Update on hantavirus in Oklahoma: are we missing cases?

Hantavirus Pulmonary Syndrome (HPS) was first recognized in 1993. Through July 6, 2005, 396 cases have been reported in the US, including 50 from Kansas, Texas, and Oklahoma. We report the second case of HPS in Oklahoma and present data from rodent testing to support the presence of hantaviruses across Oklahoma. We examined Oklahoma death certificates for 1999-2003 for possible unreported HPS cases. The rate of death in young adults 15-49 years due to acute respiratory distress syndrome was 69% higher and the death rate due to unspecified respiratory failure was three times higher in the grassland area of Oklahoma as compared to the non-grassland. It appears the highest risk of HPS is in the Oklahoma grasslands but Sin Nombre virus is present in the non-grassland area as well. We request physician collaboration in detection and reporting of HPS cases and present brief recommendations for prevention.