Tularemia linked to wells in Norway

Investigators in Norway investigating an upsurge in cases of tularemia in early 2011 have linked the disease to consumption of water from private drinking water wells and streams.*

The disease, caused by infection with the bacterium Francisella tularensis, is rare but can be life-threatening if not recognised and treated promptly with appropriate antibiotics. The organism was detected by PCR testing in water samples from several wells, with contamination presumed to have occurred due to ingress of snowmelt carrying rodent excreta or carcases.

Private wells are common in rural areas of Norway although no official figures exist on the number of people using such water sources. Cyclic fluctuations in wild rodent numbers occur every three to four years, and high lemming populations were recorded in the region during summer and autumn of 2010. Fatal tularemia infections were also observed to be prevalent in the wild mountain hares during the same period.

The investigators hypothesise that warm weather in January 2011 following unusually cold temperatures in November/December 2010 may have led to contamination of poorly protected wells by snowmelt carrying contamination from rodent excreta or carcases.

Public health advisories have been issued about the outbreak, and owners of private wells have been urged to ensure that wells are protected from ingress of surface water and access by rodents. Three previous outbreaks of tularemia in Norway have also been linked to contamination of water sources.

You can read more about this research in issue 63 of WQRA's HealthStream. The reference for the paper reported on is included below.

*Outbreak of tularaemia in central Norway, January to March 2011. Larssen KW et al. (2011). Euro Surveillance; 16(13):pii=19828.