Characterization of an astrovirus genotype 2 strain causing an extensive outbreak of gastroenteritis among Maxakali Indians, Southeast Brazil.

Background: Human astroviruses (HAstVs) are a common cause of sporadic diarrhea in children but large outbreaks occur in children's day care centers, schools and in homes for the elderly.

Objectives: To report a large outbreak of acute gastroenteritis that occurred in January 2004 among Indians from the Maxakali Reserve in the State of Minas Gerais, Brazil.

Study Design: Fecal samples from 46 Maxakali patients were collected and tested for a range of enteric pathogens. HAstVs was detected by EIA and strains were confirmed by RT-PCR and typed by direct sequencing. Clinical information was collected.

Results: The illness which affected more than 100 children under 6 years of age was characterized by watery diarrhea, fever and vomiting. HAstV-2 was the sole enteropathogen detected in 26 (56%) of 46 samples analyzed by EIA and/or RT-PCR. The 17 positive samples sequenced were identical in a 348bp region used for phylogenetic analysis and were classified as genotype 2.

Conclusions: This is the first description of an outbreak of HAstV-2 gastroenteritis in a population of Brazilian Indians. The magnitude of the outbreak and the severity of the disease underscore the need to better understand the epidemiology of astrovirus and other enteric agents in these populations.