AIDS 1995. Epidemiology: overview.
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Biomedical subjects
Publications and source records attributed to M Laga.
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Sexually transmitted diseases (STDs) are a major cause of morbidity and mortality in developing countries and may play a key role in enhancing the heterosexual transmission of human immunodeficiency virus (HIV). Treatment of STDs is one of the most cost-effective of all health interventions in developing countries; however, STDs among women in rural populations have received little attention. In this study, we report that prevalences of STDs among 964 women attending antenatal clinics in a rural area of the United Republic of Tanzania. A total of 378 (39%) of these women were infected with at least one STD pathogen, 97 (10%) had syphilis, and 81 (8%) has Neisseria gonorrhoeae (NG) and/or Chlamydia trachomatis (CT) infection. The recommended syndromic approach to screening for NG/CT infection, based on reported genital symptoms, had a low sensitivity (43%) and failed to discriminate between infected and uninfected women. A risk score approach that we developed, based on sociodemographic and other factors associated with NG/CT infection, had a higher sensitivity and lower cost per true case treated than other approaches, although its positive predictive value was only about 20%.
A cross-sectional study was conducted among 395 patients presenting with genital ulcers at a primary health care centre in Kigali, Rwanda. Using clinical data and the results of a rapid plasma reagin (RPR) test, we simulated the diagnostic outcome of two simple WHO flowcharts for the management of genital ulcers. These outcomes and a clinical diagnosis were then compared with the laboratory diagnosis based on culture for genital herpes and Haemophilus ducreyi and serology for syphilis. The prevalence of HIV infection was high (73%) but there was no difference between HIV-positive and HIV-negative patients in the clinical presentation and etiology of genital ulcer disease. The proportion of correctly managed chancroid and/or syphilis cases was 99% using a syndromic approach, 82.1% using a hierarchical algorithm including an RPR test, and 38.3% with a clinical diagnosis. In situations where no laboratory support is available, a simple syndromic approach is preferable to the clinical approach for the management of genital ulcer. If an RPR test can be included in the diagnostic strategy, patients with a reactive RPR test should be treated for both syphilis and chancroid infection.
The control of sexually transmitted diseases, including HIV-1, among sex workers and their clients in urban areas in developing countries, is considered a valuable and cost-effective intervention to contain the spread of HIV-1. The effect of a programme of STD treatment combined with condom promotion on HIV-1 incidence has so far not been measured. During an intervention including condom promotion, as well as monthly sexually transmitted disease screening and treatment among 531 initially HIV-1 negative female sex workers in Kinshasa, Zaire, 70 became infected with HIV-1 (incidence of 8.0 per 100 women-years [wy]). A decline of HIV-1 incidence was observed over time, from 11.7/100 wy during the first 6 months, to 4.4/100 wy over the last 6 months, 3 years later (p = 0.003). Simultaneously, regular use of condoms with clients went up from 11% to 52% and 68%, after 6 and 36 months of intervention, respectively. Risk factors for HIV-1 seroconversion after multivariate analysis included irregular condom use (RR 1.6 [95% Cl 1.1-2.8]), gonorrhoea (RR 2.5 [1.1-6.4]), trichomoniasis (RR 1.7 [1.1-2.8]), and genital ulcer disease (RR 2.5 [1.1-6.4]), during the probable period of acquisition of HIV-1. In women who attended more than 90% of their clinic appointments, the HIV-1 incidence was 2.7/100 wy compared to 7.1, 20.3, and 44.1 per 100 wy among women who attended 76-90%, 50-75%, and less than 50% of the monthly appointments, respectively (p < 0.0001). These trends remained after controlling for reported condom use and number of clients. This study confirms earlier findings that STDs facilitate transmission of HIV-1 and shows that a clinic-based intervention consisting of STD care and condom promotion can result in a major decline of HIV-1 incidence among female sex workers.
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Cericovaginal lavage samples from 124 human immunodeficiency virus type 1 (HIV-1)-seropositive and 126 HIV-1-seronegative women were collected monthly for 8 months and tested for human papillomavirus (HPV) DNA. The estimated prevalence of HPV was 42.8% in HIV-1-seropositive and 13.4% in -seronegative women (P < .001). There was no significant difference in HPV DNA detection in HIV-1-seropositive women with CD4 cell counts of < 300/mm3 (50% HPV-positive), 300-499/mm3 (36.4% HPV-positive), or > or = to 500/mm3 (40.5% HIV-positive). However, HIV-1-seropositive women who were more immunocompromised, as indicated by lower CD4 cell counts, were more likely to shed HPV persistently. The quantity of HPV DNA detected in cervicovaginal lavage samples was similar in HIV-1-seropositive and -seronegative women. This study further defined the characteristics of HPV infections in HIV-1-infected women.
A substantial proportion of women with gonococcal and/or chlamydial infection are asymptomatic. Thus active case detection is problematical, particularly in developing countries, where facilities and materials for laboratory testing are limited. We assessed the diagnostic validity of the hierarchical clinical algorithms recommended by the World Health Organization as well as that of a nonhierarchical scoring system, using data for 1,160 pregnant women (a low-prevalence group) and 1,222 prostitutes (a high-prevalence group) in Kinshasa, Zaire. Neisseria gonorrhoeae and/or Chlamydia trachomatis was detected in 6.5% and 31.0% of pregnant women and prostitutes, respectively. No single variable that was both sensitive (> 60%) and specific (> 60%) was associated with infection. A simple hierarchical algorithm based only on reported symptoms had a sensitivity of 48.0% and 54.9% and a specificity of 75.2% and 52.2% for the screening of pregnant women and prostitutes, respectively. A second algorithm that included a speculum examination had a sensitivity of only 29.3% but a specificity of 85.3% in pregnant women. When a nonhierarchical scoring system was used, the sensitivity was 72.0% and 71.0% and the specificity was 73.5% and 55.8% for pregnant women and prostitutes, respectively. Scoring systems that incorporate risk markers as well as symptoms and signs may represent affordable alternative methods of screening for gonococcal and/or chlamydial infections among women in resource-poor settings.
OBJECTIVES: The heterosexual spread of HIV-1 is occurring at different rates in different parts of the world. The transmission probability of HIV-1 per sexual contact is low, but may be greatly enhanced by several cofactors. Sexually transmitted diseases (STD), especially genital ulcers, may be such factors. So far, epidemiological evidence that other STD facilitate HIV-1 transmission is weak. The objective of this study was to determine whether treatable STD enhanced sexual transmission of HIV-1 in a cohort of female prostitutes in Kinshasa, Zaire. METHODS: We conducted a nested case-control study of 431 initially HIV-1-negative women followed prospectively for a mean duration of 2 years (with monthly STD check-ups and 3-monthly HIV-1 serology). Cases (seroconverters, n = 68) were compared with controls (women who remained HIV-1-negative, n = 126) for incidence of STD and sexual exposure during the presumed period of HIV-1 acquisition. RESULTS: The annual incidence of HIV-1 in this cohort was 9.8%. Seroconverters were younger than HIV-1-negative women (mean age, 24.6 versus 26.8 years; P = 0.04). During the period of HIV-1 acquisition, cases had a much higher incidence of gonorrhoea, chlamydial infection and trichomoniasis, and engaged in unprotected sex with clients and partners more frequently than controls. After controlling for sexual exposure by multivariate analysis, adjusted odds ratios for seroconversion were 4.8 [95% confidence interval (CI), 2.4-9.8] for gonorrhoea, 3.6 (95% CI, 1.4-9.1) for chlamydial infection and 1.9 (95% CI, 0.9-4.1) for trichomoniasis. Genital ulcers were more frequent in cases than controls, but much less common than other STD. CONCLUSION: Non-ulcerative STD were risk factors for sexual transmission of HIV-1 in women, after controlling for sexual exposure. Because of their high prevalence in some populations, non-ulcerative STD may represent a considerable population-attributable risk in the transmission of HIV-1 worldwide. The identification of treatable STD as risk factors for HIV-1 transmission offers an important additional strategy for the prevention of HIV/AIDS.
OBJECTIVE: To assess the extent of the sexually transmitted diseases (STDs) problem in a rural area of Mozambique. METHODS: A cross sectional study among pregnant women and patients presenting with genital complaints. Laboratory confirmation was done for gonorrhoea, chlamydial infection, active syphilis, trichomoniasis and HIV infection. SETTING: A primary health care setting in Vilanculos, Inhambane province, Mozambique. RESULTS: Evidence of one or more of the above STDs was found in 51% of 201 pregnant women, 56% of 85 women and 62% of 77 men with genital complaints. Neisseria gonorrhoea or Chlamydia trachomatis were found in 16% of pregnant women, 23% of female patients and 28% of male patients; genital ulcer disease was present in 6%, 28% and 36%, of respectively pregnant women, female and male patients. The prevalence of active syphilis was about the same in the three groups of study subjects, that is 15%. HIV infection was found in 4% of the male patients; no HIV infection could be detected in the female groups. CONCLUSION: STDs were a major health problem in this rural area in Mozambique. Though HIV infection was still low, the high prevalence of STDs indicates that the potential is there for an explosive spread of the HIV/AIDS epidemic.
Certain human genital papillomaviruses (HPV) are strongly associated with cervical dysplasia and cancer. Evidence is accumulating that HPV infection and ano-genital cancers are more common in patients with the acquired immunodeficiency syndrome. The objective of our study was to evaluate the extent to which HPV infection and associated cervical disease constitute opportunistic complications of human immunodeficiency virus (HIV) infection in a population of sexually promiscuous, HIV-infected women in Kinshasa, Zaire. In 1989 we obtained Pap smears and cervicovaginal lavage specimens for HPV DNA testing from 47 HIV-seropositive and 48 HIV-seronegative prostitutes who were part of a cohort under observation since 1988. Thirty-eight percent of the HIV-seropositive and 8% of the seronegative women (odds ratio = 6.8; p = 0.001) had HPV DNA detected by either ViraType, a dot-blot assay which detects specific genital HPV types, or low-stringency Southern blot, which detects all HPV types. Eighty-two women (86%) had an interpretable Pap smear; 11 of 41 (27%) HIV-seropositive women and one of 41 (3%) seronegative women had cervical intra-epithelial neoplasia (CIN) (odds ratio = 14.7; p = 0.002). HIV seropositivity, HPV infection and CIN were highly associated. Eight (73%) of 11 seropositive women with CIN had HPV detected. Both HPV infection and cervical cancer may emerge as opportunistic complications of HIV infection in populations in which HIV, HPV and cervical cancer are common.
Human papillomavirus (HPV) DNA was found in cervicovaginal lavage fluids from 9 of 11 human immunodeficiency virus type 1 (HIV-1)-seropositive female prostitutes with cervical intraepithelial neoplasia (CIN) in Kinshasa, Zaire. Since 7 yielded complex nucleic acid hybridization results consistent with mixed HPV infections, limited sequencing of HPV DNA was used to identify the HPVs present. Three of HPV 16 and 1 each of HPV 18, 31, 33, and 56 and ME180-HPV were identified by sequencing in 8 samples. Each of these genotypes has been found in specimens from HIV-1-seronegative women with CIN. Some DNAs had nucleic acid and amino acid sequence variations relative to the reference HPVs, but the variants were closely related to variants that have been found in HIV-1-seronegative women. Variant amino acids were found predominantly at three positions in one 40-amino-acid segment of the L1 open reading frame sequenced. The predominant HPV 16 variant observed has been found rarely in other countries.
OBJECTIVE: To determine the in vitro antimicrobial susceptibility of gonococcal strains isolated in 1988 among female prostitutes in Kinshasa, Zaire and to characterise strains with high level tetracycline resistance. METHODS: Minimal inhibitory concentrations of 8 antimicrobials were measured by agar dilution technique. Plasmid-profiles and serovars were determined. RESULTS: Two hundred and thirteen strains of Neisseria gonorrhoeae were tested of which 59% were beta-lactamase producers and an additional 21% showed intermediate or chromosomal resistance to penicillin (MIC = 0.5-8 mg/l). Eleven percent of the strains were resistant to the combination sulfamethoxazole-trimethoprim (MIC greater than 8 mg/l) and 57% of the isolates showed decreased susceptibility to thiamphenicol (MIC = 1-4 mg/l). All strains were sensitive to spectinomycin, norfloxacin and ceftriaxone and moderately sensitive to kanamycin. Chromosomal resistance to tetracycline was observed in 45% of strains (MIC = 2-8 mg/l). Ten percent were highly resistant to tetracycline (TRNG, MIC = 16-128 mg/l) and were shown to carry a plasmid borne Tet M determinant; such strains were not found in Kinshasa in 1985. TRNG belonged to 4 different serovars, which were also the dominant serovars in non-TRNG. CONCLUSION: These findings illustrate the high frequency of multiresistant gonococci in Zaire and suggest that high level tetracycline resistant strains of N. gonorrhoeae have become endemic in Central Africa.
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In 1988, 1233 prostitutes from different geographic areas of Kinshasa participated in a cross-sectional survey on HIV infection and other sexually transmitted diseases (STDs). Despite relatively good knowledge about AIDS and STDs, the reported preventive behaviour was poor. Only 12% of the women reported regular use of condoms, while greater than 50% of the women reported regular use of antibiotics and 38% reported doing nothing specific to prevent STDs. Thirty-five per cent of the women were HIV-positive compared with 27% in a similar survey in Kinshasa in 1986. The prevalence of other STDs was very high, ranging from 5% for genital ulcer disease (GUD) to 23% for gonococcal infection. HIV-positive women were older than HIV-negative women (26.9 versus 25.4 years; P less than 0.001), had a significantly lower level of reported condom use (9 versus 14%, P = 0.009), and reported more frequent use of antibiotics to prevent STDs (55 versus 42%, P = less than 0.001). The prevalence of syphilis, gonorrhoea, chlamydial infection and trichomoniasis was not higher in HIV-positive women compared with HIV-negative women. However, HIV-positive women had a higher prevalence of GUD (9 versus 3%, P less than 0.001), antibodies against Haemophilus ducreyi (82 versus 57%, P less than 0.001), antibodies against herpes simplex virus type 2 (96 versus 76%, P less than 0.001), condylomata accuminata (5 versus 1%, P = 0.003) and cytologic evidence of human papilloma virus on Papaniclaou cervical smear (11 versus 5%, P = 0.006). This study confirms the high incidence of HIV and other STDs among prostitutes in Africa.(ABSTRACT TRUNCATED AT 250 WORDS)
Detection by five different enzyme-linked immunosorbent assays (ELISAs) of antibody to human immunodeficiency virus (HIV) in sera from three Zairian populations consisting of 1,998 individuals with various risks for HIV infection was evaluated. Sera that were reactive by at least one assay and 10% of the nonreactive serum samples were analyzed by Western blot (immunoblot) by using U.S. Public Health Service interpretation criteria. Sera which were positive by ELISA for detection of antibody to HIV-1 and HIV-2 and negative or indeterminate by HIV-1 Western blot were also analyzed by HIV-2 Western blot. Overall, 443 (22.2%) serum specimens were HIV-1 Western blot positive, 390 (19.5%) had indeterminate HIV-1 Western blot patterns, and no samples were HIV-2 Western blot positive. The sensitivity of the ELISAs ranged from 97.5 to 99.8%, and the specificity ranged from 51.7 to 98.4%. By population group, the negative predictive value ranged from 97.1 to 100%, in contrast to the positive predictive value, which varied from 6.6 to 100%. Follow-up results for sera which were indeterminate for antibody to HIV-1 documented only four seroconversions (6.0%) among 67 individuals at high risk for HIV-1 infection and no seroconversions among 202 individuals at relatively low risk for HIV-1 infection. This study demonstrates the importance of evaluating commercial ELISAs with sera from appropriate geographical regions in order to select the most cost-effective and practical assay for use in that region. Furthermore, the high frequency of indeterminate Western blots for African sera emphasizes the continual need for improved confirmatory assays and interpretation criteria.
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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.