The COVID-19 pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) reached the Brazilian Amazon and spread among indigenous populations. In the present study, we demonstrate a high prevalence of infection among the Xikrin of Bacajá people (Kayapó). A sample of 100 individuals of both sexes (51 men and 49 women) with ages ranging from 2 to 82 years were clinically evaluated and tested for the presence of anti-SARS-CoV-2 IgG antibody. Among all investigated individuals, 58 were IgG-reactive (58 %) by a rapid test, and 73 (73 %) were reactive in an enzyme-linked immunosorbent assay, with no difference between sexes. Oxygen saturation ranged from 82 to 99 %, with the lowest value observed in a two-year-old girl. The results show that as expected, SARS-CoV-2 infection rapidly reached more than 70 % of the population, most likely because of the difficulties of maintaining social distance due to cultural characteristics. These results highlight the importance of indigenous health policies as a means of minimizing the impact of the pandemic on these communities.

ObjectivesThe emergence of SARS-CoV-2 and its pandemic spread generated serious concern about the impact of the infection on vulnerable indigenous populations of the Brazilian Amazon. Thus, this study aimed to perform a seroepidemiological survey of anti-SARS-CoV-2 antibodies in those populations.SettingSix indigenous ethnic groups living in the State of Pará (Northern Brazil) were investigated. The villages of Xikrin do Bacajá, Assurini, Araweté, Parakanã, Munduruku and Kararaô were visited from October 2020 to January 2021.Design and participantsWe performed a cross-sectional study to investigate the prevalence of anti-spike (S1) IgG antibodies. Plasma was tested for the presence of anti-SARS-CoV-2 IgM and IgG antibodies using two assays (a lateral flow rapid test and an ELISA). A total of 1185 individuals of both sexes were enrolled in the study.ResultsThe prevalences of IgM and IgG antibodies were 6.9% and 68.1%, respectively, ranging from 0% to 79.6%, with significant differences (p<0.001) between age groups in three communities (Araweté, Xikrin and Munduruku) and a virulence rate of 0.86%. The overall IgG prevalence obtained by rapid tests and ELISAs were similar, and the agreement of the results between the two tests was 80%, which was classified as good (kappa=0.4987; p<0.001; sensitivity of 82.1% and specificity of 71.6%). Herd immunity was probably attained, similar to that found in other communities of the Amazon.ConclusionsSARS-CoV-2 spread rapidly among the indigenous populations investigated, but it had a low mortality rate. It is necessary to expand serological investigations to other communities in the Amazon region of Brazil.

HTLV-1/2 infection is endemic in Indigenous peoples of the Americas. Its origin is attributed to the migratory flow of Amerindian ancestral peoples. The present study aimed to investigate the seroprevalence of HTLV-1/2 infection in Indigenous peoples of the Brazilian Amazon. A total of 3350 Indigenous people belonging to 15 communities were investigated. The investigation was performed using serological (ELISA), molecular (qPCR) and confirmatory (Western blot and/or Inno-Lia) tests to detect and differentiate the infection. The seroprevalence was 8.3% for HTLV-1/2 infection, with 0.1% of individuals seropositive for HTLV-1 and 8.1% for HTLV-2. The prevalence of infection was statistically higher in women (10.1%) than in men (6.5%) (p = 0.0002). This female predominance was observed in all age groups; in females the prevalence was significant from 41 years old (p < 0.0001) and in males from 51 years old (p < 0.0001). Here, we present a prevalence of HTLV-1/2 among Indigenous peoples of the Brazilian Amazon. The endemic infection in these groups must reflect the different epidemiological profiles observed in these peoples, such as sexual transmission through rejection of condom use, breastfeeding, especially in cases of cross-breastfeeding, and the high rate of pregnancy in the villages.

Background The emergence of the new causative agent of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the city of Wuhan, China, in December 2019, and its spread worldwide, led the World Health Organization (WHO) to declare a pandemic. The disease has caused high mortality among traditional populations and the most socially vulnerable groups such indigenous and refugees. The present study aims to investigate the prevalence of anti-SARS-CoV-2 IgG antibodies in the population of Venezuelan indigenous Warao refugees residing in private and public shelters in the city of Belem, capital of Para State, in the Brazilian Amazon. Methods One hundred one individuals of both sexes (43 men and 58 women) with ages varying from 18 to 77 years (average of 36 years) were investigated. Whole blood samples were collected and subsequently separated into plasma and leukocytes. Serological analysis was performed using an enzyme-linked immunosorbent assay - ELISA (Anti-SARS-COV-2 S1 IgG, EUROIMMUN, USA). Results The results indicate a positive serum prevalence of 83.2% (84), of which 77.6% (45/58) were females and 90.7% (39/43) were males. An indeterminate profile was observed in 6.9% (7), where it was not possible to confirm the presence of antibodies, and 9.9% (10) individuals were negative for IgG antibodies. Conclusions The finding of the high seroprevalence of IgG anti-SARS-CoV-2 antibodies reveals a high exposure of the Warao population in Belem to infection with the new coronavirus. These results underscore the importance of maintaining epidemiological surveillance with testing in traditional populations due to the high possibility of spreading the virus, especially among the most socioeconomically vulnerable groups, which depend exclusively on the Unified Health System (SUS), such as refugees and indigenous people.

The devastating effect of health system overload was observed after cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) peaked in April 2020 in Belém, a capital metropolis in the Brazilian Amazon. Our results showed a high seroprevalence (39.24%) of anti-SARS-CoV-2 IgG antibodies among the population of the capital of the state of Pará after the first wave of the pandemic. Old age, mixed race, a high school education level, low income and contact with infected individuals are risk factors and may be driving seropositivity and exposure to SARS-CoV-2 in this population. This study is one of the first to provide important information to understand the socioeconomic inequalities, behavioral characteristics and viral transmission dynamics associated with the risk of SARS-CoV-2 infection in the capital of the state of Pará, northern Brazil.

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) are retroviruses that originated on the African continent and dispersed throughout other continents through human migratory flows. This study describes the prevalence of HTLV-1 and HTLV-2 infection in residents of 11 quilombo remnant communities in the state of Pará, Brazil, and the associated risk factors. A total of 859 individuals (334 men and 525 women), aged between 7 and 91 years, participated in the study. All subjects answered a questionnaire with questions on sociodemographic characteristics and on risk factors associated with HTLV infection, and blood samples were collected and separated into plasma and leukocytes. An immunoenzymatic assay (ELISA; Murex HTLV-I+II, DiaSorin, Dartford, UK) was used as a screening test, and positive samples were subjected to line immunoassay confirmatory tests (Inno-LIA HTLV I/II Score FUJIREBIO) and DNA extraction for subsequent real-time PCR to differentiate the viral type. Four of the 859 individuals were seropositive for HTLV. HTLV-1 infection was confirmed in one individual from the Itamoari community (0.92%), and HTLV-2 infection was confirmed in two individuals from São Benedito (3.17%) and in one individual from Arimandeua (2.22%). Blood transfusion was the only risk factor associated with HTLV infection in this study. This study reports the occurrence of HTLV-1 and HTLV-2 in quilombo remnant communities in the state of Pará. Considering the African origin of the virus and its introduction into Brazil from the slave trade, the continued evaluation of quilombola communities in the state of Pará is essential to better characterize the distribution of infections in these populations and to create public health policies for the control of the spread of the virus and associated diseases.

IntroductionHuman T-lymphotropic virus (HTLV) infection is endemic in indigenous populations of the Americas. We describe herein the prevalence of HTLV-1 and HTLV-2 infection among Warao indigenous refugees from Venezuela living in Belém, Pará, Brazil.MethodsIn total, 101 individuals of both sexes (43 men and 58 women) between 18 and 77 years of age were investigated. Blood samples were collected and separated into plasma and leukocytes. Serological screening was performed using an enzyme-linked immunosorbent assay (ELISA; Murex HTLV-I+II, DiaSorin, Dartford, UK), and seropositive samples were submitted to proviral DNA extraction followed by real-time polymerase chain reaction (qPCR). A nested PCR of the env region (630 bp) followed by enzymatic digestion with XhoI was performed to identify the molecular subtype of HTLV-2, in addition to sequencing analysis of the 5'LTR-I and 5′-LTR-II regions.ResultsOf the 101 individuals analyzed, 3 (3.0%) were seropositive. Molecular analysis of the pol and tax genes confirmed the HTLV-1 infection in a 55-year-old woman and HTLV-2 infection in a man (68 years old) and a woman (23 years old). HTLV-2 strains were defined by enzymatic digestion as belonging to the HTLV-2b subtype. The sequencing of the 5′LTR regions confirmed the presence of subtype 2b and identified HTLV-1 as belonging to subtype 1A (Cosmopolitan) and the Transcontinental subgroup. Among the infected patients, it was possible to conduct medical interviews with two individuals after delivery of the result. One patient with HTLV-2 reported symptoms such as joint pain, foot swelling, frequent headache, dizziness and lower back pain. The HTLV-1-positive woman was diagnosed with a tumor, dementia, urinary incontinence, felt body pain, and had spots on her body. The presence of the HTLV-2b subtype highlights the prevalence of this molecular variant among indigenous South Americans, as well as the presence of HTLV-1 Transcontinental, which has a worldwide distribution.ConclusionThese results reveal a high prevalence of HTLV-1/2 infection among Warao immigrants, suggesting migratory flow as a virus spread mechanism among human populations and alert public authorities to the need to create epidemiological surveillance programs, public social and health policies aimed at welcoming immigrants in the Brazilian territory.

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) infection has been described in several Amazonian populations; however, there is still a lack of data on the prevalence of the virus in riparian populations living in rural areas of the state of Pará. The present study aimed to evaluate the prevalence of HTLV-1/2 infection in four riverine communities and one rural area in the state of Pará and to describe the possible risk factors for infection. A total of 907 individuals responded to an epidemiological survey and gave blood samples collected for anti-HTLV-1/2 antibodies by immunoenzymatic assay (EIA). The serum-reactive samples were subjected to confirmation by an in-line assay (Inno-Lia) and by proviral DNA screening using real-time PCR (qPCR). The total prevalence was 0.8% (7/907) for HTLV-1/2 (CI: 0.2−1.3%), with 0.66% HTLV-1 and 0.11% HTLV-2. The prevalence by sex was 0.7% in women (4/565) and 0.9% in men (3/342). Among seropositive patients, 83.3% (5/7) reported being sexually active, and 57.1% (4/7) reported not having the habit of using condoms during their sexual relations. Intrafamily infection was also observed. The results reinforce the need for public policies to prevent and block the spread of HTLV, especially in riparian communities that are subject to difficulties in accessing the Unified Health System (Sistema Único de Saúde/SUS) because infected individuals need clinical monitoring for surveillance and early diagnosis of symptoms associated with HTLV-1.