A review of the published literature on the impact of water supply and/or excreta disposal facilities on diarrhoeal diseases, or on infections related to diarrhoea, reveals several methodological problems that hamper the drawing of definitive conclusions from these studies. This paper examines eight of these methodological problems: lack of adequate control, the one to one comparison, confounding variables, health indicator recall, health indicator definition, failure to analyse by age, failure to record usage, and the seasonality of impact variables. It is suggested that an evaluation of the impact on health of environmental interventions may best be undertaken by the combined efforts of engineers, social scientists and epidemiologists in 'opportunistic' settings and that the intervening behavioural processes so necessary for health impact to occur should be a primary focus of such evaluations.

To determine the risk factors associated with toxic-shock syndrome (TSS) in menstruating women, we conducted a retrospective telephone study of 52 cases and 52 age-matched and sex-matched controls. Fifty-two cases and 44 controls used tampons (P < 0.02). Moreover, in case-control pairs in which both women used tampons, cases were more likely than controls to use tampons throughout menstruation (42 of 44 vs. 34 of 44, respectively; P < 0.05). There were no significant differences in brand of tampon used, degree of absorbency specified on label, frequency of tampon change, type of contraceptive used, frequency of sexual intercourse, or sexual intercourse during menstruation. Fourteen of 44 cases had one or more definite or probable recurrences during a subsequent menstrual period. In a separate study, Staphylococcus aureus was isolated from 62 of 64 women with TSS and from seven of 71 vaginal cultures obtained from healthy controls (P < 0.001).

During the summer-fall months, 39% (79 of 203) of children for whom blood cultures and/or lumbar punctures were performed for suspected bacterial infection had enterovirus infection identified as the only explanation for their illness. Of those patients with no alternative diagnosis, enterovirus infection was confirmed in 46% (79 of 179). The majority of those patients requiring hospitalization were infected with enteroviruses. The use of PCR increases the number of children for whom a specific etiology of illness can be determined and may in the future reduce the hospitalization and use of unnecessary antibiotics in patients with enterovirus infections.