What are the Filarial Diseases?

Impact

 

oncho_map_2014Onchocerciasis (River Blindness)
Over 37 million infected
About 169 million people at risk
4 million people suffer from severe itching or dermatitis
265, 000 are blind

 

 

africa_en_map

Loiasis – Loa loa
Nearly 30 million people at risk
About 13 million people infected

 

 

 

Geography

Onchocerciasis (River blindness) is almost exclusively confined to West and Central Africa, although there are localized infections in Yemen and some South American countries.

Loiasis (Loa loa infection) occurs in the rain forest and swamp areas of West Africa and in Central Africa.

Transmission

Onchocerciasis (River blindness), Lymphatic filariasis (Elephantiasis) and Loiasis (Loa loa infection) are all caused by parasitic filarial nematode worms that are transmitted between humans by blood-sucking insects.

Onchocerciasis is caused by Onchocerca volvulus, transmitted by the bite of an infected female blackfly; Brugia malayi (most of the remainder) and Brugia timori, and is transmitted by various mosquito species; Loa loa worms are transmitted by the bites of Mango flies or by deer flies (Chrysops spp.).

Social and economic impact

Filarial diseases are the most devastating of the neglected tropical diseases in terms of social and economic impact. Families and communities have to bear the brunt of long-term healthcare, coupled with loss of productivity and earnings due to the incapacity to work. The disabling and disfiguring effects on the individual lead to social stigmatization and isolation.

Symptoms

Filarial disease is not particularly life-threatening, but onchocerciasis causes long-term suffering and chronic disease with life-long disabilities in millions of people worldwide, such as blindness, severe itching and dermatitis. Loiasis is usually considered asymptomatic but can cause localized swellings associated with localized and generalized itching.

Patient treatments needs

Programmes for the treatment and control of filarial diseases through mass drug administration (MDA) have been in place for over 20 years. However current treatments target the juvenile worm (microfilariae) and need to be repeated for 10-15 years in the case of onchocerciasis. Therefore, there is an unmet medical need for a drug that can kill the adult worms (macrofilaricide). A new, safe, short-course macrofilaricidal drug could be used in individual patient treatment and to help the elimination effort in MDA programmes and ideally also in patients with Loa loa co-infection.

DNDi aims to deliver:

  • A new oral, short-course macrofilaricide treatment, with potential application to treat onchocerciasis

Fact sheet

DNDi Filarial Diseases Fact Sheet