Sapovirus Infection in Kidney Transplant Recipients: A Case Series Demonstrating the Burden of an Enteric Viral Pathogen

BACKGROUND: Sapovirus is a calicivirus, which commonly causes acute gastroenteritis. However, in immunocompromised patients, chronic infection with diarrhea and failure to thrive has been reported. Due to sapovirus emerging as an infection of concern in our kidney transplant recipients (KTRs), we sought to describe the burden of sapovirus infection in this population. METHODS: We evaluated adult KTRs with sapovirus diagnosed by stool gastrointestinal polymerase chain reaction (PCR) at our institution. Data were collected retrospectively, and included demographics, symptom burden, treatment course, and patient outcomes. RESULTS: Nine patients met inclusion criteria. The median age was 48 years old. Symptom burden was high, with a median of six patient-reported symptoms per case. Median time from symptom onset to diagnosis was 30 days. All patients reported experiencing diarrhea, and most patients reported dehydration, fatigue, and nausea. Six patients experienced weight loss relative to baseline, and four patients experienced acute kidney injury. Two patients newly required dialysis during the follow-up period, one of these due to an episode of graft rejection with subsequent graft loss. Immunosuppression was reduced in seven cases, and nitazoxanide administered in three patients. Median time from symptom onset to symptom resolution was 45 days, however several patients had very prolonged courses, including symptom duration for over a year. CONCLUSION: Sapovirus is an emerging pathogen in KTRs and was associated with significant symptom burden and morbidity, including failure to thrive, acute kidney injury, and need for dialysis. Delays in diagnosis and limited treatment options remain barriers to improving outcomes.