An Assessment of Rainfall and Temperature on Seasonal Outbreak of Lassa Fever in Nigeria for the Year 2020

Abstract

The present study examined the impacts of rainfall and temperature on the seasonal outbreak of Lassa fever in Nigeria for the year 2020. The sample size was based on cluster sampling of the seven states with the highest number of cases in 2020. Three states from the south and four states from the north. Suspected and confirmed cases were gathered from the week by week epidemiological report of the NCDC website from December 30, 2019/week 52 to June 28, 2020/week 26. Average rainfall and temperature data for each state were gathered on a weekly average basis from the weather records of AccuWeather.com. The findings showed that there were no significant relationships between the climatic variables and the number of suspected and confirmed cases. However, there were weak significant relationships between the number of deaths and average low temperature (r = – 0.24) and average temperature difference (r = 0.19). In the southern states, for every one-degree (1°F) increase in temperature (f), there are an additional 12.1, 5.6 and 1.7 suspected cases in Edo, Ondo and Ebonyi states. Average high temperature alone could explain ~50% of the increase in cases. Relationships were less clear in the northern states. In contrast to previous research, the study found that there is a non-linear relationship between the climatic variables and Lassa fever outbreaks