Emergence of human caliciviruses among diarrhea cases in southwest China

Abstract

BackgroundAcute diarrhea is one of the most serious problems in global public health that causes considerable morbidity and mortality worldwide. Human caliciviruses (HuCV) including norovirus (NoV, genogroup GI and GII) and sapovirus (SaV), is a leading cause of acute sporadic diarrhea in individuals across all age groups. However, few studies had been conducted clarifying the characteristics of HuCV in diarrhea cases across all age groups in China. Our study was aimed at assessing the HuCV-related diarrhea burden and NoV genotypes distribution in southwest China.MethodsThe study was conducted in four hospitals in Kunming city, Yunnan province, from June 2014 to July 2015. Stool specimens were collected from 1,121 diarrhea cases and 319 healthy controls in outpatient departments. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect NoV (GI, GII) and SaV. Sequencing was applied to confirm the three viral infections and phylogenetic analysis was performed to determine their genotypes. A structured questionnaire was used to record the demographic information and clinical symptoms of subjects.ResultsHuCV was detected at an 11.0 % infection rate in 1,121 diarrhea cases and at 3.4 % rate in 319 non-diarrhea subjects (p < 0.0001, OR = 3.5, 95 % CI 1.8–6.5). The prevalence of the NoV genogroup GII and genotype GII.4 in diarrhea cases was significantly higher than that found in healthy controls (p < 0.0001, p = 0.018, respectively). NoV GII (n = 118, 10.5 %) was the most common HuCV subtype in diarrhea cases, followed by SaV (n = 3, 0.3 %) and NoV GI (n = 2, 0.2 %). Of 118 NoV GII strains isolated from diarrhea patients. GII.4 (n = 55, 46.6 %) was the predominant strain, followed by GII.3 (n = 28, 23.7 %), GII.12 (n = 25, 21.2 %), GII.17 (n = 8, 6.8 %), and GII.5 (n = 2, 1.7 %). Of the 55 GII.4 strains, the GII.4 Sydney 2012 variant had absolutely predominant prevalence (n = 52, 94.5 %), followed by the NoV GII.4-2006b variant (n = 3, 5.5 %). The GII.4 Orleans 2009 variant was not found in diarrhea cases of the study.ConclusionsNoV GII was the major genogroup and GII.4 was the most predominant strain detected in diarrhea patients. The GII.17 is an emergent variant in sporadic diarrhea and might become the predominant strain in diarrhea cases in the near future. Rapid, accurate detection kits need to be developed to help us find and treat NoV-associated diarrhea in clinical settings in a timely manner.

Molecular epidemiology of genogroup II norovirus infections in acute gastroenteritis patients during 2014–2016 in Pudong New Area, Shanghai, China

“…NoV-AGE was prevalent throughout the year and peaked in the cold season, as previously reported. In Pudong New Area, the seasonal increase of NoV-AGE started in October and usually lasted until March of the following year, consistent with the results of Xue et al [ 21 ] in other districts in Shanghai and observations in other provinces in China [ 22 , 23 ]. In the study, the adult aged from 25 to 64 years old seemed vulnerable to get NoV infection, which was not consistent with previous studies [ 19 ].…”

Case–control study of diarrheal disease etiology in individuals over 5 years in southwest China

“…Fourthly, the percentage of diarrheal patients who have taken antibiotics before the admission was not known, which may influence the detection rate of bacterial pathogens. In addition, enteric protozoa were not detected with microscopy, and the concentration of DNA in 1 μL can be different and therefore, the outcome of PCR might not be comparable [56]. Therefore, further research involved diarrhea case from urban, rural, outpatient and hospitalized might be done to evaluate the burden of diarrhea disease and assess the association between diarrhea and specific enteric pathogen.…”

Prevalence and genetic diversity of human sapovirus associated with sporadic acute gastroenteritis in South China from 2013 to 2017

“…In China, a domestic Jennerian vaccine (the Lanzhou lamb rotavirus vaccine) has been licensed since 2000, and at the end of 2014, over 60 million doses had been distributed to children . SaV can cause disease in people of all age groups, but most infections occurred in children . The clinical symptoms of SaV gastroenteritis are similar as those infected by human noroviruses, mainly including diarrhea and vomiting.…”

“…3 SaV can cause disease in people of all age groups, but most infections occurred in children. 4 The clinical symptoms of SaV gastroenteritis are similar as those infected by human noroviruses, mainly including diarrhea and vomiting. SaV infection is often caused by the fecal-oral pathway through person-to-person contact or contaminated food and water.…”