How to translate text using browser tools
1 November 2009 Severe Winter Freezes Enhance St. Louis Encephalitis Virus Amplification and Epidemic Transmission in Peninsular Florida
Jonathan F. Day, Jeffrey Shaman
Author Affiliations +

Mosquito-borne arboviral epidemics tend to strike without warning. The driving force for these epidemics is a combination of biotic (vector, amplification host, and virus) and abiotic (meteorological conditions, especially rainfall and temperature) factors. Abiotic factors that facilitate the synchronization and interaction of vector and amplification host populations favor epidemic amplification and transmission. In Florida, epidemics of St. Louis encephalitis (SLE) virus (family Flaviviridae, genus Flavivirus, SLEV) have been preceded by major freezes one or two winters before the onset of human cases. Here, we analyze the relationship between severe winter freezes and epidemic SLEV transmission in peninsular Florida and show that there is a significant relationship between the transmission of SLEV and these severe freezes. We propose that by killing cold-sensitive understory vegetation in the mid-peninsular region of Florida, freezes enhance the reproductive success of ground-feeding avian amplification hosts, especially mourning doves and common grackles. In conjunction with other appropriate environmental signals, increased avian reproductive success may enhance SLEV and West Nile (WN) virus amplification and result in SLE and WN epidemics during years when all of the biological cycles are properly synchronized. The knowledge that winter freezes in Florida may enhance the amplification and epidemic transmission of SLE and WN viruses facilitates arboviral tracking and prediction of human risk of SLE and WN infection during the transmission season.

© 2009 Entomological Society of America
Jonathan F. Day and Jeffrey Shaman "Severe Winter Freezes Enhance St. Louis Encephalitis Virus Amplification and Epidemic Transmission in Peninsular Florida," Journal of Medical Entomology 46(6), 1498-1506, (1 November 2009).
Received: 17 June 2008; Accepted: 1 August 2009; Published: 1 November 2009

This article is only available to subscribers.
It is not available for individual sale.

St. Louis encephalitis virus
winter freeze
Get copyright permission
Back to Top