New Insights into Prevalence, Genetic Diversity, and Proviral Load of Human T-Cell Leukemia Virus Types 1 and 2 in Pregnant Women in Gabon in Equatorial Central Africa

Abstract

Human T-cell leukemia virus type 1 (HTLV-1) is highly endemic in areas of central Africa; mother-to-child transmission and sexual transmission are considered to be the predominant routes. To determine the prevalence and subtypes of HTLV-1/2 in pregnant women in Gabon, we conducted an epidemiological survey in the five main cities of the country. In 907 samples, the HTLV-1 seroprevalence was 2.1%, which is lower than that previously reported. Only one case of HTLV-2 infection was found. The HTLV-1 seroprevalence increased with age and differed between regions (P < 0.05), with the highest prevalence (5%) in the southeastern region. A wide range of HTLV-1 proviral loads was observed among the infected women. The level of the proviral load was correlated with a high HTLV-1 antibody titer (P < 0.02). Sequencing of HTLV-1 env and long terminal repeat fragments showed that all but one strain belonged to the central African subtype B; the outlier was of cosmopolitan subtype A. The new strains of subtype B exhibited wide genetic diversity, but there was no evidence of clustering of specific genomes within geographical regions of the country. Some strains were closely related to simian T-cell leukemia virus type 1 strains of great apes, suggesting that in these areas some HTLV-1 strains could arise from relatively recent interspecies transmission. The sole HTLV-2 strain belonged to subtype B. In this study we showed that the prevalence of HTLV-1 in the southeast is one of the highest in the world for pregnant women.

HTLV infection among foreign pregnant women living in Spain

“…For the purpose of this study, Central and South America, Sub-Saharan Africa, Japan, Iran and Australia were considered as HTLV-1 endemic areas, although a wide range of HTLV-1 rates may exist within and between each of these regions. The median age of the study population was 29 (24)(25)(26)(27)(28)(29)(30)(31)(32) years.…”

One-Step, Multiplex, Real-Time PCR Assay with Molecular Beacon Probes for Simultaneous Detection, Differentiation, and Quantification of Human T-Cell Leukemia Virus Types 1, 2, and 3

“…Thus, molecular beacon probes remain compliant and flexible. Furthermore, these probes do not undergo hydrolysis during the elon- a The results for the samples obtained from pregnant women and the sequence data were published previously by Etenna et al (13). An asterisk indicates that data for the sample are newly reported in this paper.…”

Molecular Epidemiology and Clinical Features of Human T Cell Lymphotropic Virus Type 1 Infection in Spain

“…This variant has been reported to be endemic in Cameroon, the Central African Republic, and the Democratic Republic of Congo, being to date found exclusively in central Africa. 7,34 The individual we found to be infected with HTLV-1 subtype b came from Nigeria. We also found two individuals infected with HTLV-1 subgroup B and another two infected with subgroup D. Carriers of these variants within HTLV-1 subtype a were originally from Peru and Bolivia (subgroup B) and Mauritania and Senegal (subgroup D), respectively.…”