What is the global burden?
Burden of soil-transmitted helminths
Current estimates are that at least one-quarter of the world's population is infected with intestinal parasites. In Africa, 90 million school-aged children are estimated to be infected with STH. Infection is generally most prevalent among rural communities in warm and humid equatorial regions and where sanitation facilities are inadequate. Infection can also occur in urban areas.
Burden of schistosomiasis
Schistosomiasis is endemic in 70 developing countries, and more than 200 million people are infected worldwide. S. mansoni occurs in Africa, Middle East, the Caribbean, Brazil, Venezuela, Suriname; S. haematobium occurs in Africa and the Middle East, whilst S. japonicum only occurs in China, Indonesia and the Philippines.
Most infected people live in poor communities without access to safe drinking water and adequate sanitation. An estimated 90% of infected individuals live in sub-Saharan Africa, where up to 20 million people also suffer severe, chronic health consequences of the disease. A further 20,000 people die every year from schistosomiasis-related health problems, such as bladder cancer, kidney failure and liver or spleen damage.
Burden of lymphatic filariasis
LF is endemic in 83 countries and there are an estimated 120 million cases, including 25 million men with hydroceles and 15 million people, primarily women, with lymphedema. The disease occurs throughout the tropical areas of Africa, Asia, the Americas and the Pacific, with around 66% of the infection clustered in South-East Asia and most of the remaining infection (~33%) centred in Africa.
Numerous countries have implemented LF control programmes, with significant achievements in the Americas, the Pacific and Asia. A few countries in Africa are close to their elimination goals.