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We evaluated enteric infection serology as an alternative outcome measure to diarrhea prevalence in a randomized controlled trial of household-based drinking water treatment; 492 households were randomly assigned to 5 household-based water treatment interventions or control. Individuals were followed weekly over 52 weeks to measure diarrhea prevalence. Study subjects of age ≤ 6 months and < 24 months had blood drawn at entry and exit from the study or age cohort. Serologic assays for Cryptosporidium parvum, Giardia intestinalis, enterotoxigenic Escherichia coli (ETEC), and Norovirus were done. Of 343 subjects eligible for the study, the proportions of subjects experiencing serologic responses were 56% for Norovirus, 24% for C. parvum, 10% for ETEC, and 16% for G. intestinalis. Serologic response was associated with increased diarrhea prevalence only for G. intestinalis (P = 0.0134). Serologic response to the antigens tested for G. intestinalis but not for Norovirus, C. parvum, and ETEC may be a useful health-effect measure. Larger intervention studies that yield a more marked effect on diarrheal disease, use additional and improved serologic assays, and that collect serum samples at more frequent intervals are needed.

Water and sanitation interventions in developing countries have historically been difficult to evaluate. We conducted a seroepidemiologic study with the following goals: 1) to determine the feasibility of using antibody markers as indicators of waterborne pathogen infection in the evaluation of water and sanitation intervention projects; 2) to characterize the epidemiology of waterborne diarrheal infections in rural Guatemala, and 3) to measure the age-specific prevalence of antibodies to waterborne pathogens. Between September and December 1999, all children 6-36 months of age in 10 study villages were invited to participate. We collected sufficient serum from 522 of 590 eligible children, and divided them into six-month age groups for analysis (6-12, 13-18, 19-24, 25-30, and 31-36 months). The prevalence of antibodies was lowest in children 6-12 months old compared with the four older age groups for the following pathogens: enterotoxigenic Escherichia coli (48%, 81%, 80%, 77%, and 83%), Norwalk virus (27%, 61%, 83%, 94%, and 94%), and Cryptosporidium parvum (27%, 53%, 70%, 67%, and 73%). The prevalence of total antibody to hepatitis A virus increased steadily in the three oldest age groups (40%, 28%, 46%, 60%, and 76%). In contrast, the prevalence of antibody to Helicobacter pylori was relatively constant in all five age groups (20%, 19%, 21%, 25%, and 25%). Serology appears to be an efficient and feasible approach for determining the prevalence of infection with selected waterborne pathogens in very young children. Such an approach may provide a suitable, sensitive, and economical alternative to the cumbersome stool collection methods that have previously been used for evaluation of water and sanitation projects.

We evaluated enteric infection serology as an alternative outcome measure to diarrhea prevalence in a randomized controlled trial of household-based drinking water treatment; 492 households were randomly assigned to 5 household-based water treatment interventions or control. Individuals were followed weekly over 52 weeks to measure diarrhea prevalence. Study subjects of ageor= 6 months and24 months had blood drawn at entry and exit from the study or age cohort. Serologic assays for Cryptosporidium parvum, Giardia intestinalis, enterotoxigenic Escherichia coli (ETEC), and Norovirus were done. Of 343 subjects eligible for the study, the proportions of subjects experiencing serologic responses were 56% for Norovirus, 24% for C. parvum, 10% for ETEC, and 16% for G. intestinalis. Serologic response was associated with increased diarrhea prevalence only for G. intestinalis (P = 0.0134). Serologic response to the antigens tested for G. intestinalis but not for Norovirus, C. parvum, and ETEC may be a useful health-effect measure. Larger intervention studies that yield a more marked effect on diarrheal disease, use additional and improved serologic assays, and that collect serum samples at more frequent intervals are needed.

Water and sanitation interventions in developing countries have historically been difficult to evaluate. We conducted a seroepidemiologic study with the following goals: 1) to determine the feasibility of using antibody markers as indicators of waterborne pathogen infection in the evaluation of water and sanitation intervention projects; 2) to characterize the epidemiology of waterborne diarrheal infections in rural Guatemala, and 3) to measure the age-specific prevalence of antibodies to waterborne pathogens. Between September and December 1999, all children 6-36 months of age in 10 study villages were invited to participate. We collected sufficient serum from 522 of 590 eligible children, and divided them into six-month age groups for analysis (6-12, 13-18, 19-24, 25-30, and 31-36 months). The prevalence of antibodies was lowest in children 6-12 months old compared with the four older age groups for the following pathogens: enterotoxigenic Escherichia coli (48%, 81%, 80%, 77%, and 83%), Norwalk virus (27%, 61%, 83%, 94%, and 94%), and Cryptosporidium parvum (27%, 53%, 70%, 67%, and 73%). The prevalence of total antibody to hepatitis A virus increased steadily in the three oldest age groups (40%, 28%, 46%, 60%, and 76%). In contrast, the prevalence of antibody to Helicobacter pylori was relatively constant in all five age groups (20%, 19%, 21%, 25%, and 25%). Serology appears to be an efficient and feasible approach for determining the prevalence of infection with selected waterborne pathogens in very young children. Such an approach may provide a suitable, sensitive, and economical alternative to the cumbersome stool collection methods that have previously been used for evaluation of water and sanitation projects.