Epidemiology of Diarrhea Due to Rotavirus on an Indian Reservation: Risk Factors in the Home Environment

Analysis of outpatient visits for diarrheal disease at the San Carlos Apache Reservation, Arizona, during 1977-1979 revealed a sharp increase in cases of infantile gastroenteritis of unknown etiology in October and November of each year. During the 1980 autumn diarrhea season, 19 patients and 12 control subjects were selected from among outpatients under two years of age and were interviewed and studied for bacterial and viral enteric pathogens. Eleven (58%) of 19 patients and two (170%) of 12 control subjects were positive for fecal rotavirus by enzyme-linked immunosorbent assay (P = 0.03). Ten (91%) of 11 rotavirus-positive patients were under one year of age. The most significant risk factor for illness was the presence of a household contact under the age of two years (P = 0.004). Dog ownership was also associated with rotavirus infection (P = 0.05). Seroepidemiologic studies in both developed and developing countries show that most children acquire antibody to rotavirus before three years of age [1, 2]. Early exposure to the virus is universal in spite of strikingly different sanitary conditions in different countries. However, hospital-based studies indicate that the median age of patients with diarrhea due to rotavirus differs among various ethnic subpopulations in the same geo