This Mother’s Day leads me to not only reflect on the fortunes of my own family, but also the misfortunes of other mothers. Urogenital schistosomiasis, chronic infection with Schistosoma haematobium worms, has long been suspected to affect the offspring of infected mothers. Earlier this year Fairley et al. reported an astounding 30.6% rate of S. haematobium infection among Kenyan mothers from the Kwale district, and a higher than expected rate of low birth weight offspring. Many of these mothers suffered from polyparasitism due to other infections such as malaria and soil-transmitted helminths, making it difficult to tease out the causal contribution, if any, of maternal urogenital schistosomiasis to low birth weight infants. Potential mechanisms by which urogenital schistosomiasis may lead to poor pregnancy outcomes include induction of anemia and/or chronic inflammation.
Another suspected but poorly understood association is the link between maternal urogenital schistosomiasis and priming of the fetal immune system by S. haematobium antigens that cross the placenta (Seydel et al.). Given the extraordinary ability of schistosomes to immunomodulate their hosts, it is possible that in utero exposure to S. haematobiumproducts may affect not only postnatal immune responses to urogenital schistosomiasis, but perhaps risks of allergy and resistance to non-schistosome infections. However, definitive proof of such effects of S. haematobium on the human fetus remains to be established.
Thus, on this Mother’s Day, I call for renewed efforts to reduce the burden of urogenital schistosomiasis on the next generation, the very people who are the best hope for eradication of this disease in endemic areas.
Fairley, J., Bisanzio, D., King, C., Kitron, U., Mungai, P., Muchiri, E., King, C., & Malhotra, I. (2012). Birthweight in Offspring of Mothers with High Prevalence of Helminth and Malaria Infection in Coastal Kenya American Journal of Tropical Medicine and Hygiene, 88 (1), 48-53 DOI: 10.4269/ajtmh.2012.12-0371
Seydel LS, Petelski A, van Dam GJ, van der Kleij D, Kruize-Hoeksma YC, Luty AJ, Yazdanbakhsh M, & Kremsner PG (2012). Association of in utero sensitization to Schistosoma haematobium with enhanced cord blood IgE and increased frequencies of CD5- B cells in African newborns. The American journal of tropical medicine and hygiene, 86(4), 613-9 PMID: 22492145