Duration of enterovirus shedding in stool.

Excretion of enterovirus (EV) may persist for months after an EV infection; the exact duration of excretion, however, is not yet known. Twelve children who were infected with EV between September 1998 and June 1999 were enrolled into this study. The patients included 4 boys and 8 girls, aged from 1 month to 5 years. Six patients were asked to join this virus isolation program, and the other 6 were followed-up regularly. Only 2 of the patients were infected with EV 71. To delineate the duration of EV shedding in each case, throat swabs for virus isolation were performed every 1 or 2 weeks for at least 1 month, and stools were analyzed for at least 2 months following the same schedule. After the infection, EV was identifiable in the throat in 4 patients for 1 to 2 weeks. Excretion of EV through stool was evidenced for up to 7 weeks in 6 patients, 8 weeks in 3, and 11 weeks in 1. In the 2 patients who failed to show up for follow-up visits from the 7th week, excretion of EV through stool was recorded for at least 7 weeks. Different serotypes of EV could be isolated from the same patient who was not experiencing febrile illness in 2 instances in a series of virus cultures. Coexistence of vaccine poliovirus and non-polio EV, both isolated from stool, was evidenced in 2 patients. Results from this study suggest that EV may not be identified from the throat 2 weeks after the infection, but its excretion through stool can persist for up to 11 weeks. This study also demonstrated that subclinical EV coinfection could occur, and that live vaccine poliovirus did not interfere with the invasion of other non-polio EV.