Prevalence of antibody against influenza A viruses in the Kren-Akorore, an Indian tribe of Central Brazil, first contacted in 1973

Abstract

Influenza A antibodies in serum samples obtained in 1980 from two Indian populations in Central Brazil were compared. The Kren-Akorore, who were first contacted in 1973 and two years later transferred to the Xingu Indian Park (PIX), were compared with Indians from other tribes already living in the PIX before 1975. An analysis was made of the prevalence and distribution of antibodies against the influenza A viruses which have circulated in the civilized world since 1918. Antibodies to the early influenza A viruses were absent in both Indian populations, but A/Hong Kong/1/68 (H3N2) virus apparently circulated in the PIX. No antibody to influenza A/Bangkok/1/79 or to A/Brazil/11/78 (H1N1) was found in any of the sera, whereas antibodies to these viruses were commonly found in urban populations in Brazil. The evidence from influenza antibodies agrees with the information that the Kren-Akorore Indians had been living in complete isolation until 1973, when they were first contacted.

Antes sós do que mal acompanhados: contato e contágio com povos indígenas isolados e de recente contato no Brasil e desafios para sua proteção e assistência à saúde

“…It was possible to verify that none of those examined had antibodies against the influenza viruses that circulated in the world until 1967, when Funai attraction front's work began (Chart 2). Only 5% of contact survivors had antibodies against influenza viruses that circulated until 1973, the year of official contact, and 55% of survivors had antibodies against influenza viruses that circulated until 1980, the year the study was conducted (Nascimento et al, 1985;Rodrigues, 2013).…”