Public health officials in Denmark are looking into three outbreaks that have sickened almost 50 people with one caused by Hepatitis A and two due to rare strains of Salmonella.

Since June, the Statens Serum Institut (SSI), Fødevarestyrelsen (Danish Veterinary and Food Administration) and DTU Food Institute have been investigating three suspected foodborne outbreaks that have left 29 people needing hospital treatment with cases spread throughout the country. The sources are still unknown.

The Hepatitis A outbreak involves 14 people and 11 of them were admitted to hospital. An outbreak of Salmonella Strathcona includes 23 people and another of Salmonella Kasenyi has 11 patients.

Suspicion falls on imported food
Luise Müller, an epidemiologist at SSI, said those sick have not traveled abroad or participated in joint events.

“It therefore suggests that the outbreaks are due to foods sold throughout the country. And since neither the Hepatitis A virus nor the two types of Salmonella in question are something we normally see in Denmark, we are probably looking for an imported food in all three cases,” she said.

Müller added the best advice the agency can currently give is to follow the Danish Veterinary and Food Administration’s advice on good kitchen hygiene; to rinse fruits and vegetables, to boil frozen berries and keep raw meat separate from ready-to-eat food.

The Hepatitis A outbreak involves eight women and six men aged 17 to 63 years old. They became ill from April to July 2020. Patients live all over the country and 11 have been hospitalized. Viruses from those affected have been typed to genotype 1B.

Statens Serum Institut interviews patients to find out how they become ill. Initial interviews have shown that they have not been out traveling, do not know each other and have not participated in joint events.

Hepatitis A infection is not a disease that usually causes outbreaks in Denmark. One outbreak, with a different genotype, in 2017 and 2018 had 27 patients and was linked to dates imported from Iran. A 2012 and 2013 outbreak that affected 71 Danes was traced to frozen strawberries produced in North Africa.

A hepatitis A virus (HAV) infection can range in severity from a mild illness lasting a few weeks to a severe illness lasting several months. Illness usually occurs within 15 to 50 days after eating or drinking contaminated food or water. Symptoms of infection include fatigue, nausea, vomiting, abdominal pain, jaundice, dark urine, and pale stool.

First ever outbreak of Salmonella Kasenyi
From late May to Aug. 23 people have been registered with Salmonella Strathcona in Denmark.

The sick live all over the country, and there are 19 women and four men aged 3 to 95 years old. A total of 15 patients have been hospitalized.

Whole genome sequencing found the strains were closely related to each other and the sequence type was 2559. Strathcona is a very rare serotype and it has only caused one outbreak in Denmark in the past in 2011, which was traced to small tomatoes from Italy.

From June 10 to July 16, 2020, 11 people have been recorded with Salmonella Kasenyi in the country.

The patients are nine women and two men aged 27 to 78 years old. Three of them needed hospital treatment. Seven of those sick live in Hovedstaden, two in Midtjylland and one each in Sjælland and Syddanmark.

Whole genome sequencing found the strains were closely related and of the sequence type 4546. This is a rare serotype and in Denmark an outbreak has never been seen before.

Most people infected by Salmonella develop signs 12 to 72 hours after being exposed to the bacteria. Symptoms can include diarrhea, fever, abdominal cramps and vomiting that lasts for several days.

Otherwise healthy adults are usually sick for four to seven days. Older adults, children, pregnant women and people with weakened immune systems, such as cancer patients, are more likely to develop a severe illness and serious, sometimes life-threatening conditions.