[An outbreak of giardiasis in a child day-care centre in Trondheim].

Background: The prevalence of Giardia in Norway is considered to be low, but the infection is probably under-diagnosed. In other countries, child day-care centres have turned out to be major sites of Giardiasis contamination and outbreaks. We report the first giardiasis-outbreak registered in Norway.
Materials and Methods: The outbreak occurred in a child day-care centre in Trondheim, Norway in 2004. Out of 12 microbiologically verified cases, 9 had clinical gastroenteritis. Stool samples were collected from all children and staff in the day-care centre, and from all household members of identified carriers. All carriers were treated with metronidazole and responded well to treatment. The environment of the child day-care centre was assessed, and all affected households were interviewed by telephone. Preventative measures were implemented.
Results and Interpretation: The outbreak may have started in November 2003 and lasted until July 2004. It was limited to one of the day-care centre's five sections and 44% were infected. The source of infection was not identified, but there are several possibilities: staff who changed nappies and helped with going to the toilet also prepared and served food. Washbasin taps in kitchens and nappy-changing rooms were hand-operated. Cups used for drinking were exposed to potential contamination. These conditions are regarded as important routes for infections.