Survey of virus shedding and spread mechanism in children infected with EV71

Objective To understand the virus shedding and spread mechanism in children infected with EV71 and provide evidence for the prevention and control of hand foot and mouth disease (HFMD). Methods Throat swabs and stool samples were collected to detect EV71 nucleic acid with fluorescent PCR, and 65 children with laboratory confirmed EV71 infection were followed up until no virus was detected in their stool samples. At the same time, 116 family members (close contacts) of 58 sick children with positive results in EV71 detection were surveyed by detecting their throat swabs and stool samples. And 31 stool samples were collected from medical staff providing medical care to the sick children. Results The positive rate of EV71 in 25 infected children was 100%, 88.4%, 59.4%, 22.3%, 22.3%, and 0%, respectively, from 1st week to 6th week, and the EV71 positive rate in 40 children with severe infection was 100%, 97.0%, 79.5%, 60.6%, 35.3%, 25.2%, 16.8%, 16.8%, 8.4% and 0%, respectively, from 1st week to 10th week. No EV71 or Cox A16 were detected in 31 medical staff. Among the stool samples collected from 80 close contacts, 22 were EV71 positive (27.5%). Among the throat samples collected from 36 close contacts, 35 were EV71 negative. The positive persons had no obvious HFMD symptoms. Conclusion Virus shedding may last for several weeks in children infected with EV71, This phenomenon is called latent infection, which can facilitate the transmission of HFMD. It is suggested to conduct longer time management for HFMD patients and strengthen the monitoring for the family members of HFMD patients.