Preliminary study of human Herpesvirus type 8 infection in pregnant women in Dakar (Senegal)]

HHV8 was discovered in 1994 and few studies on this virus have been conducted in Africa. The virus is related to Kaposi sarcoma, an opportunistic affection occurring during HIV infection. No studies have been carried out on this subject in Senegal, a country known for its low KS prevalence even among people living with HIV/AIDS. Thus it will be interesting to explore this field. The aim of our study has been first, to demonstrate the presence of HHV8; second, to evaluate sero-prevalence of the infection in Senegal and third, to determine the specificities of HHV8 infection in our country. We performed our study on 407 pregnant women whose average age was 29.24 years, the majority of whom were Senegalese. HIV serology was done by dot blot for the screening and western blot for the confirmation. For the diagnosis of HHV8 infection, we used the indirect immunofluorescence kit of ABI. HIV infection was low among this study population; 0.5% and no HIV1 infection was mentioned. Among the 407 women, 58 or 14.3% were HHV8 positive and there was no HHV8/HIVco-infection. Regarding marital status, no significant difference was found between HHV8 positive and HHV8 negative among unmarried, monogamous or polygamous women. However, women having had 4 to 5 children were more likely to test positive for HHV8. The difference is significant and a relationship has been established with a p value of 0.02. Regarding pregnancy, HHV8 infection is more closely related to abortion: 17.2% of women who had aborted were HHV8 positive versus 4.9% seronegative. The odds ratio calculation shows a strong correlation with a p value of 0.01. No correlation was found between HHV8 infection of the mother and neonate mortality or Apgar score. However, a relationship did show up between HHV8 infection of the mother and low birth weight. 29.2% of seropositive women had had a child with a birth weight under 2600 g whereas only 16.3% of seronegative women had had babies with low birth weight. We determined that HHV8 is indeed present in Senegal. Further studies should focus on transmission routes as well as the molecular epidemiology of this virus and diseases related to HHV8 infection in Senegal.     

Infection due to hepatitis delta virus in Africa: report from Senegal and review.

A review of the literature shows strong variations in the prevalence of hepatitis delta virus (HDV) among Africans seropositive for hepatitis B surface antigen (HBsAg). In Senegal, West Africa, prevalence of antibodies to HDV among asymptomatic HBsAg carriers appears to be linked to regional and/or socioeconomic factors. Antibodies to HDV were found in 22 (47%) of 47 HBsAg-seropositive patients with liver disease who were hospitalized in the main hospital of Dakar and in 4% to 44% of asymptomatic HBsAg carriers. Eight (36%) of 22 patients with liver disease were seropositive for IgM antibodies to HDV, whereas none of 18 asymptomatic subjects were seropositive (P less than .01). According to studies conducted in Europe and the United States, the presence of this marker may constitute support for the argument that HDV plays a role in the development of HBsAg-associated liver diseases in Senegal and, presumably, within the African continent.     

The outbreak of meningitis due to Neisseria meningitidis W135 in 2003 in Burkina Faso and the national response: main lessons learnt

Among the countries situated in the African meningitis belt, Burkina Faso is usually the one which pays the highest toll to this disease in terms of morbidity and mortality. Until 2002, the causal agent of the epidemic was usually Neisseria meningitidis serogroup A. At the onset of the 2002 epidemic, N. meningitidis W135 was identified as the predominant serogroup by the national reference hospital and the WHO, and this was confirmed by the WHO collaborating centre on meningitis in Oslo, Norway. Due to the nonavailability of an affordable and effective vaccine, the only adequate strategy was proper case management, taking advantage of the sensitivity of the bacteria to the currently used antibiotics. In order to avoid the repetition of such a situation, WHO and GlaxoSmithKline, with the financial support of the Bill and Melinda Gates Foundation, planned and actually realized the production of a trivalent ACW135 vaccine in anticipation of the 2003 epidemic season. In order for the vaccine to be effectively used in the field, it was imperative that various ethical, managerial and technical conditions be fulfilled. The successful use of the trivalent polysaccharide vaccine ACW135 in Burkina Faso during the 2003 outbreak was essentially due to the high level of leadership demonstrated by the national authorities of Burkina Faso, the facilitating role of WHO, the effective coordination of partners and activities, the transparency in the response to the epidemic and the management of the resources.     

Robust HIV type 2 cellular immune response measured by a modified anthrax toxin-based enzyme-linked immunospot assay

Evaluation of immune mechanisms responsible for control of viral replication is critical to understanding HIV-2 attenuated biological characteristics in pathogenesis and transmission. Evaluation of the cellular immune response is often based on labor-intensive techniques that limit the scope of most studies performed. A simple and rapid anthrax toxin-based ELISPOT method to assess HIV-2 cellular immune response was developed. The modified anthrax toxin-based antigen presentation process performed better than a recombinant vaccinia system and the ELISPOT method significantly enhanced the ease and simplicity of the assay. Using this method, a robust HIV-2 cellular immune response directed toward the p26 core protein was exhibited in 21 of 24 (87.5%) infected women, and all 8 seronegative subjects were negative in both assays. Cellular immune responses were associated with low HIV-2 viral load. This simple and rapid modified anthrax toxin-based ELISPOT method allowed us to demonstrate, strong cellular immune responses that may be critical determinants in the HIV-2 attenuated phenotype.     

Particularités des syndromes coronariens aigus chez la femme en Afrique subsaharienne

Introduction

Acute coronary syndromes have been rarely studied in the female population in Sub-Saharan Africa. This Sub-Saharan serie has shown an increase in the prevalence of acute coronary syndromes among the female population, compared to previous studies. Through this retrospective study, we evaluated the epidemiological, clinical, paraclinical, therapeutic and evolutionary features of acute coronary syndromes on women at the Principal Hospital of Dakar.

High levels of tumor necrosis factor-alpha and interleukin-1beta in bacterial vaginosis may increase susceptibility to human immunodeficiency virus

Bacterial vaginosis (BV) was identified recently as a cofactor that promotes sexual transmission of human immunodeficiency virus (HIV). This study was done to determine if interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha could be measured consistently in cervical secretions and if high levels of these cytokines were associated with BV. Secretions were obtained from 209 study subjects; most samples had detectable levels of TNF-alpha (84.2%) and IL-1beta (79.8%). BV was detected in 53 (27.0%) of 196 women. High cytokine levels were significantly associated with BV (adjusted odds ratio [AOR], 4.17; 95% confidence interval [CI], 1.69-10.30), oral contraceptive use (AOR, 2.78; 95% CI, 1.04-7.48), and high leukocyte counts on vaginal smear (AOR, 1.18; 95% CI, 1.03-1.36). Since these cytokines could up-regulate local HIV replication through activation of the long terminal repeat promoter region, the association of BV with high levels of IL-1beta or TNF-alpha may partly explain the mechanism by which this risk factor enhances HIV transmission.     

Measurement of HIV-1 CRF02_AG-specific T cell responses indicates the dominance of a p24gag epitope in blood donors in Abidjan, Cote d'Ivoire

Characterization of human immunodeficiency virus (HIV)-1-specific immune responses against subtypes circulating in areas where the virus is endemic is critical for the design of candidate vaccines. In Cote d'Ivoire, the most prevalent HIV-1 subtype is CRF02_AG. We detected T cell responses to CRF02_AG consensus p24(gag) or protease peptides in 81% of HIV-1- or HIV-1/2-infected blood donors in Abidjan, Cote d'Ivoire. Both the magnitude and the breadth of interferon- gamma enzyme-linked immunospot responses were inversely correlated with plasma viral load. One frequently recognized peptide in p24(gag) was mapped to the optimal epitope (TPQDLNMML). Further studies of this epitope may be important for the development of HIV-1 vaccines for West Africa and West-Central Africa.     

Genetic analysis of HIV type 2 in monotypic and dual HIV infections

A significant level of genetic variation among HIV-1 and HIV-2 has been described. The interaction of specific HIV-2 subtypes with HIV-1 may serve to identify potential biological properties associated with dual infection. To genetically characterize the HIV-2 strains circulating in Senegal and their relationship to coinfection with HIV-1, we sequenced the HIV-2 envelope C2-C3 region of 12 subjects coinfected with HIV-1 and HIV-2 and 9 subjects singly infected with HIV-2. The phylogenetic analysis showed that all subjects were infected with HIV-2 subtype A, confirming its predominance in West Africa. We did not observe specific sequences or genetic clustering based on coinfection status.     

CCR5 receptor expression is down-regulated in HIV type 2 infection: implication for viral control and protection

HIV-2 is known to display an attenuated phenotype in vivo with prolonged time to disease and decreased rate of transmission. Observational studies in Senegal have demonstrated protection from HIV-1 infection, although the putative mechanism for immunoprotection remains undefined. We evaluated HIV-2-seropositive women from a cohort of commercial sex workers in Dakar, Senegal and identified individuals with very low surface CCR5 receptor expression on CD4+ T cells. In vitro up-regulation of the CCR5 receptor was readily achieved. Down-regulation of the CCR5 was not correlated with activation markers (HLA-DR), beta-chemokine levels, or plasma viral loads. A correlation was observed with HIV-2-specific CD8+ T cell activity as measured by intracellular cytokine production. We postulate that down-regulation of the CCR5 receptor in HIV-2 infection contributes to slower disease course and to the protective mechanism against HIV-1 superinfection, mediated in part by HIV-2-specific cellular immune responses.     

Thrombose très tardive d’un stent nu dix ans après son implantation : à propos d’une observation

Very late thrombosis occurring after bare-metal stent (BMS) implantation is a rare complication. It differs from very late thrombosis of drug-eluting stents in terms of both frequency and pathophysiological mechanism. We report a case of very late stent thrombosis of a bare-metal stent 10 years after his implantation for treatment of a myocardial infarction. The patient had a new acute coronary syndrome without persistent ST-segment elevation related to bare-metal stent thrombosis. He was treated by thrombo-aspiration and implantation of a new bare-metal stent.