India is committed to eliminating Lymphatic Filariasis by 2027, three years ahead of the global target through a multi-partner and multi-sector targeted drive. The country has made considerable progress towards elimination, yet several challenges remain.
An interview with Dr. Kavita Singh, Director, Drugs for Neglected Tropical Diseases initiative, South Asia on National Filariasis Day.
What is Lymphatic filariasis (LF)?
LF, commonly known as elephantiasis, is a mosquito-borne neglected tropical disease that disfigures and disables. Infection is usually acquired in childhood and causes hidden damage to the lymphatic system. It is a major public health concern in many parts of the world, particularly in tropical and subtropical regions.
Over 882 million people in 44 countries worldwide remain threatened by lymphatic filariasis and require preventive chemotherapy to stop the spread of this parasitic infection.
It is caused by infection with the parasitic nematodes Wuchereria bancrofti, Brugia malayi, or Brugia timori. Chronic infection causes lymphatic dysfunction, resulting in progressive, irreversible swelling of the limbs and genitals. Filarial induced lymphoedema is the second leading cause of disability in the world.
How long has LF been around and what is the extent of its problems in India?
The disease was recorded in India as early as the sixth century BC by Sushruta in his book, Sushruta Samhita. The discovery of microfilariae (mf) in the peripheral blood was made first by Lewis in 1872 in Calcutta (Kolkata).
India bears around 40% of the global disease burden, with 257 LF endemic districts from 16 states and 5 union territories; close to 650 million people are at risk of contracting the disease with 31 million infected cases, 23 million suffer from lifelong disability and 26 million symptomatic cases.
How has India been tackling the LF disease?
India has adopted a five-pronged strategy as part of which multi-drug administration (MDA) will be held twice a year. The other aspects of the strategy include early diagnosis and treatment; engagement of medical colleges for strengthening morbidity management and disability services; integrated vector control with multi-sectoral coordination. Community engagement remains key to implement this strategy.
The World Health Organization launched the global programme to eliminate lymphatic filariasis in 2000. This programme comprises two key strategies: mass drug administration to prevent infection; and management of morbidity and prevention of disability.
India started Annual Mass Drug Administration in 2004 initially with single dose of DEC (Diethylcarbamazine citrate) to 5 years (of age) or more to the eligible population (except pregnant women, children below 2 years of age and seriously ill persons) to interrupt transmission of the disease. Only then in the year 2007 with DEC + Albendazole was co-administered. From 2018 Triple Drug Therapy (IDA) i.e. DEC + Albendazole + Ivermectin was launched in the country in a few districts to start with. The engagement of medical colleges for strengthening morbidity management and disability (MMDP) services has been greatly enhanced.
It is based on the premise that repeated MDA will reduce the microfilaria density in the community and thus halt transmission and thereby new infections.
How has the mass drug administration program further evolved and do we need additional intervention/ tools to support national LF elimination efforts?
Treatment coverage and compliance, should remain sufficiently high to achieve the goals of elimination. The MDA regimen requires repeated annual administration, and requires probably > 85% of the total population) to achieve elimination. In the last few years many additional steps have been introduced to make the implementation program more robust like guidelines on how to administer doses of ivermectin using dose poles: Innovative social mobilization approaches to enhance community compliance, microplans to include booths in schools as administration sites, finger marking and house marking have been introduced for door-to-door activities as well.
In addition, the Multi-drug administration (MDA) Campaign has now been synchronized with National Deworming Day on the 10th of February and the 10th of August.
Advocacy efforts have been strengthened to include central, state health ministers, district government officials, and brand ambassadors to improve community acceptance and increase drug compliance and ensuring communication campaigns at villages and panchayats.
Presently clinicians do not have access to a treatment which can treat the patient if they are harbouring large worms as there is no drug which has demonstrated this effect in a clinical study. There is a need for the development of macrofilaricidal/curative drugs in order to mop up residual foci after the disease burden has been reduced by MDA/IDA programs and it is no longer cost effective to continue, for treatment of patients in endemic areas outside IDA/MDA campaigns and in areas that are difficult to reach for IDA and accelerate achievement of elimination of LF. Hence, there is an urgent need for the recognition that an additional approach for LF elimination that is adapted to regional differences.
Drug resistance could also pose a real impediment to the control efforts. Widespread use of DEC, ivermectin and albendazole in MDA programmes entails a risk for the emergence and spread of resistance though there are no indicators at the moment.
Early diagnosis and treatment, integrated vector control with multi-sectoral coordinated efforts are areas which need more concentrated efforts. In addition to this, the inter sectoral convergence with allied departments and ministries which are in the plan need to leverage existing digital platforms for LF.
Detection of the disease is another challenge. Since the detection of parasite carriers is only effectively possible by conducting blood testing at night during Night Blood Surveys (NBS). The NBS are expensive, time-consuming, and poorly accepted by the community and if done at the wrong time, can often have misleading results. We need inexpensive, alternative tools to detect the presence of adult worms and microfilariae which can be easily implemented in remote geographies and support surveillance program.
If tests can be developed for clinicians to identify and diagnose viable adult filarial worms, it could greatly support the easy development and usage of macrofilaricidal drugs.
What social determinants are associated with LF?
The chronic manifestations of filariasis can have a significant and often very negative social impact on people. LF has traditionally been considered a disease associated with poverty, inadequate sanitation, and underdevelopment. Those afflicted with LF are often socially marginalised communities with acute attacks and chronic disability.
LF is predominantly seen in rural areas and poor urban neighborhoods, with women being more susceptible to acquiring this infection due to their work conditions involving cooking, cleaning, and standing in long queues for drinking water in areas replete with the filarial mosquito's breeding ground—stagnant, dirty water.
Building on the momentum of innovative diagnostic and treatment solutions, it is vital to embrace a holistic approach to patient care. This way, we can transcend beyond merely treating physical symptoms and start addressing the associated mental and social burdens of LF.
What is the role of inter sectoral coordination?
As we understand, this is a vector transmitted disease and numerous social determinants of living and hygiene impact transmission therefore along with the Ministry of Health and family welfare, a huge role can be played by allied departments and ministries such as Ministry of water and sanitation, Ministry of Panchayati Raj, Ministry of HRD, Ministry of Urban and Rural Development.
