Lymphatic filariasis (LF), sometimes still called elephantiasis, is a disease characterized by invasion of the human blood and lymphatic systems by filarial nematodes. Each of three species,

Wuchereria bancrofti, Brugia malayi,


B. timori,

can cause

a form of the disease

(Table 1.1)

. Wuchereria bancrofti

is much the commonest and most widely distributed species. Transmission and survival of the worms depends on the feeding behavior of susceptible female mosquitoes. The disease afflicts poor people in the south. Although few people die from LF, millions suffer from chronic ill health, disfigurement, and disability and many have to endure social rejection and psychological stress. In 1997, the World Health Assembly adopted resolution WHA 50.29, thereby making a commitment to work to eliminate LF as a public health problem. The development of new diagnostic techniques and experience with a safe, single-dose, oral drug regimen persuaded the member states that elimination might be achievable (Ottesen et al., 1997; WHO, 2001). The strategy for the elimination of LF aims (1) to disrupt helminth transmission in endemic countries and (2) control and relieve morbidity caused by LF (WHO, 2005). This chapter seeks to describe and examine the science that underpins those aims that now form the basis for the public health challenge that is the elimination of lymphatic filariasis (Zagaria and Savioli, 2002). Much of the science has been summarized in a collection of reviews edited by Nutman (2000).