Visualizing the burden of neglected tropical diseases – NTDs

Guest post by Katie Leach-Kemon, a policy translation specialist from the University of Washington’s Institute for Health Metrics and Evaluation.

Nigerian woman with long-term effects of the parasitic river blindness
Nigerian woman with long-term effects of the parasitic river blindness
Mike Urban

Last week, Humanosphere featured a story about international efforts to fight neglected tropical diseases (NTDs), which include a variety of diseases caused by parasites or worms such as hookworm, elephantiasis, trachoma, and sleeping sickness.

Through an international effort called the London Declaration on Neglected Tropical Diseases, organizations are working to secure donations from pharmaceutical companies to treat these diseases, which primarily affect the world’s poorest people. So far, the initiative has succeeded in channeling over a billion treatments for 10 of the most problematic NTDs to some of the poorest people in the world.

Today, we’ll visually explore many of the different NTDs that the London Declaration aims to address.

Unlike a lot of diseases that the global health community focuses on, much of the disease burden that comes from NTDs is disability, not death. The screen grabs below illustrate how certain NTDs (schistosomiasis, commonly known as snail fever or bilharzia, and lymphatic filariasis, also known as elephantiasis) rank in the list of the top 30 causes of disability in sub-Saharan Africa, but do not appear in the list of the top 30 causes of death in the region. The NTD that causes the largest number of deaths in sub-Saharan Africa, trypanosomiasis (also known as sleeping sickness), was the 72nd cause of death in 2010.

Top 30 causes of disability in sub-Saharan Africa, 1990 and 2010

Image 1

Top 30 causes of death in sub-Saharan Africa, 1990 and 2010

Image 2

The next screen grab below illustrates how schistosomiasis accounts for the largest number of years lived with disability in sub-Saharan Africa, starting at age 1 and through the early 20s. Schistosomiasis is a parasite transmitted by infected snails in places with little access to clean water and sanitation. It can damage internal organs and increase the risk of bladder cancer. In children, it can stunt growth and impair brain development.

Another NTD, Chagas disease, is a problem in Central and South America. Chagas disease is a parasite transmitted to people through insects. If left untreated, it can damage the heart and digestive system and even lead to death. It is mainly found in rural, impoverished areas. The map below indicates that disability rates from Chagas disease were highest in Paraguay, Guyana, and Mexico. In Central America, for example, Chagas was the 33rd leading cause of disability and the 80th-highest cause of death.

Years lived with disability due to Chagas disease per 100,000, 2010

Image 3

Note: The category “other NTD” includes conditions such as Guinea Worm (Drancunculiasis), typhus fever, and other types of neglected tropical diseases.

Intestinal worms, shown in green in the same screen grab (“intestinal nematodes”), cause the most disability in children ages 5 to 14. Severe cases of intestinal worms can lead to blockage of the intestines and can also stunt children’s growth.

Disability from lymphatic filariasis (shown in light blue), also known as elephantiasis, is most pronounced starting in the late teens. This condition can cause extreme swelling in the lower body.

Some of the NTDs targeted by the London Declaration cause the most disability in sub-Saharan Africa, such as schistosomiasis, onchocerciasis (river blindness), lymphatic filariasis, and African trypanosomiasis (sleeping sickness). The following map shows  the countries with the highest rates of years lived with disability from schistosomiasis: Sierra Leone, Liberia, Ghana, Mozambique, and Madagascar.

Years lived with disability from different neglected tropical diseases, sub-Saharan Africa, 2010

Image 4

Another NTD, Chagas disease, is a problem in Central and South America. Chagas disease is a parasite transmitted to people through insects. If left untreated, it can damage the heart and digestive system and even lead to death. It is mainly found in rural, impoverished areas. The map below indicates that disability rates from Chagas disease were highest in Paraguay, Guyana, and Mexico. In Central America, for example, Chagas was the 33rd leading cause of disability and the 80th-highest cause of death.

Years lived with disability due to Chagas disease per 100,000, 2010

Image 5

As the work to control or eliminate NTDs continues as part of the London Declaration on Neglected Tropical Diseases, the global health community can use Global Burden of Disease (GBD) data to monitor the progress that’s being made. GBD will be updated on an annual basis, with an update through 2013 scheduled to be released later this year.

Share.

About Author

Guest

Humanosphere will sometimes post articles from authors from around the globe. Although these folks are not regular contributors, we hope you enjoy this change of pace.