Abstract Background Hepatitis C virus (HCV) infection is a major global public health problem in both developed and developing countries. The prevalence and genetic diversity of HCV in pregnant women in Gabon, central Africa, is not known. We therefore evaluated the prevalence and the circulating genotypes of HCV in a large population cohort of pregnant women. Methods Blood samples (947) were collected from pregnant women in the five main cities of the country. The prevalence was evaluated by two ELISA tests, and the circulating genotypes were characterized by sequencing and phylogenetic analysis. Results Twenty pregnant women (2.1%) were infected with HCV. The seroprevalence differed significantly by region (p = 0.004) and increased significantly with age (p = 0.05), being 1.3% at 14–20 years, 1.1% at 21–25 years, 1.9% at 26–30 years, 4.1% at 31–35 years and 6.0% at > 35 years. Sequencing in the 5'-UTR and NS5B regions showed that the circulating strains belonged to genotypes 4 (4e and 4c). Conclusion We found that the HCV seroprevalence in pregnant women in Gabon is almost as high as that in other African countries and increases with age. Furthermore, only genotype 4 (4e and 4c) was found. More extensive studies aiming to evaluate the prevalence and heterogeneity of HCV genotypes circulating in the general population of the country are needed.
Abstract A serologic survey for Mayaro virus (Alphavirus, Togaviridae) in 28 wild nonflying forest mammal species in French Guiana showed a prevalence ranging from 0% to 52% and increasing with age. Species active during the day and those who spent time in trees were significantly more infected, results consistent with transmission implicating diurnal mosquitoes and continuous infectious pressure.
Since the identification of ZIKV in Brazil in May 2015, the virus has spread extensively throughout the Americas. Cases of ZIKV infection have been reported in Suriname since October 2, 2015.
Peptide vaccines able to induce high affinity and protective neutralizing antibodies must rely in part on the design of antigenic epitopes that mimic the three-dimensional structure of the corresponding region in the native protein. We describe the design, structural characterization, immunogenicity, and neutralizing potential of antibodies elicited by conformational peptides derived from the human T-cell leukemia virus type 1 (HTLV-1) gp21 envelope glycoprotein spanning residues 347-374. We used a novel template design and a unique synthetic approach to construct two peptides (WCCR2T and CCR2T) that would each assemble into a triple helical coiled coil conformation mimicking the gp21 crystal structure. The peptide B-cell epitopes were grafted onto the epsilon side chains of three lysyl residues on a template backbone construct consisting of the sequence acetyl-XGKGKGKGCONH2 (where X represents the tetanus toxoid promiscuous T cell epitope (TT) sequence 580-599). Leucine substitutions were introduced at the a and d positions of the CCR2T sequence to maximize helical character and stability as shown by circular dichroism and guanidinium hydrochloride studies. Serum from an HTLV-1-infected patient was able to recognize the selected epitopes by enzyme-linked immunosorbent assay (ELISA). Mice immunized with the wild-type sequence (WCCR2T) and the mutant sequence (CCR2T) elicited high antibody titers that were capable of recognizing the native protein as shown by flow cytometry and whole virus ELISA. Sera and purified antibodies from immunized mice were able to reduce the formation of syncytia induced by the envelope glycoprotein of HTLV-1, suggesting that antibodies directed against the coiled coil region of gp21 are capable of disrupting cell-cell fusion. Our results indicate that these peptides represent potential candidates for use in a peptide vaccine against HTLV-1.
Le virus HTLV-I (human T cell leukemia/lymphoma virus type I), isole en 1980 a partir de lymphocytes T d’un patient atteint d’un lymphome cutane, infecte environ 20 millions de personnes dans le monde et entraine une pathologie grave chez 2 a 5 % d’entre elles. Il provoque donc une infection virale qui pose un probleme de sante publique important dans certaines regions du monde. Les leucemies et lymphomes a cellules T de l’adulte (ATLL) causes par ce virus representent des tumeurs lymphoides frequentes dans les zones d’endemie au HTLV-I avec une incidence de 2 a 5 cas pour 100 000 habitants par an. L’incidence de la paraparesie spastique tropicale associee au HTLV-I (TSP/HAM) est du meme ordre mais varie selon les aires geographiques. Les modes de transmission dans les regions endemiques etant principalement l’allaitement maternel et la transmission sexuelle, et pour les pays industrialises la transmission sanguine et la transmission sexuelle, il devrait etre theoriquement facile de prevenir la transmission de ce virus. Cependant, il est tres difficile d’eviter l’allaitement maternel dans la plupart des zones endemiques, et les encouragements a utiliser les preservatifs ont ete decevants, d’ou l’importance d’une prevention vaccinale. En effet, la tres grande stabilite genetique du HTLV-I et l’existence d’anticorps neutralisants sont en faveur de la possibilite de mise au point d’un vaccin efficace. Les travaux publies sur la possibilite d’induire une protection contre le HTLV-I indiquent qu’une immunisation protectrice est possible, mais les tentatives de vaccination effectuees jusqu’a present n’ont protege que partiellement. Cela tient au choix du vecteur vaccinal ainsi qu’au choix du modele animal. C’est pourquoi, la mise au point du vaccin necessite la presence d’un bon modele animal d’infection par ce virus. L’utilisation des vecteurs vaccinaux contenant le gene env parait proteger partiellement, et l’inclusion des genes env et gag apparait necessaire pour induire une reponse humorale neutralisante anti-env prevenant l’infection, mais aussi une reponse cellulaire T cytotoxique contre gag pour eliminer les cellules infectees. La disponibilite d’un modele experimental chez un primate est tres favorable au developpement d’un vaccin HTLV-I/II, lequel representerait le premier vaccin contre un onco-retrovirus humain associe a deux maladies graves.
Abstract Background Although a wide variety of non‐human primates are susceptible to simian T‐cell leukaemia virus type 1 (STLV‐1), little is known about the virological or molecular determinants of natural STLV‐1 infection. Methods We determined STLV‐1 virus tropism in vivo and its relation to the immune response by evaluating cytokine production and T‐cell subsets in naturally infected and uninfected mandrills. Results With real‐time PCR methods, we found that STLV‐1 in mandrills infects both CD4 + and CD8 + T cells; however, proviral loads were significantly higher ( P = 0.01) in CD4 + than in CD8 + cells (mean STLV‐1 copies number per 100 cells (± SD) was 7.8 ± 8 in CD4 + T cells and 3.9 ± 4.5 in CD8 + T cells). After culture, STLV‐1 provirus was detected in enriched CD4 + but not in enriched CD8 + T cells. After 6 months of culture, STLV‐1‐transformed cell lines expressing CD3 + , CD4 + and HLADR + were established, and STLV‐1 proteins and tax/rex mRNA were detected. In STLV‐1 infected monkeys, there was a correlation between high proviral load and elevated levels of interleukin (IL)‐2, IL‐6, IL‐10, interferon‐γ and tumour necrosis factor‐α. The two monkeys with the highest STLV‐1 proviral load had activated CD4 + HLADR + and CD8 + HLADR + T‐cell subsets and a high percentage of CD25 + in CD4 + and CD8 + T cells. Conclusions Our study provides the first cellular, immunological and virological characterization of natural STLV‐1 infection in mandrills and shows that they are an appropriate animal model for further physiopathological studies of the natural history of human T‐cell leukaemia viruses.
Major chikungunya outbreaks have affected several Central African countries during the past decade. The chikungunya virus (CHIKV) was isolated from humans and sylvan mosquitoes in the Central African Republic (CAR) during the 1970 and 1980s but has not been found recently, despite the presence of Aedes albopictus since 2010. The risk of a massive chikungunya epidemic is therefore potentially high, as the human populations are immunologically naïve and because of the presence of the mosquito vector. In order to estimate the risk of a large outbreak, we assessed the vector competence of local Ae. aegypti and Ae. albopictus populations for ancient local strains of CHIKV in CAR. Mosquitoes were orally infected with the virus, and its presence in mosquito saliva was analysed 7 and 14 days post-infection (dpi) by quantitative reverse transcriptase polymerase chain reaction. The two species had similar infection rates at 7 and 14 days, and the dissemination rate of both vectors was ≥ 80% at 14 dpi. Only females followed up to 14 dpi had CHKV in their saliva. These results confirm the risk of transmission of enzootic CHIKV by anthropophilic vectors such as Ae. aegypti and Ae. albopictus.
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