Description of a “Trans-Saharan” Strain of Human T-Lymphotropic Virus Type 1 in West Africa

Zehender, Gianguglielmo; Ebranati, Erika; Maddalena, Chiara De; Gianelli, Erika; Riva, Agostino; Rusconi, Stefano; Massetto, Benedetta; Rankin, Fanny; Acurie, Manuel; Galli, Massimo

doi:10.1097/qai.0b013e31816649a4

Cited by 16 publications

(17 citation statements)

References 29 publications

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“…In this study, HIV and HTLV-1 infections showed a cross-sectional association, as has been shown before in this study area in 1990 [25] and in the general adult population [16,41], elderly people [10], an occupational cohort [42] and pregnant women [43] in Bissau. Why this association is stronger for women than for men remains unclear.…”

Section: Discussionsupporting

confidence: 74%

HTLV-1 in rural Guinea-Bissau: prevalence, incidence and a continued association with HIV between 1990 and 2007

et al. 2010

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BackgroundHTLV-1 is endemic in Guinea-Bissau, and the highest prevalence in the adult population (5.2%) was observed in a rural area, Caió, in 1990. HIV-1 and HIV-2 are both prevalent in this area as well. Cross-sectional associations have been reported for HTLV-1 with HIV infection, but the trends in prevalence of HTLV-1 and HIV associations are largely unknown, especially in Sub Saharan Africa. In the current study, data from three cross-sectional community surveys performed in 1990, 1997 and 2007, were used to assess changes in HTLV-1 prevalence, incidence and its associations with HIV-1 and HIV-2 and potential risk factors.ResultsHTLV-1 prevalence was 5.2% in 1990, 5.9% in 1997 and 4.6% in 2007. Prevalence was higher among women than men in all 3 surveys and increased with age. The Odds Ratio (OR) of being infected with HTLV-1 was significantly higher for HIV positive subjects in all surveys after adjustment for potential confounding factors. The risk of HTLV-1 infection was higher in subjects with an HTLV-1 positive mother versus an uninfected mother (OR 4.6, CI 2.6-8.0). The HTLV-1 incidence was stable between 1990-1997 (Incidence Rate (IR) 1.8/1,000 pyo) and 1997-2007 (IR 1.6/1,000 pyo) (Incidence Rate Ratio (IRR) 0.9, CI 0.4-1.7). The incidence of HTLV-1 among HIV-positive individuals was higher compared to HIV negative individuals (IRR 2.5, CI 1.0-6.2), while the HIV incidence did not differ by HTLV-1 status (IRR 1.2, CI 0.5-2.7).ConclusionsTo our knowledge, this is the largest community based study that has reported on HTLV-1 prevalence and associations with HIV. HTLV-1 is endemic in this rural community in West Africa with a stable incidence and a high prevalence. The prevalence increases with age and is higher in women than men. HTLV-1 infection is associated with HIV infection, and longitudinal data indicate HIV infection may be a risk factor for acquiring HTLV-1, but not vice versa. Mother to child transmission is likely to contribute to the epidemic.

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Section: Discussionsupporting

confidence: 74%

HTLV-1 in rural Guinea-Bissau: prevalence, incidence and a continued association with HIV between 1990 and 2007

et al. 2010

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“…Within the latter subtype, one large transcontinental clade (a-TC) and three geographically restricted clades were identified: we named these the Senegalese (aSen), North African (a-NA), and West African (a-WA) clades. Of note, the a-Sen group has previously been described and named "trans-Saharan" or "clade N" (within the subgroup HTLV-1a D) (23,24).…”

Section: Resultsmentioning

confidence: 99%

Northern African Strains of Human T-Lymphotropic Virus Type 1 Arose from a Recombination Event

Desrames

Cassar

Gout

et al. 2014

J Virol

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Although recombination is a major source of genetic variability in retroviruses, no recombinant strain had been observed for human T-lymphotropic virus type 1 (HTLV-1), the first isolated human-pathogenic retrovirus. Different genotypes exist for HTLV-1: Genotypes b and d to g are restricted to central Africa, while genotype c is only endemic in Australo-Melanesia. In contrast, the cosmopolitan genotype a is widely distributed. We applied a combination of phylogenetics and recombination analysis approaches to a set of new HTLV-1 sequences, which we collected from 19 countries throughout Africa, the continent where the virus has the largest endemic presence. This led us to demonstrate the presence of recombinants in HTLV-1. Indeed, the HTLV-1 strains currently present in North Africa have originated from a recombinant event between strains from Senegal and West Africa. This recombination is estimated to have occurred around 4,000 years ago. This recombination seems to have been generated during reverse transcription. In conclusion, we demonstrate that, albeit rare, recombination can occur in HTLV-1 and may play a role in the evolution of this retrovirus. IMPORTANCEA number of HTLV-1 subtypes have been described in different populations, but none of the genetic differences between these subtypes have been ascribed to recombination events. Here we report an HTLV-1 recombinant virus among infected individuals in North Africa. This demonstrates that, contrary to what was thought, recombination can occur and could play a role in the evolution of HTLV-1.

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“…35 Likewise, subgroup D has previously been found in Africans, including subjects from Algeria and Guinea Bissau. 36 Finally, we identified a young boy from East Africa living in Spain infected with a new HTLV-1 subgroup within the Cosmopolitan subtype A, which we potentially nominated as subgroup F. To confirm this new subgroup it would be important to get more HTLV-1-infected samples from the Ethiopian population to investigate the molecular epidemiology of this virus in that region.…”

Section: Discussionmentioning

confidence: 99%

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

Treviño¹,

Alcântara

Benito

et al. 2014

AIDS Research and Human Retroviruses

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Human T cell lymphotropic virus type 1 (HTLV-1) infection in Spain is rare and mainly affects immigrants from endemic regions and native Spaniards with a prior history of sexual intercourse with persons from endemic countries. Herein, we report the main clinical and virological features of cases reported in Spain. All individuals with HTLV-1 infection recorded at the national registry since 1989 were examined. Phylogenetic analysis was performed based on the long terminal repeat (LTR) region. A total of 229 HTLV-1 cases had been reported up to December 2012. The mean age was 41 years old and 61% were female. Their country of origin was Latin America in 59%, Africa in 15%, and Spain in 20%. Transmission had occurred following sexual contact in 41%, parenteral exposure in 12%, and vertically in 9%. HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) was diagnosed in 27 cases and adult T cell leukemia/lymphoma (ATLL) in 17 subjects. HTLV-1 subtype could be obtained for 45 patients; all but one belonged to the Cosmopolitan subtype a. One Nigerian pregnant woman harbored HTLV-1 subtype b. Within the Cosmopolitan subtype a, two individuals (from Bolivia and Peru, respectively) belonged to the Japanese subgroup B, another two (from Senegal and Mauritania) to the North African subgroup D, and 39 to the Transcontinental subgroup A. Of note, one divergent HTLV-1 strain from an Ethiopian branched off from all five known Cosmopolitan subtype 1a subgroups. Divergent HTLV-1 strains have been introduced and currently circulate in Spain. The relatively large proportion of symptomatic cases (19%) suggests that HTLV-1 infection is underdiagnosed in Spain.

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Description of a “Trans-Saharan” Strain of Human T-Lymphotropic Virus Type 1 in West Africa

Cited by 16 publications

References 29 publications

HTLV-1 in rural Guinea-Bissau: prevalence, incidence and a continued association with HIV between 1990 and 2007

HTLV-1 in rural Guinea-Bissau: prevalence, incidence and a continued association with HIV between 1990 and 2007

Northern African Strains of Human T-Lymphotropic Virus Type 1 Arose from a Recombination Event

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

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