Experts shared findings on outbreaks of Cryptosporidium, Listeria, Trichinella and Salmonella at an event in Europe.
One of the presentations at the European Scientific Conference on Applied Infectious Disease Epidemiology (ESCAIDE) was one on the Danish perspective on two multi-country outbreaks. These included an outbreak of Salmonella linked to chicken meat from Poland and Listeria in fish from a Danish producer.
The meeting, organized by the European Center for Disease Prevention and Control (ECDC), also discussed a July 2023 botulism outbreak linked to potato omelettes (tortilla de patata) eaten in Spain. Italy and Norway had two cases from people who had been to Spain. Potential routes of infection remain unknown.
Major outbreaks of Cryptosporidium linked to lamb contact events in England were highlighted. One incident affected almost 800 people.
In recent years, working farms normally closed to the public have invited visitors during lambing season. They are not subject to the same supervision as farms that are permanently open to the public. Scientists assessed the public health burden and findings of three major outbreaks of Cryptosporidium parvum linked to lambs on working farms in England in 2023 and 2024.
The events provided contact and feeding with lambs and received 2,400 and more than 8,000 visitors. In the three outbreaks there were 264, 482 and 775 cases of Cryptosporidium, with microbiological and epidemiological evidence of transmission through lambs. The cases mainly involved women aged 18 to 49 and children under 16. In two outbreaks, 42 percent of cases reported seeking health care and 75 people were hospitalized. Visitors described cuddling and feeding lambs. In the first outbreak, a fecal sample from lambs was positive and the samples were compared to those from patients.
Environmental researchers found inadequate infection prevention and control practices, including concerns about handwashing facilities, animal health, animal handling and feeding, and staff preparedness. Food was also served in or near where animals were treated.
Listeria in Germany
In March 2023, Listeria monocytogenes was isolated twice in eight days from the blood and once from the pleural fluid of three patients taking synthetic glucocorticoids at a hospital in Germany. They were between 55 and 90 years old and two people died.
Sequencing showed that all three isolates were related. Food supply data suggested sliced scalded sausage as the likely source, and Listeria monocytogenes isolated from four stored packaged sliced sausage and ham samples matched patient isolates.
Bacterial counts in all samples were below the legal limit of 100 CFU/gram for Listeria before the end of shelf life in ready-to-eat foods. Researchers said a universal threshold of 100 CFU/gram is insufficient to protect at-risk groups. They advocated greater caution in the supply, preparation and consumption of processed meats in German hospitals and recommended the development of nutritional recommendations.
Trichinella in Lebanon
In November and December 2023, 147 suspected cases of trichinellosis were identified in Jahliyeh, Lebanon, and 43 people were hospitalized. The age range of cases was 2 to 82 years and 59 percent were women.
Nearly all people reported purchasing meat from a local butcher shop, with 126 consuming beef or lamb but not eating pork and 18 eating pork. Also, 60 ate uncooked meat, while 71 ate it fried or barbecued. An inspection of the butchers revealed inadequate hygiene practices and improper meat storage. Both ground and beef sausage samples contained Trichinella.
One study suggested that contaminated beef was the vehicle of infection. The butcher shop probably mixed pork with other types of meat.
Salmonella in Malta
In August 2023, two hospitalized cases of Extended-spectrum beta-lactamase (ESBL) producing Salmonella Kentucky were reported from the same location in Malta.
Food history identified consumption of eggs from the same farm. The traceback investigation identified five farms that supply this location. Human isolates clustered with each other and were related to a sample from a laying hen from one of the supply farms that tested positive for ESBL-producing Salmonella Kentucky.
Several problems were identified on the farm, including antibiotic misuse and improper separation of flocks regardless of age. No cull or targeted measures have been implemented as Salmonella Kentucky is not a target species under EU and Maltese legislation.
“We recommend that existing local and EU legislation be amended to include relevant Salmonella strains or multi-resistant bacteria to prevent zoonotic transmission of these pathogens through food,” scientists said.
Long term E. coli problems
Finally, researchers have described long-term complications that can occur up to thirty years after E. coli O157 and E. coli-associated haemolytic uremic syndrome (HUS) in Wales.
Scientists compared complications in individuals at least one year after E. coli O157 or HUS with comparisons from the general population. The exposed individuals were Welsh residents registered with a general practice with laboratory-confirmed E. coli O157 and a specimen date between January 1990 and 2019. Complications were categorized as renal, neurological, cardiac, gastrointestinal or respiratory and as mild. , serious, or either.
The team identified 1,245 individuals with E. coli O157 infections, 53 of whom developed HUS. The most common complications were renal, respiratory, gastrointestinal and cardiac complications.
“Long-term complications were identified in up to one in three people after STEC O157 and HUS. We recommend that individuals exposed to STEC be monitored for late-onset complications,” they said.
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