Predicted Hantavirus Risk in 2006 for the Southwestern U.S.

Landsat Thematic Mappers (TM) imagery taken in the year before the outbreak of hantavirus pulmonary syndrome (HPS) was previously related to the location of human cases of disease. In the paper we show that the logistic regression approach developed from that analysis was consistent for subsequent years during the 1990s. During the past six years a drought has affected the southwestern US and the numbers of HPS cases diminished, but with the interruption of the drought in 2004, there was concern that HPS would re-emerge. Analyses of TM images for 2004 indicated a generally low level of risk in the study area - a prediction substantiated by the occurrence of four cases in the lone high risk area. Examination of TM images for portions of southern Colorado and north-central New Mexico also indicated relatively low risk for 2005 and these results were confirmed. Risk analysis for 2006 predicts the HPS cases in the Four Corners area will be similar in frequency and distribution to those seen in 1998 and 1999. However, areas of southern Colorado and north central New Mexico show a marked increase in the level and geographic extent of predicted risk. Survey samples of Peromyscus maniculatus at two sites in north central New Mexico show crude prevalence rates of 23-34% to Sin nombre virus.