A study conducted to the Tsimane people of the Amazon shows that women infected with roundworms are more fertile than healthy women, while patients infected with hookworms are less fertile. These worms are called helminths, and it affect 70 percent of the population.

Aaron Blackwell, an anthropologist at the University of California, Santa Barbara (UCSB) gathered the data from 984 women over the course of nine years as part of the Tsimane Health and Life History Project. They inspected the issue after a colleague, Melanie Martin, also of UCSB, thought that her infection caused her to become pregnant despite failure to conceive before.

American Association for the Advancement of Science reports that the team found that hookworm infections seemed to delay women’s first pregnancies. On the other hand, women with roundworm infections got pregnant sooner and more frequent.

So far, no one knows exactly how these worms influence pregnancy. The team theorised that it has to do with how the immune system responds. Hookworm infection triggers immune cells that attack pathogens and produce antibodies. Roundworms produce responses similar to the response that occurs during pregnancy, enabling the mother to tolerate a growing embryo.

These findings are correlated to studies showing that parasites impact women’s reproductive health, Statnews reports. Dr Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, reminds the public that parasitic infections can be fatal during pregnancy as in the case of African women.

Blackwell points out that they did not investigate the severity of the infections. Nonetheless, the findings show the possible benefits of these parasites. It has been used as clinical trials for multiple sclerosis and Crohn’s disease, and some even repel other parasites and keep allergies and asthma in check.

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