Yersinia enterocolitica – spectrum of human disease Which of the following clinical conditions can be caused by Yersinia enterocolitica infection in humans?

Introduction / Context:
Yersinia enterocolitica is a psychrotrophic enteropathogen acquired through contaminated food (notably pork) and occasionally blood transfusion. Recognizing its varied clinical manifestations helps prevent misdiagnosis and guides appropriate management.

Given Data / Assumptions:

• Pathogen: Y. enterocolitica (and Y. pseudotuberculosis as a related species).
• Transmission: foodborne, zoonotic reservoirs (swine), transfusion contamination, and contact exposures.
• Host factors such as iron overload increase risk of invasive disease.

Concept / Approach:
Typical illness presents as acute gastroenteritis with fever and diarrhea. In older children and young adults, mesenteric adenitis and terminal ileitis can mimic appendicitis (pseudoappendicitis). In susceptible hosts, especially those with iron overload or receiving contaminated blood products stored at low temperature (where the organism can proliferate), Y. enterocolitica can cause bacteraemia/septicaemia. Post-infectious sequelae like reactive arthritis and erythema nodosum may occur.

Step-by-Step Solution:
List recognized clinical syndromes: gastroenteritis, mesenteric lymphadenitis, and invasive septicaemia.Confirm that Y. enterocolitica is implicated in all listed conditions.Select the inclusive option.

Verification / Alternative check:
Public health references and infectious disease texts document this spectrum, including transfusion-associated yersiniosis leading to severe sepsis.

Why Other Options Are Wrong:

• Any single condition alone is incomplete.
• “None”: incorrect because Y. enterocolitica clearly causes each listed manifestation.

Common Pitfalls:
Overlooking mesenteric adenitis in differential diagnosis of right lower quadrant pain; ignoring the organism’s ability to grow at refrigeration temperatures (psychrotroph), which enables transfusion transmission.

Final Answer:
All of these.