Characteristics of acute diarrhea adult cases with samples positive for Norwalk virus

Abstract

Remaining unmanageable,Norwalkvirus infection is clearly tended to be recorded at higher rate, including adult patients. In many cases, clinical picture of adult acute diarrhea in patients positive for Norwalk virus in clinical samples vs. pathogenetically-caused norovirus infection differs, thereby justifying comparison of clinical and laboratory data. A cohort retrospective study with 146 hospitalized adult patients suffering from acute moderate diarrhea positive for fecalNorwalkvirus was performed. Along with standard laboratory tests (culturing, serologic for detecting 4-fold increase in titer between paired serum samples, ELISA), detection of diarrhea-linked agents included PCR kit Amplisens® AII-bacto-screen-FL Lab (Interlabservice). The data obtained demonstrated that in adult patients with acute diarrhea 54.1% of cases were positive forNorwalkvirus as well as for other enteric pathogens, including bacteria found in 36.3% of cases. Moreover, clinical samples of patients with acute diarrhea hospitalized at least on day 4 vs. day 3 after the onset were significantly more often (by 1.5-fold) positive for association between Norwalk virus and other acute enteric infection agents mainly due to astrovirus (р = 0.03; PCR data) and Shigella spp. (culture-based and serologic methods; р = 0.03). In addition,Norwalkvirus was associated with rotavirus, but not other enteric pathogens, at 2.1-fold higher rate in clinical samples from patients treated vs. untreated with antimicrobials before hospitalization. Finally, clinical samples positive for Norwalk virus from patients with vs. without developed colitis syndrome were at higher risk of developing virus-bacterial enteric infection detecting Salmonella spp. at 7.6and 3-fold higher rate verified by culture-based and PCR assay, respectively. Importantly, patients with vs. without hemorrhagic colitis Salmonella spp. verified primarily a culture-based method was detected by 11-fold more frequently (p = 0.01).