Rash and fever illness caused by herpes simplex virus type 1 needs to be distinguished from hand, foot and mouth disease / 病毒学报

An epidemic of rash and fever illnesses suspected of hand, foot and mouth disease (HFMD) occurred in Gansu Province of China in 2008, laboratory tests were performed in order to identify the pathogen that caused this epidemic. Eight clinical specimens collected from the 4 patients (each patient has throat swab and herpes fluid specimens) with rash and febrile illness, were inoculated onto RD and HEp-2 cells for virus isolation, and the viral nucleic acid was then extracted with the positive virus isolates, the dual-channel real-time reverse transcript-polymerase chain reaction (RT-PCR) was performed to detect the nucleic acid of human enterovirus (HEV) in the viral isolates at the same time. For the viral isolates with the negative results of HEV, a sequence independent single primer amplification technique (SISPA) was used for "unknown pathogen" identification. Totally, 6 viral isolates were identified as herpes simplex virus type 1 (HSV-1). Comprehensive analyses results of the clinical manifestations of the patients, epidemiological findings and laboratory test indicated that this epidemic of rash and febrile illness was caused by HSV-1. The differences among the gG region of 6 HSV-1 isolates at nucleotide level and amino acid level were all small, and the identities were up to 98. 8% and 97.9%, respectively, showing that this outbreak was caused by only one viral transmission chain of HSV-1. HSV-1 and other viruses that cause rash and febrile illnesses need differential diagnosis with HFMD. The etiology of rash and febrile illness is sometimes difficult to distinguish from the clinical symptoms and epidemiological data, the laboratory diagnosis is therefore critical.

Analysis of genetic characteristics of type II non-wild poliovirus in mainland China, 2010 / 病毒学报

To study the genetic characteristics of 123 type II non-wild polioviruses isolated from acute flaccid paralysis (AFP) cases in mainland China in 2010, provide the scientific basis for maintaining the "polio-free" status, and the switching use of polio vaccine for China. VP1 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the PCR products were then sequenced. The sequence results were analyzed with Sequencher 4.8, BioEdit 7.0.9 and MEGA 5.0. Of 65 strains, nt2909 was found to be a mutation hotspot, and also a neurovirulence determinant in VP1 region. During 2010, two vaccine-derived polioviruses (VDPVs) were isolated from Yunnan province, China and no wild poliovirus (WPV) was isolated. The epidemiological studies and laboratory results of the two VDPVs showed that they were newly discovered VDPVs because of the genetic difference from other VDPVs strains isolated in the world, implying the sensitive poliovirus surveillance network could timely detect the transmission of VDPVs and the importation of WPV.

Genetic characterization of coxsackievirus A16 isolated in Ningxia Hui Municipality in 2008 / 中华流行病学杂志

Objective To study the genetic characterization of coxsackievirus A16 (CVA16)strains isolated during an epidemic of hand, foot, and mouth disease (HFMD) in Ningxia Hui Municipality in 2008. Methods Clinical samples were collected from HFMD patients in Ningxia Hui Municipality and CVA16 strains were isolated by viral isolation methods. Reverse transcriptionpolymerase chain reactions (RT-PCR), specific for CVA16 were performed with these CVA16 strains.Entire VP1 coding region amplification and sequencing were then performed and finally phylogenetic tree was constructed among Ningxia CVA16 strains and CVA16 representative strains of known genotypes and subgenotypes. Results 70 Ningxia CVA16 strains were isolated from HFMD patients in Ningxia in 2008 and the homology of nucleotide and amino acid were 90.8%-100.0% and 98.9%-100.0%, respectively. Phylogenetic characteristics of the strains reconfirmed that they could be divided into two distinct genotypes-A and B. Genotype B could be further divided into the subgenotypes B1 and B2, while all the 70 Ningxia CVA16 strains belonged to the co-circulated clusters B1a and Blb within subgenotype B1, which belonged to 2 viral transmission chains.Conclusion Our results indicated that subgenotype B1 CVA16 strains continued to circulate over a wide geographic area of mainland China since the first reported episode in Shenzhen city in 1999. Like other CVA16 strains isolated elsewhere in China, both Bla and Blb evolution branches were co-circulating in Ningxia Hui Municipality. Based on the close phylgenetic and chronological relationship with CVA16 isolated in other countries and regions near China. Our data confimed that these strains co-evolved and co-circulated with those from neighboring countries and regions.

The epidemiologic and virological analysis of an outbreak of hand, foot, and mouth disease in Inner Mongolia in 2007 / 病毒学报

In 2007, an outbreak of hand, foot, and mouth disease (HFMD) occurred in Jungar Banner, Erdos city, Inner Mongolia Autonomous Region, China Fever, vesicular exanthema on the hands, feet, mouth, and buttocks were presented in most of the patients. Most of the patients were infants less than 5 years old, and an obvious peak period appeared in the disease outbreak. From 28 hospitalized patients, 23 stool specimens and 6 throat swab specimens were collected for enterovirus isolation, and 15 enteroviruses were isolated, 9 were identified as Human Enterovirus 71 (HEV71, the isolation rate is 31.03%) and 1 was identified as Coxsackievirus A16 (CVA16). According to the comprehensive analysis of clinical manifestation, epidemiology data and laboratory results, this outbreak was probably mainly caused by HEV71. The variability at nucleotide acid level and amino acid level among 9 HEV71 was relatively low, and the homology was more than 99.4% and 99.0% respectively, showing that this outbreak was caused by only one viral transmission chain. Phylogenetic analysis of 9 HEV71 strains isolated during this outbreak revealed that they all belonged to subgenotype C4, which has been continuously circulating in mainland China since its first reported occurrence in Shenzhen City in 1998. It was also suggested that subgenotype C4 HEV71 had a widely distribution and transmission in mainland China.

Outbreak of acute hemorrhagic conjunctivitis in Beijing City in 2007 caused by coxsackievirus A24 variant: molecular identification and phylogenetic analysis / 病毒学报

In 2007, an outbreak of acute hemorrhagic conjunctivitis (AHC) occurred in Beijing. In order to identify the etiology of this outbreak, 57 eye conjunctival swabs were collected from 57 outpatient patients, and detected for adenovirus, human enterovirus 70 (HEV70) and Coxsackievirus A24 variant (CVA24v) genes by using RT-PCR or PCR methods. The results showed that 38 were positive for CVA24v, the positive rate was 66.7%, but none was positive for HEV70 and adenovirus, showing that this outbreak was caused by CVA24v. 9 viral isolates were obtained from 57 clinical specimens by using viral isolation method, and all were identified as CVA24v by molecular typing method. All 9 CVA24v isolates were performed by VP1 sequencing, the results showed that except for strain 0744/BJ/CHN/2007, the variability at nucleotide acid level and amino acid level among other 8 CVA24v were relatively low, and the homologies were more than 99.6% and 100.0%, respectively; the homologies of nucleotide acid and amino acid between strain 0744/BJ/CHN/2007 and other 8 CVA24v were 96.8%-97.2% and 99.7%, respectively. Phylogenetic analysis of 9 CVA24v revealed that they represented the Clade 4 and Clade 5 in Group I, showed that this outbreak was caused by at least 2 viral transmission chains. Comparing to 3C region of CVA24v frequently used before, VP1 region was considered as the most rigorous target for molecular epidemiology study of CVA24v. To enhance the research of sero-epidemiology and molecular epidemiology of CVA24v and to know the genetic characterizations and molecular evolution of CVA24v are most important to prevent and control the outbreaks of AHC in China.

In vitro study on the effect of ribavirin reducing the EV71 replication / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>Observe the effect of Ribavirin on reducing the EV71 replication, inactivating EV71 and protecting the RD-A cells against the EV71 infection in vitro.</p><p><b>METHODS</b>Using the EV71 isolated from Anhui Fuyang HFMD outbreak, the effect of Ribavirin on RD-A cells during the EV71 infection was observed.</p><p><b>RESULTS</b>In the experiment of Ribavirin inhibiting the EV71 replication, comparing with the no-Ribavirin-dealed virus control group, the group of 1:640 dilution of Ribavirin delayed the CPE for 2 days, while the normal cell group was growing very well. In the experiment of protecting cell from EV71 infection, comparing with the no-Ribavirin-dealed virus control group, the group of 1:8 dilution of Ribavirin delayed the CPE for 4 days. In the experiment of Ribavirin effect on the inactivation of EV71, the group of 1:40 dilution of Ribavirin delayed the CPE for 2 days comparing with the virus control group.</p><p><b>CONCLUSION</b>Ribavirin could inhibit the replication of the EV71 and inactivate the EV71 in vitro. Additionally, Ribavirin could protect RD-A cells from EV 71 infection. The observation will contribute to EV71 infection control and quick medicine therapy.</p>

Seroepidemical study of Coxsackievirus A 16, in four provinces, China, 2005 / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the situation of 1- 5-years-old children's antibody against Coxsackievirus A group 16 strain (CVA16) in Guangdong, Heilongjiang,Yunnan Province and Xinjiang Uygur Autonomous Regions, China, 2005, it can offer scientific evidences for preventing and controlling CVA16 causative hand-food and mouth disease.</p><p><b>METHODS</b>Using microneutrilization test, to study 503 serum samples randomly selected from sera collected in 2005.</p><p><b>RESULTS</b>Positive rate of anti-CVA16 antibody were 41.90%, 9.40%, 40.00% and 34.40% in Guangdong, Heilongjiang,Yunnan and Xinjiang, respectively. Antibody titer was relative low (average, 1: 6.1) and there was no statistical difference of geometry mean of antibody titer (GMT) among Guangdong, Heilongjiang, Yunnan (F = 0.97, 0.40, 1.06, respectively; P > 0.05), while there had statistical difference of GMT between Heilongjiang and other three regions( F = 10.61, P < 0.00).</p><p><b>CONCLUSIONS</b>There had probably existed local epidemic in some regions of Guangdong, Heilongjiang, Yunnan Province and Xinjiang Uygur Autonomous Regions, China, 2005 or even before, but the area and degree of transmission and epidemic had difference. Children aged from 1- 5-years-old were relatively susceptible population of CVA16 infection.</p>

Reevaluate the effect of G-480 point mutation that determines the neurovirulence of type I vaccine polioviruses / 病毒学报

Whole genome sequencing of 9 type I circulating vaccine-derived polioviruses (cVDPVs) isolated in Guizhou Province in China revealed that reverse mutations did not occur in G-480 and U-525 which are known as the most important neurovirulence determinate sites, while other known neurovirulence determinate sites such as A-2438, A-2795, C-6203 and G-7441 did revert to Mahoney type. 5 type I cVDPVs were selected for neurovirulence test on PVR-Tg21 transgenic mice which express human poliovirus receptor gene based on their different nucleotide sequences, they all showed higher neurovirulence than P1/Sabin strain, and the neurovirulence of CHN8184 and CHN8229-1. 1 were comparable to that of wild type P1/Mahoney. The neurovirulence of CHN8229-1.1, CHN8229-2 and CHN8229-3 presented a trend of decreasing, but still laid in high level. There were 7 nucleotide mutations between CHN8229-1.1 and CHN8229-2, and only 2 between CHN8229-2 and CHN8229-3 in their whole genomes, but the neurovirulence among them were relatively different, showing that there must be some unknown neurovirulence determinate sites among these mutations. Computer predicted RNA secondary structure of stem-loop V of the poliovirus 5' NCR of Guizhou type I cVDPVs was relatively stable. In the situation that no reverse mutation occurred in G-480, some type I cVDPVs already showed high neurovirulence nearly equal to P1/Mahoney, it meant that the effect of G-480 point mutation that determined neurovirulence of P1/Sabin strain has been overestimated, G-480 was not the only important site to determine neurovirulence in P1/Sabin strain, others also may play the very important role. More details are needed to elucidate the mechanism of attenuation in type I polioviruses.