A case-control study of Hodgkin's disease in Brazil. I. Epidemiogic aspects.

A number of epidemiologic variables were investigated in a case-control interview study, conducted in São Paulo, Brazil, of 70 Hodgkin's disease (HD) patients, 70 tumor control subjects matched for age and sex, and 128 siblings of the patients. The major epidemiologic findings were a high percentage of total cases among children, with a high sex ratio, a relative predominance of the mixed cellularity histologic subtype, and a bimodal age-specific incidence curve with the highest rates among young adults and the elderly. When the matched controls were used as the comparison group, high socioeconomic status (SES) was found to be associated with an increased risk for HD (p = 0.001). On the basis of the case-sibling comparison, an association between prior tonsillectomy and risk for HD was found (p = 0.04), and the relative risk for HD among tonsillectomized persons as compared to individuals who had not had the operation was 2.5. Other variables, including sibship size, birth order, marital status, occupational exposure, prior use of amphetamines or diphenylhydantoin, intensity of exposure to children and history of viral illnesses were not found to be determinants of risk for HD in this study.

A case-control study of Hodgkin's disease in Brazil II. Seroepidemiologic studies in cases and family members.

A case-control study of antibody titers to the viral capsid antigen of Epstein-Barr virus was carried out in 70 patients with Hodgkin's disease (HD) and in 92 siblings, 50 parents and 19 children of the HD patients, each paired with a control matched for age and sex. The geometric mean titer (GMT) of the HD patients was significantly greater than that of the controls (t69 = 6.30, p < 0.0005), and the proportion of HD cases with titers greater than or equal to 1:320 was significantly elevated (35.5% vs. 2.9%). No significant differences in GMTs were found when the HD patients were grouped by sex or by histologic subtype. An inverse correlation between age and titer was noted among HD patients but not among controls. The GMT of the 161 relatives of the HD cases was similar to that of their respective controls. Likewise, there was no significant elevation of the GMT of the subset consisting of family members of HD patients with high titers when compared to controls. However, when the GMT of the family members of HD patients with high titers was compared to that of the relatives of the HD patients with low titers, a significant difference was found (t159 = 2.54, p < 0.01).

Feasibility and efficacy of in-home water chlorination in rural North-eastern Brazil.

The purpose of this study was to assess the feasibility, acceptability and effect of an in-home water chlorination programme in a rural village. Previous studies at this site showed high levels of faecal coliforms in household water, high diarrhoea rates in children, and enterotoxigenic Escherichia coli and rotaviruses were the most common pathogens isolated from patients. Household water came from a pond and was stored in clay pots. No homes had sanitary facilities. A blind, cross-over trial of treatment of household water with inexpensive hypochlorite by a community health worker was carried out over 18 weeks among 20 families. Water in the clay pots was sampled serially, and symptom surveillance was done by medical students. The programme was generally acceptable to the villagers and no change in water use patterns were apparent. The mean faecal coliform level in the chlorinated water was significantly less than in the placebo treated samples (70 vs 16000 organisms/dl, P less than 0.001). People living in houses receiving placebo treatment had a mean of 11.2 days of diarrhoea per year, and the highest rate of 36.7 was among children less than 2 years old. Diarrhoea rates were not significantly different among the participants while exposed to water treated with hypochlorite. We conclude that a low-cost programme of this type, which utilizes community resources, is logistically feasible, appears to be culturally acceptable in this setting, and can result in a marked reduction in water contamination. The lack of effect on diarrhoea rates suggests that improvement in water quality may affect morbidity only when other variables relating to faecal-oral agent transmission are ameliorated at the same time.

Prospective study of diarrheal illnesses in northeastern Brazil: patterns of disease, nutritional impact, etiologies, and risk factors.

Diarrhea is a leading cause of death in tropical countries. One of the highest childhood mortalities is in northeastern Brazil, where little is known about the morbidity, etiology, and risk factors of diarrhea. Prospective village surveillance over 30 months revealed diarrhea attack rates of more than seven episodes per child-year at six to 11 months of age among the children of the poorest families. Other risk factors included early weaning and the lack of toilets. Diarrhea led to weight loss and stunted growth. Enterotoxigenic Escherichia coli and rotaviruses were the most common pathogens, accounting for 21% and 19% of cases, respectively, followed by Shigella species (8.0%), Campylobacter jejuni (7.5%), Giardia species (6.7%), Strongyloides species (5.3%), and enteropathogenic E coli serotypes (4.6%). Most (84%) enterotoxigenic E coli were isolated during the rainy season of October to March (P less than 0.03), whereas 71% of rotaviral illnesses occurred during the drier months of June to October (P less than 0.03). In the present study, the early occurrence and nutritional impact of diarrhea and weaning, as well as the major etiologic agents of diarrhea and their different seasonal patterns have been defined for this region in which life-threatening diarrhea is endemic.