Current status of soil-transmitted nematode infection in China.
OBJECTIVE
To carry out national surveys for ascertaining the current status and trends of soil-transmitted nematode infections in China, providing scientific basis for further developing control strategies.


METHODS
In 1988-1992 (hereinafter abbreriated as "survey in 1990"), a stratified cluster random sampling method was used in the survey. In 2001-2004 (hereinafter abbreriated as "survey in 2003"), in order to compare with the survey in 1990, two-characteristic stratified cluster random sampling method was used and 687 investigation spots were sampled from the 2848 spots selected in the survey in 1990. Kato-Katz thick smear method was used to examine the eggs of soil-transmitted nematodes in fecal samples.


RESULTS
The prevalence rates were 53.6% and 19.6% for soil-transmitted nematodes, 14.6% and 6.120% for hookworms, 44.6% and 12.7% for Ascaris lumbricoides, 17.4% and 4.630% for Trichuris trichiura in survey 1990 and survey 2003, respectively. The prevalence rates of soil-transmitted nematodes were higher in 13 provinces than the average level in China in the survey in 1990, and higher in 8 provinces than the average level in the survey in 2003. The prevalence of hookworms, Ascaris lumbricoides, Trichuris trichiura and the overall prevalence of soil-transmitted nematodes were higher in females than in males. It is estimated from the results of survey in 2003 that the number of persons with soil-transmitted nematode infections in the country is about 129 million, less than that in the survey in 1990.


CONCLUSIONS
The prevalence of soil-transmitted nematodes has declined considerably but is still relatively high in some provinces and autonomous regions. Control activities and socioeconomic development may have contributed to the decreased prevalence.
Chen
Ying-Dan
YD
National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention, Shanghai 200025, China. cyingdan@yahoo.com.cn
Tang
Lin-Hua
LH
Xu
Long-Qi
LQ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009349:Nematode Infections / Q000453:epidemiology / Q000635:transmission*; D016273:Occupational Exposure; D015995:Prevalence