Helminth infections among people using wastewater and human excreta in peri-urban agriculture and aquaculture in Hanoi, Vietnam.
OBJECTIVE
To assess the prevalence of helminth infections and their associated risks in a community using both wastewater and human excreta in agriculture and aquaculture.


METHODS
A cross-sectional study was conducted in a peri-urban area in Hanoi, Vietnam. Data on the demography, socioeconomics and sanitation were collected from a survey of 400 agricultural households. Parasitological examination for the eggs of Ascaris sp., Trichuris sp. and hookworm was performed on single stool specimens obtained from study household members' 15-70 years and 0-72 months of age.


RESULTS
Of 807 stool samples collected from 620 adults and 187 children, 39% were infected with helminths. The prevalence of infections with Ascaris sp., Trichuris sp. and hookworm was 21.6%, 9.8% and 21.8%, respectively. Univariate and multivariate analyses showed that being an adult, female gender, living in a household without a latrine, excreta composted for less than 1 month and use of fresh human excreta were significantly associated with co-infection with all three helminths. Being an adult was an independent determinant for infections with individual helminths. The absence of a latrine and use of stored urine for irrigation were associated with an increased risk of Ascaris infection. Risk factors for Trichuris infection were inadequately composted excreta and year-round wastewater contact; risk factors for hookworm infection were female gender, household without a latrine and use of fresh human excreta.


CONCLUSIONS
Wastewater exposure did not pose a major risk for helminth infection in this community. Instead, lack of sanitation facilities and use of fresh or inadequately composted human excreta in agriculture were important risk factors.
Do
Thuy Trang
TT
Division of Enteric Infections, National Institute of Hygiene and Epidemiology, Hanoi, Vietnam. tranghai16@yahoo.com
Mølbak
Kåre
K
Phung
Dac Cam
DC
Dalsgaard
Anders
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000383:Agriculture; D000818:Animals; D017756:Aquaculture; D017164:Ascaris lumbricoides / Q000469:parasitology; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D006373:Helminthiasis / Q000175:diagnosis* / Q000469:parasitology / Q000517:prevention & control; D006725:Hookworm Infections / Q000175:diagnosis* / Q000469:parasitology / Q000517:prevention & control; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012499:Sanitation / Q000592:standards*; D014201:Trematode Infections / Q000175:diagnosis* / Q000469:parasitology / Q000517:prevention & control; D014257:Trichuriasis / Q000175:diagnosis* / Q000469:parasitology / Q000517:prevention & control; D014744:Vietnam; D014871:Water Microbiology