Abstract
The human T-lymphotropic virus (HTLV) is part of the group of retroviruses that share similar routes of transmission to the human immunodeficiency virus (HIV). Coinfection of these viruses can affect the clinical course of both infections, and reports have shown a quicker progression to AIDS and the development of HIV-related opportunistic infections. The current study investigated the demographic characteristics, prevalence, and the subtypes of HTLV among people living with HIV/AIDS (PLWHA) in the State of Pará, Northern Brazil. Blood samples were obtained from patients who were attending a reference unit that provides medical assistance to HIV-infected individuals in the State of Pará, Brazil, during the period of May 2016 to June 2017. Plasma samples were screened by ELISA tests to detect antibodies anti-HTLV-1/2. DNA and viral types were identified by real-time polymerase chain reaction (qPCR). All samples with viral DNA were submitted to nested PCR and nucleotide sequencing. The overall coinfection rate was 1.4% (5/368), and all samples were from subtype HTLV-1a. No cases of HTLV-2 infection were detected. The prevalence of HTLV-1 was higher in females (80%), individuals between 31 and 50 years of age, heterosexual, unmarried, with low monthly income, with secondary educational level or higher, sporadic condom usage, limited number of sexual partners, and no history of sexually transmitted infections. All samples from HTLV-1-infected patients were identified as strains belonging to the subtype 1a (Cosmopolitan), subgroup A (Transcontinental). This study identified that the prevalence of HIV/HTLV coinfection has dropped from 8 to 1.3% in the current investigation. There was a shift of HTLV subtype from a predominance of HTLV-2 infection in the past to an actual exclusively HTLV-1a. There was no significant association between economic, sociodemographic, and behavioral characteristics in HIV/HTLV coinfection.
Highlights
The human T-lymphotropic virus (HTLV) is part of a family of human retroviruses with four types, where the HTLV-1 and HTLV-2 are the most well-studied subtypes of HTLV
The numbers of HTLV-positive and -negative cases detected in this study were compared with the results found in two studies conducted with people living with HIV/AIDS (PLWHA) in the Brazilian State of Pará in 1998 (Vallinoto et al, 1998) and 2005 (Laurentino et al, 2005) in order to assess the epidemiological trend of HTLV infections
A big shift has been observed over time, showing a continuous decrease in human immunodeficiency virus (HIV)/HTLV coinfection prevalence, dropping from 8% in 1998 (Vallinoto et al, 1998) to 3.5% in 2005 (Laurentino et al, 2005) and to 1.3% in the current investigation
Summary
The human T-lymphotropic virus (HTLV) is part of a family of human retroviruses with four types, where the HTLV-1 and HTLV-2 are the most well-studied subtypes of HTLV. Transmission occurs mainly through vertical transmission (mother to child), unprotected sex, and exposure to infected blood such as blood transfusion and injectable drug users (Yoshida et al, 1982). These two retroviruses share transmission routes and are found in coinfection, which can result in quicker progression to AIDS, poorer prognosis of HIVrelated opportunistic infections, and a higher risk of developing neurological manifestations; the real impact of this coinfection remains controversial (Brites et al, 2009; Silva et al, 2012; de Mendoza et al, 2019). The prevalence of HTLV2 is lower than HTLV-1 in most places; it affects specific populations, such as native Amerindian groups and PWUDs (Ishak et al, 1995; Catalan-Soares et al, 2005; Murphy et al, 2015; Braço et al, 2019)
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