Wastewater quality and the risk of intestinal nematode infection in sewage farming families in hyderabad, India.

Use of sewage or wastewater in agriculture is becoming increasingly common as a result of a global water scarcity. Intestinal nematode infections have been identified as the main health risk associated with this practice. To protect consumer and farmer health, the World Health Organization (WHO) has established an intestinal nematode water quality standard. However, because of a lack of well-designed studies, the validity of this guideline is questioned. This report presents the findings of a study on the risk of intestinal nematode infections in farming families occupationally exposed to untreated and partially treated wastewater in Hyderabad, India. The study found an increased risk of hookworm (odds ratio [OR] 3.5, 95% confidence interval [CI] = 2.2-5.5), Ascaris lumbricoides (OR = 5.3, 95% CI = 2.0-14), and Trichuris trichiura (OR = 5.6, 95% CI = 1.8-18) infection when untreated wastewater (150 intestinal nematode ova/liter) was used for crop production. Use of partially treated wastewater (28 intestinal nematode ova/liter) was only associated with an increased risk (OR = 3.2, 95% CI = 1.2-8.6) of A. lumbricoides infection. The findings of the study suggest that the current WHO intestinal nematode guideline of 1 ova/liter is sufficient to protect farmer health.

Seroepidemiology and risk factors for sporadic norovirus/Mexico strain.

Risk factors associated with transmission of sporadic norovirus (NV; formerly Norwalk-like virus)/Mexico strain were identified in a seroepidemiological study conducted in rural Mexico. Acquisition of Mexico strain IgA antibodies was age-related; 34% of 1-4-year-olds were seropositive, compared with 81% of adults (P<.001). After 12 months, 42% of 1-4-year-olds showed a seroresponse to Mexico strain, compared with 27% of adults (P<.01). Personal and domestic hygiene measures, such as hand washing, general cleanliness of the mother's clothing, and the type of room assigned for cooking were significantly associated with odds of a seroresponse. For infants, having a dog in or near the home was a risk factor for seroresponse (P<.01), whereas, for older children, the mother's involvement in agricultural activities was a risk factor (P<.001). This study provides initial evidence of risk factors associated with sporadic NV infection. Data indicate some similarities to risk factors associated with outbreaks of NV infection.