Increased Avian Diversity Is Associated with Lower Incidence of Human West Nile Infection: Observation of the Dilution Effect

• DOI: 10.1371/journal.pone.0002488
• Publication Date: 2008-06-24T21:54:59Z
• Authors: John P. Swaddle; Stavros E. Calos
• Keywords: West Nile virus; Dilution

Recent infectious disease models illustrate a suite of mechanisms that can result in lower incidence areas higher host diversity--the 'dilution effect'. These are particularly applicable to human zoonoses, which diseases wildlife spill over into populations. As many recent emerging the underlie effect' potentially widely and could contribute greatly our understanding diseases. The dilution effect has largely been observed context Lyme predictions underlying have rarely examined for other on broad geographic scale. Here, we explored whether be relationship between West Nile virus (WNV) infection bird (host) diversity eastern US. We constructed novel geospatial contrasts analysis compares small differences avian neighboring US counties (where one county reported cases WNV no cases) with associated between-county disease. also controlled confounding factors climate, regional variation mosquito vector type, urbanization, socioeconomic all likely affect incidence. found there is greater (viral host) diversity. This pattern exists when examining diversity-disease relationships both before reached (in 1998) once epidemic was underway 2002). robust disease-diversity confirm another an important ecosystem service provided by biodiversity, further supporting growing view protecting biodiversity should considered public health safety plans.