Early warning disease surveillance after a flood emergency--Pakistan, 2010.

During July-August 2010, Pakistan experienced extreme flooding that affected approximately 18 million persons. In response to the emergency, Pakistan's Ministry of Health and the World Health Organization (WHO) enhanced an existing disease early warning system (DEWS) for outbreak detection and response. This report summarizes surveillance results early after implementation, describes system usefulness, and identifies areas for strengthening. Daily disease counts were reported from health facilities in four provinces containing 98% of the flood-affected population. During July 29, 2010-September 15, 2010, approximately 5.6 million new patient visits were reported. The most frequent conditions reported were skin diseases (18.3%), acute respiratory infection (15.1%), and acute diarrhea (13.3%). A total of 130 outbreak alerts were documented, of which 115 (88.5%) were for acute watery diarrhea (AWD) (suspected cholera). Of these, 55 alerts (47.8%) had at least one microbiological sample with confirmed cholera. Overall, DEWS was useful in detecting outbreaks, but it was limited by problems with data quality. Improvements in DEWS have increased system usefulness in subsequent emergencies. This report highlights the need to follow updated WHO guidelines on early warning disease surveillance systems to improve their usefulness.