Complex Interactions between Soil-Transmitted Helminths and Malaria in Pregnant Women on the Thai-Burmese Border

Intestinal worms, particularly hookworm and whipworm, can cause anaemia, which is harmful for pregnant women. The WHO recommends deworming in pregnancy in areas where hookworm infections are frequent. Some studies indicate that coinfection with worms and malaria adversely affects pregnancy whereas other studies have shown that coinfection with worms might reduce the severity of malaria. On the Thai-Burmese border malaria in pregnancy has been an important cause of maternal death. We examined the relationship between intestinal helminth infections in pregnant women and their malaria risk in our antenatal care units. In total 70% of pregnant women had worm infections, mostly hookworm, but also roundworm and whipworm; hookworm was associated with mild anaemia although ova counts were not high. Women infected with hookworm had more malaria and their babies had a lower birth weight than women without hookworm. In contrast women with roundworm infections had the lowest rates of malaria in pregnancy. Deworming eliminates all worms. In this area it is unclear whether mass deworming would be beneficial

Risk of malaria by geohelminth group.

<p>* =  +/− Trichuris trichuria.</p><p><i>PF</i> = <i>P. falciparum, PV</i> = <i>P. vivax, AOR</i> = Adjusted Odds Ratio, 95% CI = 95% Confidence Interval, HW = Hookworm, AL = <i>A. lumbricoides</i> Significant results are presented in bold.</p

Proportions of soil transmitted geohelminths and hookworm infection intensity in pregnant women by year of survey.

<p>Data are presented in number, (%). Significant results are presented in bold.</p

Baseline characteristics of pregnant women enrolled in the 1996 and 2007 surveys.

<p>Data are presented in number, (%), unless stated differently.</p><p>Significant results are presented in bold.</p><p>EGA = Estimated Gestational Age, Hct = Haematocrit, Pf = <i>P. falciparum,</i> Pv = <i>P. vivax</i></p>a<p>Data presented as mean ± standard deviation, [range].</p>b<p>At least one smear positive for malaria during intermittent screening during the whole pregnancy.</p>c<p>Data are median [range].</p>d<p>Intermittent screening – number of weeks the woman was screened for malaria during the whole pregnancy.</p

Proportion of geohelminths and malaria by age and gravid group among 794 pregnant women.

<p>Proportion of geohelminths and malaria by age and gravid group among 794 pregnant women.</p

The proportion of women with geohelminth infection by malaria species.

<p>Footnote: *  =  +/- <i>Trichuris trichuria</i>.</p

The proportion of women with malaria by density of geohelminth.

<p>Footnote: Low, medium and high defined as >0–499, 500–999, ≥1000 ova/ml for hookworm and 1–3, 4–10, >10 ova per slide for <i>A. lumbricoides</i>, respectively. *  =  +/− <i>Trichuris trichuria</i>.</p

Chloroquine pharmacokinetics in pregnant and nonpregnant women with vivax malaria.

PURPOSE: We compared the pharmacokinetics of chloroquine in pregnant and nonpregnant women treated for Plasmodium vivax malaria. METHODS: Twelve pregnant women and 15 nonpregnant women of child-bearing age with acute P. vivax malaria were treated with 25 mg chloroquine base/kg over 3 days on the northwestern border of Thailand. Blood concentrations of chloroquine and desethylchloroquine were measured using hydrophilic interaction liquid chromatography coupled with fluorescence detection. Twenty-five women completed the pharmacokinetic study. RESULTS: Although increasing gestational age was associated with reduced chloroquine AUC0-->infinity, there was no significant difference overall in the pharmacokinetics of chloroquine between pregnant and nonpregnant women. Fever was associated with lower chloroquine AUC0-->infinity values. Desethylchloroquine area under the curve (AUC) values were not significantly affected by pregnancy. CONCLUSIONS: Pregnancy did not significantly affect blood concentrations of chloroquine or its metabolite, desethylchloroquine, in women with P. vivax malaria