中国云南省与缅甸接壤地区健康儿童肠道病毒携带情况调查

Status of enterovirus infection and molecular identification among healthy children at the areas bordering Myanmar, in Yunnan province, China

目的了解缅甸入境健康儿童和云南省口岸地区健康儿童肠道病毒（EV）携带情况及病毒型别特征。方法在10个边境口岸〈15岁的健康儿童中采集粪便标本，进行病毒分离和型别签定。共采集到319份粪便标本。脊髓灰质炎（脊灰）病毒（PV）用抗体中和试验鉴定，并送围家脊灰实验室进行型内鉴别；非脊灰肠道病毒（NPEV）用基因测序方法进行鉴定；腺病毒用血清学方法鉴定。结果共检测到Ev53株（带病毒率为16．6％），其中PV23株（阳性率7．2％）经同家脊灰实验室证实均为疫苗株，未发现脊灰野病毒；NPEV30株（阳性率9．4％），经VP1区核苷酸序列测定，除1株未被所有EV通用引物扩增外，其余29株分别属于HEV-A组（1株，1个血清型，占3．3％）、HEV-B组（20株，11个血清型，占66．7％），HEV-C组（8株，4个血清型，占26．7％），未检测HEV-D组病毒。同时还检测到腺病毒4株，阳性率为1．25％。分别做B组和C组病毒基因树，相同型别的分离株都与对应的标准株聚集在一起。同源性计算表明，分离株与对应标准株的核苷酸同源性及氨基酸同源性分别在75％和85％以上，符合国际测序定型标准。结论在中国云南省与缅甸接壤地区，EV携带率较高，特别是PV阳性率高于急性弛缓性麻痹常规监测。EV中以HEV-B组病毒为主，病毒血清型的分布具有多样性，并发现EV73（2株）、EV75（1株）、EV80（1株）和EV96（4株）等新型EV。

Objective To explore the enterovirus infection status among healthy children under 15 years old in the border areas of Yunnan province that connecting Myanrnar. Methods A total of 319 stool samples were collected from healthy children in the l0 entrance ports. Enterovirus was isolated from these stool samples and then poliovirus and adenovirus were serotyped by neutralization test using specific anti-sera. All the non-polio enteroviruses（NPEVs） were identified by partial sequencing of VP1 gene. Results All 53 enterovirus were isolated from 319 stool samples and 16.6% of them carried the virus. 23 polio virus （PVs） and 30 NPEVs were isolated with rates of carrying the virus were 7.2% and 9.4% respectively. 4 adenovirus were also isolated with a rate as 1.25%. 1 isolate could not be amplified by any Pan-enterovirus primers or by RT-PCR so was not able to be sequenced. The results of NPEVs sequencing showed that： 1 isolate （3.3%） was classified into 1 serotype of HEV-A while 20 isolates （66.7%） were classified into 11 serotypes of HEV-B and 8 isolates （26.7%） were classified into 3 serotypes of HEV-C. However, we could not isolate any viruses that belong to HEV-D. nt. Result from the aa identify calculation showed that the nt and aa identification between isolates and corresponding standard strains were more than 75% and 85% respectively. The findings were similar to the international standards. Conclusion Our results showed that the rate of carrying the enterovirus especially poliovirus in some areas of Yunnan province that bordering Myanmar was higher than that of rate through the routine acute flaccid paralysis detection system. Of the enterovirus isolated, HEV-B group appeared the predominant with the wide spread of enterovirus serotype. Some newer enterovirus were also detected such as EV73 （2 strains）, EV75（ 1 strain）, EV80（ 1 strain） and EV96（4 strains）.