Climatic and Environmental Patterns Associated with Hantavirus Pulmonary Syndrome, Four Corners Region, United States

Abstract

To investigate climatic, spatial, temporal, and environmental patterns associated with hantavirus pulmonary syndrome (HPS) cases in the Four Corners region, we collected exposure site data for HPS cases that occurred in 1993 to 1995. Cases clustered seasonally and temporally by biome type and geographic location, and exposure sites were most often found in pinyon-juniper woodlands, grasslands, and Great Basin desert scrub lands, at elevations of 1,800 m to 2,500 m. Environmental factors (e.g., the dramatic increase in precipitation associated with the 1992 to 1993 El Niño) may indirectly increase the risk for Sin Nombre virus exposure and therefore may be of value in designing disease prevention campaigns.

Association between Hemorrhagic Fever with Renal Syndrome Epidemic and Climate Factors in Heilongjiang Province, China

“…4,[6][7][8][9][10][11][12] For example, increased grass seed production followed by heavy precipitation, as a result of the El Niñ o Southern Oscillation (ENSO), was found to be associated with higher Peromyscus maniculatus rodent density in southwestern United States and provides reservoirs for Sin Nombre virus. 13,[15][16][17] However, this result was not duplicated in other areas in the United States.…”

“…6,7,11,12 Some studies found that temperature had a positive effect, 6,11 and others found a negative effect on HFRS incidence. 7,12,13 The present study showed that monthly maximum temperature was positively associated with the monthly number of HFRS cases in this province, and other temperature factors, such as monthly minimum temperature and monthly mean temperature, were not included in the final model. A possible underlying mechanism for this finding is that temperature may affect the population density and hantavirus infection rate of rodents.…”

“…The association between HFRS epidemics and rainfall is still a matter of debate. Some studies showed that heavy rainfall followed by increased grass seed production was associated with higher deer mouse (Peromyscus maniculatus) densities, which caused an outbreak of hantavirus pulmonary syndrome in the Four Corners region of the United States, 13,16,17 and a negative relationship between rainfall and HFRS has also been reported. 8 There is no clear explanation for such difference, which may reflect heterogeneity in local climate conditions.…”

“…5,6 Although the infection rate and population dynamics of rodents are believed to be influenced by climatic factors, [7][8][9][10][11][12][13] the association between climate and host populations is complex in most places. 14 Studies in different areas have suggested that climate factors, such as temperature, precipitation, and relative humidity, may influence the incidence of HFRS.…”

Climate Change: Impact on Viral Diseases

“…It followed a dramatic increase in precipitation associated with the 1992 and 1993 El Niño phenomenon. This resulted in an abundance of rodent food resources (vegetation and insects) and a 20-fold rodent population increase, favouring viral transmission from rodent to human [15].…”