There is no vaccine to protect against filarial infection. While current anti-filarial drugs are effective against the larval forms of the parasite, development of resistant strains of nematodes has recently been indicated [14], [15], [16] and [17]. None of the current drugs have significant activity against adult worms, which can survive in human hosts for up to 10–15 years. Because of the long fertile adult survival time, current treatments must be administered annually or semi-annually on a community-wide basis for many years to break the infection cycle. There is still an urgent need to develop novel macrofilaricidal (adulticidal) drugs.