Sweden suspects sprouts in Salmonella investigation

A rise in Salmonella infections in Sweden has been linked to the consumption of alfalfa sprouts.

Folkhälsomyndigheten (the Public Health Agency of Sweden) said 92 people from 18 regions have been infected with one of 12 genetically closely related Salmonella Typhimurium sequence type (ST) 36 variants.

Patients fell sick beginning in August. There are 60 women and 32 men who are ill. Cases range in age from 1 to 89 and the median is 44 years old. Most are in the age groups 0 to 10 and 40 to 50 years old.

Folkhälsomyndigheten and regional infection control units have carried out a case-control study. Questionnaires about food intake in the week before illness have been sent to outbreak cases and the responses have been compared with answers from healthy controls.

Alfalfa sprouts link
Results available so far show that outbreak cases have eaten alfalfa sprouts more often compared to the healthy control subjects. These alfalfa sprouts have been purchased in different stores or were served in different restaurants or canteens.

An investigation involving regional infection control units, municipalities, the Swedish Food Agency (Livsmedelsverket), and Folkhälsomyndigheten is ongoing.

In September, an outbreak investigation was opened for people infected with a specific variant of Salmonella Typhimurium ST 36. Initial work did not detect what caused illnesses and the investigation was closed. However, it was restarted and broadened earlier this month after several new variants of sequence type 36 were identified.

Officials have also alerted EU networks to detect any possible spread of Salmonella Typhimurium ST 36 in other European countries.

Campylobacter levels back to normal
Meanwhile, Swedish officials have declared a Campylobacter outbreak over after a decrease in domestically infected cases.

During the latter part of July and in August, the number of reported cases of Campylobacter infection was at its highest with 150 to 200 cases per week.

A gradual reduction followed from mid-August until late October when the number of cases increased again to around 90 per week. Reported infections decreased in the latter part of October to around 50 cases per week.

Seasonal variation with an increase in cases in late summer is seen annually. The rise coincides with the higher occurrence of Campylobacter in broiler chickens. Poor handling of fresh chicken and insufficient cooking are believed to be common reasons for infection.

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