The genus Norovirus comprises large genetic diversity, and new GII.4 variants emerge every 2-3 years. It is unknown in which host these new variants originate. Here we study whether prolonged shedders within the immunocompromised population could be a reservoir for newly emerging strains.
Sixty-five fecal samples from 16 immunocompromised patients were retrospectively selected. Isolated viral RNA was enriched by hybridization with a custom norovirus whole-genome RNA bait set and deep sequenced on the Illumina MiSeq platform.
Patients shed virus for average 352 days (range, 76-716 days). Phylogenetic analysis showed distinct GII.4 variants in 3 of 13 patients (23%). The viral mutation rates were variable between patients but did not differ between various immune status groups. All within-host GII.4 viral populations showed amino acid changes at blocking epitopes over time, and the majority of VP1 amino acid mutations were located at the capsid surface.
This study found viruses in immunocompromised hosts that are genetically distinct from viruses circulating in the general population, and these patients therefore may contain a reservoir for newly emerging strains. Future studies need to determine whether these new strains are of risk to other immunocompromised patients and the general population.

OBJECTIVE: To investigate the etiological characteristics of human rotavirus (HRV), human calicivirus (HuCV), human astrovirus (HAstV) and human enteral adenovirus (HAdV) in Ningxia province during 2011.
METHODS: Stool specimen was collected from acute diarrhea case of Ningxia during 2011. HRV was detected by ELISA and serotype/genotype identified on those RT-PCR positive specimens. HuCV, HAstV and HAdV were detected by RT-PCR.
RESULTS: In this study, a total of 690 specimens were detected, with the infection rates of HRV, HuCV, HAstV and HAdV as 2.17%, 21.74%, 3.19% and 6.52%, respectively. Co-infections were found in 4.20% of all the samples being tested. Among 15 HRV positive cases, serotypes G1, G3 and P[4] were the most predominant strains.
CONCLUSIONS: Children who were under 2 years of age were the majority among patients infected by diarrhea viruses while HuCV was recognized as the main pathogen responsible for the viral diarrhea cases in Ningxia, 2011.

Gastrointestinal infections caused by noroviruses may be prevented by the inhibition of their binding to histo-blood group carbohydrate antigens. A fragment-based virtual screening approach was used, employing docking followed by molecular dynamics simulations in order to enable binding free energy calculations using the linear interaction energy method. The resulting structures, composed of high-affinity fragments, can be a good starting point for lead optimizations and four molecules that pass both REOS and SYLVIA filters, which can remove known toxic features and assess the synthetic accessibility, respectively, are proposed as inhibitors.

OBJECTIVE: To study the infected information, clinical symptom and molecular epidemiological characteristics of HuCV infection among children under 5 years old in Nanjing.
METHODS: In Nanjing Children\'s Hospital of Nanjing Medical University from July 2010 to June 2011, we collected 428 stool specimens from children with diarrhea and 428 asymptomatic controls. Human Calicivirus were tested by using RT-PCR. Then we sequenced the nucleic acid of PCR amplifications and identified the genotype and gene group of prevalent strains.
RESULTS: 63 (14.72%) out of 428 stool samples were detected as HuCV. 58 were norovirus and 5 were sapovirus, while GII-4 2006b was the predominant strain of NoV. In the 428 control samples, 19 samples were positive for calicivirus, there were 8 NoV and 13 SaV (Including 3 co-infection cases).
CONCLUSIONS: Human caliciviruses with different genotypes circulated among children in Nanjing,and GII. 2006b is the dominant genotype.

OBJECTIVE: To study the pathogen and characteristics of viral diarrhea in children in Changchun area.
METHODS: 460 stools specimens were collected from children with acute diarrhea cured in the childrens, hospital of Changchun in 2010. Rotavirus were detected by ELISA, caliceverus and astrovirus were detected by reverse transcription-polymerase chain reactions (RT-PCR), adenovirus were detected by polymerase chain reactions (PCR).
RESULTS: A total of 460 specimens were detected. The detection rate of rotavirus, caliceverus, astrovious, adenovious respectively is 35.22%, 20.43%, 9.78%, 3.70%, the detectablerate of mixed infection is 7.61%, children under 2 years old were the major patient. The main genotypes of the virus: rotavirus (G3P[8]), caliceverus (GII-4), astrovious (type I), adenovious (Ad41).
CONCLUSIONS: Rotavirus is the main pathogen in Changchun. Followed by caliceverus, astrovious, adenovious.

OBJECTIVE: To study the epidemiologic characteristics of viral diarrhea in children under 5 years old in Lanzhou, understand the four major virus in children of distribution.
METHODS: In the first hospital of Lanzhou university from Jul 2009 to Jun 2010,we collected 290 stool specimens from children with diarrhea and 114 asymptomatic controls. Rotavirus was detected by ELISA,further strain characterization was carried out by nested PCR. The human calicivirus, astrovirus, adenovirus were detected by RT-multiplex PCR and PCR.
RESULTS: At least one of the four viral agents was found in 60% of the specimens. Rotavirus, human calicivirus, adenovirus, and astrovirus were identified in 39.31%, 11.38%, 10.69%, and 4.83% in 290 specimens respectively. Rotavirus G3 was the most prevailing serotype, P [8] was the most common genotype. In the 114 control samples, 7 sample was positived for calicivirus, 5 samples were positived for human adenovirus and 1 sample was positived for astrovirus.
CONCLUSIONS: The results indicated clearly the impact of viral agents causing diarrhea and the importance of long-term systematic surveillance.

OBJECTIVE: To understand the major viral pathogens for infant diarrhea in Chizhou, Anhui.
METHODS: Fecal specimens were collected from 428 infants hospitalized with diarrhea in People\'s Hospital of Chizhou, Anhui between January 2005 and December 2006. Enzyme immunoassay (EIA) and enzyme-linked immunosorbent assay (ELISA) were performed to detected specific antigens of rotavirus, astrovirus, adenovirus or calicivirus. For rotavirus, specimens were tested for typing by serum virology and reverse transcription PCR (RT-PCR).
RESULTS: The positive test rates for rotavirus, calicivirus and adenovirus were 29.2%, 10.5% and 2.4%, respectively, in infants with diarrhea from Chizhou, Anhui. Among them, 3 cases (2.4%) were infected with two or more viruses. Forty-four fecal specimens were tested with ELISA and RT-PCR for rotavirus, and the results showed that the two methods got consistency of 97.7%. Another 48 rotaviruses of serotype G were further typed as serotype I (3 cases), II (1 case), III (35 cases) and IX (2 cases), with 7 cases untyped. Among the cases that could be typed, 26 cases were collected from 2005, and 15 from 2006. RV type ml was the major pathogens for infant diarrhea, with 24 from 2005 and 11 from 2006. Among the 8 rotaviruses of type P, 7 were type as G3P8 and one G9P8. The epidemic of rotavirus showed significant season privilege, with a high prevalence in winter-spring, while the prevalence of calicivirus was prone to be high in Fall.
CONCLUSIONS: Rotavirus was the major viral pathogen accounting for infant diarrhea in Chizhou, Anhui, followed by calicivirus and adenovirus Type G3 was the main rotavirus, especially type G3P8.

Human noroviruses (NoVs) are the leading cause of food- and waterborne outbreaks of acute nonbacterial gastroenteritis worldwide. As a result of the lack of a mammalian cell culture model for these viruses, studies on persistence, inactivation, and transmission have been limited to cultivable viruses, including feline calicivirus (FCV). Recently, reports of the successful cell culture of murine norovirus 1 (MNV-1) have provided investigators with an alternative surrogate for human NoVs. In this study, we compared the inactivation profiles of MNV-1 to FCV in an effort to establish the relevance of MNV-1 as a surrogate virus. Specifically, we evaluated (i) stability upon exposure to pH extremes; (ii) stability upon exposure to organic solvents; (iii) thermal inactivation; and (iv) surface persistence under wet and dry conditions. MNV-1 was stable across the entire pH range tested (pH 2 to 10) with less than 1 log reduction in infectivity at pH 2, whereas FCV was inactivated rapidly at pH values < 3 and > 9. FCV was more stable than MNV-1 at 56 degrees C, but both viruses exhibited similar inactivation at 63 and 72 degrees C. Long-term persistence of both viruses suspended in a fecal matrix and inoculated onto stainless steel coupons were similar at 4 degrees C, but at room temperature in solution, MNV-1 was more stable than FCV. The genetic relatedness of MNV-1 to human NoVs combined with its ability to survive under gastric pH levels makes this virus a promising and relevant surrogate for studying environmental survival of human NoVs.

OBJECTIVE: To investigate the epidemiological features of human calicivirus( HuCV) infection in children with diarrhea in a hospital in Guangzhou.
METHODS: Stool specimens were collected from children with viral diarrhea diagnosed between October, 2003 and January, 2004 and between October, 2004 and January, 2005. HuCV was detected by means of RT-PCR and sequence analysis of the PCR products.
RESULTS: Eighty specimens positive for Norwalk-like viruses (NLVs) were identified from 648 stool specimens, with a positivity rate of 12.35%, and sapporo-like viruses (SLVs) were identified in 2 specimens (0.31%). The monthly NLV positivity rate was 11.74% (Oct.), 14.16% (Nov.), 9. 09% (Dec.) and 13.95% (Jan.), respectively, showing no significant variation in these months. NLVs mainly infected children below 2 years old. Twenty-two strains of NLVs were sequenced and analyzed, and 21 of them were identified as GII and the genotype of 1 strain could not be determined. The prevalent viral population were GII-3 and GII-4 in 2003 and was GII-4 in 2004, and both of the SLVs belong to GI-1.
CONCLUSIONS: NLVs is one of the important pathogens causing sporadic acute gastroenteritis in children admitted in the hospital in Guangzhou, and the prevalent strains are GII-3 and GII-4 , but different prevalent strains are possible in different periods.

OBJECTIVE: To study molecular epidemiology of four major etiological viruses among children with acute diarrhea in Lanzhou, Gansu province.
METHODS: Stool specimens were collected from all 400 inpatients less than 5 years old with acute diarrhea admitted in Department of Pediatrics, the First Hospital, Lanzhou University from Jul. 2004 through Jun. 2005. Dako IDEIA kits were used for detection of rotavirus, adenovirus and astrovirus. Calicivirus detection was done by both reverse transcription-polymerase chain reactions (RT-PCR) and ELISA. Further strain characterization of rotavirus and astrovirus was carried out with RT-PCR.
RESULTS: A total of 400 stool samples were collected and tested. Rotavirus was present in 47.3% of the cases: calicivirus in 15.5%, astrovirus in 9.5% and adenoviruses in 7.5%. Mixed infections with multiple enteric viruses were present in 13.5% of all samples. Among 189 rotavirus positive samples, serotype G2 (34.4%) was the predominant strain followed by G3 (32.8%), G1 (1.1%) and mixed-G infection (5.8%). 25.9% of strains remained to be non-typeable. P genotyping showed P [4] (45%) was most common followed by P [8] (22.1%), and non-typeable (32.9%). Strain P [4] G2 (43.6%) was the most common combination followed by P [8] G3 (25.6%), P [4] G3 (13.8%), and P [8] G2, P [4] G1 and P [8] G1. Among 38 astrovirus strains, serotypes 1 (57.8%) was the predominant. Serotype 3 and 8 were found only in one case respectively, 14 strains remained to be non-typeable. A peak admission of rotavirus diarrhea was observed from October through December. More than 95.0% of viral diarrhea patients under hospitalization occurred among children younger than 2 years. The incidence rates of rotavirus were highest in infants aged 6 - 23 months.
CONCLUSIONS: Rotavirus was the most important pathogen for viral diarrhea among children hospitalized in Lanzhou followed by calicivirus, astrovirus, and adenovirus. The predominant rotavirus strain circulated was P [4] G2, which was different from the finding in the previous years. The high rate of mixed infection with different viral agents was notable.