2014-2015年云南省健康儿童肠道病毒带毒状况调查

Surveillance for enteroviruses in healthy children in Yunnan Province from 2014 to 2015

目的：了解2014—2015年云南省健康儿童中肠道病毒（ enterovirus, EV）带毒情况和病毒型别,并对埃可病毒6型（echovirus type 6, ECHO6）、ECHO25和ECHO11的基因特征进行分析。方法采集3个内地州（市）6-7个县及5个边境州8-9个县〈15岁健康儿童粪便标本共921份进行病毒分离和基因测序定型,其中2014年共采集453份（均为单份便,其中内地儿童213份,边境儿童240份）,2015年共采集468份（内地儿童195份,边境儿童273份）。结果2014年,从内地儿童粪便标本中分离到EV 20株,分离率为9.39%（20/213）,从边境儿童中分离到EV 16株,分离率为6.67%（16/240）。2014年病毒总体分离率为7.95%（36/453）。从病毒型别来看,B种病毒分离率最高（88.89%,32/36）,其次为A种病毒（11.11%,4/36）,未分离到C种（包括脊髓灰质炎病毒）和D种病毒。2015年,从内地儿童粪便标本中分离到EV 13株,分离率为6.67%（13/195）,从边境儿童中分离到EV 33株,分离率为12.09%（33/273）。2015年病毒总体分离率为9.83%（46/468）。从病毒型别来看,B 种病毒分离率最高（78.26%,36/46）,其次为 C 种病毒（19.57%,9/46）和 A 种病毒（2.17%,1/46）,未分离到 D 种病毒。两年共从921份粪便标本中检测到 EV 82株（分离率为8.90%,82/921）,其中,从内地儿童分离到33株,分离率为8.09%（33/408）,从边境儿童中分离到EV 49株,分离率为9.55%（49/513）。82株EV中,脊髓灰质炎病毒（poliovirus, PV）9株（阳性率为0.98%,9/921）,均为疫苗株,未发现脊灰野病毒；检测到非脊灰肠道病毒（non-poliovirus, NPEV）73株（阳性率为7.93%,73/921）。结论2014年,内地儿童病毒分离率（9.39%）高于边境儿童（6.67%）,而2015年边境儿童分离率（12.09%）高于内地儿童（6.67%）,两年的病毒型别均以B种病毒为主。未分离到脊灰野病毒和肠道病毒D种,云南省维持无脊灰状态良好。

Objective To investigate the enterovirus （ EV）-carrying status and the circulating se-rotypes in healthy children from inner and border areas of Yunnan Province in 2014 and 2015 and to analyze the genetic characteristics of echovirus 6 （ECHO6）, ECHO25 and ECHO11 strains. Methods Stool sam-ples were collected from children less than 15 years old living in 6 to 7 counties of 3 inner prefectures/cities and 8 to 9 counties of border prefectures/cities. Altogether 921 samples were collected including 453 sam-ples in 2014 （213 samples in inner counties and 240 samples in border counties） and 468 samples in 2015 （195 samples in inner counties and 273 samples in border counties）. Viruses were isolated from the stool samples and their serotypes were identified by gene sequencing. Results The numbers of EV strains isola-ted from the samples collected in inner counties and border counties in 2014 were 20 （ isolating rate：9.39%, 20/213） and 16 （isolating rate： 6. 67%, 16/240）, respectively. The overall isolating rate for 2014 was 7. 95% （36/453）. The predominant species was enterovirus B, accounting for 88. 89% of all iso-lated strains （32/36）, followed by enterovirus A species （11. 11%, 4/36）. No strains of enterovirus spe-cies C （including poliovirus） and D was detected in 2014. In total, 46 EV strains were isolated in 2015 with an overall isolating rate of 9. 83% （46/468）, including 13 strains in inner counties （isolating rate：6. 67%, 13/195） and 33 strains in border counties （isolating rate：12. 09%, 33/273）. Most of the strains were enterovirus B species, accounting for 78. 26% （36/46）, followed by enterovirus C species （19. 57%, 9/46） and enterovirus A species （2. 17%, 1/46）. Altogether 82 EV strains were isolated in 2014 and 2015 with an isolating rate of 8. 90% （82/921）, of which 33 strains were isolated in inner counties （8. 09%, 33/408） and 49 strains were isolated in border counties （9. 55%, 49/513）. Among the 82 EV strains, 9 strains were polioviruses （0. 98%, 9/921） and all of them were Sabin-like polioviruses. The rest of the strains were non-polio enterovirus （7. 93%, 73/921）. Conclusion In 2014, the EV isolating rate in inner counties （9. 39%） was higher than that in border counties （6. 67%）. However, the EV isolating rate in border counties （12. 09%） was higher than that in inner counties （6. 67%） in 2015. Enterovirus B was the predominant species in both 2014 and 2015. No wild type polioviruses and enterovirus D species were detec-ted. Polio-free status was maintained well in Yunnan Province.