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The Potential Effect of Global Warming on the Geographic and Seasonal Distribution of Phlebotomus papatasi in Southwest Asia
Eleanor R. Cross and Kenneth C. Hyams
Infectious Disease Threat Assessment Division, Naval Medical Research Institute, Bethesda, MD 20889-5607 USA
Abstract The distribution of Phlebotomus papatasi in Southwest Asia is thought to be highly dependent on temperature and relative humidity. A discriminant analysis model based on weather data and reported vector surveys was developed to predict the seasonal and geographic distribution of P. papatasi in this region. To simulate global warming, temperature values for 115 weather stations were increased by 1°C, 3°C, and 5°C, and the outcome variable coded as unknown in the model. Probability of occurrence values were then predicted for each location with a weather station. Stations with positive probability of occurrence values for May, June, July, and August were considered locations where two or more life cycles of P. papatasi could occur and which could support endemic transmission of leishmaniasis and sandfly fever. Among 115 weather stations, 71 (62%) would be considered endemic with current temperature conditions ; 14 (12%) additional stations could become endemic with an increase of 1°C ; 17 (15%) more with a 3°C increase ; and 12 (10%) more (all but one station) with a 5°C increase. In addition to increased geographic distribution, seasonality of disease transmission could be extended throughout 12 months of the year in 7 (6%) locations with at least a 3°C rise in temperature and in 29 (25%) locations with a 5°C rise. Key words: global warming, leishmaniasis, Phlebotomus papatasi, sandfly, sandfly fever, Southwest Asia. Environ Health Perspect 104:724-727 (1996) Address correspondence to E.R. Cross, Naval Medical Research Institute, 12300 Washington Avenue, Rockville, MD 20852 USA. This research was supported by the U.S. Naval Medical Research and Development Command, workunit number 62787A001.01EAX1288. The opinions and assertions contained herein are those of the authors and are not to be construed as official or as reflecting the views of the U.S. Departments of the Navy or Defense. Received 16 January 1996 ; accepted 2 April 1996. The full version of this article is available for free in HTML format. |