Search

Background: After being polio free for more than 10 years, an outbreak following importation of wild poliovirus (WPV) was confirmed in Xinjiang Uygur Autonomous Region, China, in 2011., Methods: A cross-sectional study was conducted prior to supplementary immunization activities (SIAs), immediately after the confirmation of the WPV outbreak. In selected prefectures, participants aged ≤ 60 years old who visited hospitals at county-level or above to have their blood drawn for reasons not related to the study, were invited to participate in our study. Antibody titers ≥ 8 were considered positive., Results: Among the 2,611 participants enrolled, 2,253 (86.3%), 2,283 (87.4%), and 1,989 (76.2%) were seropositive to P1, P2 and P3 respectively, and 1744 (66.8%) participants were seropositive to all the three serotypes. Lower antibody seropositivities and geometric mean titers were observed in children <1 year of age and in adults aged 15-39 years., Conclusion: Serosurveys to estimate population immunity in districts at high risk of polio importation might be useful to gauge underlying population immunity gaps to polio and possibly to guide preparedness and response planning. Consideration should be given to older children and adults during polio risk assessment planning and outbreak response.

Background: The last case of infection with wild-type poliovirus indigenous to China was reported in 1994, and China was certified as a poliomyelitis-free region in 2000. In 2011, an outbreak of infection with imported wild-type poliovirus occurred in the province of Xinjiang., Methods: We conducted an investigation to guide the response to the outbreak, performed sequence analysis of the poliovirus type 1 capsid protein VP1 to determine the source, and carried out serologic and coverage surveys to assess the risk of viral propagation. Surveillance for acute flaccid paralysis was intensified to enhance case ascertainment., Results: Between July 3 and October 9, 2011, investigators identified 21 cases of infection with wild-type poliovirus and 23 clinically compatible cases in southern Xinjiang. Wild-type poliovirus type 1 was isolated from 14 of 673 contacts of patients with acute flaccid paralysis (2.1%) and from 13 of 491 healthy persons who were not in contact with affected persons (2.6%). Sequence analysis implicated an imported wild-type poliovirus that originated in Pakistan as the cause of the outbreak. A public health emergency was declared in Xinjiang after the outbreak was confirmed. Surveillance for acute flaccid paralysis was enhanced, with daily reporting from all public and private hospitals. Five rounds of vaccination with live, attenuated oral poliovirus vaccine (OPV) were conducted among children and adults, and 43 million doses of OPV were administered. Trivalent OPV was used in three rounds, and monovalent OPV type 1 was used in two rounds. The outbreak was stopped 1.5 months after laboratory confirmation of the index case., Conclusions: The 2011 outbreak in China showed that poliomyelitis-free countries remain at risk for outbreaks while the poliovirus circulates anywhere in the world. Global eradication of poliomyelitis will benefit all countries, even those that are currently free of poliomyelitis.

Objective: To isolate and identify the influenza virus that caused four influenza-like-illness outbreaks in Jining city of Shandong Province in 2009 and analyze the genetic characteristics of hemagglutinin (HA) and neuraminidase (NA) gene, the variation of these genes were studied., Methods: 34 nasopharyngeal swabs from fever patients of four influenza-like-illness outbreaks were collected and diagnosed by real time quantitative RT-PCR method. The positive samples were incubated and cultured for virus. HA and NA genes of isolated pandemic influenza A (H1N1) virus were sequenced, the homology analysis was done with DNAStar software and the genetic evolution and amino acid substitutions were performed with Mega 4.0 software. The sequences were compared with WHO recommended vaccine virus, native reference virus., Results: Seventeen of 34 nasopharyngeal swabs were positive, 11 pandemic influenza A (H1N1) viruses were isolated and HA and NA genes of 7 strains were sequenced. Phylogenetic analysis for hemagglutinin and neuraminidase gene of Shandong outbreak strains showed that there were 98.4% - 99.6% and 99.2% - 100.0% sequence identity. Compared with WHO-recommended vaccine strain, the reference virus in mainland China strain, eleven amino acids were changed for HA protein, including position 38, 40, 56, 90, 100, 145, 172, 173, 220, 303 and 338, and 38, 40, 303 of HA protein were located in the antigenic determination C cluster, 172, 173 in the D cluster, 56 in the E cluster, site 40 of HA protein were glycosylated. In NA protein, seven amino acids were changed, including position 80, 106, 241, 248, 351, 369 and 386, site 40 of NA protein were glycosylated. No mutations of 275 in NA protein were found., Conclusion: The HA and NA genes of the epidemic strains showed high homology, some mutations in the HA and NA proteins were found, the antigenic site and glycosylation site of some strains were changed during the epidemic process.

Objective: To identify the pathogen that caused an outbreak of aseptic meningitis in Shandong province in 2005. Phylogenic analysis was carried out on Coxsackie-virus B5 (CVB5) which was isolated during this outbreak., Methods: 78 stool and 58 cerebrospinal fluids (CSF) specimens were collected from some inpatients during this outbreak. Virus isolation and reverse transcription-polymerase chain reaction (RT-PCR) was then performed. Phylo-genetic trees based on entire and partial VP1 sequences were constructed among CVB5 isolates and others published in GenBank., Results: The isolation rates of stool and CSF specimens were 38.5% (30/78) and 48.3% (28/58) respectively. Among the results of serotype identification and molecular typing of 58 positive isolates, 54 were identified as CVB5, 2 as ECHO24, 1 as CVB3 and 1 as CVA9. Results from viral investigation showed that CVB5 was the main pathogen causing this outbreak. Data from homological comparisons indicated that Shandong strains had the highest nucleotide acid identity with the Zhejiang/12/02 strain (97.5% - 97.8%), and lower identity (78.3% - 78.6%) with the prototype strain (Faulkner strain). Phylogenic tree in VP1 region showed that CVB5 could be separated into four genotypes. Isolates of this outbreak belonged to genotype D., Conclusion: CVB5 was the major etiological agent correlated with this outbreak. The shift of predominant genotype might serve as one of the causes that associated with the outbreaks of aseptic meningitis.

Objective: To identify the pathogen caused an outbreak of aseptic meningitis in Tancheng county of Shandong province in 2008, and to analyze the molecular characterization of VP1 gene of the Coxsackievirus B3(CVB3) isolates., Methods: Stool and cerebrospinal fluid(CSF) specimens were collected from this outbreak for virus isolation with RD and Hep-2 cell. After typing by neutralization test, the VP1 gene of the isolates were amplified by RT-PCR and sequenced. Homologous comparison and phylogenetic analysis were performed., Results: 35 strains of enteviruse were isolated from 22 stools and 120 CSFs(7 from stools and 28 from CSFs), 34 strains identified as CVB3 and 1 as Echovirus 30(ECHO30) by neutralization test. The nucleotide homologies were 90.5%-100.0% in the partial VP1 gene (381 bp) among 34 CVB3 isolates. Homology comparisons indicated that Shandong strains have the identity of 79.5%-81.6% with the CVB3 prototype strain Nancy. 012/2008TC/SD/CHN and 177/2008TC/SD/CHN showed the highest nucleotides homologies (98.2% and 91.0% respectively) with Fuyang19 strain of Anhui province in 2008 in complete VP1 gene. The phylogenetic tree based on complete VP1 genes showed that all the CVB3 correlated with aseptic meningitis in China recently came from the same evolution linkage and formed a monophyletic cluster., Conclusion: The causative agent of this outbreak of aseptic meningitis was CVB3. CVB3 circulated in China was genetically different from other countries.

Background: An outbreak of hand, foot, and mouth disease (HFMD) included 1149 people in Linyi City, Shandong Province, China, in 2007: three children died., Objectives: To characterize the pathogens responsible for this outbreak and to analyze their genetic features., Study Design: A total of 233 clinical specimens were collected from 105 hospitalized patients, including 11 patients with severe HFMD. Virological investigations (direct RT-PCR, viral isolation and molecular identification) and phylogenetic analysis were performed., Results: Human enterovirus 71 (HEV71) was the main pathogen that caused this outbreak, based on clinical manifestations, epidemiological data, and laboratory results. Phylogenetic analysis indicated that the Shandong HEV71 isolates belonged to 3 lineages in subgenotype C4. Subgenotype C4 could be further divided into two clusters (C4a and C4b), which corresponded to two time periods. Cluster C4a HEV71 has been the predominant virus circulating in mainland China in the past 5 years., Conclusions: The 2007 HFMD outbreak was mainly caused by HEV71 subgenotype C4 with 3 transmission chains. This virus has been continuously circulating in China since 1998. The Shandong strains co-evolved with isolates from other provinces in mainland China and neighboring countries.

Objective: To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 (E19) isolates collected from an outbreak associated with hand, foot and mouth disease (HFMD) in Tai'an city of Shandong Province of China from July to September, 2003., Methods: Thirty seven Echovirus 19 isolates were isolated from stool specimens and throat swabs collected during the outbreak, then major capsid (VP1) genomic sequence was determined, and phylogenetic tree was done based on the VP1 sequences among these 37 and other E19 viruses deposited in the Genbank. Also a representative strain named CHN-SD03-TN12 was selected for sequencing of 5'-untranslated regions (5'-UTR)., Results: The identity rate was about 98.9%-100% among all these 37 E19 viruses. The genetic relationships between these 37 E19 isolates and other strains reported were also depicted. The identity rate was about 78.4%-78.9% compared with E19 reference strain Burke. The substitutions in the sequence of 5'-UTR resulted in changes in the conjectural properties of 5'-UTR of E19 viruses., Conclusion: The genetic features of E19 viruses isolated during the outbreak in Shandong Province in 2003 may be associated with a genetic and antigenic drift that changes the virulence of the Shandong isolates, but the molecular changes in Shandong E19 viruses contributing to their phenotype remain to be further illuminated. However, the sequences described in this paper substantiate the changes taken place in capsid VP1 and 5'UTR regions. These substitutions may contribute to their tropism and virulence, and play a significant role in pathogenesis and clinical manifestations of the disease.

Objective: To study the variation and evolution rules and analyze the genetic characterization of echovirus 30 during an outbreak of aseptic meningitis., Methods: For all the echovirus 30 isolates during the outbreaks in Zhangqiu city in 2003, complete VP1 genes were determined. Phylogenetic tree reconstruction and pairwise sequence were determined to compare the homological relationship and evolution rules between Zhangqiu strains and the other reported echovirus 30 in GenBank., Results: Pairwise sequence comparisoms in VP1 region indicated that there were 98.9%-99.5% identity of nucleotide acid among Zhangqiu strains, and having the highest homology with Taian strains (98.5%-99.0%) isolated in Shandong province. At the same time, when comparing with Zhejiang and Jiangsu strains, the nucleotide homology showed 98.2%-98.9%, relatively low identity with Taiwan strains (87.4%-87.6%) and French strains (89.1%-89.7%) but only 82.4%-82.8% identity when comparing with echovirus 30 prototype strain Bastianni. Data from phylogenetic tree analyses indicated that all the echovirus 30 correlated with aseptic meningitis in China recently came from the same evolution linkage and formed a monophyletic cluster., Conclusion: In 2003, there was an circulation of echovirus 30 in Shandong province which causing an endemic of aseptic meningitis in local areas. Data from phylogenetic tree analyses indicated that the antigenic characteristics of echovirus 30 in mainland China might be different from strains early isolated in other continents and formed a new genotype.