Lymphatic filariasis (LF), and elephantiasis, is a mosquito-borne parasitic worm (Wuchereria bancrofti) disease affecting 120 million people in (sub) tropic areas. Of the 1.23 billion people that are at risk, 80% live in the following countries: Bangladesh, Côte d’Ivoire, Democratic Republic of Congo, India, Indonesia, Myanmar, Nigeria, Nepal, Philippines and the United Republic of Tanzania. Data recently published by the World Health Organization (WHO) show that more than 556 million people worldwide were treated for lymphatic filariasis in 2015, compared with 538 million in 2014.
Transmission occurs by the bite of an infected mosquito, whereafter the worm enters the body and migrate into lymphatic and blood vessels. Here, they block the lymphatic system which results in lymphedema: fluid collection and tissue swellings in legs, arms, breast, and genitalia (hydrocele in men). The lymphedema decreases the ability of the body to fight against germs and infections. Consequently, these patients are more susceptible to bacterial infections in the skin and lymphatic system. Moreover, their lymphedema can progress into hardening and thickening of the skin (e.g. elephantiasis), fusion of the toes, ulceration, bacterial superinfection and hydrocele (scrotal swelling). Such body disfigurements can result in social stigma, exclusion from work and increased medical expenses. Nonetheless, the bacterial infections and the deteriorating of the lymphedema can be prevented with appropriate skin hygiene, compression of the legs, physical exercises and wound care.
Podoconiosis, also known as non-filarial elephantiasis, is the second most common tropical lymphoedema, caused by chronic exposure to irritant soils. It is found in bare-foot populations living on irritant soil in highland areas of tropical Africa, Central America and north-west India. Just like lymphatic filariasis, the disease is characterised by prominent swelling of the lower extremities which can progress into disfigurement and disability. Primary prevention consists of avoiding or minimizing exposure to irritant soils by wearing shoes. Prevention of disability activities are similar to those in lymphatic filariasis.
Successful project - Global Programme to Eliminate Lymphatic Filariasis
The Global Programme to Eliminate Lymphatic Filariasis, launched by the WHO in 2000, aims to eliminate lymphatic filariasis as a public health problem. The strategy has two elements: to interrupt transmission and to alleviate suffering. In order to interrupt transmission, endemic areas must be localised by mapping followed by the implementation of community-wide mass drug treatment to treat the at-risk population. Alleviating the suffering of affected persons is targeted by health education for communities. Here the focus is on intensive local hygiene practices and the prevention of debilitating and painful episodes of inflammation.
Recently, China and the Republic of Korea were declared to have eliminated lymphatic filariasis as a public health problem. Of the 73 countries endemic for lymphatic filariasis, 68 have completed mapping. The number of countries that have entered the surveillance phase to assess whether the elimination targets have been achieved has increased up to 18. The remaining 55 countries still require mass drug treatment. Furthermore, only 24 countries registered morbidity management and disability prevention (MMDP) services, this needs to be scaled up in order to achieve elimination by 2020. Read here the latest WER report on the Global Programme to Eliminate Lymphatic Filariasis.