Search

Introduction: Respiratory Syncytial Virus (RSV) is a significant cause of respiratory illnesses worldwide, particularly in infants and elderly individuals. Despite the burden RSV imposes, effective preventive measures are limited. The research application of adeno-associated virus (AAV) in vaccine platforms has been expanding, and its potential in prevention and treatment has garnered much attention. Methods: In this study, we explored the potential application of a recombinant adeno-associated virus 5 (rAAV5) vector-based RSV vaccine, focusing on the expression of the pre-fusion (Pre-F) protein structure. Through intramuscular immunization in mice. The immunogenicity of the vaccine was evaluated in Balb/ c mice immunized intramuscularly and intranasal, respectively. Results: The rAAV5-RSV-Fm vaccine demonstrated positive humoral and induced antibody titers against RSV strains A and B for up to 120 days postimmunization. Notably, intranasal administration also elicited protective antibodies. Characterization studies confirmed the ability of the vac-cine to express the Pre-F protein and its superior immunogenicity compared to that of full-length F protein. Conclusion: These findings underscore the potential application of rAAV5 vector platforms in RSV vaccine development and further investigation into their protective efficacy is warranted. [ABSTRACT FROM AUTHOR]

Introduction: At present, there is an urgent need for the rapid and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies (NAbs) to evaluate the ability of the human body to resist coronavirus disease 2019 (COVID-19) after infection or vaccination. The current gold standard for neutralizing antibody detection is the conventional virus neutralization test (cVNT), which requires live pathogens and biosafety level-3 (BSL-3) laboratories, making it difficult for this method to meet the requirements of large-scale routine detection. Therefore, this study established a time-resolved fluorescence-blocking lateral flow immunochromatographic assay (TRF-BLFIA) that enables accurate, rapid quantification of NAbs in subjects. Methods: This assay utilizes the characteristic that SARS-CoV-2 neutralizing antibody can specifically block the binding of the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and angiotensin-converting enzyme 2 (ACE2) to rapidly detect the content of neutralizing antibody in COVID-19-infected patients and vaccine recipients. Results: When 356 samples of vaccine recipients were measured, the coincidence rate between this method and cVNT was 88.76%, which was higher than the coincidence rate of 76.97% between cVNT and a conventional chemiluminescence immunoassay detecting overall binding anti-Spike-IgG. More importantly, this assay does not need to be carried out in BSL-2 or 3 laboratories. Discussion: Therefore, this product can detect NAbs in COVID-19 patients and provide a reference for the prognosis and outcome of patients. Simultaneously, it can also be applied to large-scale detection to better meet the needs of neutralizing antibody detection after vaccination, making it an effective tool to evaluate the immunoprotective effect of COVID-19 vaccines. [ABSTRACT FROM AUTHOR]

We prospectively assessed 49 coronavirus disease cases in Guangdong, China, to estimate the frequency and duration of detectable severe acute respiratory syndrome coronavirus 2 RNA in human body fluids. The prolonged persistence of virus RNA in various body fluids may guide the clinical diagnosis and prevention of onward virus transmission. [ABSTRACT FROM AUTHOR]

The substantial increase in prevalence and emergence of antigenically divergent or highly pathogenic influenza A(H7N9) viruses during 2016-17 raises concerns about the epizootic potential of these viruses. We investigated the evolution and adaptation of H7N9 viruses by analyzing available data and newly generated virus sequences isolated in Guangdong Province, China, during 2015-2017. Phylogenetic analyses showed that circulating H7N9 viruses belong to distinct lineages with differing spatial distributions. Hemagglutination inhibition assays performed on serum samples from patients infected with these viruses identified 3 antigenic clusters for 16 strains of different virus lineages. We used ancestral sequence reconstruction to identify parallel amino acid changes on multiple separate lineages. We inferred that mutations in hemagglutinin occur primarily at sites involved in receptor recognition or antigenicity. Our results indicate that highly pathogenic strains likely emerged from viruses circulating in eastern Guangdong Province during March 2016 and are associated with a high rate of adaptive molecular evolution. [ABSTRACT FROM AUTHOR]

During 2016 in Guangzhou, China, we detected infectious avian influenza viruses (AIVs) in 39.8% of samples from chicken carcasses slaughtered at live poultry markets but none from carcasses supplied to supermarkets by facilities bypassing live poultry markets. Promoting supply chains with high biosecurity may reduce the risk for zoonotic AIV transmission. [ABSTRACT FROM AUTHOR]

The recent increase in zoonotic avian influenza A(H7N9) disease in China is a cause of public health concern. Most of the A(H7N9) viruses previously reported have been of low pathogenicity. We report the fatal case of a patient in China who was infected with an A(H7N9) virus having a polybasic amino acid sequence at its hemagglutinin cleavage site (PEVPKRKRTAR/GL), a sequence suggestive of high pathogenicity in birds. Its neuraminidase also had R292K, an amino acid change known to be associated with neuraminidase inhibitor resistance. Both of these molecular features might have contributed to the patient's adverse clinical outcome. The patient had a history of exposure to sick and dying poultry, and his close contacts had no evidence of A(H7N9) disease, suggesting human-to-human transmission did not occur. Enhanced surveillance is needed to determine whether this highly pathogenic avian influenza A(H7N9) virus will continue to spread. [ABSTRACT FROM AUTHOR]

Since 2015, 84 countries and territories reported evidence of vector-borne Zika Virus (ZIKV) transmission. The World Health Organization (WHO) declared that ZIKV and associated consequences especially the neurological autoimmune disorder Guillain-Barré syndrome (GBS) and microcephaly will remain a significant enduring public health challenge requiring intense action. We apply a standardization of the multi-subcutaneous dorsal inoculation method to systematically summarize clinical neurological manifestation, viral distribution, and tissue damage during the progress of viremia and systemic spread in suckling mouse models. We found that C57BL/6 and Kunming mice (KM) both showed remarkable and uniform neurologic manifestations. C57BL/6 owned the highest susceptibility and pathogenicity to the nervous system, referred to as movement disorders, with 100% incidence, while KM was an economic model for a Chinese study characterized by lower limb weakness with 62% morbidity. Slight yellow extraocular exudates were observed in BALB/c, suggesting the association with similar ocular findings to those of clinical cases. The virus distribution and pathological changes in the sera, brains, livers, kidneys, spleens, and testes during disease progression had strong regularity and uniformity, demonstrating the effectiveness and plasticity of the animal models. The successful establishment of these animal models will be conducive to expound the pathogenic mechanism of GBS. [ABSTRACT FROM AUTHOR]

Background: We examined associations between single-nucleotide polymorphisms (SNPs) of IFITM3, TLR3, and CD55 genes and influenza clinical outcomes in Chinese.Methods: A multicenter study was conducted on 275 adult cases of avian (H7N9) and pandemic (H1N1pdm09) influenza. Host DNA was extracted from diagnostic respiratory samples; IFITM3 rs12252, TLR3 rs5743313, CD55 rs2564978, and TLR4 rs4986790/4986791 were targeted for genotyping (Sanger sequencing). The primary outcome analyzed was death.Results: IFITM3 and TLR3 SNPs were in Hardy-Weinberg equilibrium; their allele frequencies (IFITM3/C-allele 0.56, TLR3/C-allele 0.88) were comparable to 1000 Genomes Han Chinese data. We found over-representation of homozygous IFITM3 CC (54.5% vs 33.2%; P = .02) and TLR3 CC (93.3% vs 76.9%; P = .04) genotypes among fatal cases. Recessive genetic models showed their significant independent associations with higher death risks (adjusted hazard ratio [aHR] 2.78, 95% confidence interval [CI] 1.29-6.02, and aHR 4.85, 95% CI 1.11-21.06, respectively). Cumulative effects were found (aHR 3.53, 95% CI 1.64-7.59 per risk genotype; aHR 9.99, 95% CI 1.27-78.59 with both). Results were consistent for each influenza subtype and other severity indicators. The CD55 TT genotype was linked to severity. TLR4 was nonpolymorphic.Conclusions: Host genetic factors may influence clinical outcomes of avian and pandemic influenza infections. Such findings have important implications on disease burden and patient care in at-risk populations. [ABSTRACT FROM AUTHOR]

We compared the detection frequency of avian influenza H7 subtypes at live poultry markets in Guangdong Province, China, before and after the introduction of a bivalent H5/H7 vaccine in poultry. The vaccine was associated with a 92% reduction in H7 positivity rates among poultry and a 98% reduction in human H7N9 cases. [ABSTRACT FROM AUTHOR]

Background: In recent decades, the GII.4 norovirus genotype has predominated in epidemics worldwide and been associated with an increased rate of evolutionary change. In 2014, a novel GII.17 variant emerged and persisted, causing large outbreaks of gastroenteritis in China and sporadic infections globally. The origin, evolution, and transmission history of this new variant are largely unknown.Methods: We generated 103 full capsid and 8 whole-genome sequences of GII.17 strains collected between August 2013 and November 2015 in Guangdong, China. Phylogenetic analyses were performed by integrating our data with those for all publically available GII.17 sequences.Results: The novel emergent lineage GII.17_Kawasaki_2014 most likely originated from Africa around 2001 and evolved at a rate of 5.6 × 10(-3) substitutions/site/year. Within this lineage, a new variant containing several important amino acid changes emerged around August 2013 and caused extensive epidemics in 2014-2015. The phylodynamic and epidemic history of the GII.17_Kawasaki lineage shows similarities with the pattern observed for GII.4 norovirus evolution. Virus movements from Hong Kong to neighboring coastal cities were frequently observed.Conclusions: Our results provide new insights into GII.17 norovirus evolution and transmission and highlight the potential for a rare norovirus genotype to rapidly replace existing strains and cause local epidemics. [ABSTRACT FROM AUTHOR]

Respiratory syncytial viruses (RSVs) including subgroups A (RSV-A) and B (RSV-B) are an important cause of acute respiratory tract infections worldwide. RSV-A include major epidemic strains. Fundamental questions concerning the evolution, persistence and transmission of RSV-A are critical for disease control and prevention, yet remain unanswered. In this study, we generated 64 complete G gene sequences of RSV-A strains collected between 2008 and 2015 in Guangdong, China. Phylogenetic analysis was undertaken by incorporating 572 publicly available RSV-A sequences. Current data indicate that genotypes GA1, GA4, and GA5 are endemic with limited epidemic activity. In contrast, the GA2 genotype which likely originated in 1980 has spread rapidly and caused epidemics worldwide. By analyzing GA2 genotype sequences across epidemic seasons within Guangdong, we find that RSV-A epidemics in Guangdong are caused by a combination of virus importation and local persistence, although the magnitude of the latter is likely overestimated due to infrequent sampling in other regions. Our results provide new insights into RSV-A evolution and transmission at global and local scales and highlights the rapid and wide spread of genotype GA2 compared to other genotypes. In order to control RSV transmission and outbreak, both local persistence and external introduction should be taken into account when designing optimal strategies. [ABSTRACT FROM AUTHOR]

First identified in May 2014 in China's Sichuan Province, initial cases of H5N6 avian influenza virus (AIV) infection in humans raised great concerns about the virus's prevalence, origin, and development. To evaluate both AIV contamination in live poultry markets (LPMs) and the risk of AIV infection in humans, we have conducted surveillance of LPMs in Guangdong Province since 2013 as part of environmental sampling programs. With environmental samples associated with these LPMs, we performed genetic and phylogenetic analyses of 10 H5N6 AIVs isolated from different cities of Guangdong Province from different years. Results revealed that the H5N6 viruses were reassortants with hemagglutinin (HA) genes derived from clade 2.3.4.4 of H5-subtype AIV, yet neuraminidase (NA) genes derived from H6N6 AIV. Unlike the other seven H5N6 viruses isolated in first 7 months of 2014, all of which shared remarkable sequence similarity with the H5N1 AIV in all internal genes, the PB2 genes of GZ693, GZ670, and ZS558 more closely related to H6N6 AIV and the PB1 gene of GZ693 to the H3-subtype AIV. Phylogenetic analyses revealed that the environmental H5N6 AIV related closely to human H5N6 AIVs isolated in Guangdong. These results thus suggest that continued reassortment has enabled the emergence of a novel H5N6 virus in Guangdong, as well as highlight the potential risk of highly pathogenic H5N6 AIVs in the province. [ABSTRACT FROM AUTHOR]

Since early 2013, H7N9-subtype avian influenza virus (AIV) has caused human infection in eastern China. To evaluate AIV contamination and the public risk of infection, we systematically implemented environmental sampling from live poultry markets in Guangdong Province. Through real-time polymerase chain reaction assays and next-generation sequencing, we generated full nucleotide sequences of all 10 H6N6 AIVs isolated during sampling. Focusing on sequence analyses of hemagglutinin genes of the 10 H6N6 AIVs revealed that the viruses were low pathogenic AIVs with the typical hemagglutinin cleavage site of P-Q-I-E-T-R-G. The hemagglutinin, neuraminidase, and nucleocapsid genes of nine AIVs were of ST2853-like (H6-subtype) lineage, ST192-like (N6-subtype) lineage, and HN573-like (H6-subtype) lineage, respectively; whereas the other five genes were of ST339-like (H6-subtype) lineage. However, the polymerase PB2 and nucleocapsid genes of one strain (HZ057) were of GS/GD-like (H5N1-subtype) and ST339-like lineages. Phylogenic analysis revealed that all eight genes of the 10 viruses belonged to Eurasian avian lineage. Altogether, the 10 AIVs were reassortants of different genetic groups of exchanges with the same virus subtype, thus illustrating the genetic diversity and complexity of H6N6-subtype AIVs in Guangdong Province. [ABSTRACT FROM AUTHOR]

Background: Non-typhoidal Salmonella is a common cause of infectious diarrhea in humans. Antimicrobial-resistant Salmonella has become a global concern. Methods: Using laboratory-based surveillance system for Salmonella from September 2009 to December 2012 in Guangdong Province of China. The clinical information and samples of diarrhea patients were collected, according to the surveillance case definition. The lab tests were followed by standardized protocols, including sample isolation, isolates confirmation, serotyping, and antimicrobial susceptibility testing (AST). Results: A total of 1,826 Salmonella isolates were identified from 40,572 patients in 28 hospitals in 11 prefectures. The isolates ratio was highest in autumn (38.8%, 708/1826) and lowest in winter (6.4%, 117/1826). Children aged <5 years were the group most affected by Salmonella in Guangdong Province accounting for 73% (1,329/1,826), of whom the infants (<1 year) were 81.5% (1084/1329) especially. A total of 108 serotypes were identified among the isolates. S. Typhimurium represented the most common serotype followed by serotype 4,5,12:i:-. S. Typhimurium was also the common serotype followed by S. Enteritidis among infants and children aged 1-3 years old. However, S. Enteritidis became the common serotype followed by S. Typhimurium among children aged 3-5 and >5 years. Resistance to at least one antimicrobial was found in 72% (1321/1,826) of the isolates. Resistance to at least three antimicrobials was found in 46% (850/1,826) of the isolates. Resistance to all 12 antimicrobials screened was observed in 8 isolates (0.44%, 8/1,826). The resistant prevalence to quinolones including nalidixic acid and ciprofloxacin was 61.9% (1131/1826), of which ciprofloxacin resistance rate was 8.05% (147/1826). The prevalence resistance to all three cephalosporin antimicrobials (cefepime, cefotaxime, and caftazidime) in <5 yr age group was accounted for 90% (89/99). Conclusions: Additional data and more refined methods can improve future surveillance. The invasive Salmonella isolates should also be included to the antibiotic resistance surveillance for clinical care or public health. [ABSTRACT FROM AUTHOR]

Human adenoviruses (HAdVs) are highly contagious pathogens causing acute respiratory disease (ARD), among other illnesses. Of the ARD genotypes, HAdV-7 presents with more severe morbidity and higher mortality than the others. We report the isolation and identification of a genome type HAdV-7d (DG01_2011) from a recent outbreak in Southern China. Genome sequencing, phylogenetic analysis, and restriction endonuclease analysis (REA) comparisons with past pathogens indicate HAdV-7d has re-emerged in Southern China after an absence of twenty-one years. Recombination analysis reveals this genome differs from the 1950s-era prototype and vaccine strains by a lateral gene transfer, substituting the coding region for the L1 52/55 kDa DNA packaging protein from HAdV-16. DG01_2011 descends from both a strain circulating in Southwestern China (2010) and a strain from Shaanxi causing a fatality and outbreak (Northwestern China; 2009). Due to the higher morbidity and mortality rates associated with HAdV-7, the surveillance, identification, and characterization of these strains in population-dense China by REA and/or whole genome sequencing are strongly indicated. With these accurate identifications of specific HAdV types and an epidemiological database of regional HAdV pathogens, along with the HAdV genome stability noted across time and space, the development, availability, and deployment of appropriate vaccines are needed. [ABSTRACT FROM AUTHOR]

An unusual prevalence of recombinant GII.2 noroviruses (GII.P16-GII.2) in Guangdong, China, at the end of 2016 caused a sharp increase in outbreaks of acute gastroenteritis. This event was another non-GII.4 epidemic that emerged after the GII.17 viruses in 2014 and 2015 and warrants global surveillance. [ABSTRACT FROM AUTHOR]

Background Considered an epicenter of pandemic influenza virus generation, southern China has recently seen an increasing number of human H7N9 infections. However, it is not the only threat. On 30 November 2013, a human H10N8 infection case was first described in China. The origin and genetic diversity of this novel virus is similar to that of H7N9 virus. As H10N8 avian influenza virus (AIV) was first identified from a duck in Guangdong Province during 2012 and there is also evidence of H10N8 infected dogs in this region, we sought to examine archived sera from animal workers to see if there was evidence of subclinical human infections before the first human H10N8 cases. Methods We studied archived serum samples (cross-sectional study, convenience sample) collected between May and September 2013 from 710 animal workers and 107 non-animal exposed volunteers living in five cities of Guangdong Province. Study participants' sera were tested by horse red blood cells (RBCs) hemagglutination inhibition (HI) and microneutralization (MN) assays according to World Health Organization guidelines. The A/Jiangxi- Donghu/346-1/2013(H10N8) virus was used. Sera which have an HI assay ⩾1:20 were further tested with the MN assay. Questionnaire data were examined for risk factor associations with positive serological assays. Risk factor analyses failed to identify specific factors associated with probable H10N8 infections. Results Among the 827 sera, only 21 animal workers had an HI titer ⩾1:20 (18 had an HI titer of 1:20 and 3 had an HI titer of 1:40). None of these 21 subjects reported experiencing any influenza symptoms during the three months before enrollment. Among the three subjects with HI titers of 1:40, two had MN antibody titers of 1:40, and one had a MN antibody titer of 1:80 (probable H10N8 infections). Conclusions Study data suggest that animal workers may have been infected with the H10N8 virus before the first recognized H10N8 human infection cases. It seems prudent to continue surveillance for H10N8 viruses among animal workers. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to assess the prevalence of the novel avian influenza A virus (H7N9) in three high risk groups. The groups were divided into those exposed through infected individuals, those exposed through poultry and those individuals exposed through the external environment, in the early stage of the epidemic in Guangdong Province, which is located in the southern region of China. Methods: Serologic studies were conducted among samples collected from individuals who had close contact with the first H7N9 infected patient reported in Guangdong Province, those who were most likely exposed to the first group of H7N9 infected poultry, and those who might have been exposed to H7N9 in the environmental settings, namely hemagglutinin inhibition (HI) and microneutralizaiton(MN) assays using three viruses as antigens. Results: The alignment results of the viral sequences indicated the similarity of the HA gene sequence among viruses from exposure to infected poultry, infected humans and contaminated environments were highly conserved. Seven samples of individuals exposed to contaminated environments were positive in the HI assay and one sample among them was positive in the MN assay using poultry H7N9 virus as the antigen. One sample was positive against human H7N9 virus and 3 samples were positive against environmental H7N9 among those that were in contact with infected patients in HI assay. None of these were positive in MN assay. All HI titers of the 240 samples from those individuals in contact with infected poultry were less than 40 aganist the antigens from three viruses. Conclusions: The results suggest that when the H7N9 virus was in the early stages of circulation in Guangdong Province, the antigenic sites of the HA proteins of the H7N9 strain isolated from different hosts were highly conserved. The risk of new infection is low in individuals who have contact with the infected patients, poultry or a contaminated environment in the early stages of the circulation of the H7N9 virus. [ABSTRACT FROM AUTHOR]

Background: Hand, foot and mouth disease (HFMD) is a common pediatric illness. Mainly induced by the Enterovirus 71 and Coxsackievirus A 16 infections, the frequently occurred HFMD outbreaks have become a serious public health problem in Southeast Asia. Currently,only a few studies have investigated the human immunity to HFMD in China. In this study, we conducted a cohort study in Guangdong province, China. Methods: Stored serum samples from children less than 10 years old were analyzed. The levels of EV71 and CA16 specific antibodies before, during and shortly after the 2008 large outbreak of HFMD were evaluated by the microneutralization test. The geometric mean titer (GMT) was calculated and compared. Statistical significance was taken as P < 0.05. Results: The seroprevalence data showed a continuous circulation of EV71 and CA16 in Guangdong province China in 2007-2009. The low positive rate in 2009 correlated well with the unprecedented outbreak of HFMD in 2010. Age related increase of seroprevalence was identified in 1-3 years old children for EV71 and in 1-5 years old children for CA16 in Guangdong province. High GMT of EV71 and CA16 antibody titers were also found for these age groups. Conclusions: All of the above findings indicated common infections for these age groups. And they should clearly be at the top of the priority in periodical seroprevalence survey and future vaccination campaign. [ABSTRACT FROM AUTHOR]

Background: Evaluation of the primary etiologic agents that cause aseptic meningitis outbreaks may provide valuable information regarding the prevention and management of aseptic meningitis. An outbreak of aseptic meningitis occurred from May to June, 2012, in Guangdong Province, China. In order to determine the etiologic agent, CSF specimens from 121 children hospitalized for aseptic meningitis at Luoding People’s Hospital of Guangdong Province were tested for virus isolation and identification. Results: Enterovirus RNA was positive in 62.0% of 121 CSF sspecimens by real-time polymerase chain reaction (RT-PCR). Amplification and sequencing of the VP1 region of enterovirus isolates revealed Echovirus 30 (E30) was the most common isolated serotype (80% of 40 enterovirus strains).For the molecular characterization of the E30 isolates, the VP1 gene sequence of 20 Luoding E30 isolates was compared pairwise using the MegAlign with reference strains from GenBank. The pairwise comparison of the nucleotide sequences of the VP1 genes demonstrated that the sequences of the strains differed from those of lineage groups C, D, E, F, and G. Reconstruction of the phylogenetic tree based on the VP1 nucleotide sequences resulted in a monophyletic tree, with seven clustered lineage groups. Most of the isolates were segregated from other lineage groups. Four E30 isolates causing this outbreak aggregated into the Lineage A cluster which was derived from E30 strains that circulated in other regions of China from 2003–2010. Conclusions: This study demonstrated the Luoding strains were a distinct lineage of E30, and a probable cause of this outbreak. The study also demonstrated that different E30 variants existed in the local meningitis outbreak. [ABSTRACT FROM AUTHOR]

Background: CHIKV is a mosquito-borne emerging pathogen that has a major health impact in humans in tropical zones around the globe. A new variant of the virus, E1-A226V caused a large outbreak in the Indian Ocean islands and India from 2004-2007. CHIKV outbreak was initially reported in Dongguan region of Guangdong in 2010 in China, another smaller CHIKV outbreak was found in Yangjiang region of Guangdong two weeks later. The viral agent causing the two outbreaks was inferred to be the new E1-A226V variant and Yangjiang CHIKV might be introduced from Dongguan. To confirm the hypothesis and determine the origin of CHIKV causing the outbreaks, we described Yangjiang outbreak in this study, and the molecular characterization of CHIKV from Yangjiang and Dongguang outbreaks were analyzed. Results: 27 clinical cases of CHIK fever were reported in outbreak in Yangjiang region. Sera sample from 12 clinical cases were collected from the outbreak, and nucleic acid and antibody tests for CHIKV were performed using Real-time RT-PCR and indirect immunofluorescence. Positive samples of Real-time RT-PCR were subjected to viral isolation. The results showed 3/12 samples positive for Real-time RT-PCR. 7/12 and 4/12 samples were positive for IgM and IgG against CHIKV respectively, two virus strains were isolated. Four viral genomes from Dongguan and Yangjiang were sequenced, characterized and phylogeneticly analyzed. Phylogenetic analysis revealed that the four seqeunced viruses had the closest relationship (99.4∼99.6% identify) with the Singapore 2008 isolate belonging to the Indian ocean clade. A common mutation at the site of the E1-A226V was observed among four viruses. Four and three aa substitutions were detected in the CHIKV sequence from the Dongguan and Yangjiang outbreak strains respectively. Conclusion: CHIKV with an E1-A226V mutation that originated from Southeast Asia isolates caused two outbreaks in China in 2010, and originated from two different infectious sources. [ABSTRACT FROM AUTHOR]

Background: Since 1997, several countries within the Asian Pacific region have been affected by one or more massive outbreaks of Hand Foot and Mouth Disease (HFMD). Virus typing experiments revealed that these outbreaks were caused by strains of human enterovirus 71 (EV71) belonging to several different, recently emerged subgenogroups. In mainland China, a different situation was observed. The first outbreak, localized in Shangdong Province, was reported in 2007, and was followed by a wide-spread outbreak in mainland China in 2008. Since then, numbers of reported HFMD cases have been persistently high. Methodology/Principal Findings: To gain insight in the epidemiological behavior of EV71 in China, we studied genetic diversity and EV71 population dynamics to address whether the increase in number of reported EV71 infections reflects a real increase in viral spread or is just the result of increased awareness and surveillance. We used systematically collected VP1 gene sequences of 257 EV71 strains collected in Guangdong province from 2008 to 2010 as part of HFMD surveillance activities, and supplemented them with 305 GenBank EV71 reference stains collected in China from 1998 to 2010. All isolates from Guangdong Province belonged to subgenogroup C4. Viral population dynamics indicated that the increased reporting of HFMD in China since 2007 reflects a real increase in viral spread and continued replacement of viral lineages through time. Amino acid sequence comparisons revealed substitution of amino acid in residues 22, 145 and 289 through time regularly with the VP1 gene of EV71 strains isolated in mainland China from 1998 to 2010. Conclusions: EV71 strains isolated in mainland China mainly belonged to subgenogroup C4. There was exponential growth of the EV71 virus population in 2007 and 2008. There was amino acid substitution through time regularly with the VP1 gene which possibly increased viral spread and/or ability of the virus to circulate persistently among the Chinese population. [ABSTRACT FROM AUTHOR]

The article discusses a study which confirmed that 15 serovars and diverse genotypes of Haemophilus parasuis were widely distributed in southern China. A total of 112 H. parasuis strains were subjected to serovar analysis by gel diffusion (GD) and indirect hemagglutination (IHA) tests and to genotype analysis by means of pulse-field gel electrophoresis (PFGE). The study found that the 23 nontypeable strains showed 22 different PFGE profiles.

Background: To evaluate the temporal trends of seroprevalence to pH1N1 among the Guangdong population following 2009 H1N1 pandemic wave, we conducted three cross-sectional serology surveys in 2010. Methodology/Principal Findings: Three surveys were carried out consecutively in 2010 from January 8 to January 24, from March 15 to April 10 and from August 23 to September 4. Sample populations comprising of 4725, 4727, and 4721 subjects respectively were randomly selected for study in these three surveys. The level of antibodies against pH1N1 was evaluated by hemagglutination inhibition assay. In survey 1, the seroprevalence of pH1N1 among all the subjects is 25.1%, declining to 18.4% in survey 2 and increasing to 21.4% in survey 3. Among vaccinated subjects, the seroprevalence was 49.0%, 53.0%, and 49.4% in the three consecutive surveys, showing no significant differences. In contrast, among non-vaccinated subjects, the seroprevalence declined significantly from 22.8% (survey 1) to 14.3% (survey 2) and subsequently increased to 18.1% (survey 3). The multivariate logistic regression analysis revealed that seroprevalence to pH1N1 in non-vaccinated individuals correlated with the investigated order of the surveys, age, and region (all P<0.05). However, it was not correlated with gender (P = 0.650), seasonal influenza vaccination history (P = 0.402) and symptoms (P = 0.074). Conclusions/Significance: In Guangdong, the seroprevalance to pH1N1 decreased initially and then rebounded modestly during the first 9 months following the 2009 pandemic wave. Our results suggest that the prevalence of pH1N1 is still correlated with age and population density during the post-pandemic period. An early end to the free pH1N1 vaccination program might be another important reason for the slight rebound in seroprevalance. Our study findings can help the Guangdong authorities to make evidence-based decisions about a long-term vaccination strategy and boost immunity in specific population groups (such as children and people living in the capital-city) to prevent further transmission in the future. [ABSTRACT FROM AUTHOR]

Background: Relying on surveillance of clinical cases limits the ability to understand the full impact and severity of an epidemic, which urges a deep insight into the serological evidence of infection and transmission feature of pandemic H1N1 2009 (pH1N1) virus in Guangdong province. Methods: In this cross-sectional serological survey, serum samples were collected by multi-stage stratified random sampling in Jan 2010. Antibody titers were measured by hemagglutination inhibition (HI) assay. Age-specific and region-specific prevalence were calculated based on the results of HI assay (positive, HI titer≥1:40). Results: A total of 4,319 serum samples had been collected from subjects without vaccination with pH1N1 vaccine. The seroprevalence was 22.82% (985/4,319). By contrast, there was a marked spatial heterogeneity in prevalence. The seroprevalence was 27.3% in large city, 21.4% in medium cities, higher than that of 20.2% in rural areas. The seroprevalence was highest in 11-20 age group (32.8%), however, in those above 60 years of age group, which was 12.6%, lower than other age groups. On the other hand, antibody titers to pH1N1 virus were highest in school children, which were followed by a gradual decrease in adult. However, in the elderly groups from cities, especially from large city, the antibody titer to pH1N1 increased significantly and reached a much higher level. Conclusion: Our results showed that the prevalence for pH1N1 was correlated with age and population density. Preexisting antibody may have protected the very old from pH1N1 infection, while original antigenic sin and immunosenescence may have contributed to greater severity once infected. These should be considered when studying the pathogenesis and transmission of influenza virus and formulating strategies on vaccination and treatment. [ABSTRACT FROM AUTHOR]

large outbreak of hand, foot and mouth disease (HFMD) occurred in Guangdong, China, in 2009. A total of 92,749 cases were officially reported to the Center for Disease Control and Prevention of Guangdong (GDCDC). To clarify the pathogen causing the outbreak, 600 specimens, including stool, rectal swabs, vesicular swabs, cerebrospinal fluid, and throat swabs, were collected from 541 patients and subjected to one-step RT-PCR. Four hundred eighty-nine of 541 patient samples were positive for enterovirus. All positive samples were cultured on RD and Hep2 cells; 307 specimens displayed CPE. Sequence analysis of PCR fragment and typing real-time PCR indicated that these isolates included EV71 (56%), CAV16 (35.5%), CAV6 (2.0%), CAV10 (1.0%), CAV2 (0.7%), CAV4 (1.3%), Echo30 (0.7%), Echo25 (1.0%), Echo4 (0.3%), CBV5 (1.0%) and human rhinovirus (0.7%). 100% (12/12) of fatal cases and 97.2% (140/144) of severe cases carried EV71 and CAV16. The results implied that EV71 and CAV16 were mainly responsible for the outbreak. Comparison with the three global types of EV71 and the five clusters of genotype C showed that the sequences from mainland China (not including the Hong Kong region) are located in subgenogroup C-4 and originate from isolates from the Shenzhen area of Guangdong Province. Results from this study show that the C-4 genotype has been a prevalent pathogen in mainland China since 1998. [ABSTRACT FROM AUTHOR]

The article looks into the role that financing and abandonment options play in the value of Chinese real estate development projects. Financing and abandonment options create important value in the real estate projects of China, and produce enormous profits for the developers. The Chinese government should improve the legislative and regulatory frameworks to control excessive value produced by the financing and abandonment options. It should restrict the ability of developers to amass social wealth by exploiting legal loopholes.

In the past decade, the most prevalent norovirus genotype causing viral gastroenteritis outbreaks worldwide, including China, has been GII.4. In winter 2014-15, norovirus outbreaks in Guangdong, China, increased. Sequence analysis indicated that 82% of the outbreaks were caused by a norovirus GII.17 variant. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated whether Asian musk shrews are a reservoir for rat hepatitis E virus (HEV). The researchers examined 260 shrews that were trapped in Zhanjiang City, Guangdong Province, China. It was found that rat HEV might have the capability to induce an immune response in humans.

A letter to the editor is presented on the hand-foot-mouth disease (HFMD) disease transmission in China, with topics including its complications, mortality, and outbreaks.

The article discusses a study of the changes in the genetic characteristics of avian influenza A H7N9 virus that reemerged in China in 2013. Topics discussed include the influenza A H7N9 virus RNA segments acquired from influenza A H9N2 virus, genetic difference between the reemerged influenza A H7N9 viruses from the first cases of viruses and a suggestion of rapid and continued reassortment with circulating H9N2 virus subtype in the reemerged virus.