Helminth Infections in Neonates and Young Children

Andrea J. Lack, MD; Jill E. Weatherhead, MD; Laila Woc-Colburn, MD, DTM&H

Disclosures

June 25, 2014

Antenatal Helminth Infections and Neonatal Health

In general, helminth infections are more common in children than in young infants. Nevertheless, maternal infection is common and can profoundly affect neonatal health. In the case of EB, his mother had a history of anemia and a previous preterm delivery.

Iron-deficiency anemia induced by hookworms poses particular problems for pregnant, breastfeeding, or menstruating women, who have increased iron demands. Iron-deficiency anemia during pregnancy is a known risk factor for intrauterine growth restriction, low birthweight, preterm birth, and low neonatal iron stores.[4,8,9] In areas with poor resources to care for preterm or low-birthweight infants, this can significantly increase neonatal morbidity and mortality.

Furthermore, an emerging body of evidence suggests that antenatal or early childhood helminth infections can impair responsiveness to vaccines and increase susceptibility to later infection.[10,11] Chronic helminth infection induces regulatory T lymphocytes and anti-inflammatory cytokines, while reducing the TH1 cytokine production required for optimal vaccine response.[12,13] Human studies have shown improved vaccine response to bacille Calmette-Guérin and oral cholera vaccine when vaccination is preceded by albendazole.[14,15,16] This suggests that chronic helminth infections may blunt vaccine efficacy.

Antenatal exposure to parasites may have a similar effect. Although true vertical transmission of lymphatic filariasis is rare,[17] intrauterine exposure to parasite antigen occurs commonly.[18,19] Several studies have demonstrated an increased risk for helminth tolerance and subsequent helminth infection after in utero filarial antigen exposure.[20,21]

A Kenyan cohort study[21] of 159 newborns found that infants exposed and sensitized to the W bancrofti antigen in utero had a 4.8-fold increased risk of acquiring W bancrofti infection later in life. Infants exposed to W bancrofti antigen, but with evidence of immune tolerance, had an even higher (12.9-fold) increase risk for subsequent infection.Another study[22] reported a reduced immune response to Haemophilus influenza B vaccine in neonates born to mothers with lymphatic filariasis infection during pregnancy. Finally, a significantly higher rate of mother-to-child HIV transmission (48% vs 10%) has been demonstrated in mothers coinfected with 1 or more helminthes compared with those without such infection.[23]

Given the many deleterious effects of helminth infection on maternal and fetal health, the WHO recommends routine deworming of pregnant women with albendazole or mebendazole after the first trimester of pregnancy. It also affirms the safety of praziquantel for trematode infections at any stage of pregnancy and during lactation.[24]

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