A CASE-CONTROL STUDY OF HANTAVIRUS PULMONARY SYNDROME DURING AN OUTBREAK IN THE SOUTHWESTERN UNITED-STATES

In May 1993, an outbreak of hantavirus pulmonary syndrome (HPS) occurr ed in the southwestern United States. A case-control study determined risk factors for HPS. Seventeen case-patients were compared with 3 gro ups of controls: members of case-patient households (household control s), members of neighboring households (near controls), and members of randomly selected households greater than or equal to 24 km away (far controls). Investigators trapped more small rodents at case households than at near (P = .03) or far control households (P = .02). After the number of small rodents was controlled for, case-patients were more l ikely than household controls to hand plow (odds ratio [OR], 12.3; 95% confidence interval [CI], 1.1-143.0) or to clean feed storage areas ( OR, 33.4; 95% CI, 1.7-666.0). Case-patients were more likely than near controls to plant (OR, 6.2; 95% CI, 1.1-34.0) and more likely than fa r controls to clean animal sheds (OR, 11.9; 95% CI, 1.4-103.0). Perido mestic cleaning, agricultural activities, and an increased number of s mall rodents at the household were associated with HPS.