Yersinia - diarrheal illness

Yersinia enterocolitica, Yersinia pseudotuberculosis

Changed on: 17.12.2020
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Yersiniosis is a food-borne infectious disease caused by bacteria mainly of the species Yersinia (Y.) enterocolitica and more rarely Y. pseudotuberculosis.

Occurrence

Enteric yersiniosis is a disease that is spread worldwide. It is the third most common bacterial zoonosis in the EU. Y. enterocolitica is widespread in the environment and in animal populations, primarily in pigs, less frequently in dairy cows. Y. enterocolitica is also found in wild animals. Y. pseudotuberculosis is found mainly in the environment. Similar to listeria, Y. enterocolitica can also multiply on contaminated food in the refrigerator.

Reservoir

Animals, mainly pigs and, to a lesser extent dairy cows, are considered to be the main reservoir of human pathogenic Y. enterocolitica.

Mode of transmission

Yersiniosis is usually transmitted by a facal-oral route. The main source of infection is consumption of contaminated food and water, especially raw or medium-cooked pork and raw or unheated dairy products. The bacteria can also multiply at 4 °C (e.g. refrigerator). In major foodborne Y. pseudotuberculosis outbreaks in the EU, contaminated vegetables (bean sprouts, tofu), water, and milk have been confirmed as vehicles for infection. Transmission can also occur through contaminated blood supplies. Direct transmission from infectious animals and humans occurs rarely.

Incubation period

3 to 7 days

Symptoms

Common symptoms in children are gastrointestinal symptoms, whereas adults may show signs of appendicitis (pseudo-appendicitis). The classic symptoms are diarrhoea, fever and severe abdominal pain (for a period of 1-3 weeks, if untreated). Diarrhoea can be watery but also bloody. After a few days, joint pain, joint inflammation and skin changes can occur, in rare cases the so-called Reiter's syndrome (arthritis, urethritis, conjunctivitis) can develop.

Therapy

Infections with Y. enterocolitica and Y. pseudotuberculosis are usually self-limiting, therefore symptomatic treatments are sufficient to maintain water and electrolyte balance. Severe cases justify the use of antibiotic therapy.

Prevention

Hygiene during slaughtering of pigs; avoidance of raw pork and raw pork products, as well as raw milk.

Situation in Austria

Human

In 2019, 112 laboratory confirmed cases of yersiniosis were reported. The National Reference Center for Yersiniosis received 95 isolates, 94 were specified as Y. enterocolitica and one as Y. pseudotuberculosis. The incidence was 1.1 cases per 100,000 population, slightly lower than 2018 but within the incidences of the last 10 years.


Legende

    Food

    In 2019, no samples were tested for Yersinia.

    Livestock

    In pigs, which are considered to be the main reservoir of Y. enterocolitica, bloody diarrhoea may occur in individual cases. Joint inflamations and pneumonia may be found in young animals. In most cases, however, infections remain asymptomatic and go unnoticed by the animal owner.

    Professional information

    Human Medicine

    Yersinia are facultatively anaerobic (i.e. growing even in the absence of oxygen), pleomorphic, gram-negative (stained red in the so-called Gram stain) rods, which belong to the Enterobacteriaceae family. As psychrophilic (= cold-loving) germs, they can be cultivated at temperatures between 4 °C and 42 °C. They are often found in the temperate climate zones.

    14 species belong to the genus Yersinia. Enteropathogenic Yersinia (Y. enterocolitica and Y. pseudotuberculosis) as obligatory pathogenic pathogens are of importance for human medicine.

    In 2019, typing of the 94 Y. enterocolitica isolates in the National Reference Centre for Yersiniosis revealed 90.4% bioserovar 4/O:3 and 9.6% bioserovar 2/O:9. In recent years, the disease incidence was highest in the age groups up to 14 years, while the incidence in the youngest age group up to 4 years has decreased significantly.

    Diagnostics

    A purely symptomatic diagnosis based on the clinical picture alone is very difficult. Cultivation of bacteria from stool is the method of choice. This method is also used to determine sero- and biotypes. Blood, liquor, punctate, lymph node aspirate or peritoneal fluid can also be used. In untreated patients, bacteria can be excreted with the stool for weeks after clinical symptoms have ceased. Molecular biological methods such as PCR testing can also be used for pathogen detection.

    Symptoms

    Yersiniosis shows a wide range of symptoms.

    Infants and toddlers usually experience  a self-limiting acute gastroenteritis with vomiting, watery to bloody diarrhoea and fever. The disease can last up to one or two weeks.

    Older children and adolescents usually experience acute mesenteric lymphadenitis (inflammatory swelling of abdominal lymph nodes) with abdominal pain. The clinical picture may resemble appendicitis (= inflammation of the appendix) ("pseudo-appendicitis").

    In adults different clinical forms occur, such as flu-like symptoms with pharyngitis (= inflammation of the throat), myalgia (= muscle pain) and fever, or ileocolitis (= inflammation of the large and small intestine) with involvement of the mesenteric lymph nodes ("Pseudo-Crohn's disease").

    Yersiniosis can be associated with concomitant or secondary symptoms: reactive arthritis, erythema nodosum (= acute inflammation of the subcutaneous fat tissue), arthralgia (= joint pain) or myalgia (= muscle pain). Y. enterocolitica is more likely to lead to a gastro-enteritic clinical picture, Y. pseudotuberculosismore often lead to pseudo-appendicitis.

    Contact, forms

    National Reference Centre for Yersinia (except Yersinia pestis)

    Beethovenstraße 6
    8010 Graz

    Dr. Shiva Pekard-Amenitsch
    Phone: +43 50 555-61210
    E-Mail: shiva.pekard-amenitsch@ages.at

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