Guifang Hu

An outbreak caused by GII.17 norovirus with a wide spectrum of HBGA-associated susceptibility

During the past norovirus (NoV) epidemic season, a new GII.17 variant emerged as a predominant NoV strain, surpassed the GII.4 NoVs, causing outbreaks of acute gastroenteritis (AGE) in China. Here we report a study of an AGE outbreak in an elementary school in December 2014 caused by the new GII.17 NoV to explore the potential mechanism behind the sudden epidemics of the GII.17 NoV. A total of 276 individuals were sick with typical NoV infection symptoms of vomiting (93.4%), abdominal pain (90.4%), nausea (60.0%), and diarrhea (10.4%) at an attack rate of 5.7–16.9%. Genotyping of the symptomatic patients showed that individuals with a secretor positive status, including those with A, B, and O secretors and Lewis positive blood types, were sensitive to the virus, while the non-secretors and the Lewis negative individual were not. Accordingly, the recombinant capsid P protein of the GII.17 isolate showed a wide binding spectrum to saliva samples of all A, B, and O secretors. Thus, the broad binding spectrum of the new GII.17 variant could explain its widely spread nature in China and surrounding areas in the past two years.

Isolation and phylogenetic characterization of bat astroviruses in southern China.

Astroviruses are associated with acute gastroenteritis of human and many animal species. Recently, two studies have reported that novel astroviruses were found in bats. In order to extensively understand the genetic and phylogenetic characterization of bat astroviruses, we tested fecal samples of nine bat species that were collected at four natural habitats in three areas of southern China. The geographic distributions of the bats involved differed from previous reports. Three out of nine species of bats were observed to harbor astroviruses. These included Miniopterus schreibersii, Scotophilus kuhlii, and Rousettus leschenaultia. Phylogenetic analysis based on amino acid sequences of partial ORFs of astroviruses revealed that the bat astroviruses are not only divergent from previously described human and other animal astroviruses but also show remarkable diversity among themselves. However, five bat astroviruses were phylogenetically related to mink astrovirus, ovine astrovirus, and the recently discovered human astroviruses VA1, VA2, and VA3. The results indicate that astroviruses may have adapted to the Chiroptera, and bats may transmit astroviruses to humans and other animals, or vice versa.

Characterization of severe hand, foot, and mouth disease in Shenzhen, China, 2009–2013

Hand, foot, and mouth disease (HFMD) is caused by human enteroviruses, especially by enterovirus 71 (EV71) and coxsackievirus A16 (CA16). Patients infected with different enteroviruses show varied clinical symptoms. The aim of this study was to determine whether the etiological spectrum of mild and severe HFMD changed, and the association between pathogens and clinical features. From 2009 to 2013, a total of 2,299 stool or rectal specimens were collected with corresponding patient data. A dynamic view of the etiological spectrum of mild and severe HFMD in Shenzhen city of China was provided. EV71 accounted for the majority proportion of severe HFMD cases and fatalities during 2009–2013. CA16 and EV71 were gradually replaced by coxsackievirus A6 (CA6) as the most common serotype for mild HFMD since 2010. Myoclonic jerk and vomiting were the most frequent severe symptoms. Nervous system complications, including aseptic encephalitis and aseptic meningitis were observed mainly in patients infected by EV71. Among EV71, CA16, CA6, and CA10 infection, fever and pharyngalgia were more likely to develop, vesicles on the hand, foot, elbow, knee and buttock were less likely to develop in patients infected with CA10. Vesicles on the mouth more frequently occurred in the patients with CA6, but less in the patient with EV71. Associations between diverse enterovirus serotypes and various clinical features were discovered in the present study, which may offer further insight into early detection, diagnosis and treatment of HFMD. J. Med. Virol. 87:1471–1479, 2015.

Molecular epidemiology of norovirus gastroenteritis in children in Jiangmen, China, 2005-2007.

Human noroviruses (NoVs) are an important cause of epidemic acute gastroenteritis. Their role in sporadic cases, however, is less clear. In this study, we performed a two-year surveillance (September 2005 to August 2007) of NoV gastroenteritis in outpatient clinics in a southern city of China, Jiangmen City. NoVs were detected in 115 patients (115/881, 13.1%) with 30 (26.1%) co-infections with rotaviruses. Sequence analysis showed that all 115 NoVs belonged to genogroup II, with GII.4 being the most predominant (87.8%). NoV-associated infection can be seen year-around, with autumn and winter peaks. This study provides basic information on sporadic cases of major NoV gastroenteritis in children in different seasons, which is valuable for future disease control and prevention.

Molecular Phylogeny of Coxsackievirus A16 in Shenzhen, China, from 2005 to 2009

ABSTRACT Phylogenetic analysis of a Coxsackievirus A16 (CA16) sequence from Shenzhen, China, and other Chinese and international CA16 sequences revealed a pattern of endemic cocirculation of strains of clusters B2a and B2b within subtype B2 viruses. Amino acid evolution and nucleotide variation in the VP1 region were slight for 5 years.

P[8] and P[4] Rotavirus Infection Associated with Secretor Phenotypes Among Children in South China.

Rotaviruses are known to recognize human histo-blood group antigens (HBGAs) as a host ligand that is believed to play an important role in rotavirus host susceptibility and host range. In this study, paired fecal and saliva samples collected from children with viral gastroenteritis, as well as paired serum and saliva samples collected from the general population in south China were studied to evaluate potential association between rotavirus infections and human HBGA phenotypes. Rotavirus was detected in 75 (28%) of 266 fecal samples and P[8] rotaviruses were found to be the predominant genotype. The HBGA phenotypes of the rotavirus-infected children were determined through their saliva samples. Secretor statuses were found to correlate with the risk of rotavirus infection and all P[8]/P[4] rotavirus infected children were secretors. Accordingly, recombinant VP8* proteins of the P[8]/P[4] rotaviruses bound saliva samples from secretor individuals. Furthermore, correlation between serum P[8]/P[4]-specific IgG and host Lewis and secretor phenotypes has been found among 206 studied serum samples. Our study supported the association between rotavirus infection and the host HBGA phenotypes, which would help further understanding of rotavirus host range and epidemiology.

Characterization of a novel HIV-1 unique recombinant form between CRF07_BC and CRF55_01B in men who have sex with men in Guangzhou, China

Here, we report the genetic diversity of HIV-1 and emergence of novel HIV-1 unique recombinant forms (URF) in both HIV-infected intravenous drug users (IDU) and men who have sex with men (MSM) in Guangzhou, China. We further characterized a novel URF strain isolated from an HIV-infected MSM, GD698. Near full-length genome (NFLG) phylogenic analysis showed that this novel URF was composed of CRF07_BC and CRF55_01B, with two recombinant breakpoints (nt 6,003 and 8,251 relative to the HXB2 genome) in the vpu/env and env genes, respectively. Twenty six percent of the genome is classified as CRF55_01B, spanning part of vpu and most of the env gene. The remaining 74% of the genome is classified as CRF07_BC. Both the backbone CRF07_BC sequence and CRF55_01B fragment were clustered with the HIV-1 isolates found in MSM. The emergence of the novel HIV-1 recombinant indicates the ongoing recombinants derived from the CRF07_BC and CRF55_01B isolates, and provides critical insights into our understanding of the dynamics and complexity of the HIV-1 epidemic in China.

Development and evaluation of a rapid recombinase polymerase amplification assay for the detection of human enterovirus 71

Enterovirus 71 (EV71) is one of the most common pathogens of hand, foot, and mouth disease (HFMD). A rapid reverse transcription recombinase polymerase amplification (RT-RPA) assay was established to detect EV71 subgenotype C4 (EV71-C4). The 95% detection limit of the RT-RPA was 3.767 log10 genomic copies (LGC)/reaction. The specificity was 100%. In a clinical sample evaluation, this approach demonstrated sufficient clinical performance when compared with a commercial RT-qPCR diagnostic kit. Thus, the RT-RPA assay may be a promising alternative for the detection of EV71-C4.