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Biomedical subjects

P Piot

Publications and source records attributed to P Piot.

At least 127 records · Page 7Linked to original sources
PubMed1991

Declining trends in some sexually transmitted diseases in Belgium between 1983 and 1989.

OBJECTIVE: To examine trends in some sexually transmitted diseases in Belgium and to discuss them in the light of the European background. DESIGN: Analysis of the time trends of C trachomatis and N gonorrhoeae infections diagnosed by a network of microbiological laboratories, and of male urethritis diagnosed by a network of general practitioners. SETTING: Belgium. SUBJECTS: Reports of C trachomatis and N gonorrhoeae infections by a network of microbiological laboratories, and of male urethritis by a network of general practitioners, to the Institute of Hygiene and Epidemiology. RESULTS: Whereas an increase in the number of C trachomatis infections, more pronounced among women, was observed up to 1986, a small decrease has been observed afterwards in males. The mean number of chlamydial infections per laboratory and per year was 4.2 in 1983, 15.7 in 1986 and 13.9 in 1989. A decrease in the number of N gonorrhoeae infections, more pronounced among men, has been observed. The mean number of cases of gonorrhoea per laboratory and per year was 10.9 in 1983 and only 2.2 in 1989. The same declining trend has been observed in another surveillance programme of male urethritis, based on a network of general practitioners. The number of cases of male urethritis per 100 patient encounters went down from 0.06 in 1982-3 to 0.04 in 1988-9. CONCLUSION: The declining trend in Western Europe in incidence of gonococcal infections and of urethritis in men is also occurring in Belgium, but genital chlamydial infections remain an important public health problem.

Adult↗
PubMed1991

Simplified and less expensive confirmatory HIV testing.

The conventional approach to human immunodeficiency virus (HIV) antibody testing, which relies on confirmation of all initially positive screening results using a Western blot assay, is expensive. In an alternative approach, we retested sera that were positive in an initial screening assay using a second screening assay, which differed from the first, and limited the use of Western blot to those sera that gave discrepant results in the two screening assays. This resulted in 100% sensitivity and specificity at a cost that was, on average, 6.1 times less than that of the conventional approach. This level of sensitivity and specificity was also achieved at a cost that was 9.0 times less than the conventional approach if the Western blot was replaced by a third screening assay that differed from the previous two. Retesting positive sera using the same assay did not increase the accuracy of the results obtained by testing the sera only once.

AIDS Serodiagnosis↗
PubMed1991

Comparative evaluation of 36 commercial assays for detecting antibodies to HIV.

Summarized are the results of an assessment of the major operational characteristics of 36 commercially available assays for detection of antibodies to human immunodeficiency virus type 1 (HIV-1) and/or type 2 (HIV-2). For this purpose, 20 enzyme-linked immunosorbent assays (ELISAs), 11 simple immunoassays with visual reading, four supplemental assays, and one discriminatory assay were assessed using a panel of 537 sera (65% of which were of African, 26% of European, and 9% of South American origin); the prevalence of HIV-1 was 39.1% and of HIV-2, 15.7%. The following operational parameters of the assays were investigated: ease of performance; suitability for use in small blood collection centres; sensitivity and specificity; positive predictive values at different prevalences; inter-reader variability for simple assays whose results were read visually; the proportion of indeterminate results; and, for some of the ELISA assays, delta-values, as quantitative measures of sensitivity and specificity. The results will be of use to health policy decision-makers, managers of national AIDS prevention and control programmes, directors of blood banks, and laboratory specialists in the selection of appropriate HIV antibody assays.

AIDS Serodiagnosis↗
PubMed1991

A simplified and less expensive strategy for confirming anti HIV-1 screening results in a diagnostic laboratory in Lubumbashi, Zaire.

The conventional algorithm for HIV testing based on the confirmation of all positive anti-HIV screening reactions by Western blot (WB) is too expensive for developing countries. We investigated the validity of confirming positive screening assay reactions by a second screening test, limiting the use of the supplemental assay to the discrepant test results (algorithm 3), or screening all sera with 2 different assays and retesting all discrepant results by a supplemental assay (algorithm 4) on a panel of 519 sera in a regional reference laboratory in Lubumbashi, Zaire. Combining the Vironostika anti-HTLV-III ELISA with HIV Chek 1 + 2 or Clonatec Rapid HIV 1/2 Ab on all samples and retesting the discrepant results in WB or a line immunoassay (INNO-LIA) (algorithm 4), yielded a sensitivity of 100% and specificities of 98.4% and 99.0% respectively, at costs of 7.3 US $ and 9.3 US $ per test, respectively, for a 40% prevalence of HIV antibody positive samples. The conventional algorithm scored a sensitivity of 97.1% and a specificity of 100% for 11.3 US $ per test. The testing strategy of combining HIV Chek 1 + 2 and Clonatec Rapid HIV 1/2 Ab, an interesting option for small isolated centra, had a 96.6% sensitivity, but yielded only a slightly better specificity of 99.0%, as compared to 97.8% for HIV Chek alone. The price of combining the two simple assays using algorithm 3 was 6.8 US $ per test, using algorithm 4 was 10.6 US $. HIV testing strategies based on ELISA and a simple HIV test are a valuable alternative for reference laboratories faced with a high prevalence of HIV positive samples.

AIDS Serodiagnosis↗
PubMed1991

The Nairobi STD program. An international partnership.

Since 1980, Canadian, Belgian, and American scientists have been working together with colleagues in Kenya to understand the epidemiology and biology of sexually transmitted diseases (STDs) in Africa. The rapid spread of human immunodeficiency virus has dramatically increased the importance of this information. Interventions to slow the spread of all STDs and to reduce their consequences are now our major priority. However, this will require continuing research, ongoing training of scientists, epidemiologists, and technologists, and increasing financial support from industrialized societies.

Developing Countries↗
PubMed1991

[Epidemiology of sexually transmissible diseases in developing countries in the era of AIDS].

Recent developments in the epidemiology of sexual transmitted diseases (STD) in developing countries are reviewed. STD are very frequent in the tropics, particularly in large urban areas. They put a heavy burden on public health because they affect the economically most important age groups and because their sequellae may be fatal. Pelvic inflammatory disease and its consequences, and morbidity during pregnancy and the neonatal period are among the most important causes of mother and child morbidity. STD favour sexual transmission of HIV and may therefore explain the explosive AIDS epidemics in many developing countries. Antimicrobial resistance has made treatment of gonorrhoea and chancroid more difficult and more expensive. STD and HIV infection may be responsible for up to 17% of productive years lost to disease in certain regions. Strategies to control STD should be developed and linked with the AIDS programs. Both should be integrated in the primary health care system.

Developing Countries↗
PubMed1991

Detection of salivary HIV-1-specific IgG antibodies in high-risk populations in Zaire.

Saliva and blood samples were tested for human immunodeficiency virus-1 (HIV-1) antibodies in two high-risk populations in Kinshasa, Zaire. In a seroprevalence study of 458 sexually transmitted disease (STD) clinic attendees, 142 of 145 seropositive individuals had enzyme-linked immunosorbent assay (ELISA)-positive saliva samples (97.9% sensitivity). All saliva samples from seronegative patients were ELISA-negative (100% specificity). Of the 142 ELISA-positive saliva specimens, 137 were also Western blot-positive (94.5% sensitivity). In a subsequent seroincidence study of 315 initially seronegative female prostitutes followed during 183 woman-years of observation, 9 of 14 women who seroconverted (7.7% seroincidence) had ELISA-positive saliva samples at the time seroconversion was detected. Only three of these saliva specimens could be confirmed by Western blot. Although salivary testing for HIV-1 antibodies using conventional assays was not sensitive in detecting recent seroconversions, screening of salivary samples for HIV-1 antibody provides a convenient alternative method for conducting seroprevalence surveys in populations in whom venipuncture is not possible or convenient.

Adult↗
PubMed1991

HIV-2 infection among prostitutes working in The Gambia: association with serological evidence of genital ulcer diseases and with generalized lymphadenopathy.

Three hundred and fifty-five prostitutes working in The Gambia were enrolled in a study of retroviral infections. Eight-seven (24.6%) were infected with HIV-2 only, two (0.6%) with HIV-1 only, four (1.1%) had sera showing double HIV-1/HIV-2 reactivity, and 37 (10.4%) were seropositive for HTLV-I. After allowing for socioeconomic and serological variables in a multivariate analysis, HIV-2 infection was associated with serological evidence of a previous episode of syphilis [a rapid plasma reagin (RPR) positive/Treponema pallidum haemagglutination assay (TPHA) positive; odds ratio (OR) = 2.18, 95% confidence interval (CI) = 1.19-3.98], with having antibodies against Haemophilus ducreyi (OR = 2.05, 95% CI = 0.89-4.70) or against HTLV-I (OR = 2.17, 95% CI = 0.91-5.19). HIV-2-seropositive prostitutes were three times more likely [17 out of 78 (22%) versus 15 out of 219 (7%), P less than 0.001] to have generalized lymphadenopathy than those who were seronegative. These data suggest that genital ulcer diseases may facilitate the transmission of HIV-2, and that HIV-2 rapidly induces the appearance of generalized lymphadenopathy in a substantial proportion of infected individuals.

AIDS-Related Complex↗
PubMed1990

Hepatitis B: transmission by sexual contact and needle sharing.

In the Western world most cases of hepatitis B virus (HBV) infection are acquired through sexual intercourse and through needle sharing by intravenous drug users (IVDU). The major risk factors for HBV infection in homosexual men include the number of sex partners and receptive anal intercourse. In heterosexuals, this risk also rises with an increasing number of sex partners. IVDU consistently show the highest HBV infection rates in Europe and North America, presently accounting for 25 to 50% of all hepatitis B cases. Infection with the human immunodeficiency virus affects the course of HBV infection as well as the immunological response to hepatitis B vaccines. Thus, in the industrialized world, interventions against HBV infection should primarily be targeted to homosexual men, heterosexuals with multiple partners, and IVDU.

HIV Infections↗
PubMed1990

Protective efficacy of a recombinant DNA vaccine against hepatitis B in male homosexuals: results at 36 months.

An open study with a recombinant DNA yeast-derived hepatitis B vaccine (YDV) was carried out in homosexual men to assess the protective efficacy of this vaccine. A total of 278 seronegative volunteers were enrolled to receive three intramuscular doses of either 20 or 40 micrograms at months 0, 1 and 6. Serum specimens were taken at various times up to 36 months; relevant information regarding the occurrence of other sexually transmitted diseases (STDs) and sexual behaviour was also collected annually. One month after the third injection, the seroconversion rate in both groups was 99%. The geometric mean anti-HBs titre at this time was higher for subjects receiving 40 micrograms doses although a similar percentage of the vaccinees had titres greater than 10 mIU ml-1 in both groups. Compared with a historical control group in which the annual incidence of hepatitis B infection was 12%, only two vaccinees developed markers of infection during the immunization period and none thereafter. While an important increase in the use of condoms was noted during the 1984-87 study period and the incidence of some STDs declined, these changes could not solely account for the decrease in hepatitis B infection in the study population.

Adolescent↗
PubMed1990

Impact of single session post-partum counselling of HIV infected women on their subsequent reproductive behaviour.

During an ongoing study investigating the impact of maternal HIV infection on pregnancy outcome at a large maternity hospital in Nairobi, Kenya, asymptomatic HIV positive women who had recently delivered were informed of their HIV sero-status and counselled by a trained nurse regarding contraception and reproductive behaviour in a single session. Both HIV infected women and a comparison group of uninfected women matched for pregnancy outcome were followed up after an interval of one year. Contraceptive use, condom use and pregnancy rates were similar in both groups. Only 37% of HIV infected women had informed their partners of their sero-status. The single session of counselling for the HIV positive women did not seem to influence decisions on subsequent condom use or reproductive behaviour. More intensive approaches to counselling need to be developed and evaluated, but may be difficult to implement in the busy maternity and antenatal clinics commonly found in developing countries.

Abortion, Induced↗
PubMed1990

HIV screening during pregnancy. Results of 2 attitude surveys on antenatal HIV screening in Belgium.

Two postal questionnaires were sent to Belgian gynaecologists in order to have information on their current policy of antenatal HIV screening. Of the 815 contacted, 446 (54.7%) completed the first questionnaire. 91.0% offers HIV testing in pregnancy; 49.1% to all pregnant women and 41.9% only to those with behavioural risks. Only 6.5% never offers HIV testing during pregnancy. The majority of these gynaecologists (79.8%) never had to deal with the problem of HIV-seropositivity in a pregnant woman. A second questionnaire with more detailed questions about HIV testing was sent to the identified respondents of the first survey. 237 of 340 (69.7%) responded. Of those, 48.9% perform HIV testing without informing the patient, whereas 43.4% always inform their patients before HIV testing. The majority performs the test at the first antenatal consultation (73.5%; 14.9% offers the test twice. These findings let us conclude that there is a need for recommendations concerning the policy of antenatal screening and information of patients.

AIDS Serodiagnosis↗