Salmonella bacteria are shown in red in this image from the National Institute of Allergy and Infectious Diseases.

Swedish public health officials are investigating an outbreak of  Salmonella that is believed to be foodborne.

Since October 2017, there have been 63 cases of Salmonella Kentucky infections reported by Swedish health authorities. Of those, 37 are in Västra Götaland, nine in Uppsala, three each in Skåne and Värmland, seven in Stockholm and four in Kronoberg, according to the Swedish Public Health Agency Folkhalsomyndigheten.

In all cases, the patients lived in homes for the elderly or had been hospitalized prior to becoming ill.

The investigation continues as officials try to identify a possible common source of infection. It is believed to be foodborne.

Antibiotic-resistant Salmonella Kentucky, first isolated in 2002 in a French tourist who had visited Egypt, spread throughout Africa and the Middle East in the space of only a few years, according to a 2013 study.

Most people infected with Salmonella develop diarrhea, fever and abdominal cramps 12 to 72 hours after infection, according to the Centers for Disease Control and Prevention. The illness usually lasts four to seven days. Most people recover without treatment. However, in some cases, the diarrhea may be so severe that the patient needs to be hospitalized.

In recent years, Sweden has reported only one to six cases each year, according to Folkhalsomyndigheten.

The median age of the people sick with Salmonella Kentucky in the current outbreak is 85, with a range from 30 to 98 years, and 68 percent of ill cases are women. Folkhalsomyndigheten said that since the majority of cases do not have a date for onset of disease, it is virtually impossible to establish an epidemiological timeline.

“Also, as the Salmonella infection seems to be quite mild it may have contributed to a delayed sampling,” said the agency. “For this reason a case-control study has not been considered feasible.

“Moreover, the cases are spread in six different counties in Sweden and more than one hospital or nursing home in each county have cases. Hence, we think the source is most likely foodborne.”

In most cases, Folkhalsomyndigheten said, there is no clear onset date due to their precondition or because the Salmonellosis has passed asymptomatic.

“All but two of the cases are old and/or very sick, with co-morbidity, and the Salmonella infection seems to be quite mild,” the agency said. “Therefore, hospitalization and death among the cases may primarily be due to other factors than the Salmonella infection.”

Uptick in cases in cats, small birds
In addition to the Salmonella Kentucky cases, the Swedish Veterinary Medicine Agency reported earlier this month that more than 1,000 Salmonella cases have been reported in cats since the beginning of this year, the most cats ever to have been reported to have Salmonella in Sweden in a year’s time.

In addition, cases are also being reported in small birds.

Folkhalsomyndigheten reports about 10 people may have been infected with Salmonella after contact with small birds or sick cats. Most of those cases have hit preschool-aged children. For some of the cases, there is also a confirmed connection to a cat with Salmonella infection, Outbreak News Today is reporting.

The cases associated with birds or cats have been reported from Kalmar, Stockholm, Värmland, Västra Götaland, Örebro and Östergötland County.

Public health officials recommend washing hands thoroughly after cleaning litter boxes and after contact with birds, and, as always, before handling food. People should wear gloves when handling dead or sick birds, and officials recommend paying close attention to symptoms in cats. Children, especially young children, should not come into contact with a cat that is ill.

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