Investigating the Relationship Between Rainfall and Ciguatera Fish Poisoning Cases in Vanuatu

The escalating number of ciguatera fish poisoning (CFP) cases in Vanuatu has become a public health issue. Previous studies focused on tropical cyclones and sea surface temperatures as potential causes of CFP; our study aims to investigate the relationship between rainfall and CFP cases. We use the monthly CFP dataset (1989–1996) from the South Pacific Epidemiological and Health Information Services, the daily cases (2021–2023) from the Vanuatu Ministry of Health, and the monthly and daily rainfall data from the Vanuatu Meteorology and Geo-Hazard Department. We also interviewed people about their local knowledge and perceptions of CFP causes and treatments. Cross-correlation analysis was used to determine the lag time between rainfall and CFP cases, whereas the Rainfall Anomaly Index (RAI) assessed variations in rainfall patterns. This study shows a strong positive correlation between rainfall and CFP cases, with lag times ranging from 0 to 8 months. Interview data highlight the integration of Indigenous knowledge and scientific information in CFP prevention and treatment practices. Our results emphasize the need for improved surveillance and early warning systems. This research supports targeted public health interventions and policy measures to mitigate CFP risks in Vanuatu and other Pacific Island nations.