STH

Soil-transmitted helminthiasis (STH) is a group of parasitic infections of the intestine caused by nematode worms. STH is the most prevalent of neglected tropical diseases and is responsible for significant morbidity and, indirectly, mortality in poor developing countries.

STH contributes to general weakness, malnutrition, iron-deficiency anemia, and impaired physical and intellectual development in school-age children

The Global Burden of STH Infections

STH is highly prevalent in some areas of sub-Saharan Africa, Southeast Asia and Latin America, where the tropical climate supports the life cycle of the worms in the soil. According to the World Health Organization (WHO), some 2 billion people are thought to have active infections. STH is most prevalent in school-age children, the group most vulnerable to the long-term consequences of the infection.

An estimated 39 million¹ disability adjusted life years (DALYs) may be lost each year due to STH infections. Thus, the morbidity caused by STH approaches that due to malaria or tuberculosis. Large-scale, periodic deworming campaigns have proven effective in significantly improving the health of both children and adults and are deemed “best buys” by a World Bank study. The WHO is actively promoting these efforts and in 2001 the World Health Assembly passed a resolution with the goal of providing regular treatment against STH and schistosomiasis to at least 75% of all school-age children in endemic areas by 2010.

Currently, there are only four drugs used to treat STH, and all were introduced over twenty years ago. There are growing concerns and evidence that these drugs are losing efficacy in the field and that resistance to the drugs could increase.

OneWorld Health’s Response

The health benefits of deworming, the anticipated increase in use of a limited number of drugs, and concerns over the reduced efficacy of existing drugs have intensified the need to develop new drug(s) against STH.

OneWorld Health has identified a global need to develop safe, effective, and affordable drugs to control STH in infected populations, especially school-age children and women of child-bearing age in endemic areas. These drugs should complement existing drugs by targeting a different mechanism of action, be suitable for mass delivery through existing distribution programs and be compatible with treatment for other neglected diseases.

OneWorld Health has received an exploratory grant from the Bill and Melinda Gates Foundation to explore drug candidates in this area. We are actively seeking suitable development candidates against a Target Product Profile developed with expert input. Please contact us at partnerships@oneworldhealth.org if you wish to discuss
sharing compounds or research information relevant in these diseases.

Illustration: Margaret Shear, Public Library of Science adapted from de Silva NR, Booker S. Hotez PJ, Montresor A, Engels D, et al. (2003) Soil-transmitted helminth infections: Updating the global picture. Trends Parasitol 19: 547-551