By Maggie Brown
Posted: January 27, 2012
Diarrhea, abdominal pain, malaise, anemia, and delayed child development: these are the debilitating effects of one group of diseases, the soil-transmitted helminths (worms). As indicated by the name, these diseases are transmitted via contaminated soil; as such, good sanitation has a key role in prevention. However, because sanitation systems vary greatly, their impact is difficult to study. Now, a PLoS Medicine systematic review and meta-analysis (a reanalysis of data from already published studies), by Ziegelbauer and coauthors, quantifies the benefits of sanitation: for all three of the STHs, when sanitation was both available and regularly used, the odds of getting a worm disease was cut in half.
One billion of the world’s people experience a diminished ability to work, learn, and thrive as a result of infection by these parasites – roundworm, whipworm, and hookworm. The resulting losses in quality of life and productivity can trap people in a cycle of poverty and stigma and diminish their ability to care for themselves and their families.
Currently, the primary approach to the problem is repeat drug treatment. As important as drugs are, though, they also have limitations: reinfection in endemic areas; possible reduced efficacy and development of resistance; and supply, delivery, and compliance problems. Drug administration can go only so far, and currently many programmatic goals are not being met. For the STHs, many authors argue that integrated control is the only hope for lasting improvement (see Further Reading).
Integrated control of infectious diseases involves not only drug treatment to knock down the illness itself, but preventive measures such as education of at-risk communities, surveillance and research, strong healthcare systems, vector control, safe water supplies, good hygiene practices, and adequate sanitation systems.
Thus, Ziegelbauer and coauthors urge, drug treatment should be only part of efforts toward STH control; sanitation should also be emphasized. And the authors point out something that drug treatment does not do: “Implementation of sanitation facilities and integrated control approaches go far beyond the prevention and control of intestinal helminths; they impact other neglected tropical diseases, such as schistosomiasis, trachoma, and diarrhea…and can even help promote social and educational advances for women and girls…”
Policy and funding support for integrated control that includes good sanitation should be a focus as the world fast approaches the deadline for the Millennium Development Goals with disappointing progress toward #7C (to “Halve, by 2015, the proportion of the population without sustainable access to safe drinking water and basic sanitation.”).
Hotez PJ (2008) Hookworm and poverty. In: Reducing the Impact of Poverty on Health and Human Development: Scientific Approaches. Ann NY Acad Sci 1136: 38–44.
The 2010 PLoS Water and Sanitation collection
Ziegelbauer K, Speich B, Mäusezahl D, Bos R, Keiser J, et al. (2012) Effect of Sanitation on Soil-Transmitted Helminth Infection: Systematic Review and Meta-Analysis. PLoS Med 9(1): e1001162. doi:10.1371/journal.pmed.1001162