L. Belec

Evaluation of the efficacy of a low-passage bovine rotavirus (strain WC3) vaccine in children in Central Africa

The safety and efficacy of a WC3 rotavirus vaccine was evaluated in a double-blind placebo-controlled trial involving 472 children in Bangui (Central African Republic). Each child received two doses of either placebo (235 children) or vaccine (237 children) at a 1-month interval, the first dose being given at 3 months of age. During the follow-up survey 9 months after the first dose, 117 rotavirus diarrhoeas were observed, 59 in the placebo group, 58 in the vaccinated group. The only positive effect of the vaccine was a significantly higher proportion of mild rotavirus diarrhoeal episodes in the vaccinated group than in the placebo group. Of the children in the vaccinated group, 60% had a positive immune response to WC3 rotavirus when tested by plaque reduction seroneutralization.

Peripheral facial paralysis and HIV infection: report of four African cases and review of the literature.

SummaryFour cases of infranuclear facial palsy associated with infection by the human immunodeficiency virus in young heterosexual African patients are reported. Two cases were healthy HIV carriers, one patient manifested AIDS-related complex, and one case fulfilled the CDC criteria for AIDS. Two patients had a typical Bells palsy, one presented with manifest cephalic Herpes zoster infection and one, who suffered from facial diplegia, could be considered to have a cephalic form of Guillain-Barré syndrome. A review of the literature confirmed that peripheral facial palsy can occur at any stage of HIV infection and in various clinical contexts. In stages I and II of the HIV infection, patients may develop either Bells palsy or Guillain-Barré syndrome. In stages III and IV, when the cellular immunity has begun to decline, Herpes zoster-related facial paralysis, seventh cranial nerve involvement secondary to meningeal lymphomatosis, and peripheral facial paralysis as one aspect of widespread chronic peripheral neuropathy may also occur.

Antenatal HIV prevalence in Yaounde, Cameroon

Summary: From June 1994 to July 1996, 4100 pregnant women living in Yaounde, Cameroon, were tested for human immunodeficiency virus type 1 HIV 1 and syphilis. The HIV seroprevalence was 4.2 95 confidence interval CI : 3.6- 4.8 , and that of antibodies to Treponema pallidum was 17.4 95 CI: 16.3- 18.6 HIV infection was twice as common in women with positive syphilis serology 7.2 vs 3.6 . Over the study period, the antenatal seroprevalence of syphilis remained stable, while there was an increase in the HIV seroprevalence rate. There was an increase in HIV seropositivity in women uninfected with syphilis between 1994 1995 and 1995 1996 from 2.9 to 4.3 . By the end of the study, HIV infection was no commoner in women with negative compared with positive syphilis serology. It is therefore postulated that HIV infection in Yaounde has entered the general, sexually active female population. We suggest that manage ment of pregnant women in Cameroon should include routine screening for both HIV infection and other sexually transmitted diseases STDs .

Detection of hepatitis C virus RNA by a reliable, optimized single-step reverse transcription polymerase chain reaction

A single-step reverse transcription polymerase chain reaction (SRT-PCR) method was optimized for hepatitis C virus (HCV) RNA detection. Extraction procedures by proteinase K and guanidinium isothiocyanate gave similar results. The optimal MgCl2 concentration for the SRT-PCR method was 2 mM with 10 units of superscript M-MLV RNase H-reverse transcriptase and 1 unit of Taq polymerase. Shorter PCR cycling steps gave a 10-fold-increased PCR product compared with longer cycling steps. Twenty-five anti-HCV-positive sera from chronic hepatitis C patients were positive with SRT-PCR, whereas only 17 out of 25 were positive by dissociated RT and PCR (dRT/PCR). Specificity was assessed by twenty negative controls. SRT-PCR was 5-fold more sensitive (5 HCV RNA copies per assay) than dRT/PCR with an HCV RNA transcript. Our SRT-PCR method for HCV RNA detection appears fully adapted for routine use in a medical virology laboratory.

Comparison of cervicovaginal humoral immunity in clinically asymptomatic (CDC Al and A2 category) patients with HIV-1 and HIV-2 infection

Paired sera and cervicovaginal secretions (CVS) from 11 HIV-1- and 11 HIV-2-infected women, all clinically asymptomatic (CDC A1 and A2 categories), were analyzed for total IgG, IgA, albumin (HSA), IgG, and IgA antibodies toenvencoded surface glycoproteins of HIV-1 (gp160) and of HIV-2 (gp105), by comparison to 15 age-matched healthy controls. Secretion rates of IgG and IgA into CVS were evaluated by calculation of their relative coefficients of excretion (RCE) by reference to HSA. Cervicovaginal production of anti-HIV antibodies was evaluated by comparison between specific antibody activities of IgG and of IgA to HIV in CVS and in sera. In HIV-1-infected women, total IgG and IgA in CVS were, respectively, 6- and 4-fold increased, whereas the secretion rate of total IgG was 2.1-fold increased and that of total IgA was 2.5-fold reduced. In contrast, total IgG and IgA as well as their secretion rates were normal in HIV-2-infected women. In HIV-1- but not in HIV-2-infected women, HSA levels in cervicovaginal washings were twofold increased, demonstrating alteration of the mucosal barrier in HIV-1 infection. In HIV-1-infected patients, IgG and IgA to gpl60 were detected in all sera and CVS. In HIV-2-infected patients, IgG to gp105 was detected in all sera and CVS, whereas IgA to gp105 could be detected in only half of sera and one-third of CVS. Cross-reactivity by IgG and/or IgA to HIV-1 or HIV-2 against the surface glycoprotein of the other HIV type was observed in sera as well as in CVS, and more frequently in HIV-2- than in HIV-1-infected women. Finally, the mean specific activities of IgG and of IgA to gp160 or gp105 were higher in CVS than in sera, evidencing a possible local synthesis of both isotypes in HIV-1 as well as in HIV-2 infections. As early as the asymptomatic stages, HIV-1 affects the cervicovaginal mucosa more than HIV-2 does, suggesting higher viral replication within the female genital tract in HIV-1 infection than in HIV-2 infection.

Low prevalence of neuro-psychiatric clinical manifestations in central African patients with acquired immune deficiency syndrome.

In order to evaluate the frequency of neurological and psychiatric disorders in central African patients with acquired immune deficiency syndrome (AIDS), 93 inpatients at the National Hospital Centre of Bangui were selected according to the World Health Organization (Bangui) clinical definition of AIDS and were confirmed to be serologically positive for human immunodeficiency virus (HIV) 1 (92/93) or HIV 2 (1/93) by Western blot. Neurological (11/15) and psychiatric (4/15) abnormalities were clinically detected in 16% (15/93) of African patients with AIDS. In this series, the prevalence of neuro-psychiatric disorders appeared to be lower than in Europe and North America.

Antibodies to HIV2 in genital secretions

In order to study the local immune response to HIV2, three exclusively heterosexual, infected West African patients were selected: one male with full blown AIDS, one female with ARC and one healthy HIV2-carrier female. Sera and genital secretions were obtained and tested for anti-HIV2 IgG and IgA antibodies by Western blotting. In semen and in vaginal secretions, IgG antibodies directed against all viral antigens were detected. In comparison with the IgG response, local IgA antibody response was less intense and heterogenous. Two out of 3 patients had local antibodies of the IgA class directed against the envelope glycoprotein GP105. Such antibodies of both the IgG and IgA classes in genital secretions could play a protective role in heterosexual transmission of HIV2.

Intrathecal Synthesis of β2-Microglobulin and Lysozyme: Differential Markers of Nervous System Involvement in Patients Infected with Human Immunodeficiency Virus Type 1

beta 2-Microglobulin and lysozyme were determined in paired serum and cerebrospinal fluid samples from 137 patients, using immunofluorometry and ELISA, respectively. Of these patients, 54 were infected by human immunodeficiency virus type 1 (HIV1) (including 20 AIDS dementia patients), 73 were HIV1-seronegative with neurological diseases (meningitis (n = 10), multiple sclerosis (n = 29), other neurological diseases (n = 34)) and 10 were controls. Intrathecal synthesis of beta 2-microglobulin occurred in each group. Conversely, lysozyme intrathecal synthesis was found only in meningitis (10/10) and in HIV1-infection (24/54). A pathological increase in beta 2-microglobulin intrathecal synthesis (> or = 2 mg/l) was observed in 45 patients (34 HIV1-infected patients and 11 HIV1-seronegative patients with neurological diseases). Serum concentration and intrathecal synthesis of beta 2-microglobulin were correlated only in the 20 AIDS dementia patients. The cerebrospinal fluid beta 2-microglobulin and lysozyme concentrations were correlated in the 54 HIV1-infected patients only. Blood CD4 + T-cell count was correlated negatively with beta 2-microglobulin intrathecal synthesis but not with lysozyme intrathecal synthesis. These data suggest that in the absence of any central nervous system opportunistic process the increase of beta 2-microglobulin intrathecal synthesis (> or = 2 mg/l) may be a reliable marker of central nervous system involvement in HIV1-infected patients. Intrathecal synthesis of lysozyme was related principally to HIV1-encephalitis and central nervous system opportunistic processes.