Risk Factors for a Cholera Outbreak after Severe Flooding in Western Samar, Philippines 2011


Background: On January 2011, the National Epidemiology Center received a report of an increasing number of diarrhea cases after a severe flood hit Eastern Philippines. An FETP team was sent to conduct an epidemiologic investigation. Methods: A matched case-control study was done. A case was a resident of Barangay Y who developed profuse watery diarrhea from January 10 to 29, 2011. A control was a well resident from the same or next nearest household of a case and negative for Vibrio cholera. Records review, key informant interviews (KII), ocular inspection and environmental sampling were done. Rectal swab specimens were sent for culture. Results: Nineteen cases and 76 controls were identified. Median age of cases was 10 years (range: 3 months-70 years). There were no deaths. Heavy rainfall preceded the outbreak. Community water pipes were laid on muddy tracks and small creeks before reaching the intake box. Leaking pipes were submerged in dirty canals. Water samples were positive for Vibrio cholerae non-01. V