News - History of Syndromic Surveillance - Part 1

The concept of syndromic surveillance is believed to have originated in 1993, following an outbreak of cryptosporidiosis in the city of Milwaukee (Wisconsin, United States) that affected 400,000 people and caused 40 deaths. Following this outbreak, several data sources were retrospectively analyzed to assess their ability to detect the outbreak early. The results showed an increase in cases of gastroenteritis in emergency departments and nursing homes, as well as a rise in school absenteeism several days before the biological confirmation of Cryptosporidium in the water. Another study revealed that sales of over-the-counter anti-diarrheal medications had more than tripled several days before this outbreak was brought to the attention of public health authorities. It was based on these observations and the potential value of such data for the rapid detection of abnormal phenomena within the population that syndromic surveillance was developed.

• March 28, 1993: peak in water turbidity

• April 5, 1993: increase in cases of gastroenteritis in emergency departments

• April 12: biological confirmation of Cryptosporidium

Key points:

• Réunion: activity stable over the past two weeks.

• Mayotte: activity has remained stable over the past two weeks.