Pathogen seasonality and links with weather in England and Wales: a big data time series analysis

Cherrie, Mark P. C.; Nichols, Gordon; Iacono, Gianni Lo; Sarran, Christophe; Hajat, Shakoor; Fleming, Lora E.

Temperature was most often used to explain any relationship between climate and pathogens previously [1, 32] . However, there must be careful consideration of the measure of temperature used as shown in our analysis of Influenza A and B. Influenza A was most strongly correlated with extreme weather events (i.e. snow lying days), which may indicate specific circumstances around these events that are important for transmission of the pathogen (i.e. temperature of below 2°C with moisture in the air). We also found that other temperature-related variables showed consistent associations with various pathogens. Vapour pressure has been used previously in a study investigating the effect of meteorological variables on the risk of Legionnaires' disease in Switzerland [33] . Vapour pressure may have such strong associations with several infectious diseases such as influenza [34] , because it represents a set of meteorological parameters, i.e. warm, humid and wet conditions. Similar inferences were made in a study of RSV activity in the Netherlands, which found that humidity and temperature combined explained more variability than these parameters individually [35] . This may be due to the dual impact of increased contact from lower temperature and increased immunosusceptibility associated with by higher relative humidity [36] . The approach here was probably not optimal for linking waterborne diseases to rainfall because of the local linkage needed, as there are significant variations by geographic region.