First new treatment for Elephantiasis (lymphatic filariasis)

Jun 21 2005

Scientists at the Liverpool School of Tropical Medicine have proved that a single course of one antibiotic may hold the key to curing the parasitic worm disease Elephantiasis (lymphatic filariasis) that has been one of the most common causes of global disability since Biblical times. The discovery offers the first new treatment for this distressing disease for decades.

The disease causes cruel and severe disfigurement with debilitating swelling of the limbs. It leads to many sufferers being social outcasts, deprives them of the ability to work and impairs sexual function Scientifically known as Bancroftian filariasis, the disease is transmitted by the mosquito and affects the most deprived and marginalised populations in the poorest countries.

The findings of Dr Mark Taylor and his team of the Liverpool School of Tropical Medicine are based on their research in Tanzania and will bring new hope to millions off sufferers of Elephantiasis worldwide. They were published in the leading medical journal, the Lancet on Friday June 17th, 2005 and show that by using simple antibiotics it is possible to eliminate the adult worms which cause the gross pathology of the lymphatic system.

Dr Taylor, Senior Wellcome Research Fellow said: "This is a very significant breakthrough indeed. We haven't had a new treatment for filariasis for decades so this is of major importance. A key factor is that the treatment is available now. We know how it works and it is already a tried and tested treatment widely used for other bacterial diseases, avoiding all the long and expensive trials of a new drug. The drugs are readily available to people with filariasis and are cheap as well which is very important in countries where the disease is endemic. What we need to do now is to optimise the treatment to make it suitable for mass community programmes."

As Dr Taylor explained, the antifilarial drugs currently used, diethylcarbamazine and ivermectin, are predominantly active against the larval offspring of the parasite. These treatments form the basis of global programmes used to eliminate lymphatic filariasis in which the School also plays a leading role. However, drugs with adult worm activity could greatly improve the prospects of programme closure.

Dr Taylor and colleagues tested whether treatment against Wolbachia - a bacterium the adult worms are dependent on - could be effective for filariasis. They recruited 72 men infected with W bancrofti from Kimanga village, Pangani , Tanzania , aged 15­-68 years. Half were assigned to placebo and half to an 8-week course of doxycycline. They found that doxycycline treatment resulted in almost complete elimination of adult worms 14 months after treatment and a sustained loss of microfilaraemia (the larval offspring) from at least 8 to 14 months after treatment.

Dr Taylor explains: "In our study, an 8-week course of doxycycline against W bancrofti induced both sustained reductions in the larval offspring and, most notably, the adult worm activity. This is especially important since the adult worms cause the disease pathology in lymphatic filariasis and no safe, effective treatment against adult worms exists. However, an 8-week course of doxycycline treatment is not applicable to mass treatment strategies because of both the logistical difficulties of delivering long-term treatments and doxycycline being contraindicated in children younger than 8 years and pregnant women."

Said Dr Taylor: "We now need to address other issues such as reducing the length of time over which the drugs have to be taken. We have already found that it works at eight weeks, and then six weeks so we will be looking to see if we can reduce that further. "We will also be looking at ways of using different antibiotics or combinations that are suitable for use with children and pregnant women."