According to Swedish public health officials, there has been an increase in Yersinia infections in recent weeks. Since the second week of January, more than twice as many people have fallen ill with yersiniosis compared to the same period over the past years. An increased number of patients has been observed in the regions of Stockholm, Västra Götaland and Halland, which account for 33 of 48 cases reported since January 11.
Most of those sick are between the ages of 11 and 40 years old and are women. Five girls and one boy aged zero to 10 years old have also been infected.
Folkhälsomyndigheten, the Swedish Public Health Agency, and local infection control units in affected regions are trying to identify the source of infection by interviewing patients. The agency is also collecting samples and has detected Yersinia isolates from patients in these regions. The isolates will be subject to whole genome sequencing to clarify if people have been affected by a common source of infection.
A recent Yersinia enterocolitica O3 outbreak in Norway that affected 10 people was traced to salad.
Between 200 and 300 Yersinia infections are reported annually in Sweden. In mid-2019, more than 20 people fell ill in the country in a Yersinia outbreak. A few months earlier, another outbreak, that also affected Denmark, sickened 37 people and was linked to imported fresh spinach from Italy or Spain.
Meanwhile, 29 countries reported 7,048 confirmed yersiniosis cases in Europe in 2019, according to officials. The highest rates came from Finland, Lithuania and the Czech Republic, according to a report published by the European Centre for Disease Prevention and Control (ECDC).
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