Cryptosporidiosis surveillance and water-borne outbreaks in Europe.

Cryptosporidium causes diarrhoeal disease that can be particularly severe in immuno-compromised individuals. Cryptosporidiosis is a notifiable disease at European Union level, and surveillance data are collected through the European Basic Surveillance Network. The disease distribution in Europe for 2005 showed 7,960 cryptosporidiosis cases reported from 16 countries. The crude incidence rate was 1.9 cases per 100,000, although there were considerable differences in the rates of cryptosporidiosis between countries. Infection was more commonly reported in young children. A pronounced seasonal peak was observed in the autumn of 2005, with 59% of the cases reported between August and November, although Ireland and Spain experienced a peak in spring and summer, respectively. Cryptosporidiosis outbreak investigations and analytic studies have associated the disease with drinking water supplies, animal contact, travel, and swimming pools. Contamination of the source water for drinking water supplies, as well as inadequate water treatment can be responsible for cryptosporidiosis outbreaks. Routine cryptosporidiosis surveillance from North West England over 17 years showed that the cases occurred predominantly in spring and autumn. British drinking water regulations and improvements in drinking water treatment have coincided with a decline in cryptosporidiosis incidence. Improvements in cryptosporidiosis surveillance such as detection, recording and reporting will help to recognise outbreaks and monitor interventions.