Human T-cell lymphotropic virus type II in Guaraní Indians, Southern Brazil

Menna-Barreto, Marcio; Bender, Ana Lígia; Bonatto, Sandro L.; Freitas, Loreta B.; Salzano, Francisco M.; Tsuneto, Luiza Tamie; Petzl-Erler, María Luiza

doi:10.1590/s0102-311x2005000600045

Cited by 16 publications

(8 citation statements)

References 23 publications

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“…The history of HTLV is a fascinating one regarding its possible origin in the African continent and its spread in different directions according to human migration routes [4], and the ARB is of paramount importance because of the presence of a specific strain of the virus that originated during human migration into the area and its further dissemination to other geographical areas in the country and abroad [36,51,[91][92][93][94][95][96][97].…”

Section: The Amazon Region Of Brazilmentioning

confidence: 99%

The challenge of describing the epidemiology of HTLV in the Amazon region of Brazil

Ishak

Vallinoto

2020

Retrovirology

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HTLV-1 was the first described human retrovirus and was soon found to be associated with severe clinical diseases, including a devastating lymphoma/leukemia and other inflammatory diseases. Although HTLV-2 is not usually pathogenic, it is widely distributed among native Indian populations in Brazil, particularly in the Amazon region of the country. Presently, HTLV spreads mainly by the sexual route and from mother to child, and virus persistence is an active biological factor aiding its transmission. Recently, the use of illicit drugs has been shown to be an additional risk factor, showing the influence of new habits on the epidemiology of HTLV in the region. Despite the detection of the virus in several different populations in the Amazon region of Brazil for almost 30 years, the exact prevalence of HTLV-1/2 is not well defined. The original biases in sampling and the selection of epidemiologically unsuitable populations were commonly repeated in most prevalence studies, generating unreliable and conflicting figures that do not represent the actual prevalence of HTLV. The improvements in clinical and laboratory facilities have resulted in the description of several clinical manifestations that were previously unknown in the region. The extent of the spread of the virus must be defined in this region, which is the largest geographical area of the country. As prophylaxis advances toward the use of vaccines against HTLV-1, it is important to determine who is at risk of being infected and developing a disease to successfully implement preventive measures, particularly as proposals are made to eradicate the virus among humans.

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Section: The Amazon Region Of Brazilmentioning

confidence: 99%

The challenge of describing the epidemiology of HTLV in the Amazon region of Brazil

Ishak

Vallinoto

2020

Retrovirology

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“…HTLV-2 is prevalent in native populations, such as indigenous peoples in the Americas and Pygmy tribes in Africa, and in intravenous drug users [15][16][17][18][19] . Despite a 65% homology with HTLV-1, HTLV-2 has not been consistently associated with human disease; however, neurological disorders similar to HAM/TSP have been observed in patients with HTLV-2 infection 15,20 .…”

Section: Introductionmentioning

confidence: 99%

Sexual transmission of human T-cell lymphotropic virus type 1

Paiva

Casseb

2014

Rev. Soc. Bras. Med. Trop.

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Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic in many parts of the world and is primarily transmitted through sexual intercourse or from mother to child. Sexual transmission occurs more effi ciently from men to women than women to men and might be enhanced by sexually transmitted diseases that cause ulcers and result in mucosal ruptures, such as syphilis, herpes simplex type 2 (HSV-2), and chancroid. Other sexually transmitted diseases might result in the recruitment of infl ammatory cells and could increase the risk of HTLV-1 acquisition and transmission. Additionally, factors that are associated with higher transmission risks include the presence of antibodies against the viral oncoprotein Tax (anti-Tax), a higher proviral load in peripheral blood lymphocytes, and increased cervicovaginal or seminal secretions. Seminal fl uid has been reported to increase HTLV replication and transmission, whereas male circumcision and neutralizing antibodies might have a protective effect. Recently, free virions were discovered in plasma, which reveals a possible new mode of HTLV replication. It is unclear how this discovery might affect the routes of HTLV transmission, particularly sexual transmission, because HTLV transmission rates are signifi cantly higher from men to women than women to men.

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“…[1][2][3] In Brazil, considered the country with the largest number of people infected by HTLVs, 4 HTLV-2 is considered endemic among indigenous populations of the Amazon region and among Indians of the south region, and is present in IDUs of urban areas and in patients with HIV/AIDS. [5][6][7][8][9][10] The HTLV-1/2 are low replicating viruses, thus have little genetic sequence variation. 11,12 However, the env structural gene and the long terminal repeat (LTR) region containing the viral promoter are the most variable regions, thus are useful for virus subtyping.…”

Section: Introductionmentioning

confidence: 99%

Human T Cell Lymphotropic Virus Type 2a Strains Among HIV Type 1-Coinfected Patients from Brazil Have Originated Mostly from Brazilian Amerindians

Magri

Brígido²,

Morimoto³

et al. 2013

AIDS Research and Human Retroviruses

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The human T cell lymphotropic virus type 2 (HTLV-2) is found mainly in Amerindians and in intravenous drug users (IDUs) from urban areas of the United States, Europe, and Latin America. Worldwide, HTLV-2a and HTLV-2b subtypes are the most prevalent. Phylogenetic analysis of HTLV-2 isolates from Brazil showed the HTLV-2a subtype, variant -2c, which spread from Indians to the general population and IDUs. The present study searched for the types of HTLV-2 that predominate among HIV-1-coinfected patients from southern and southeastern Brazil. Molecular characterization of the LTR, env, and tax regions of 38 isolates confirmed the HTLV-2c variant in 37 patients, and one HTLV-2b in a patient from Paraguay. Phylogenetic analysis of sequences showed different clades of HTLV-2 associated with risk factors and geographic region. These clades could represent different routes of virus transmission and/or little diverse evolutionary rates of virus. Taking into account the results obtained in the present study and the lack of the prototypic North American HTLV-2a strain and HTLV

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Human T-cell lymphotropic virus type II in Guaraní Indians, Southern Brazil

Cited by 16 publications

References 23 publications

The challenge of describing the epidemiology of HTLV in the Amazon region of Brazil

The challenge of describing the epidemiology of HTLV in the Amazon region of Brazil

Sexual transmission of human T-cell lymphotropic virus type 1

Human T Cell Lymphotropic Virus Type 2a Strains Among HIV Type 1-Coinfected Patients from Brazil Have Originated Mostly from Brazilian Amerindians

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