Outbreak of cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013

• DOI: 10.1186/s12879-015-0807-1
• Publication Date: 2015-02-21T08:30:59Z
• Authors: Maximilian Gertler; Matthias Dürr; Peter Renner; Sven Poppert; Mona Askar; Janina Breidenbach; Christina Frank; Karina Preußel; Anika Schielke; Dirk Werber; Rachel Chalmers; Guy Robinson; Irmgard Feuerpfeil; Egbert Tannich; Christine Gröger; Klaus Stark; Hendrik Wilking
• Keywords: Parasitology; Tropical Medicine

During weeks 32–33, 2013, 24 cases of cryptosporidiosis were notified in the city Halle (annual mean 2008–2012: 9 cases). We investigated outbreak to identify source and recommend control measures, considering that between 23–25 river Saale which flows through centre overflowed floodplain, parts damaged sewage systems. defined a case as resident with gastroenteritis, Cryptosporidium-positive stool disease onset 27 47. In case–control study among kindergarten children, we compared controls regarding environmental exposure, use swimming pools, zoo visits tap water consumption 14 days pre-onset or corresponding 14-days-period (controls) adjusted for residence. Stool specimens tested by microscopy PCR, Cryptosporidium DNA was sequenced. Samples from public system, pools examined oocysts (microscopy PCR). Overall, 167 detected, 40/167 (24%) classified secondary cases. First onsets occurred during week 29, numbers peaked 34 started decrease 36. Median age 8 years (range: 0–77). Compared (n = 61), 20) more likely report previously flooded areas (OR: 4.9; 95%-CI: 1.4-18) 2.6; 0.9-7.6). multivariable analysis floodplain remained sole risk factor 5.5; 1.4-22). Only C.hominis single genotype (IbA9G2) detected stools. Oocysts samples river, two local lakes three microscopy, but not supply. Evidence suggests activities dried out led infection children. Secondary transmissions may be involved. Consequently, authorities recommended avoid playing, having picnics flood-affected area. Health should consider potential health risks long-term surviving parasites persisting on grounds open waters even several after flooding bathing places close spill-overs. Preventive measures comprise sampling (involving parasites), information prolonged closures potentially contaminated sites.