Human T-lymphotropic virus 1 and 2 among people who used illicit drugs in the state of Pará, northern Brazil

Abstract

People who used illicit drugs (PWUDs) represent an important population group for acquisition and viral dispersion. In Brazil, high rates of the human T lymphotropic virus 1 (HTLV-1) and 2 (HTLV-2) have been reported in epidemiological studies. However, the epidemiological scenario of HTLV-1/2 infections in PWUDs is still poorly understood. Thus, this cross-sectional study determined the prevalence, frequency of subtypes and factors associated with HTLV-1/2 infections among PWUDs in the Brazilian state of Pará, an area considered endemic for this virus and with poor health services. Among 826 PWUDs, 53 (6.4%) presented anti-HTLV-1/2 antibodies by EIA and 44 (5.3%) presented proviral DNA by PCR. HTLV-1 and HTLV-2 were detected in 25 (3.0%) and 19 (2.3%) PWUDs, respectively. Subtypes 1a (25/44), transcontinental (23/44) and Japanese subgroups (2/44), 2b (6/44) and 2c (13/44) were identified. Involvement in illicit/criminal activity, daily use of illicit drugs, illicit drug use over 12 years, unprotected sex with other PWUDs, changes in genitalia (including ulcers and wounds), and more than 12 sexual partners were associated with HTLV-1/2 in PWUDs. This high prevalence and intense circulation of subtypes and subgroups of HTLV-1/2 is very worrying, and indicate the need for urgent actions for its control, prevention and treatment.

Figure 1

Geographic location of collection points and information of people who used illicit drugs in 28 municipalities in the state of Pará (PA), northern Brazil. Points = municipalities: (1) Afuá*; (2) Anajás*; (3) Soure*; (4) Salvaterra*; (5) Ponta de Pedras*; (6) São Sebastião da Boa Vista*; (7) Curralinho*; (8) Bagre*; (9) Breves; (10) Melgaço*; (11) Gurupá*; (12) Belém; (13) Benevides; (14) Bragança; (15) Castanhal; (16) Marituba; (17) Abaetetuba; (18) Almeirim*; (19) Cametá; (20) Capanema; (21) Marabá; (22) Parauapebas; (23) Altamira; (24) Óbidos; (25) Porto de Moz*; (26) Santarém; (27) Tucuruí; (28) Augusto Correa*. *Municipality considered small (<50,000 inhabitants).

Figure 2

Rooted phylogenetic tree, showing the evolutionary relationship of human T-lymphotropic virus 1 strains, including the strains detected among people who used illicit drugs in the Brazilian state of Pará (indicated by arrows). The tree was constructed by the Bayesian method after alignment of 409 nucleotides of the 5′ LTR. The statistical support was applied using 1000 bootstrap replicates. *Boostrap values: ≥90% and posterior probabilities ≥0.95.

Figure 3

Rooted phylogenetic tree, showing the evolutionary relationship of human T-lymphotropic virus 2 strains, including the strains detected among people who used illicit drugs in the Brazilian state of Pará (indicated by arrows). The tree was constructed by the Bayesian method after alignment of 408 nucleotides of the 5’ LTR. The statistical support was applied using 1000 bootstrap replicates. *Boostrap values: ≥90% and posterior probabilities ≥0.95.