Lymphatic filariasis (also known as elephantiasis) is another mosquito borne disease that plagues much of the population in malaria endemic areas. In fact is is the same anophelene species of mosquitoes which carry malaria that also transmit lymphatic filariasis in much of Africa. With talk of integration of disease control programs, one wonders what are the potential synergies of combining efforts against malaria and lymphatic filariasis?
Both share the preventive measure of bed nets, which is a major strategy for malaria control, but the main approach to eliminating filariasis is Mass Drug Administration (MDA). Two drugs in combination, ivermectin (or diethylcarbamizine citrate) and albendazole, are given annually. These annual doses kill the microfilaria and have some effect on the adult worms. Success as measured by prevalence below 1% can b achieved after 6 rounds of MDA depending on 1) initial level of LF endemicity; 2) effectiveness of vector mosquitoes; 3) MDA drug regimen; 4) population compliance.
If the two diseases share geography and in some cases a vector, have there been any actual attempts at a joint effort? At least two countries have attempted such within the context of their global fund grants for malaria, Togo and Papua New Guinea (PNG). Togo’s Round 4 GFATM grant aimed at “demonstrating the synergy effect of MDA on the impact of malaria control activities” in co-endemic areas. This was based in part of research that showed a negative impact of helminths on malaria infection.
An innovation in the PNG GFATM proposal is “Training of field staff to disseminate information about malaria and HIV/AIDS (who) will also be used for annual mass drug administration for lymphatic filariasis elimination.”
An NGO example of integration has been piloted by the Carter Center. “In 2004, the Carter Center-assisted Lymphatic Filariasis Elimination Program received 57,000 bed nets from the Nigerian Ministry of Health in a combined effort to prevent the spread of lymphatic filariasis, being addressed by the Center, and malaria, a project of the health ministry. The nets are treated with the insecticide deltamethrin, which is safe for humans yet kills the mosquitoes that are the carriers of both diseases in rural Africa. The bed nets have been distributed in four local government areas of Plateau and Nasarawa states in Nigeria, which are endemic for both diseases.”
The Carter Center has been using the same community distribution system found effective for onchocerciasis control. “Community volunteers distributed 38,600 insecticide-treated bed nets, while simultaneously treating 150,800 persons with ivermectin/albendazole.” A 30-cluster survey found a 9-fold increase in bednet ownership compared to baseline. “This first linkage of insecticide-treated bed net distribution with mass drug administration resulted in substantial improvement in insecticide-treated bed net ownership and usage, without adversely affecting mass drug administration coverage. Such integration allowed two programs to share resources while realizing mutual benefit, and is one model for rapidly improving insecticide-treated bed net coverage objectives.”
Since the Global Fund programs have yet to focus on neglected tropical diseases, these examples of integration between malaria and lymphatic filariasis, may be the best way to ensure parasite-free populations in endemic areas.