Virus de l'hepatite C et hepatopathies chroniques a Dakar : etude cas-temoins

En Afrique noire; la place de l'infection par le virus de l'hepatite C (VHC) dans la survenue des hepatopathies chroniques reste discutee; en particulier au Senegal ou la prevalence du VHC est moderee. C'est pourquoi une etude cas-temoins a ete menee a l'Hopital Principal de Dakar; en 1995; incluant 73 malades et 73 temoins. Les malades etaient repartis en 2 hepatites chroniques; 25 cirrhoses et 46 carcinomes hepatocellulaires. Les malades et les temoins ont fait l'objet d'etude serologique vis-a-vis du VHC (test ELISA de depistage; test ELISA de 3e generation en cas de positivite; puis confirmation par immunoblot) avec determination du serotype du VHC par methode immunoenzymatique; une recherche d'infection par le virus de l'hepatite B et une recherche d'anticorps anti-delta ont complete l'etude. Seulement 2 malades etaient porteurs d'anticorps anti-VHC (3 p. 100) et la serologie etait douteuse chez 2 autres ; le serotype 2 a ete mis en evidence chez l'un de ces malades ; aucun temoin n'etait positif vis-a-vis du VHC. Cinquante-quatre malades (74 p. 100) et 15 temoins (21 p. 100) etaient porteurs de l'antigene HBs parmi lesquels 13 malades (24 p. 100) et 1 temoin (7 p. 100) etaient porteurs d'anticorps anti-delta. Cette etude montre le role actuellement negligeable du VHC dans la survenue des hepatopathies chroniques en milieu hospitalier au Senegal et confirme le role predominant du virus de l'hepatite B et aggravant du virus de l'hepatite delta. Ces resultats sont confrontes aux donnees de la litterature concernant les pays d'Afrique noire. Au Senegal; l'impact du VHC parait inferieur a celui qui est oberve en Afrique centrale

First identification of the causative agent of visceral leishmaniasis in Djibouti: Leishmania donovani.

The first identification of the Leishmania species responsible for visceral leishmaniasis in Djibouti is described. Four strains, obtained from three autochthonous cases, were identified by starch-gel electrophoresis and iso-enzyme analysis of 15 enzymatic systems. The strains were found to belong to two newly recognized zymodemes of L. donovani: MON-268 and MON-287.

[Evaluation of the OptiMal test in the diagnosis of imported malarial outbreak]. / Evaluation du test OptiMal dans le diagnostic des accès palustres d'importation.

The OptiMal test is an immuno-chromatographic dipstick test that permits indiscriminate detection of Plasmodium falciparum and other species of human malaria. The purpose of this study was to evaluate the efficacy of the test for diagnosis of imported malaria. A total of 244 patients with a presumptive diagnosis of imported malaria in France were included during the study period. The reference test, i.e., combined thick and thin blood films, demonstrated infection by Plasmodium falciparum in 58 cases, Plasmodium vivax in 12, P. ovale in 8 and Plasmodium malariae in 2. The OptiMal test detected only 46 of the 55 Plasmodium falciparum cases. The sensitivity of the test for diagnosis of that species was 80%, its specificity was 98%, and its positive and negative predictive values were 95 and 93% respectively. Parsitemia studies showed poor test reliability for densities lower than 150/ul. Detection of other species was accurate in 21 out of 22. The results of this study demonstrate that the current version of the OptiMal test should be used with great caution for the diagnosis of malarial infection in hospital practice.

[Pemphigoid and acquired hemophilia]. / Pemphigoïde et hémophilie acquise.

INTRODUCTION: The association of bullous pemphigoid and acquired haemophilia is reported. CASE-REPORT: A 74 year-old man developed a bullous pemphigoid after decreasing corticotherapy, ecchymosis and haematomas revealing a high level of acquired anti-VIII antibodies (110 Bethesda UB units; TCA 98 s). Immunosuppressive treatment (cyclosporine, prednisone, azathioprine and bolus of cyclophosphamide) did not stop the disease. Perfusion of recombinant factor VIIa, human immunoglobulins and prednisone-azathioprine association permitted clinical and biological remission. DISCUSSION: Acquired haemophilia is idiopathic half the time. It can appear in autoimmmune diseases. Mortality is high. Only 4 cases of association with bullous pemphigoid have been reported in the literature. At the haemorrhagic phase, porcine factor VIII or more recombinant activated factor VII with human immunoglobulins are necessary. Immunosuppressive treatment is used to decrease production of anti-factor VIII antibodies.

Serological HLA class I alleles in Senegalese blood donors detected HBs Ag positive.

We analysed the HLA class I alleles in 96 blood donors HBs Ag positive compared with 93 healthy control individuals (HBs negative). The most frequent HLA-A, -B, -C alleles found were, A23 (33.6%); A2 (25%); A30 (25%); B8 (31.5%); B7 (16.3%); B58 (11.9%); B35 (11.9%); B49 (11.9%); B53 (10.8%); Cw7 (39.1%); Cw3 (36.9%); Cw4 (36.9%). Significant differences (P<0.001) were found between the blood donors and the controls for the following HLA alleles, A1; A23; B8 and Cw3. The detection of HBe antigen was positive in 26/84 blood donors. It was observed a significant difference (P<0.01; odds ratios (OR)=6.25) between positive and negative HBe antigens blood donors for HLA-A1 allele.

[Hepatitis C virus and chronic hepatopathies in Dakar: case-control study]. / Virus de l'hépatite C et hépatopathies chroniques à Dakar: étude cas-témoins.

In Black Africa, the role of hepatitis C virus (HCV) in the onset of chronic hepatic disease is unclear. This is particularly true in Senegal where the prevalence of HCV is moderate. To gain insight into this question, a case-control study including 73 patients and 73 controls was carried out at Principal Hospital in Dakar in 1995. The patients included in this study presented chronic hepatitis in 2 cases cirrhosis in 25 and hepatocellular carcinoma in 46. Patients and controls underwent serologic testing for HCV (ELISA screening test followed by 3rd generation ELISA test in case of positive results and confirmation by immunoblot) with determination of HCV serotype using the immunoenzymatic method. Testing also included research for infection by hepatitis B virus and for anti-delta antibodies. Anti-HCV antibodies were detected in two patients (3 p. 100) and serology was suspicious in two others. Serotype 2 was detected in one of these patients. No positive results were recorded in controls. Fifty-four patients (74 p. 100) and 15 controls (21 p. 100) presented the HBs antigen including 13 patients (24 p. 100) and I control (7 p. 100) with anti-delta antibodies. This study shows that HCV currently plays a minor role in the onset of hepatic disease in hospitalized patients in Senegal. It also confirms the predominant role of hepatitis B and complicating effect of the delta hepatitis virus. These findings are compared with reported data for Black African countries. The impact of HCV appears to be lower in Senegal than in central Africa.

The 1998 Senegal epidemic of meningitis was due to the clonal expansion of A:4:P1.9, clone III-1, sequence type 5 Neisseria meningitidis strains.

Between January and April 1998, a meningitis outbreak due to serogroup A meningococcus took place in Senegal. The outbreak began in Gandiaye, 165 km to the east of Dakar, and progressed towards the towns of Gossas, Niakkhar, Guinguineo, Fatik, Foundiougne, Dioffior, Sokone, Kaolack, and Nioro. At the same time, the outbreak reached regions of Kaffrine, Koungheul, and Tambacounda in the east of Senegal. A total of 1,350 cases and 200 deaths were reported. The WHO Collaborating Center in Marseilles received 24 strains for analysis. All were serogroup A Neisseria meningitidis, type 4 and subtype P1.9. Multilocus enzyme electrophoresis, performed by Institut Pasteur Paris, showed that the strains belonged to clone III-1. DNA restriction fragments generated by endonuclease BglII and analyzed by pulsed-field gel electrophoresis showed 24 indistinguishable fingerprint patterns similar to those of meningococcus strains isolated from African outbreaks since 1988. Three strains were studied by multilocus sequence typing (MLST) with seven loci. The comparison between sequences and existing alleles on the MLST website () allowed us to assign these strains to sequence type 5 (ST5), as their sequences were identical to the consensus at seven loci. All 24 strains were susceptible to penicillin, amoxicillin, chloramphenicol, and rifampin. Subgroup III is finishing its spread towards west of the meningitis belt of Africa. To our knowledge, this is the first time subgroup III, and more precisely ST5, strains are reported as being responsible for a meningitis outbreak in Senegal.

[Prevalence of hepatitis B and C viruses in a chronic hemodialysis center in Dakar]. / Prévalence des virus des hépatites virales B et C dans un centre d'hémodialyse chronique à Dakar.

In endemic areas of hepatitis B and C, hemodialysis patients are highly exposed to these infections. So the authors studied the prevalence of hepatitis B and C viruses among chronic hemodialysis patients of CHU A. Le Dantec of Dakar in a cross study carried out from June 1996 to June 1997, in order to identify risk factors and suggest appropriate prophylaxis. The study concerned fifteen chronic hemodialysis patients in an unit of hemodialysis in Dakar. For each patient, clinical and biochemical data were collected serological markers of B and C viruses were tested and HCV-RNA in case of seropositivity to C virus. The mean age of patients were 48 years and average duration of hemodialysis was 40 months. Hepatic injury was silent in all cases. Only one patient (6.7%) was AgHBs carrier while 9 patients (60%) were positive for antibodies anti HBs without previous hepatitis B vaccine. Twelve patients (80%) were found to be HCV-antibody positive and half of them were HCV. RNA positive. Average value of alanine amino transferase was higher in HCV-viremic patients than in seropositive but non viremic patients, although normal. Genotype 2 ac was found in 3 HCV viremic patients but it could not be determined in 3 other patients. Hemodialysis duration and number of blood transfusions were found to be risk factors of HCV infection. The high prevalence of HCV seropositivity among chronic hemodialysis patients in Dakar has led to strengthen precautions in our hemodialysis unit. HCV serological screening in blood donors is advocated.

PCR-RFLP-detected human papilloma virus infection in a group of senegalese women attending an STD clinic and identification of a new HPV-68 subtype.

Cancer of the cervix is the most common malignant tumor among women in Africa and, in particular, Senegal. Studies of the prevalence of human papilloma virus (HPV) infection in Africa have mainly focused on carcinomas. Data on the presence of the virus in women with normal cervical cytology are scarce. In this study, 158 cytologically normal women who had been referred to the 'Institut Pasteur de Dakar' (Senegal) for various genital complaints were investigated for the presence of HPV on exfoliated cells by PCR-RFLP. HPV was detected in 13.9% of cases. Oncogenic type HPV 16 was the most common type (40.9%), followed by HPV 53 and HPV 58, both detected in 13.6% of cases. Mixed HPV infections were present in 13. 6% of the subjects. Only HPVs belonging to the intermediate-high risk group were detected. These data suggest the need for careful cytological control of patients. A PCR-HPV fragment (GA115) possessing an original RFLP pattern was isolated. After sequencing, it showed a nucleotide homology of 97.1% with HPV 68 and should therefore be considered a new HPV 68 subtype. The use of PCR-RFLP strategy enables detection and typing of all known and as yet unknown genital HPVs. Variant and subtype classification of HPV types identified by oligonucleotide probe methods may need to be refined, especially for less prevalent HPVs and in areas where little information on HPV prevalence is available. More studies are needed to characterize satisfactorily the epidemiology of HPV in Africa.

[Association between Class I HLA alleles and HBs antigen carrier status among blood donors in Senegal]. / Association entre allèles HLA de classe I et portage de l'antigene HBs chez des donneurs de sang au Sénégal.

The course of hepatitis B virus (HBV) infection may be influenced by the host immune response. A prospective study was carried out in ninety-eight subjects (mean age = 23 years) HBs antigens carriers of hepatitis B and living in Dakar, Senegal. We analysed the HLA-A, -B, and C antigens distribution compared to that one of a control (HBs negative) healthy senegalese population (n = 96) living in Dielmo village where a longitudinal study was set-up since 1990. The HLA class I typing was performed by microlymphocytotoxicity assays. The most frequent HLA-A, -B, -C antigens found were: locus A: A23 (33.6%), A2 (25%), A30 (25%), locus B: B8 (31%), B7 (16.3%), B58 (11.9%), B35 (11%), B49 (11%), B53 (10.8%) and locus C: Cw7 (39.1%), Cw17 (39.1%), Cw3 (36.9%), Cw4 (36.6%). Significant differences (P < 0.001) were found between the donors and the control group for the following HLA antigens: A1, A23, B8 and Cw3. The detection of HBe antigen was positive in 26/84 blood donors. It was observed a significant difference (p < 0.01) between positive and negative HBe donors for HLA-A1 allele with an odds ratio of 6.25. All the donors carrying the HLA haplotype: A1-B8-Cw7 (11.5%) were positive in HBe antigen. HLA: B8-Cw7 haplotype (detected in 8.5% of positive donors) seems to be likely associated with a liver cancer according to many reports. An adequate follow-up should be set-up for positive HBe subjects carrying a susceptible HLA type.

Re-emergence of yellow fever in Senegal in 1995.

An outbreak of yellow fever (YF) occurred in the central part of Senegal during October 1995. Thirty-one probable cases were detected and 79 cases were confirmed either by IgM ELISA or by virus isolation (30 strains isolated). The case fatality rate was 18.9%. Incidence of the infection was evaluated by a serosurvey in the area. Males 10-29 years old belonging to the Peul ethnic group were more affected. Moreover, 28 YF virus strains were isolated from mosquitoes and larvae pools and vertical transmission of YF virus by Aedes aegypti was also demonstrated for the first time in the field. This outbreak occurred after the major amplification of the wild cycle of YF virus in 1993 in West Africa. This epidemic represented a typical example of intermediate transmission of YF: both humans and wild vertebrates are involved in the virus cycle through wild mosquitoes with semidomestic habits, mainly Ae. furcifer, Ae. luteocephalus, and domestic vector Ae. aegypti. It was controlled by a prompt immunization campaign. The impact of inclusion of YF vaccine in the Expanded Program of Immunization, which has been conducted in Senegal for eight years, is discussed.