[Seroprevalence of rubella in Kinshasa (Zaire)]. / Séroprévalence de la rubéole a Kinshasa (Zaïre).

A serosurvey of rubella was carried out by haemagglutination inhibition and IgM assay among 106 newborn infants (91% positive); 101 suckling infants aged 9-18 months (32.7% positive); 100 children aged 2-4 (58% positive); and 100 young girls 9-11 (68% positive), while 93% of mothers showed the presence of protective antibodies. These figures indicated that large numbers of women old enough to bear children are susceptible to infection with rubella, at least early in life. A vaccination programme is therefore recommended for one year-old children of both sexes and again for young girls prior to puberty.

Voluntary blood donor recruitment: a strategy to reduce transmission of HIV-1, hepatitis-B and syphilis in Kinshasa, Zaïre.

We evaluated the use of voluntary blood donor recruitment in Kinshasa, Zaïre, as a means of reducing transmission of HIV-1 and other infectious agents by blood transfusion. Between January 1, 1989, and April 7, 1989, 2,237 blood donors were enrolled in the study at the transfusion centre of the Mama Yemo Hospital. Each donor was tested for antibodies to HIV-1 confirmed by IFA and Western blot, Treponema pallidum, antibodies to hepatitis B virus (HBV) core antigen and screened for the presence of the HBV surface antigen. Test results were related to the data of the blood donors: age, sex, haematocrit, voluntary blood donor, family member donor, paid donor. The serological results of all donors for Anti-HIV-1. Anti-HBc, HBsAg and TPHA were 4.8%, 70.9%, 13.1% and 13.3% respectively. Lower seroprevalence rates were found among voluntary blood donors. However, only TPHA seroprevalence was significantly lower in voluntary blood donors (8.4%, 23/275) compared with paid donors (15.2%, 87/571) (p less than 0.01). A greater proportion of voluntary donors provides a store of blood which allows more extensive screening of blood for HIV-1 and other infectious diseases. Voluntary blood donor recruitment is critical for the provision of safe blood supplies in Kinshasa.

[Anti-HIV2 antibody research in Kinshasa, Zaire]. / Recherche des anticorps anti-VIH2 a Kinshasa, Zaire.

880 suspect sera were analysed for HIV2 antibodies (ELISA, Western Blot) during the 2nd and 3rd trimester of 1988. Results show that Kinshasa is not yet an endemic zone for this virus. The authors recommend the use of a mixed test for diagnostics.

[Immunization against the human immunodeficiency virus in Zaire]. / Immunisation contre le virus de l'immunodéficience humaine au Zaïre.

The first experimental immunization of human against the AIDS retrovirus HIV-1 was started in a series of HIV seronegative healthy volunteers in november 1986. Priming used a vaccinia virus recombinant (V25) expressing Gp 160 env determinants of HTLV III B at the surface of infected cells. This priming which induced a weak immune reaction was performed on HIV seronegative French and Zaïrian individuals living in Zaïre (Kinshasa). These results prompted to boost the primary immune response. Four different protocols were used: slow drip intravenous infusion with paraformaldehyde fixed autologous cells infected with V25 (first protocol), repeated scarification with V25 for the second protocol. The third protocol used scarifications with fragment of Gp 120 env protein, and the fourth protocol used intramuscular injections of purified autologous cell membrane infected with V25. Results of the immune reaction obtained after these boosts: The three last protocols showed a cell mediated immunity (CMI) that not significantly enhanced in comparison with CMI obtained after V25 priming alone. Moreover, the sera showed low and variable neutralizing antibodies titers one to four months after boosting. By contrast boosting with V25 infected fixed cells (D.Z. individual) provide strong humoral and cellular group specific anamnestic immune response. Indeed, high levels of antibodies to viral envelope and neutralizing antibodies against divergent HIV-1 strains were observed. Group specific CMI and cell mediated cytotoxicity were enhanced by boosts. Skin-tests showed high mediated and delayed hypersensitivity to GP 160 in vivo. For the first time, these results show that an immune stage against HIV can be obtained in a man.

PIP: The 1st experimental immunization of humans against the AIDS retrovirus HIV-1 was begun in November 1986 among a group of HIV-seronegative healthy volunteers. A priming, involving a vaccine virus recombinant (V25) expressing Gp 160 env determinants of HTLV-III B at the surface of the infected cells was utilized. This priming, which induced a weak immune reaction, was performed on HIV-seronegative French and Zairian individuals living in Kinshasa, Zaire. These results prompted a boost to the primary immune response. 4 different protocols were used: the slow drip intravenous infusion with paraformaldehyde-fixed autologous cells infected with V25; repeated scarification with V25 for the 2nd protocol; scarifications with fragments of Gp 120 env protein; and intramuscular injections of purified autologous cell membrane infected with V25. The results of the immune reaction obtained after these boosts indicated the following: The last 3 protocols showed a cell- mediated immunity (CMI) that did not significantly enhance in comparison with CMI obtained after V25 priming alone. Moreover, the sera showed low and variable neutralizing antibody titers 1-4 months after boosting. By contrast, boosting with V25 infected fixed cells (D.Z.) provided strong humoral and cellular group specific anamnestic immune responses. Indeed, high levels of antibodies to viral envelope and neutralizing antibodies against divergent HIV-1 strains were observed. Group- specific CMI and cell mediated cytotoxicity were enhanced by boosts. Skin tests showed high mediated and delayed hypersensitivity to Gp 160 in vivo. For the 1st time, these results show that an immune state against HIV can be obtained in a man. (author's modified)

[Randomization of a population for a clinical trial of immunization against the human immunodeficiency virus (HIV)]. / Randomisation d'une population pour un essai clinique d'immunisation contre le virus de l'immunodeficience humaine (VIH).

Serum HIV antibodies has been investigated in different subpopulation from four different regions in Zäire by Elisa (Elavia Pasteur) and Western Blot. Seropositive prevalence differed from 2.4% (rural population) to 12.5% (urban population) according to the regions. When the group with 2.4% migrated to the area with 12.5% positives, after 8-12 months the number of seropositives in this group raised to 8%, showing an increase of 5.6% within one year. Such population is suitable for a large scale clinical trial (with anti-AIDS vaccine) to be performed on individuals with high risk of natural infection.

PIP: Major obstacles to development of a vaccine against the HIV infection have apparently been resolved by utilizing viral signals not directly from the virus or its products, but from membranes of infected cells. Evaluation of the level of protection provided by the vaccine requires a large scale clinical trial in a population with a high rate of infection. Screening studies have been conducted in different areas and in different subgroups in Zaire in order to identify such a group. A population living or working at a site some 30 km east of Kinshasa was studied between December 1986-March 1988, and a parallel study was conducted of persons residing in Kinshasa. Groups from 2 rural regions were also studied. The 1554 persons screened were divided into 8 groups based on their residence histories. Serum HIV antibodies were assessed by ELISA and Western Blot. The 4 groups composed of men living and working in Kinshasa or within a suburban radius of 30 km had a seroprevalence rate of 12.67%, with no significant difference by residence. A population of 136 pregnant women in the same locations had a seroprevalence rate of 12.5%, for a sex ratio of 1.1. A group of 71 persons studied in a provincial city of southern Zaire who had spent time in Kinshasa several years previously had a seroprevalence of 4.23%. A group of new arrivals to the Kinshasa vicinity from the provinces who had never previously resided in Kinshasa had a seroprevalence of 2.45%. The final group was also composed of new arrivals from the same provinces with no previous urban experience. Screening after 8-12 months in the city showed that their seropositive rate had increased from 2.45% to 8.00%. This increase of 5.6% within 1 year indicates that this group would be appropriate for a large scale clinical trial on individuals with high risk of natural infection.

Plasmodium falciparum in Kinshasa, Zaire: in vitro drug susceptibility studies.

In June 1986, Plasmodium falciparum parasites were collected from 33 children presenting at the Mama Yemo Hospital in Kinshasa (Zaire) and were successfully tested in vitro by a 48-hr reinvasion test for their susceptibility to various antimalarial drugs. In vitro resistance to chloroquine was found in 82% of the isolates, a marked increase over findings obtained by the same technique 3 years ago in Kinshasa. In vitro chloroquine resistance was not associated with a history of previous drug intake. The inhibitory endpoints for quinine varied from 0.03 to 1 microM, and correlated with the chloroquine endpoints in the corresponding isolates (r = 0.64). Pyrimethamine resistance in vitro was demonstrated in 52% of the isolates tested.

Loa loa: a simple method for isolation of microfilariae from blood with production of antigen in extraction medium.

A simple method for isolating Loa loa microfilariae from the blood of patients is described. This involves sedimentation on Ficoll followed by migration of the microfilariae into an extraction medium. During migration the microfilariae release antigen-rich excretory or secretory products. The procedure thus yields two products: pure microfilariae and large amounts of antigen in the extraction medium.

[Current aspects of the ELISA technic applied to the serological diagnosis of helminthiasis]. / Aspect actuel de la technique ELISA appliquée au diagnostic sérologique des helminthiases.

The authors reviewed the data acquired in ELISA technique for serological diagnosis of parasitosis. They reviewed the literature on Schistosomisis, Fasciolasis, Cestode infections (hydatidoses and cysticercoses) and nematode infections. They described their adaptation of the technique for detection of antimicrofilaria Loa loa antibodies and concluded that ELISA technique is reliable in the diagnosis of parasitic diseases even in areas where they are endemic.

Age of appearance of IgG, IgM, and IgE antibodies specific for Loa loa in Gabonese children.

IgG, IgM, and IgE antibodies against the filaria Loa loa were measured in umbilical cord blood and in blood from young Gabonese children by an ELISA technique using a homologous metabolic antigen. For children in eight consecutive age groups and adults the percentage of the population positive for each of the antibody classes was determined. The number of children with maternal IgG decreased until one year of age when new synthesis began to become apparent. IgM antibodies were detected only after six months, probably indicating an early infancy as opposed to a fetal infection. The percentage of individuals positive for IgM or IgE reached a peak between two and three years old, followed by a slight decline. Over half of the individuals over one year of age had IgM antibody against L. loa, indicating long-term synthesis of this class of immunoglobulin in many people. In the first two years of life, IgE antibodies were usually accompanied by L. loa-specific IgM. This specific IgE did not appear to trigger the synthesis of nonspecific IgE. By the age of two, 95% of the population had some antibodies against L. loa and by five the percentage of individuals positive for each antibody class had reached adult levels.

The intestinal entodiniomorph ciliates of wild lowland gorillas (Gorilla gorilla gorilla) in Gabon, West Africa.

Examination of 109 fecal samples from wild lowland gorillas revealed the presence of five species of entodiniomorph ciliates: Troglodytella abrassarti, Troglodytella gorillae, and three unclassified species. These latter three species were also found in the feces of a captive gorilla in Gabon and are considered to be intestinal parasites or commensals.