In only four years, a massive World Health Organization-led global program to eliminate one of the world's most disfiguring and disabling tropical diseases, lymphatic filariasis (LF), has already provided remarkable benefits for the populations of at least 37 endemic countries.
A simple 2-drug, once-yearly treatment of all 'at risk' individuals using very safe and effective medicines (albendazole plus either ivermectin or DEC) has been responsible for the fastest ramp up of a global public health program in history. The World Health Organization (WHO) reports that today nearly 80 million people -- 30 million of whom are children -- have begun to be protected from LF by stopping transmission of the disease, which can lead to the huge enlargement and disfigurement of the arms, legs and genital organs known as elephantiasis. Two of these drugs are being donated by their manufacturers - albendazole by GlaxoSmithKline and Mectizan (ivermectin) by Merck & Co., Inc.
"Our company has already donated 250 million treatments of albendazole to this program, and we will continue to donate as much of the drug as is needed," says J.P. Garnier, CEO of GlaxoSmithKline. "We estimate that it will take about 20 years to break the cycle of the disease globally. But we have the proof now that it is practical to eliminate this ghastly disease completely, within our lifetimes."
Some one billion people in 80 tropical countries are at risk from LF, and 120 million people actually carry the infection, which is spread by a microscopic, parasitic worm that invades the human lymphatic system. The disease is spread by parasite-carrying mosquitoes, which act as vectors for the disease when they bite multiple people.
In many endemic regions, the infection is found in as much as 25 percent of children 4-6 years old. However, early damage is hidden and no immediate signs of LF are visible. LF generally begins to be recognized only in the victim's teen years. The disease often leads to profound psychological disability as a very understandable consequence of the severe physical disfigurements.
Efforts to eliminate the carrier of the parasite, the mosquito, are rarely sufficient to stop the spread of infection. Medical studies of the 1990s showed that the best opportunity for eliminating lymphatic filariasis is through medicines-combinations of the inexpensively purchased diethylcarbamazine (DEC) and the donated albendazole and Mectizanä (ivermectin). The principal goal of treating affected communities is to eliminate the microfilariae from the blood of infected individuals so that transmission of infection by the mosquito can be interrupted.
The crucial research of the 1990s demonstrated that a single dose of two drugs administered concurrently (albendazole with either DEC or ivermectin) could be 99 per cent effective in killing microfilariae from the blood for a full year after treatment. It is this level of treatment effectiveness that has made feasible the new global efforts to eliminate lymphatic filariasis. But everyone living in areas at risk for the disease must be targeted for drug treatment. In Yemen and Sub-Saharan African countries where river blindness (treated with Mectizan) and LF co-exist, the two donated drugs - albendazole and Mectizan (ivermectin) - are used against the disease. Elsewhere in the world the combination of DEC and albendazole is used.