title: Complex Interactions between soil-transmitted helminths and malaria in pregnant women on the Thai-Burmese border.
abstract: BACKGROUND
  Deworming is recommended by the WHO in girls and pregnant and lactating women to reduce anaemia in areas where hookworm and anaemia are common. There is conflicting evidence on the harm and the benefits of intestinal geohelminth infections on the incidence and severity of malaria, and consequently on the risks and benefits of deworming in malaria affected populations. We examined the association between geohelminths and malaria in pregnancy on the Thai-Burmese border.
  
  
  METHODS
  Routine antenatal care (ANC) included active detection of malaria (weekly blood smear) and anaemia (second weekly haematocrit) and systematic reporting of birth outcomes. In 1996 stool samples were collected in cross sectional surveys from women attending the ANCs. This was repeated in 2007 when malaria incidence had reduced considerably. The relationship between geohelminth infection and the progress and outcome of pregnancy was assessed.
  
  
  RESULTS
  Stool sample examination (339 in 1996, 490 in 2007) detected a high prevalence of geohelminths 70% (578/829), including hookworm (42.8% (355)), A. lumbricoides (34.4% (285)) and T.trichuria (31.4% (250)) alone or in combination. A lower proportion of women (829) had mild (21.8% (181)) or severe (0.2% (2)) anaemia, or malaria 22.4% (186) (P.vivax monoinfection 53.3% (101/186)). A. lumbricoides infection was associated with a significantly decreased risk of malaria (any species) (AOR: 0.43, 95% CI: 0.23-0.84) and P.vivax malaria (AOR: 0.29, 95% CI: 0.11-0.79) whereas hookworm infection was associated with an increased risk of malaria (any species) (AOR: 1.66, 95% CI: 1.06-2.60) and anaemia (AOR: 2.41, 95% CI: 1.18-4.93). Hookworm was also associated with low birth weight (AOR: 1.81, 95% CI: 1.02-3.23).
  
  
  CONCLUSIONS
  A. lumbricoides and hookworm appear to have contrary associations with malaria in pregnancy.
authors.affiliation: Shoklo Malaria Research Unit, Tak, Thailand. machteld@shoklo-unit.com
authors.forename: Machteld
authors.initials: M
authors.lastname: Boel
authors.forename: Verena I
authors.initials: VI
authors.lastname: Carrara
authors.forename: Marcus
authors.initials: M
authors.lastname: Rijken
authors.forename: Stephane
authors.initials: S
authors.lastname: Proux
authors.forename: Mathieu
authors.initials: M
authors.lastname: Nacher
authors.forename: Mupawjay
authors.initials: M
authors.lastname: Pimanpanarak
authors.forename: Moo Koo
authors.initials: MK
authors.lastname: Paw
authors.forename: Oh
authors.initials: O
authors.lastname: Moo
authors.forename: Hser
authors.initials: H
authors.lastname: Gay
authors.forename: Wendi
authors.initials: W
authors.lastname: Bailey
authors.forename: Pratap
authors.initials: P
authors.lastname: Singhasivanon
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: White
authors.forename: François
authors.initials: F
authors.lastname: Nosten
authors.forename: Rose
authors.initials: R
authors.lastname: McGready
mesh_terms: D000293:Adolescent; D000328:Adult; D000740:Anemia / Q000453:epidemiology / Q000469:parasitology; D000818:Animals; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology* / Q000469:parasitology; D006376:Helminths / Q000302:isolation & purification; D006801:Humans; D008288:Malaria / Q000453:epidemiology* / Q000469:parasitology; D002052:Myanmar / Q000453:epidemiology; D010961:Plasmodium / Q000302:isolation & purification; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000453:epidemiology* / Q000469:parasitology; D015995:Prevalence; D012307:Risk Factors; D012423:Rural Health; D012987:Soil / Q000469:parasitology*; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
chemical_list: D012987:Soil