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.
National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention, Shanghai 200025, China. cyingdan@yahoo.com.cn
Ying-Dan
YD
Chen
Lin-Hua
LH
Tang
Long-Qi
LQ
Xu
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