MDA-Lymphatic Filariasis.

Lymphatic filariasis is one of the neglected tropical diseases. It is estimated that 120 million people are currently infected in 73 countries where filariasis is endemic. Lymphatic filariasis is a leading cause of chronic disability worldwide, including of 15 million people who have lymphoedema (elephantiasis) and 25 million men who have hydrocoele.

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) has been one of the most rapidly expanding global health programmes in the history of public health. The programme was launched in 2000 in response to resolution WHA50.29, with the goal to eliminate lymphatic filariasis as a public-health problem by 2020 (Fig. 1).

Fig. 1

Global status

The GPELF has two strategic aims: (i) interruption of transmission, using combinations of two medicines delivered to entire populations at risk, a strategy known as mass drug administration (MDA); and (ii) morbidity management and disability prevention (MMDP), by providing access to basic care to every affected person in endemic areas (Fig. 2.).

Fig. 2

Global elimination programme

The World Health Organization has developed a GPELF framework and guidelines for Member States to accelerate their efforts towards elimination of lymphatic filariasis by 2020 (Fig. 3).

Fig. 3

Framework

The GPELF strategy for transmission interruption has two objectives with microfilariacide; the first one is to reduce the density of the microfilariae in the blood of infected people to a level at which they can no longer be transmitted by mosquito vectors to a new human host, and the scond one is to reduce the prevalence of microfilariae in the community to a level at which transmission can no longer be sustained, even in the presence of mosquito vectors. These two objectives are achieved by mass drug administration, MDA (Fig. 4).

Fig. 4

Why MDA

MDA should cover everybody except children age below 2, pregnant women and very sick people in the community at the same time to make the microfilariae free situation in the community once a year. Then, MDA should continue for at least 5 years, which is generally considered to be the reproductive lifespan of an adult worm in an infected host (Fig. 5).

Fig. 5

Perspective of MDA

The technical policies for MDA involve 1) combination of drugs, 2) single-dose annual treatment for 5 years and 3) to cover all eligible individuals in the entire endemic area (Fig. 6).

Fig. 6

Technical policy

Of the 73 endemic countries, 53 are implementing MDA, and 12 have moved to the post-MDA surveillance phase. During 2000–2012, more than 4.2 billion doses of medicine were delivered to a cumulative targeted population of 979 million people (Fig. 7).

Fig. 7

Progress

The first decade of GPELF was characterized by rapid scaling up of mapping and MDA. In addition, nine out of originally endemic countries at the start of GPELF were re-classified as non-endemic in 2010. A number of countries have even successfully moved up to the post-MDA surveillance stage. Intensified activities in the next five years will be essential to achieving the global elimination goal by 2020 (Fig. 8).

Fig. 8

Global strategy