Article published by POLS ONE on October 25,2012
Background: Enteroviruses include over 100 serotypes and usually cause self-limited infections with non-specific symptoms in children, with the exceptions of polioviruses and enterovirus 71 which frequently cause neurologic complications. Therefore, early detection and serotyping of enteroviruses are critical in clinical management and disease surveillance. Traditional methods for detection and serotyping of enteroviruses are virus isolation and immunofluorescence assay, which are time-consuming. In this study, we compare virus isolation and two molecular tests for detection and serotyping of enteroviruses in clinical samples.
Methods: One hundred and ten throat swabs were collected from pediatric outpatients with enterovirus-like illnesses (hand-foot-mouth disease, herpangina, and non-specific febrile illness). Virus isolation was conducted using multiple cell lines and isolated viruses were serotyped using immunofluorescent assay. In the molecular tests, a semi-nested RT-PCR and a novel CODEHOP platform were used to detect the 59UTR and VP1 genes of enteroviruses, respectively. Amplified nucleotides were sequenced and genotyped.
Results: Among the 110 cases, 39(35%), 52(47%), and 46(42%) were tested positive with these three tests, respectively. Using the consensus results of these three tests as the gold standard, agreement of the VP1 CODEHOP test was 96%, which is higher than those of the virus isolation (89%) and the 59-UTR test (88%). The VP1 CODEHOP test also has the best performance on serotyping confirmed with serum neutralization tests.
Conclusions: The VP1 CODEHOP test performed well for detection and serotyping of enteroviruses in clinical specimens and could reduce unnecessary hospitalization cares during enterovirus seasons.
5Comparing molecular methods for early detection and serotyping of enteroviruses in throat swabs of pediatric patients_
Le Phan Kim Thoa, Pai-Shan Chiang, Truong Huu Khanh, Shu-Ting Luo, Tran Ngoc Hanh Dan, YaFang Wang, Tang Chi Thuong, Wan-Yu Chung, Nguyen Thanh Hung, Jen-Ren Wang, Le Nguyen Thanh Nhan, Le Quoc Thinh, Ih-Jen Su, Than Duc Dung, Min-Shi Lee
Article Published by POLS ONE on July 19, 2013
Enterovirus 71 (EV71) frequently causes fatal infections in young children in Asia. In 2011, EV71 epidemics occurred in southern Vietnam. We conducted genetic and antigenic analysis of the EV71 isolates and found that 94% of them were genotype C4a related to two lineages circulating in China and 6% were genotype C5 which have circulated in Vietnam since 2003. Antigenic variants were not detected. EV71 vaccines are being developed. Longitudinal enterovirus surveillance data are critical to formulate vaccination policy in Vietnam.
3Genetic and Antigenic Characterization of Enterovirus 71 in Ho Chi Minh City, Vietnam, 2011
Min-Yuan Chia, Pai-Shan Chiang, Wan-Yu Chung, Shu-Ting Luo, Min-Shi Lee
Article Accepted by ELSEVIER on July 17, 2013
Enterovirus 71 (EV71) was first described in USA in 1969 but retrospective studies in The Netherlands further detected EV71 in the clinical specimens collected in 1963. EV71 has one single serotype measured by using hyperimmune animal antisera but can be phylogenetically classified into three genogroups (A, B, and C) including 11 genotypes (A, B1eB5, C1eC5). In Taiwan, EV71 caused a large-scale nationwide epidemic in 1998. Retrospective studies further detected EV71 in clinical specimens collected from handefootemouth disease patients in 1980 and 1986. Therefore, EV71 may have circulated in Taiwan prior to 1980. Since 1998, EV71 has cyclically caused nationwide epidemics with different predominant genotypes in 1998 (geno- type C2), 2000e2001 (B4), 2005 (C4), 2008 (B5), and 2012 (B5). Phylogenetic analysis revealed that C4 viruses isolated in 2005 were probably from China, B5 viruses isolated in 2008 were probably from South Eastern Asia, and B5 viruses isolated in 2012 were probably from Xiamen, China. Several studies have collected postinfection sera from children to measure cross- reactive neutralizing antibody titers against different EV71 genotypes and found that antigenic differences between genogroup B and C viruses did not have a clear pattern but that genotype A virus was antigenically different from genogroup B and C viruses. In conclusion, EV71 cycli- cally caused nationwide epidemics through international importations. EV71 surveillance in Taiwan should combine genetic and serological methods.
2.Epidemiology of Enterovirus 71 Infections in Taiwan
Article Published by POLS ONE on December 1, 2016
Traditional methods for detection and serotyping of enterovirus infections are virus isolation and immunofluorescence assay (VI-IFA), which are labor-intensive and time-consuming. Recently, VP1 gene has been targeted to develop a CODEHOP-based RT-PCR (VP1- CODEHOP) for the same purpose. In this study, we conducted a 5-year enterovirus surveil- lance comparing the VI-IFA and VP1-CODEHOP tests. Throat swabs were collected from 431 pediatric patients and 208(48%) and 250(58%) were tested positive by the VI-IFA and VP1-CODEHOP tests, respectively. Among the 47 cases who had inconsistent results between the VI-IFA and VP1-CODEHOP tests and provided paired sera for serological verifications, correct diagnosis for the VI-IFA and VP1-CODEHOP were 5(11%) and 40(85%) cases, respectively. Therefore, the VP1-CODEHOP is more reliable for detection of human enteroviruses than the VI-IFA. Based on serological verifications for the eight cases who had inconsistent serotypes between the two tests and provided paired sera, five and two showed consistent serotypes with the VP1-CODEHOP and VI-IFA tests, respec- tively. CVA16, CVA6 and EV71 were the most prevalent serotypes in northern Taiwan, 2008~2012. Moreover, variant CVA2, CVA6 and EV71 viruses were further identified based on phylogenetic analysis of partial VP1 sequences. In conclusion, the VP1-CODEHOP test could be used as the primary method for enterovirus surveillance to support decision-mak- ing for outbreak control.
A Molecular Approach Applied to EV Surveillance in Northern Taiwan 2008-2012
Press released by CDC, Taiwan
Date: July 25, 2017
As enterovirus activity in Taiwan gradually peaks, during July 16 and 22,2017, the number of visits to outpatient services and ER for enterovirus infection in the nation exceeded the epidemic threshold, indicating enterovirus activity has reached its peak. In addition, one new case of enterovirus infection with severe complications was confirmed. Currently, coxsackie A virus is the dominant strain circulating in the community, while enterovirus 71 continues to circulate. Taiwan CDC stresses that enterovirus is highly contagious, especially among family members. Therefore, the public is urged to heighten vigilance, wash hands with soap and water frequently, and practice good personal hygiene. Adults returning home from work are advised to change clothes and wash hands with soap and water before coming into contact with children to lower the risk of infection and transmission. Continue reading