The surveillance on human soil-borne nematode infections from 2006 to 2010 in Pingan County, Qinghai Province

Objective To monitor the human soil-borne nematode infections in Sanhe Town of Pingan County,Qinghai Province and to analyze the epidemic trend and features of the infections thus to provide scientific basis for further development of control and prevention strategy.Methods From 2006 to 2010,the residents of Sanhe Town were investigated for soil-borne nematode infections.The stool samples of the residents aged above 3 years old were collected and examined for soil-borne nematode eggs with Kato-Katz method and pinworm eggs were examined with anal swab method for aged under 12.Ascaris eggs in soil of kitchen,yard,garden and outside of toilet were examined using improved saturated sodium nitrate floatation method.Results The overall infection rates of human soil-borne nematode infections from 2006 to 2010 were 14.35％(152/1 059),6.46％ (77/1 192),11.43 ％ (126/1 102),6.65 ％ (80/1 204) and 6.20 ％ (72/1 162),respectively,in Pingan County.A.lumbricoides and E.vermicularis were the major infection parasites.The infections of A.lumbricoides were mild.The difference between year's human Ascaris infection rate was significant (x2=64.04,P＜0.05).From 2006 to 2010,the hightest Ascaris infection rates were in pre-school children among different occupations,which were 28.28％ (28/99),11.30％ (13/115),17.53％ (17/97),10.00％ (4/40) and 12.50％ (5/40),respectively.The second was students,the third was farmers.Each year the highest infection rate of Ascaris was in people with education of elementary school among different eduction levels.The highest infection rate of Ascaris was in age group of 5～10 years old.The infection rate of Ascaris declined in general as they grew older.In 2006 and 2008,the infection rates of E.vermicularis were 4.35％(8/184) and 1.36％(2/147) under age of 12 children.The detection rate of Ascaris eggs in soil from 2006 to 2010 were 20.00％(8/40),10.00％(4/40),2.27％(1/44),17.31％(9/52) and 15.00％(6/40),respectively.Conclusion The overall infection rate of human soil-borne nematode declined in general in surveillance site in Qinghai from 2006 to 2010,A.lumbricoides was the major infective parasite. Key words: Soil-borne nematode infection;  A.lumbricoides;  Surveillance;  Analyze