abdominal pain; adolescent; body weight loss; case report; cecum; child; chronic infection; clinical article; clinical assessment; colon; colonoscopy; conference abstract; diarrhea; duodenum; edema; endoscopy; female; hematochezia; histopathology; history; human; Leporidae; long COVID; loss of appetite; medical history; medical record review; nausea and vomiting; nocturnal awakening; nonhuman; pediatric patient; Peyer patch; prevalence; sample size; satiety; severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; tenesmus; terminal ileum; virus nucleocapsid; calgranulin; endogenous compound; monoclonal antibody