The interplay of El Niño–Southern Oscillation and immunity in infectious disease outbreaks
Variations in temperature, precipitation, and humidity can have a significant impact on the spread of infectious diseases. These factors can alter the habitats of disease transmitters, such as mosquitoes, and disrupt health care responses during extreme weather events. One phenomenon that has been studied extensively in relation to infectious disease outbreaks is the El Niño–Southern Oscillation (ENSO).
ENSO consists of alternating warm (El Niño) and cold (La Niña) phases that can influence extreme weather patterns and potentially impact the spread of diseases such as cholera, dengue, malaria, respiratory syncytial virus (RSV), and Rift Valley fever. While ENSO events can be forecasted months in advance, there have been limited successful public health interventions resulting from these predictions.
Research published in GeoHealth by Maya V. Chung and collaborators aimed to model the longer-term interactions between ENSO cycles and various infectious diseases. The study utilized two modeling approaches to investigate how ENSO’s influence on disease outbreaks may vary from year to year.
The first modeling effort focused on how back-to-back ENSO events could affect populations susceptible to disease outbreaks over multiple years. The second approach examined the impact of ENSO-associated humidity variations on the transmission of an airborne human coronavirus, HCoV-HKU1.
The research findings revealed that immune responses for infectious diseases often lagged behind the initial El Niño and La Niña events, sometimes by more than a year. This delay in immune responses could lead to longer-lasting and larger disease effects when ENSO events occur consecutively.
Based on these findings, the researchers suggest that risk managers should consider population immunity as a predictor of ENSO’s influence on infectious disease spread. By improving the understanding of climate-disease interactions, interventions could be planned in advance, potentially leading to better health outcomes.
Overall, this study highlights the complex relationship between ENSO cycles and infectious disease outbreaks. By incorporating climate data and population immunity into disease modeling, public health officials may be able to implement more effective strategies to mitigate the impact of ENSO events on disease transmission.
