A latitudinal diversity gradient in virus infections in humans in England and Wales

This paper reports the presence of a latitudinal diversity gradient in reports of human viral infections in the various health regions of England and Wales. The data used in this study are reports of the laboratory diagnosis of virus infections made to the Public Health Laboratory Service Communicable Disease Surveillance Centre. Two indices of diversity were calculated from the data--Fisher's and Simpson's. Both indices were shown to correlate with latitude but not longitude. Possible mechanisms for this diversity gradient are discussed. It is suggested that such a gradient in the class of human viruses is more likely to be due to increasing environmental stress in colder climates, than to the after-effects of major climatic change.