Old friends and friendly fire: Pregnancy, hookworm infection, and anemia among tropical horticulturalists

Abstract

Objectives Despite public health concerns about hookworm infection in pregnancy, little is known about immune profiles associated with hookworm (Necator americanus and Ancylostoma duodenale) infection during pregnancy. Fetal tolerance requirements may constrain maternal immune response to hookworm, thereby increasing susceptibility to new infections or increasing hemoglobin loss. To explore this possibility, we study systemic immune response and hemoglobin levels in a natural fertility population with endemic helminthic infection. Methods We used Bayesian multilevel models to analyze mixed longitudinal data on hemoglobin, hookworm infection, reproductive state, eosinophils, and erythrocyte sedimentation rate (ESR) to examine the effects of pregnancy and hookworm infection on nonspecific inflammation, cellular parasite response, and hemoglobin among 612 Tsimane women aged 15‐45 (1016 observations). Results Pregnancy is associated with lower eosinophil counts and lower eosinophil response to hookworm, particularly during the second and third trimesters. Both hookworm and pregnancy are associated with higher ESR, with evidence for an interaction between the two causing further increases in the first trimester. Pregnancy is moderately associated with higher odds of hookworm infection (OR: 1.23, 95% CI: 0.83 to 1.83). Pregnancy and hookworm both decrease hemoglobin and may interact to accentuate this effect in the first‐trimester of pregnancy (Interaction: β: −0.30 g/dL; CI: −0.870 to 0.24). Conclusions Our findings are consistent with a possible trade‐off between hookworm immunity and successful pregnancy, and with the suggestion that hookworm and pregnancy may have synergistic effects, particularly in the first trimester.

Faecal parasites increase with age but not reproductive effort in wild female chimpanzees

“…Furthermore, post hoc examinations of Oesophagostomum intensity support an increase in faecal egg count throughout pregnancy. Pregnancy has previously been associated with higher parasitism in a natural fertility human population [32,77] and a few non-human primate species (reviewed in [27]). The higher parasite burden observed during pregnancy in our study could be the result of energy deficits to immunity created by the growing fetus.…”

Evidence for height and immune function trade-offs among preadolescents in a high pathogen population

“…From an early age, children are exposed to an array of pathogens, and parasitic infections among the Tsimane are common [ 36 ]. About half of Tsimane men and women have anemia, with children and adolescents showing the highest risk (56% for girls, 63% for boys) [ 37 ].…”

Adherence to screening and management guidelines of maternal Group B Streptococcus colonization in pregnancy

“…Various factors may affect the maternal immune system including anthropometric measures and racial background (Lao, 2019). Different immune responses occur in women of high-income countries, compared with women from non-industrialized population groups, over the course of pregnancy, including pro and anti-inflammatory processes possibly due to contrasting immunological demands in pregnancy between these ecologically distinct population groups (Anderson et al, 2020).…”