Objective: To explore the enterovirus infection status among healthy children under 15 years old in the border areas of Yunnan province that connecting Myanmar.
Methods: A total of 319 stool samples were collected from healthy children in the 10 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).