[Etiology surveillance of hand-foot-mouth disease in Henan province between 2008 and 2011].
OBJECTIVE
To understand etiological types and distribution features of hand-foot-mouth disease (HFMD) in Henan province between 2008 and 2011.


METHODS
A total of 30 486 specimens of feces, rectal swabs or throat swabs from HFMD patients were collected by each Municipal CDC in Henan from 2008 to 2011. The enterovirus 71 (EV71), coxsackie virus A16 (CA16) and other enterovirus (EV) were detected by RT-PCR or real time RT-PCR. The VP1 gene of EV71 was amplified and the sequences were analyzed by bioinformatics software. A genetic evolution tree of the sequence was constructed as well.


RESULTS
The positive rates of EV71, CA16 and other EV were 62.70% (11 209/17 876), 12.03% (2150/17 876), 25.27% (4517/17 876) in 17 876 laboratory diagnosed cases, respectively. The differences were statistically significant (χ(2) = 157.17, P < 0.05). The positive rates of EV71, CA16 and other EV were 63.40% (7370/11 624), 11.58% (1346/11 624) and 25.02% (2908/11 624) in male patients and 61.40% (3839/6252), 12.86% (804/6252) and 25.74% (1609/6252) in female patients, respectively. The differences were statistically significant (χ(2) = 4.06, P < 0.05). The children under 5 years old were high-risk population of HFMD, accounting to 97.67% (17 459/17 876) of the laboratory-diagnosed patients.86.92% (15 537/17 876) cases were children between 1 to 3 years old. Constituent ratio of EV71 changed seasonally during a year, there was a high infection ratio of EV71 between April and June, especially in May, the infection ratio reached 69.34% (2384/3438). The positive rates of EV71, CA16 and other EV were 82.48% (5715/6929), 1.76% (122/6929) and 15.76% (1092/6929) among the 6929 laboratory-diagnosed severe cases, respectively. The positive rates of EV71 was higher than CA16 and other EV (χ(2) = 9259.17, 6170.81, P < 0.05, respectively). There were 117 deaths because of severe HFMD, 55 (47.01%) of which were laboratory confirmed. 50 death cases were infected by EV71, and according to the genetic evolution analysis, the VP1 gene of EV71 strain was belonged to subtype C4 of gene C.


CONCLUSIONS
The EV71 and CA16 were the main pathogens which caused HFMD in Henan province, and EV71 virus was the dominant strain, belonging to C4 subtype of gene C.
Institute for Infectious Disease Control and Prevention, Henan Provincial Center for Disease Prevention and Control, Zhengzhou 450016, China.
Xue-yong
XY
Huang
Kai
K
Kang
Yu-ling
YL
Xu
Hai-yan
HY
Wei
Xing-le
XL
Li
Hong
H
Ma
Ai-guo
AG
You
Hao-min
HM
Chen
Bian-li
BL
Xu
D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D029821:Enterovirus A, Human / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D019143:Evolution, Molecular; D005260:Female; D006232:Hand, Foot and Mouth Disease / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology*; D006801:Humans; D007223:Infant; D008297:Male; D010802:Phylogeny