 inhabitants in 2024. Cases were widely distributed across all regions, with clusters of municipalities showing high rates. The risk of reported dog bites was twice as high in outdoor compared to indoor settings (adjusted incidence rate ratio [aIRR]=2.01; 95% CI 1.98-2.03), and disproportionately affected males (aIRR=1.47; 95% CI 1.45-1.49) and individuals aged 10-69 years, whereas indoor bites presented more uniform risk patterns across demographic groups. Time series revealed an increasing trend since 2022 and a seasonal pattern. Regression models showed the highest reported bite rate occurred during the spring months in both indoor (aIRR=1.14; 95% CI 1.12-1.17) and outdoor (aIRR=1.2; 95% CI 1.18-1.22) settings. Dog bite incidents are a growing public health concern in Chile, influenced by human, animal, and environmental factors. This increase may reflect both a true rise in dog bite occurrence and improvements in surveillance sensitivity. Addressing this multifactorial problem requires a comprehensive One Health approach, including reducing the number of unsupervised dogs outdoors, raising public awareness, and establishing a comprehensive registry of severe and non-severe cases to assess the burden of dog bites. These measures are critical for the effective prevention and control of dog bite incidents.