title: [Current prevalence of Clonorchis sinensis infection in endemic areas of China].
abstract: OBJECTIVE
  To investigate the current prevalence of Clonorchis sinensis infection in the known endemic areas of China.
  
  
  METHODS
  According to different endemic level and river system, the lamination stochastic group sampling was carried out in 27 Provinces/Municipalities/Autonomous Regions (P/M/A) from 2002 to 2004. Eggs in stool were examined by modified Kato-Katz thick smears method.
  
  
  RESULTS
  A total of 5,230 cases of Clonorchis infection was found from 217,829 sampled population of 27 P/M/A, and the mean prevalence was 2.40% by which the number of infected people was estimated to be 12.49 millions. The geometry mean worm egg density was 2,208 EPG (stool). Light, moderate and heavy infection occupied 78.93%, 17.40%, and 3.67% respectively. Infection was found in 19 out of 27 P/M/A investigated, with the highest prevalence in the provinces of Guangdong (16.42%, 2,278/13,876), Guangxi (9.75%, 1,365/13,990) and Heilongjiang (4.72%, 636/13,458). Males showed higher prevalence (2.94%, 3,267/111,262) than females (1.84%, 1,963/106,567). There was infection in all age groups,with the highest prevalence in the group of 50 to 59 years (9.16%). By occupations, more infections were found in businessmen (13.42%, 124/924), followed by factory workers ((7.9%, 298/3,773), and retirees and veterans (5.28%, 70/1,327). Adults showed heavier infection in some provinces where the main infection way was raw fish-eating, but in children in other provinces. For geographical distribution, the terrain in network of rivers and lakes showed higher prevalence (5.23%, 687/13,125) than the hilly terrain (2.34%, 1,111/47,552). Prevalence showed family-aggregation feature.
  
  
  CONCLUSIONS
  Clonorchiasis is widely endemic in China with a high prevalence in some provinces. Male adults have been more involved with a family aggregation.
authors.forename: Yue-Yi
authors.initials: YY
authors.lastname: Fang
authors.forename: Ying-Dan
authors.initials: YD
authors.lastname: Chen
authors.forename: Xue-Ming
authors.initials: XM
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Qi-Ming
authors.initials: QM
authors.lastname: Zhang
authors.forename: Cai-Wen
authors.initials: CW
authors.lastname: Ruan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015982:Bias; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003003:Clonorchiasis / Q000453:epidemiology*; D003004:Clonorchis sinensis; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count; D015995:Prevalence; D055815:Young Adult