Bacteria, viruses and parasites have frequently been associated with gastroenteritis among Amerindians living in the Amazon region. Shigella flexneri has been found in 4% of diarrhoeic specimens collected from Parakanã Indians. In addition, antibodies to the E. coli labile toxin have been detected in 98% of Indians belonging to the Menkrangnotí, Parakanã, Xikrín and Asuriní communities. Both wild edemata and marsupials seem to be important Salmonella sp. reservoirs as studies have demonstrated the occurrence of infection in 63% and 20% of them, respectively. Shigella disenteriae has been isolated from 4.2% of Suruí Amerinds. Among the Kantiána, Shigella boydii (one isolate) and E. coli (11 isolates) were recovered from 85 specimens processed for bacterial enteropathogens. Rotaviruses were the causative agent of an extensive outbreak of diarrhoea among the Tiriyó, in July-August, 1977. By using the counter-immune-electro-osmophoresis, seroconversions were detected in 25.6 % of paired (pre- and post-epidemic) serum samples. Birmingham serotype I was identified as the causative agent of the outbreak, which affected at least 80% of the population at risk: the clinical attack rates were more prominent among both young children and the elderly. Studies on the prevalence of rotavirus antibody among 13 Indian communities in the Amazon region yielded, in general, positivity rates greater than 50%. However, the Parakanã Novo were found to be non-immune to rotaviruses. The increasing rates of seropositivity with age suggest the persistence of rotaviruses in these communities; in addition, high rates of positivity among young children suggest that rotavirus infection may be endemic. Both Suruí and Karitiána were found to have high prevalence rates of rotavirus antibody: 67.8 and 77.4, respectively. Wild marsupials may possibly play a role in the transmission of rotaviruses among Indians. Parasites have also been associated with gastrointestinal disease among Indians in the Amazon region. S. stercoralis and Entamoeba hystolitica have been detected among the Suruí in frequencies of 33.3%, 3.3% and 0.8%, respectively. Among the Pacaánova the same parasites have been recorded in frequencies of 3.9%, 12.7% and 8.8%, respectively. Entamoeba hystolitica was found in 40% of the Yanomámi The poor sanitation conditions and hygiene practices, as well as the possibility of the contact of Indians with wild reservoirs, account for the spread of enteropathogens within these communities in the Amazon region. Special precautions should be currently taken with respect to the possibility of the introduction of cholera among these Amerindians.
Amerindians; Diarrhea; Amazon Region
