Prevalence of human T-lymphotropic virus type 1 and 2 (HTLV-1/-2) infection in pregnant women in Brazil: a systematic review and meta-analysis

Augusto Bacelo Bidinotto,Vanessa Martins de Oliveira,Eliana Márcia Wendland,William Jones Dartora,Luana Giongo Pedrotti,Bruna Angelo Vieira

doi:10.1038/s41598-021-94934-7

Abstract

Human T-lymphotropic virus type 1 (HTLV-1) infection may cause serious disease, while pathogenicity of HTLV-2 is less certain. There are no screening or surveillance programs for HTLV-1/-2 infection in Brazil. By performing this systematic review, we aimed to estimate the prevalence of HTLV-1/-2 infections in pregnant women in Brazil. This review included cohort and cross-sectional studies that assessed the presence of either HTLV-1/-2 infection in pregnant women in Brazil. We searched BVS/LILACS, Cochrane Library/CENTRAL, EMBASE, PubMed/MEDLINE, Scopus, Web of Science and gray literature from inception to August 2020. We identified 246 records in total. Twenty-six of those were included in the qualitative synthesis, while 17 of them were included in the meta-analysis. The prevalence of HTLV-1 in Brazilian pregnant women, as diagnosed by a positive screening test and a subsequent positive confirmatory test, was 0.32% (95% CI 0.19–1.54), while of HTLV-2 was 0.04% (95% CI 0.02–0.08). Subgroup analysis by region showed the highest prevalence in the Northeast region (0.60%; 95% CI 0.37–0.97) for HTLV-1 and in the South region (0.16%; 95% CI 0.02–1.10) for HTLV-2. The prevalence of HTLV-1 is much higher than HTLV-2 infection in pregnant Brazilian women with important differences between regions. The prevalence of both HTLV-1/-2 are higher in the Northeast compared to Center-West region.

Highlights

The human T-lymphotropic virus type 1 (HTLV-1), known as human T-cell leukemia virus, was the first human retrovirus to be discovered and isolated[1], and over the years other human T-lymphotropic viruses subtypes have been discovered[2,3,4]
We found that the prevalence of Human T-lymphotropic virus type 1 (HTLV-1) in pregnant women in Brazil is much higher than HTLV-2 with important differences between regions
The prevalence of both HTLV-1 and -2 are higher in the Northeast compared to Center-West region

Summary

Introduction

The human T-lymphotropic virus type 1 (HTLV-1), known as human T-cell leukemia virus, was the first human retrovirus to be discovered and isolated[1], and over the years other human T-lymphotropic viruses subtypes have been discovered[2,3,4] It is mainly transmitted through sexual contact, sharing of syringes and needles, blood transfusion and vertical transmission from mother to child through breastfeeding[5]. Adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are the conditions most commonly associated with HTLV-1 infection; while development of these conditions is relatively rare, their unfavorable prognosis makes them important. Despite significant morbidity and mortality in some cases, persons with HTLV-1 infection are otherwise mostly asymptomatic[5,17] This makes cases hard to detect and creates silent networks of transmission in restricted areas with high endemicity, contributing to the HTLV-1 distribution in somewhat well-delimited clusters. Its main modes of transmission tend to vary by study area; sexual transmission is predominant in some a reas[18], while some authors report that transmission is common through b reastfeeding[19,20,21]

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