Texas lifestyle limits transmission of dengue virus

Abstract

Urban dengue is common in most countries of the Americas, but has been rare in the United States for more than half a century. In 1999 we investigated an outbreak of the disease that affected Nuevo Laredo, Tamaulipas, Mexico, and Laredo, Texas, United States, contiguous cities that straddle the international border. The incidence of recent cases, indicated by immunoglobulin M antibody serosurvey, was higher in Nuevo Laredo, although the vector, Aedes aegypti, was more abundant in Laredo. Environmental factors that affect contact with mosquitoes, such as air-conditioning and human behavior, appear to account for this paradox. We conclude that the low prevalence of dengue in the United States is primarily due to economic, rather than climatic, factors.

Figure

Laredo, Texas (east of the Rio Grande river) and Nuevo Laredo, Taumalipas (west of the river). Blue, water; green, vegetation; blue-violet, roads and buildings; blue-violet areas on the western side of Nuevo Laredo, low-income neighborhoods; pink, land with little or no vegetation. (National Aeronautics and Space Administration (NASA)/U.S. Geological Survey LANDSAT 7 image [TM bands 7, 4, and 3];courtesy of NASA.)