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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.

The objective of this study was to compare an indirect immunofluorescence assay with culture methods for the identification of Legionella pneumophila serogroups 1 to 6 in hot water samples taken from domestic environments. Hot water samples were obtained from the water heater, the shower heads, and the most frequently used faucet of 211 private houses. Concentrated water samples were inoculated on buffered charcoal yeast extract agar (BCYE) and on a semi-selective culture medium (GPV). Colonies with a morphology similar to that of Legionellaceae were subcultured on BCYE and on blood agar plates; those that grew on the former but not the latter were further characterized and identified by direct immunofluorescence techniques. The concentrated samples were also smeared on multiple-well microscope slides and tested by indirect immunofluorescence with monoclonal antibodies against L. pneumophila, serogroups 1 to 6. Of the houses studied, 30% were found to contain culturable L. pneumophila in at least one water sample, whereas 63% were positive by indirect immunofluorescence. The sensitivity of this assay compared with culture varied from 16.7-21.1%, and its specificity was between 76.7% and 88.3% depending on the sample source (water heater, shower heads, or faucet). In the 38 houses with at least one positive sample found by both immunofluorescence and culture, total or partial agreement between serogroups identified by both techniques was only 34%. The results obtained in this study strongly suggest that indirect immunofluorescence is not an adequate alternative for the identification of L. pneumophila in hot water systems.

To identify factors associated with the contamination of hospital water distribution systems by legionellae, 84 Quebec hospitals provided 3284 hot water specimens from 839 different sites. Concentrated samples were seeded on buffered charcoal yeast extract agar and a semi-selective medium. At least one water sample was contaminated by legionellae in 57 hospitals (67.9%). In 22 hospitals (26.2%), greater than 30% of samples were contaminated by these bacteria. In 9 (12.2%) of 74 hospitals, distilled water was colonized. The presence of at least one positive sample was found to be associated with localization and number of hospital beds (P = .02 for both). Heavy contamination was associated with large volume hot water tanks (P = .01), low water temperature at faucet (P = .03), and old water heaters (P = .06). Conditions required for the occurrence of nosocomial legionellosis may be present in numerous hospitals.

The 1989 measles outbreak in the province of Quebec has been largely attributed to an incomplete vaccination coverage. In the Quebec City area (pop. 600,000) 1,363 confirmed cases of measles did occur. A case-control study conducted to evaluate risk factors for measles allowed us to estimate vaccination coverage. It was measured in classes where cases did occur during the outbreak. This population included 8,931 students aged 5 to 19 years old. The 563 cases and a random sample of two controls per case selected in the case's class were kept for analysis. The vaccination coverage among cases was at least 84.5%. Vaccination coverage for the total population was 99.0%. Incomplete vaccination coverage is not a valid explanation for the Quebec City measles outbreak.

In June 1987, an outbreak of acute enteritis occurred over a period of 2 weeks in a small rural community where the potable water supply is unfiltrated and unchlorinated. Campylobacter jejuni was isolated from 6 patients. A case-control study performed in a local fiberglass shop where workers drink a lot of water, showed an association between the occurrence of enteritis and the consumption of 10 or more 8-ounce glasses of water per day (Odds Ratio = 6, p = 0.04). The attack rate of enteritis was 23.2% (13/56) in that industry where a dose response relationship was also noted (p = 0.05). C. jejuni was not recovered from the local water supply, which had temporarily been chlorinated the day before the samples were drawn. However, samples taken just before the outbreak showed high coliform counts. This episode suggests that unprotected water systems may be contaminated by C. jejuni.