Pig is the most important animal from the viewpoint of human infections, but Yersinia bacteria exist also in many other farmed and wild animals.
The most common route of infection is via foodstuff that has been contaminated by bacteria of animal origin.
Y. pseudotuberculosis multiply in foodstuffs also in refridgerator temperatures, and therefore it is a more common cause of foodborne epidemics than Y. enterocolitica.
It is common that only a small share of people eating the same contaminated food will fall ill.
In practice, yersiniosis is not transmitted directly from person to person.
Erythema nodosum Erythema Nodosum is the most common skin manifestation (about 10% of erythema nodosum cases are caused by Yersinia, and about 5% of patients with yersiniosis develop erythema nodosum); it can be the only symptom of yersiniosis.
Cardiac findings
Transient ECG abnormalities matching those in myocarditis Myocarditis. Cardiac involvement is, however, very rare.
Valvular disease is not associated with yersiniosis.
A nucleic acid detection test followed by culture in case of a positive sample
Sensitivity testing performed together with the culture guides possible antimicrobial therapy.
Useful in the acute phase
The sensitivity decreases rapidly after the symptoms of enteritis have disappeared.
Serology
Yersinia infections are often detected by serological tests, since the gastrointestinal infections they cause often have mild symptoms and in that phase do not lead to investigations. It is common that the results of faecal examinations performed due to symptoms of reactive arthritis are negative, when these are carried out at the same time with serological tests.
The primary diagnostic method in post-infectious symptoms (arthritis). Antibodies can also be determined when investigating the aetiology of erythema nodosum, erythema multiforme, carditides and fever of unknown origin.
Bacterial agglutination test measures particularly IgM antibodies. In addition, a more specific EIA test can be used.
A recent infection can be diagnosed on the basis of one serum sample.
Class IgM antibodies appear in a few days and usually disappear after a few months.
Class IgG antibodies can be detected for a longer time, often years.
Class IgA antibodies are particularly associated with arthritis.
A cross-reaction occurs between Y. enterocolitica 9 and brucella, but an ELISA inhibition test confirming the diagnosis is automatically performed in positive cases.
Treatment
The disease is usually cured spontaneously.
Chronic carriers have not been detected.
There is little evidence on the effect of antibiotic treatment; its effect on the occurrence of post-infectious symptoms is not known.
Arthritis and other elements of Reiter's syndrome usually resolve spontaneously within a few months, but they may initially require NSAID or glucocorticoid therapy.
Indications for antimicrobial treatment
Treatment is often indicated for patients with severe symptoms and in need of hospitalization.
In septic infection, ceftriaxone 2 g/day is an intravenous treatment alternative; duration of treatment or switch to oral medication according to clinical response.
Consultation
Refer a patient with severe symptoms to a hospital.
If acute appendicitis is suspected, refer the patient to a surgeon.
In the case of severe post-infectious symptoms, refer the patient to a respective specialist.
References
Gupta V, Gulati P, Bhagat N et al. Detection of Yersinia enterocolitica in food: an overview. Eur J Clin Microbiol Infect Dis 2015;34(4):641-50. [PubMed]
Tuuminen T, Lounamo K, Leirisalo-Repo M. A review of serological tests to assist diagnosis of reactive arthritis: critical appraisal on methodologies. Front Immunol 2013;(4):418. [PubMed]