Annual Treatments

Thus far, tablet-based mass drug administration (MDA) has been our principal tool for line at the clinicstopping LF transmission in Haiti. We use two drugs in concert, proven to be safe and effective microfilaricides: diethylcarbamazine at a dosage of 6 mg/kg and albendazole at a constant dosage of 400 mg. DEC is purchased from WHO-recommended foreign suppliers, while albendazole is donated by GlaxoSmithKline. These drugs primarily destroy juvenile LF worms (microfilariae), but recent studies using ultrasound and biopsies of post-treatment nodules indicate that when given in single doses of 6 mg/kg or more, DEC also kills a proportion of adult worms1, 2. Albendazole is particularly effective in ridding the body of other helminths, such as hookworms that can cause deadly anemia. Combining lymphatic filariasis eradication efforts with treatment for intestinal helminths dramatically increases the benefit to treated populations and bolsters community support for the MDA.           

 

Since the adult female LF worms can live in the body up to eight years, in order to eliminate the disease, drugs must be administered annually to destroy progeny worms until the females die naturally. However, since the circulating juvenile worms are the form of LF parasite available for mosquitoes to transmit, killing these worms halts transmission of the infection, so each treatment has a significant effect. In our pilot MDA in the Leogane commune in 2000, we treated 109,000 people, 70% of the at-risk population—and subsequently detected a 56% reduction in microfilaremia prevalence.  

 

LF is truly a national disease in Haiti, present in 118 of 135 communes, making 88% of the country a potential risk zone. But current WHO models suggest that drug coverage of only about 80% of the population in endemic areas is needed to stop transmission and eliminate the disease. After our pilot treatment in Leogane, we expanded treatment to include 17 of the 21 communities with the highest prevalence of infection. By reaching 81% of these areas with highest endemicity, administering a total of 2.6 million treatments, we believe we have covered fully half of the LF-infected population in Haiti. Continued MDA in these high prevalence zones—and adding salt-delivered coverage of moderately endemic regions—must be a priority to keep breaking transmission. With continued support and resources, we can use our momentum to permanently lift the scourge of this disease from Haiti.

 

1. Dreyer, G., Amaral, F., Noroes, J., Medeiros, Z. and Addiss, D. (1995a). A new tool to asses in vivo the adulticidal efficacy of antifilarial drugs for bancroftian filariasis. Transactions of the Royal Society of Tropical Medicine and Hygiene, 89, 225-226.

 

2. Noroes, J., Dreyer, G., Santos, A., Mendes, V.G., Medeiros, Z., and Addiss, D. (1997). Assessment of the efficacy of diethylcarbamazine on adult Wuchereria bancrofti in vivo. Transactions of the Royal Society of Tropical Medicine and Hygiene, 91, 78-81.

 

 

 

 

 

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