Spread of Human T-Lymphotropic Virus 1 and 2 Among Relatives of People Who Use Illicit Drugs in Northern Brazil

Aldemir Branco Oliveira-Filho; Paula Cristina Rodrigues Frade; Ricardo Roberto de Souza Fonseca; Leila Sawada; Luísa Caricio Martins; Luiz Fernando Almeida Machado; Antonio Carlos Rosário Vallinoto; Ricardo Ishak; José Alexandre Rodrigues de Lemos; Benedikt Fischer; Emil Kupek

doi:10.3389/fmicb.2022.889948

Spread of Human T-Lymphotropic Virus 1 and 2 Among Relatives of People Who Use Illicit Drugs in Northern Brazil

Front Microbiol. 2022 Jun 3:13:889948. doi: 10.3389/fmicb.2022.889948. eCollection 2022.

Authors

Aldemir Branco Oliveira-Filho^{1

2}, Paula Cristina Rodrigues Frade², Ricardo Roberto de Souza Fonseca³, Leila Sawada⁴, Luísa Caricio Martins^{2

5}, Luiz Fernando Almeida Machado^{3

6}, Antonio Carlos Rosário Vallinoto^{3

6}, Ricardo Ishak^{3

6}, José Alexandre Rodrigues de Lemos⁶, Benedikt Fischer^{7

8}, Emil Kupek⁹

Affiliations

¹ Instituto de Estudos Costeiros, Universidade Federal do Pará, Bragança, Brazil.
² Programa de Pós-graduação em Doenças Tropicais, Universidade Federal do Pará, Belém, Brazil.
³ Programa de Pós-graduação em Biologia de Agentes Infecciosos e Parasitários, Universidade Federal do Pará, Belém, Brazil.
⁴ Seção de Virologia, Instituto Evandro Chagas, Ministério da Saúde, Ananindeua, Brazil.
⁵ Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Brazil.
⁶ Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil.
⁷ Faculty of Medical and Health Sciences, University of Auckland, Grafton, New Zealand.
⁸ Centre for Applied Research in Mental Health and Addiction, Faculty of Health Sciences, Simon Fraser University, Vancouver, BC, Canada.
⁹ Departamento de Saúde Pública, Universidade Federal de Santa Catarina, Florianópolis, Brazil.

Abstract

The human T-lymphotropic virus 1 (HTLV-1) and 2 (HTLV-2) can be transmitted between humans by mechanisms associated with horizontal and vertical routes. Recently, high prevalence rates and levels of genetic diversity for HTLV-1 and HTLV-2 were detected among people who use illicit drugs (PWUDs) in the Brazilian state of Pará. None of the PWUDs with HTLV-1 or HTLV-2 were aware of their carrier condition of the retrovirus, and they ability to spread it to their family group, sexual partners, and other contacts. Thus, this study evaluated the presence of HTLV-1 and HTLV-2 in families of PWUDs in the state of Pará, in Northern Brazil. This descriptive study used convenience sampling and accessed 37 PWUDs and their respective families (n = 97) in 18 municipalities in the state of Pará, northern Brazil. All participants provided personal data and were tested for the presence of HTLV-1 and HTLV-2 using enzyme-linked immunosorbent assay and western blotting. HTLV positive samples were selected for Nested-PCR, and viral genotyping by nucleotide sequencing and phylogenetic analysis. HTLV-1 or HTLV-2 infections were detected in 15 families of PWUDs: 27 family members of PWUDs were infected with HTLV-1 (27.8%) and another 20 of them with HTLV-2 (20.6%). Subtypes 1a [subgroup A (54.5%)], 2b (20.5%), and 2c (25.0%) were detected. High horizontal (76.9%) and vertical (61.4%) transmission rates of HTLV were ascertained. Factors that facilitate the acquisition and transmission of HTLV-1 and HTLV-2 were reported by the participants, such as long-term relationships, unprotected sex, breastfeeding, and lack of knowledge about the condition of being a carrier of the retrovirus. Evidence indicates intrafamilial transmission of HTLV from PWUDs to members of their respective families. Key interventions should urgently be employed for the control and prevention of HTLV-1 and HTLV-2 to reduce the spread of this retrovirus in PWUDs and the general population in Northern Brazil and elsewhere.

Keywords: Brazil; HTLV; epidemiology; intrafamilial transmission; prevention; public health strategies; use of illicit drugs.