Lymphatic filariasis (LF), also known as elephantiasis, is a parasitic disease caused by infection with roundworms of the family Filarioidea. World Health Organisation data reveals that 1 billion people (a whopping 20% of the world's population) in over 54 countries are at a risk of developing the disease. India, Indonesia, Nigeria and Bangladesh contribute to 70% of the infection worldwide. India had set the ambitious target of eradicating filariasis by the year 2020, but in the current scenario it seems unlikely.
Each year nearly 120 million people get infected by filariasis, over 40 million get severely disfigured and disabled and nearly 76 million have hidden damage to lymphatic and renal system while remaining symptomless. Although filariasis does not kill, it causes frailty and imposes severe social and economic burdens on the affected individuals, their families and the endemic communities.
India accounts for 40% of the world's LF burden... Currently there may be up to 31 million microfilaraemics, 23 million cases of symptomatic filariasis, and about 500 million individuals at risk of contracting the disease...
Lymphatic filariasis is spread by blood-feeding black flies and mosquitoes. There are three types of filarial worms which cause LF, namely Wuchereria bancrofti, Brugia malayi and Brugia timori; 90% of cases reported are due to infection by Wuchereria bancrofti. The worm blocks the lymphatic system which causes swelling in the legs and other part of the body, making them look large, puffy and elephant-like.
Infected people can be treated with diethylcarbamazine (DEC) that kills the microscopic worms circulating in the blood. While DEC does not kill all of the adult worms, it does prevent transmission of infection. A one-year regimen of DEC decreases the levels of microfilaraemia to a greater extent. A two-drug regimen (optimally albendazole with DEC or albendazole with ivermectin) is 99% effective in removing microfilariae from the blood after one year of treatment.
The WHO is working towards eliminating the disease by the year 2020 with support from three pharma giants—Merck, GlaxoSmithKline and Eisai—which have offered to provide free drugs to eliminate the disease. A clinical trial involving three drugs (ivermectin, diethylcarbamazine and albendazole) has shown effective results. These require only two to three rounds of administration as against the previous drug regimen that was administered for multiple rounds. The new drug regimen, termed IDA and currently under trial in five countries, could be a potential turning point in eradicating lymphatic filariasis.
LF is a public health problem in India despite the existence of National Filaria Control Programme since 1955. It is prevalent in 17 states and 6 union territories. India accounts for 40% of the world's LF burden. Currently there may be up to 31 million microfilaraemics, 23 million cases of symptomatic filariasis, and about 500 million individuals potentially at risk of contracting the disease in the country.
Achieving the LF elimination goal in India requires greater coordination amongst all the stakeholders, incorporating necessary realignments and taking into account recent advances in technology
Since 2004, a mass drug administration program to protect people from LF has been underway. This is one of the most ambitious among the Government of India's public health campaigns. The "Hathipaon Mukt Bharat" (Filaria Free India) is a creative project initiated by the Ministry of Health and Family Welfare along with the Global Network for Neglected Tropical Diseases to deliver preventive medications to high-risk communities within 17 states including the four most endemic states—Uttar Pradesh, Jharkhand, Bihar and West Bengal.
The MDA programme has been quite effective in other countries and has successfully eliminated lymphatic filariasis from Japan, Taiwan, South Korea and Solomon Islands and markedly reduced the transmission in China. However it has not been able to achieve its desired objective, with India missing the target in 2015 and at the current rate being set to fail meeting the goal of complete eradication by 2020. Lack of leadership, a convoluted multi-step drug regimen, lack of drug providers, logistical challenges, supply chain issues, poor quality control, diagnostic limitations, etc., has caused MDA to not succeed completely.
An alternative approach, surprisingly not adopted in the Indian scenario, is to follow the footsteps of the very successful IDD (Iodine Deficiency Disorder) control programme, and to mandate the use of DEC mediated salt in endemic areas to accelerate the ELF (Elimination of Lymphatic Filaria) process. This method is safe and effective, is a WHO approved strategy for ELF and interestingly has achieved success in Karaikal district in South India in the early 1990s.
Achieving the LF elimination goal in India requires greater coordination amongst all the stakeholders, incorporating necessary realignments and taking into account recent advances in technology and with a renewed and pragmatic timeline. Lymphatic filariasis causes huge economic and social burden which an India of the 21st century should be doing away with.