Prevalence and Risk Factors for HTLV-1/2 Infection inRiverside and Rural Populations of the State of Pará.

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.

The Relevance of a Diagnostic and Counseling Service for People Living With HTLV-1/2 in a Metropolis of the Brazilian Amazon.

Introduction: To identify the prevalence of infection in the urban area of the capital city of Belém, Brazil, the Laboratory of Virology of the Federal University of Pará implemented, as a public service, serological screening for human T-lymphotropic viruses 1 and 2 (HTLV-1/2) infection and, if necessary, counseling service and referral to specialized medical care. The project is funded by the National Council of Science and Technology, the Ministry of Health of Brazil and the Pan American Health Organization. Methods: From January 2020 to June 2021, 1,572 individuals of both sexes were approached to answer a questionnaire and were tested using an enzyme immunoassay (Murex HTLV-I+II, DiaSorin, Dartford, UK). Seropositive samples were confirmed as HTLV-1 and HTLV-2 infection by line immunoassay (INNO-LIA® HTLV I/II Score, Fujirebio, Japan) and/or by real-time polymerase chain reaction. G and Fisher's exact tests were applied to identify the association between epidemiological characteristics and HTLV-1/2 infection. Results: Of the 1,572 screened individuals, 63.74% were females between the ages of 30 and 59 years (49.04%). Infection was confirmed in six individuals (0.38%), among whom three (0.19%) were infected with HTLV-1 and three with HTLV-2 (0.19%). Blood transfusion before 1993 was the main risk factor associated with the route of exposure to the virus (p = 0.0442). The infected individuals were referred to a counseling session with a nursing professional, and two patients who manifested signs and symptoms suggestive of myelopathy associated with HTLV were referred to a neurologist. Conclusion: The implementation of the screening service revealed the occurrence of moderate endemicity of HTLV-1/2 in Belém, reinforcing the importance of continuing the service as a means of establishing an early diagnosis and providing counseling as a measure to prevent and control viral transmission in the general population.

HTLV-1 and HTLV-2 Infection Among Warao Indigenous Refugees in the Brazilian Amazon: Challenges for Public Health in Times of Increasing Migration.

INTRODUCTION: Human 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. METHODS: In 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. RESULTS: Of 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. CONCLUSION: These 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.

Isolation of the Arawete and Asurini Indians keeps the tribes free from HTLV infection during 36 years of follow-up.

Arawete and Asurini Indian tribes were revisited after a 36-year follow-up in search of HTLV infections. 46 persons (23 from each tribe) were tested for HTLV-1/2 antibodies and viral DNA. None were positive; this was probably because of their social/cultural isolation from neighboring tribes where HTLV-2c is hyperendemic.

High prevalence of human T-lymphotropic virus 2 (HTLV-2) infection in villages of the Xikrin tribe (Kayapo), Brazilian Amazon region.

BACKGROUND: Studies have shown that the human T-lymphotropic virus 2 (HTLV-2) is endemic in several indigenous populations of the Brazilian Amazon and molecular analyses have shown the exclusive presence of HTLV-2 subtype 2c among the indigenous groups of this geographical region. METHODS: The present study characterizes the prevalence of HTLV-2 infection in three new villages of the Xikrin tribe, in the Kayapo group, according to their distribution by sex and age. The study included 263 samples from individuals from the Kateté, Djujeko and Oodjã villages. Plasma samples were tested for the presence of anti-HTLV-1/2 antibodies using enzyme-linked immunosorbent assays (ELISA). Seropositive samples were confirmed using real-time PCR, nested PCR and sequencing. RESULTS: The serological and molecular results confirmed the sole presence of HTLV-2 in 77 (29%) samples, with a prevalence of 38% among women and 18% among men. In these communities, it was found that the prevalence of HTLV-2 infection increased with age. Nucleotide sequences (642 bp, 5'LTR) from eight samples were subjected to phylogenetic analysis by the neighbor-joining method to determine the viral subtype, which confirmed the presence of HTLV-2c. CONCLUSIONS: The results of the present study establish the presence of HTLV-2 infection in three new villages of the Xikrin tribe and confirm the high endemicity of the infection in the Kayapo indigenous group of the Brazilian Amazon.

Human JCV infections as a bio-anthropological marker of the formation of Brazilian Amazonian populations.

JC polyomavirus (JCV) is a member of the Polyomaviridae family. It presents a tropism to kidney cells, and the infection occurs in a variety of human population groups of different ethnic background. The present study investigated the prevalence of JCV infection among human populations from the Brazilian Amazon region, and describes the molecular and phylogenetic features of the virus. Urine samples from two urban groups of Belém (healthy subjects), one Brazilian Afro-descendant "quilombo" from the Rio Trombetas region, and native Indians from the Wai-Wai, Urubu-Kaapor, Tembé, Assurini, Arara do Laranjal, Aukre, Parakanã, Surui and Munduruku villages were investigated for the presence of the virus by amplifying VP1 (230 bp) and IG (610 bp) regions using a polymerase chain reaction. Nucleotide sequences (440 nucleotides, nt) from 48 samples were submitted to phylogenetic analysis. The results confirmed the occurrence of types A (subtype EU), B (subtypes Af-2, African and MY, Asiatic) and C (subtype Af-1) among healthy subjects; type B, subtypes Af-2 and MY, among the Afro-Brazilians; and type B, subtype MY, within the Surui Indians. An unexpected result was the detection of another polyomavirus, the BKV, among Afro-descendants. The present study shows, for the first time, the occurrence of JC and BK polyomaviruses infecting humans from the Brazilian Amazon region. The results show a large genetic variability of strains circulating in the region, infecting a large group of individuals. The presence of European, Asiatic and African subtypes associated to the ethnic origin of the population samples investigated herein, highlights the idea that JCV is a fairly good marker for studying the early migration of human populations, reflecting their early and late history. Furthermore, the identification of the specific mutations associated to the virus subtypes, suggests that these mutations have occurred after the entrance of the virus in the Amazon region of Brazil.