ABSTRACT Objective To detect and treat cases of viral hepatitis B, C and D in patients seen at the Native American Outpatient Clinic of Universidade Federal de São Paulo. Methods This sample comprised 81 indigenous recruited between 2018 and 2020. Volunteers were aged 7 months to 70 years (mean age of 28±20 years), belonged to 26 ethnic groups spanning the Brazilian territory and answered a questionnaire, which was attached to their medical records. Peripheral blood samples (20mL) were collected, transported to the Clinical Laboratory of Hospital Israelita Albert Einstein, processed, and tested for markers of viral hepatitis B, C and D. Results In this study, 39 (48.1%) individuals were anti-HBs (+) only, 13 (16.0%) individuals were anti-HBs (+) and anti-HBc (+), and 28 (34.6%) individuals were negative for all markers. No anti-HBc IgM+ samples were found. No cases of hepatitis C and D were found. Conclusion This analysis provided evidence of previous infection by the hepatitis B virus. These findings led to prescription of vaccination against hepatitis B to all participants who were negative for all viral hepatitis B markers, given records of prior hepatitis B vaccination were unreliable.

Um estudo de soroprevalência para detectar anticorpos totais contra o Vírus da Hepatite A foi realizado com 220 amostras obtidas de 589 indivíduos de cinco aldeias indígenas das tribos Kaiabi e Kuikuro, as mais populosas do Parque Nacional do Xingu, Brasil. Utilisando um kit comercial de ensaio imunoenzimático, detectamos 97,7% amostras positivas (Intervalo de Confiança de 95%: 95%-99%), com uma soroconversão precoce, antes dos seis anos de idade, quando a doença costuma ser assintomática. Estes resultados são semelhantes aos resultados encontrados na literatura em estudos com populações não-indígenas das regiões Norte, Nordeste e Centro-Oeste do Brasil, e sugere que não há necessidade de introdução de vacinação contra Hepatite A nestas populações de alta endemicidade.

A seroprevalence study to detect total antibodies against Hepatitis A Virus was done with 220 samples from 589 Native Indians from Xingu National Park, Brazil, in five Kaiabi and Kuikuro villages, the most populous ethnic groups. Using a commercial immunoassay kit we detected 97.7% positive samples (95% Confidence Interval: 95%-99%). We noticed a precocious seroconversion, before the age of six years, when the disease is usually asymptomatic. These results are similar to those found in the literature in non-Indian population studies of the Northern, Northeastern and West Central regions of Brazil. They suggest that it is not necessary to introduce vaccination against Hepatitis A in these highly endemic populations.

O objetivo do estudo foi aferir a prevalência de anticorpos IgG contra o Vírus Varicela-Zoster (VVZ) nos dois grupos étnicos indígenas mais povoados do Parque Nacional Indígena do Xingu, Brasil, antes da introdução da vacinação contra a doença, e determinar os valores preditivos positivo e negativo da história de infecção de varicela. Em 2001, 589 habitantes de duas aldeias Kuikuro e três aldeias Kaiabi foram avaliados e forneceram dados referentes à infecção prévia por varicela. Um ensaio imunoenzimático indireto (ELISA) foi realizado em 224 amostras de sangue para detectar anticorpos IgG anti-VVZ - a seleção de voluntários não teve interferência da anamnese. A prevalência de IgG foi de 80,8% (Intervalo de Confiança de 95%: 76% - 86%). A soroepidemiologia de varicela no Parque Nacional do Xingu antes da introdução da vacina foi comparável à soroprevalência nacional descrita na literatura, assim como os valores preditivos positivo (98%) e negativo (41%) da história referida.

The purpose of the study was to estimate the prevalence of IgG antibodies against varicella zoster virus (VZV) in the two most populated indigenous ethnic groups from Xingu Indigenous National Park, in Brazil, prior to the introduction of vaccination against the disease, and to determine the positive and the negative predictive values of a history of varicella infection. In 2001, 589 inhabitants of two Kuikuro villages and three Kaiabi villages were evaluated and provided information concerning previous varicella infection. An indirect immunosorbent assay (ELISA) to detect IgG anti-VZV antibodies was performed in 224 blood samples - volunteer selection had no interference of anamnesis. IgG prevalence was 80.8% (95% Confidence Interval: 76% - 86%). The seroepidemiology of varicella in Xingu National Park prior to varicella vaccine introduction was comparable to the Brazilian national seroprevalence described in the literature, and so were the positive (98%) and the negative predictive value (41%) of the referred history.