Comparing serologic response against enteric pathogens with reported diarrhea to assess the impact of improved household drinking water quality.

This study evaluated enteric infection serology as an alternative outcome measure to diarrhoea prevalence in an RCT of household-based drinking water treatment; 492 households were randomly assigned to 5 household-based water treatment interventions or control. Of 343 subjects, 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 diarrhoea prevalence only for G. intestinalis. Serologic response to antigens for G. intestinalis but not for norovirus, C. parvum, and ETEC may be a useful health-effect measure. Am J Trop Med Hyg. 2007;77:136-41.