Methods: From March 2014 until January 2016, NoV PCR-positive stool specimens as determined by the Luminex xTAG Gastrointestinal Pathogen Panel (GPP) were included and subsequently tested by the NoV-qPCR assay. Each specimen was tested in duplicate and geometric mean copies per gram of stool (GMC) were calculated. Electronic medical records were reviewed to extract relevant information on clinical severity of NoV infections based on modified Vesikari scores (MVS).
Results: During the 23-month study period, 6,918 stool specimens were submitted for testing by GPP. A total of 234 specimens (3.4%) from 154 patients were positive for NoV (GI, 33; GII, 201). The NoV-GII GMC±standard deviation was 5.35±1.59, which was significantly higher than that of NV-GI (3.94±1.57, OR=7.87, p=0.001). Based on the MVS criteria, 210 episodes were divided into mild (n=122, GMC=4.28±1.49), moderate (n=33, GMC=5.55±1.32), and severe (n=55, GMC=6.66±0.86) clinical severity groups, respectively. In univariate analysis, higher stool NoV were associated with GII infections, longer diarrhea duration and more diarrhea frequency, longer vomiting duration and more vomiting frequency, higher fever, as well as more total parenteral nutrition and deeper dehydration. In multivariate analysis, higher stool NoV VL at the time of diagnosis correlated with GII infections (OR=3.25; 95 % CI=1.18-8.97, P=0.023) and predicted clinical severity (OR=6.56; 95 % CI=2.35-18.36, P=0.001).
Conclusion: NoV GII infections are associated with a higher VL compared to GI. Regardless of infecting NoV genogroup, higher VL at diagnosis is associated with severe clinical disease and poor outcome. This quantification method may have utility for clinical monitoring.
L. H. Chen, None
Y. Qiu, None
X. Lu, None
X. L. Pang, None
M. Kamboj, None
Y. W. Tang, None