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.

In particular, between Salmonella serotypes, there was a clear hierarchy of strength of correlation with weather. The high prevalence of Salmonella Enteritidis (n = 284,761) and Salmonella Typhimurium (n = 84,204) contributed to high seasonality for these serotypes and strong associations with temperature and the auto-correlated sunshine and vapour pressure. The examination of Salmonella data showed some of the limitations that can constrain the comparison of weather and infectious disease data. While most Salmonella serotypes were seasonal, this could not be demonstrated for most of these until they were combined together with similar serotypes showing some evidence of more cases in summer months. The serotypes that showed no evidence of seasonality may be associated with contamination from reptiles kept as pets [30] . Such exposure is thought to be relatively less seasonal in its occurrence compared to foodborne salmonellosis. Typhoid and paratyphoid infections in England and Wales are usually associated with travel abroad, particularly to the Indian subcontinent, and this is in the late spring and early autumn [31] .