FILARIASIS ERADICATION--NEW GROUND BREAKING RESEARCH
Posted by bmhegde on 1
There were hectic governmental efforts recently to push diethy-carbamazine citrate (Hatrazan) down every one’s throat in the fond hope of eradicating filariasis from India. Many recipients suffered minor and some did have major drug side effects in the bargain. No one seems to have done any audit on the effort to date. Although I couldn’t fathom the scientific reasons for that campaign, I thought there might be some political mileage accruing from such an effort to the powers that be. We have been playing with the lives of the gullible public anyway, in the field of health care!
Hatrazan will kill all the children of the adult female worms. The latter, however, sit pretty in the deep recesses of the lymphatic system deep down in the upper thigh region in all those that have microfilaraemia. Hetarazan is reasonably effective in killing microfilariae but does not touch the adult worm. The long term results of the governmental efforts would be that people with filariasis will again have microfilaraemia after a while and their disease continues unabated. The transmission of the microfilariae through the vector route of Culex fatigans mosquitoes continues for ever with the adult female producing children periodically and letting them into the host’s blood stream.
There seems to be a ray of hope for those that have been suffering from this disfiguring disease. A group of researchers in Tanzania, led by a group from the Liverpool School of Tropical Medicine in England have come up with very vital clue to filarial eradication by targeting the adult worm. This study was designed and monitored by Dr. Mark J Taylor of the Liverpool School. The study was done in Tanzania where filariasis is rampant even today.
The scientific background of the study is very interesting. The adult worm, Wuchereria bancrofti, seems to depend for its survival and fertility on a bacterium called Wolbachia. Nature is a curious scientist and all of us here are interdependent although human beings think that they are superior. This bacteria, Wolbachia, supply the symbionts (living mates)- the Wolbachia endosymbionts to the filarial nematodes vital for their larval development and adult worm fertility and viability. This vital dependency of the filarial adult worm for its survival on the bacteria, Wolbachia, provided these scientists a new approach to treat filariasis with anti-biotics that could kill the bacterium Wolbachia.
In this study reported in The Lancet, a very important scientific journal from London, in its recent edition (Lancet 2005; 365: 2116-2121) researchers tried the use of a single daily dose of a tetracycline (doxycline) for a period of eight weeks to eradicate the Wolbachia bacteria from the host of the filarial adult worm. Wolbachia responds to tetracycline treatment very effectively. The study showed almost 88% eradication of the adult worm at the end of the study and even fourteen months later. One could now study the presence of the adult worm using ultrasound. This is vital information for the health departments and those NGOs genuinely interested in getting rid of this menace from India and from the world. Hope this study experience replicates in other settings as well.