Floods and infectious diseases: public health lessons from the 2024 southern Brazil disaster

The unprecedented floods that affected Rio Grande do Sul state, Brazil, in 2024 had significant repercussions on public health, particularly infectious diseases. In the weeks following the floods, 7,818 confirmed cases of leptospirosis, 10 outbreaks of diarrheal diseases, and 1,370 incidents involving venomous animals were reported, among other conditions. These events disrupted healthcare networks, caused critical delays in diagnosis, and impaired vaccination campaigns, emphasizing the need for resilient public health systems. This report describes the 2024 climate disaster in Rio Grande do Sul, Brazil, marked by severe flooding and its repercussions on infectious diseases. We detail the epidemiological impact across zoonoses, waterborne and vector-borne diseases, skin and soft tissue infections, respiratory fungal infections, and antimicrobial resistance. The measures implemented by healthcare systems and scientific societies to mitigate these effects are presented, along with key lessons learned from the event. Considering the increasing frequency of extreme weather events due to climate change, this review aims to provide a comprehensive framework for infectious disease preparedness and response, offering critical insights for global application.