Norovirus, Astrovirus, and Sapovirus in a Tertiary Care Research Hospital

Abstract Background Norovirus, astrovirus, and sapovirus are known to cause acute gastroenteritis and are associated with chronic viral excretion in stool among immunocompromised patients. Because molecular tools for their detection only recently became widely available, the prevalence and chronic excretion of these viruses has not been well defined. We describe features of these viral infections among patients receiving care at the Clinical Center of the National Institutes of Health. Methods We identified patients with a positive BioFire FilmArray® gastrointestinal panel result for norovirus, astrovirus, or sapovirus from September 15, 2015 through November 30, 2016. We reviewed patient medical records to abstract clinical and microbiologic information. Chronic excretion was defined as more than one positive test for a given virus with more than 30 days between tests. Results Of 932 samples tested, 102 (11%) samples from 48 patients tested positive for norovirus, 15 (2%) samples from 11 patients tested positive for sapovirus, and 16 (2%) samples from 7 patients tested positive for astrovirus. One of these patients had a sample that tested positive for both sapovirus and norovirus, and one tested positive for astrovirus and sapovirus at separate points during the study period. Of the 48 patients with norovirus, 16 (33%) had evidence of chronic excretion, with a median duration of 189 days (range 72–372). Of these 16, 14 were known or suspected to be immunodeficient, and 4 had hematologic malignancies. Of 7 patients with astrovirus, 1 (14%) had evidence of chronic excretion (132 days). This patient had a hematologic malignancy and was taking immunosuppressive medication. No patients with sapovirus had evidence of chronic excretion. Overall, 20 (31%) patients additionally tested positive for another gastrointestinal pathogen, most commonly enteropathogenic E. coli and C. difficile. Conclusion Norovirus remains common in this immunocompromised patient population, and both sapovirus and astrovirus are present. Additional follow-up in this and other cohorts with new molecular tools will enable more complete description of the prevalence, excretion duration, and clinical features of infection with these enteric viruses. This research was supported by the Intramural Research Program of the NIH, NIAID, and the NIH CC. Disclosures All authors: No reported disclosures.