Antibodies to Yersinia enterocolitica, IgM

Specific IgA antibodies to Yersinia pseudotuberculosis and Yersinia enterocolitica are produced by the immune system in response to infection with these microorganisms and indicate an acute or persistent infection.

Yersinia bacteria are Gram-negative rods from the Enterobacteriaceae family. Y. pseudotuberculosis causes pseudotuberculosis, while Y. enterocolitica is responsible for intestinal yersiniosis. These microorganisms are dangerous not only for humans but also for many animals. Rodents play an important role in the spread of infection. The bacteria are environmentally resilient, able to multiply and accumulate in soil and tap water, but are quickly destroyed by sunlight and boiling.

The source of infection can be an infected person, an animal, or contaminated soil. Humans are primarily infected through consumption of meat, fish, milk, vegetables, fruits, and untreated water, as well as through contact with sick animals.

Epidemiology
Infections show seasonality, with most cases occurring during colder months due to rodent migration into food storage areas. Infections can occur as isolated cases or as epidemic outbreaks in communities.

Clinical manifestations
Symptoms of pseudotuberculosis and intestinal yersiniosis are very similar, and laboratory tests are often the only way to distinguish between them.

The severity of the disease depends on the virulence of the pathogen, the bacterial load, the patient’s age, immune status, comorbidities, and genetic factors. Children are most often affected.

The incubation period for pseudotuberculosis is 24 hours to 4 weeks (on average 7–10 days), while for intestinal yersiniosis it is shorter, ranging from a few hours to 4–5 days. The disease usually begins with diarrhea, abdominal pain, fever, and signs of intoxication. Diarrhea is more pronounced in intestinal yersiniosis and mild or absent in pseudotuberculosis. On days 1–4, 90% of patients infected with Y. pseudotuberculosis develop a scarlet fever-like rash and swelling of the hands and feet.

The infection can manifest as acute gastrointestinal disease with vomiting and diarrhea, or in more severe forms with involvement of mesenteric lymph nodes, terminal ileitis, mesadenitis, or even sepsis. In some cases, the disease mimics acute appendicitis. The kidneys, liver, pancreas, cardiovascular, and nervous systems may also be involved. Occasionally, a respiratory syndrome develops with sore throat, redness of the posterior pharynx, swelling of the palate, cough, and nasal congestion. Intestinal yersiniosis may progress to a chronic form.

Rare complications of Y. enterocolitica infection include reactive uveitis, iritis, conjunctivitis, glomerulonephritis, hemolytic-uremic syndrome, and erythema nodosum.

Immunology
IgA antibodies are produced in the first days of infection and can circulate in the blood for several months after recovery. In chronic intestinal yersiniosis, IgA can persist for much longer. Significant elevation of IgA levels is characteristic of patients with reactive arthritis, erythema nodosum, and other HLA-B27-associated rheumatic conditions.

Sample collection instructions

• Blood should be taken on an empty stomach. The last meal should be at least 8 hours before visiting our center.
• Do not smoke for at least 1 hour before the test.

Recommendations

• Avoid physical activity before the test. During the 10–20 minutes prior to blood collection, try to relax.
• ​​​​​​​Avoid taking tests immediately after paraclinical procedures (X-ray, CT, MRI) and physiotherapy, as these may affect test results.