Long persistence of EV71 specific nucleotides in respiratory and feces samples of the patients with Hand-Foot-Mouth Disease after recovery.
BACKGROUND
EV71 is associated with the fatal cases of brain stem encephalitis during large HFMD outbreaks from 1998 to 2008. EV71 may continuously shed from upper respiratory tracts and feces of HFMD patients for relatively long time after recovery. However, the persistence of viruses in the patients' secretions and excretions is not clear.


METHODS
Serial throat swabs and feces of 34 definitely diagnosed patients, including 30 mild cases and 4 severe cases, were traced and collected with the interval of 2 to 4 days for up to 32 and 48 days, respectively, and tested by a nested RT-PCR.


RESULTS
The EV-71 specific sequences were identified by a Nested RT-PCR in all specimens of 0-4 days, and 5-8 days. The positive rates of EV71 in throat swabs dropped markedly to 42.86% during 9-12 days, and maintained at 20-30% during 13-24 days, while that in feces reduced to 71.43% during 9-12 days, and maintained roughly 20% till 37-40 days. EV71 nucleotide of 36.36% cases disappeared simultaneously both in throats and feces, 39.39% cases showed longer persistence of EV71 nucleotides in feces, and 21.21% were longer in throats. The longest duration of shedding observed was 24 days for throat swabs and 42 days for fecal specimens.


CONCLUSIONS
EV71 shedding from respiratory tract may continue for nearly four weeks after onset, but its excretion through feces can persist more than five weeks.
Han
Jun
J
State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Ma
Xue-Jun
XJ
Wan
Jun-Feng
JF
Liu
Ying-Hui
YH
Han
Yan-Ling
YL
Chen
Cao
C
Tian
Chan
C
Gao
Chen
C
Wang
Miao
M
Dong
Xiao-Ping
XP
D002675:Child, Preschool; D029821:Enterovirus A, Human / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000821:virology*; D005260:Female; D005500:Follow-Up Studies; D006232:Hand, Foot and Mouth Disease / Q000821:virology*; D006801:Humans; D007223:Infant; D008297:Male; D010614:Pharynx / Q000821:virology*; D016133:Polymerase Chain Reaction / Q000379:methods; D012367:RNA, Viral / Q000302:isolation & purification*; D013997:Time Factors; D017201:Virus Shedding
D012367:RNA, Viral