Lymphatic filariasis

Lymphatic filariasis (LF) is the single largest cause of chronic permanent disability globally. It is caused by thread-like worms and is spread to humans through infective mosquito bites. Approximately 863 million people in 47 countries are at risk of acquiring LF. It causes genital disease in more than 25 million men and limb lymphoedema in more than 15 million people. 

Group of young boys, India
Credit Devaiah Mallangada Kalaiah, Unsplash

Lymphatic filariasis, one of the WHO-classified neglected tropical diseases, is an important cause of disability worldwide. The parasitic adult filarial worms, impairs the lymphatic system and this damage can eventually lead to lymphoedema, elephantiasis, or hydrocele (scrotal swelling). These abnormal enlargements of body parts cause pain, disability and stigma.

The World Health Organization (WHO) and the global health partners, implemented strategies to control and eliminate LF since 2000, predominantly using two pillars: (i) preventive chemotherapy and transmission control (PCT) through the distribution of antifilarial and anthelmintic medicines to at-risk populations on an annual basis, by so-called mass drug administration (MDA), and (ii) alleviating the suffering of the already diseased individuals through morbidity management and disability prevention (MMDP).  MDA uses the drugs diethylcarbamazine (DEC), albendazole, called a double drug therapy (DA) in most endemic countries and wherever appropriate, uses the triple drug therapy (DA plus Ivermectin, IDA) to interrupt transmission.  MMDP interventions for the various sequelae range from surgery to hygiene and exercise of affected limbs.

With more than 8.6 billion preventive treatments delivered from 2000 to 2020 in 68 countries, this has successfully reduced the number of people requiring MDA treatment by 49% (692 million). Despite this, there remain questions on the factors (host and parasite) that shape individual responses to treatment; responses to treatment in understudied groups (for example: younger age groups); drug safety and tolerability profiles, and methodological questions on how and when responses should be measured and how future studies to address these questions should be designed. 

IPD Platform Scoping and Feasibility Study

The Indian Council of Medical Research-Vector Control Research Centre (ICMR-VCRC) and IDDO are currently researching the scope and feasibility of an individual participant-level data (IPD) platform on efficacy of LF treatments, which would collate and standardise IPD to facilitate collaborative research on key questions on various LF treatments, for infection and or disease.

A systematic review of LF treatment studies to assess the availability and variety of LF efficacy data around the globe is being undertaken. Given that LF is one of the most prominent NTDs that has been around for centuries, affecting many countries and is now targeted for elimination, it is hoped that extensive data could be available to develop an IPD platform.  This platform could support in providing evidence to strengthen treatment policy through preventive chemotherapy and transmission control (PCT) and morbidity management as well as other research gaps.

ICMR – VCRC, as a WHO Collaborating Centre for Research and Training in lymphatic filariasis, is an important player in LF research in India, actively working with the national programme to generate evidence shaping LF treatment across the world. IDDO and ICMR-VCRC are looking forward to engaging with other stakeholders and collaborators from LF research communities around the globe in the development of the platform on LF treatments to understand the needs, purpose and future output that an LF IPD platform could provide to potential partners, researchers, control programmes, and policy makers.

For further information about this scoping project, please contact