Helminth Infection, Fecundity, and Age of First Pregnancy in Women
RESEARCH | REPORTS PARASITOLOGY 70% of the population, the most common being hookworm (56%) and A. lumbricoides (15 to 20%) (11, 17). In both animal and human studies, parasites Helminth infection, fecundity, and have been shown to influence host reproduction via sexual behavior, brood or litter size, offspring age of first pregnancy in women size, incubation periods, conception rates, and pregnancy loss (18–22). In most cases, parasitism Aaron D. Blackwell,1,2,3* Marilyne A. Tamayo,4 Bret Beheim,2,5 reduces host reproduction by compromising Benjamin C. Trumble,1,2,3,6,7 Jonathan Stieglitz,2,5,8 Paul L. Hooper,2,9 reproductive organs or reducing energy budgets Melanie Martin,1,2,3 Hillard Kaplan,2,5 Michael Gurven1,2,3 (14, 23). However, among Tsimane adults, mor- bidity from intestinal helminth infections is low, Infection with intestinal helminths results in immunological changes that influence particularly for A. lumbricoides. Controlling for co-infections, and might influence fecundity by inducing immunological states affecting age and co-infection in our sample, hookworm conception and pregnancy. We investigated associations between intestinal helminths and infection is associated with slightly lower body fertility in women, using 9 years of longitudinal data from 986 Bolivian forager-horticulturalists, mass index (BMI) (generalized linear model, 2 experiencing natural fertility and 70% helminth prevalence. We found that different species b = –0.77 kg/m , P < 0.001) and hemoglobin (b = of helminth are associated with contrasting effects on fecundity. Infection with roundworm –0.19 g/dl, P =0.005),whereasA. lumbricoides is 2 (Ascaris lumbricoides) is associated with earlier first births and shortened interbirth intervals, not (b = –0.34 kg/m , P = 0.180; b = –0.07 g/dl, whereas infection with hookworm is associated with delayed first pregnancy and extended P = 0.413).
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