Lymphatic filariasis: a regional parasite
Crystal Gao, Editorials and Publications Team PMSA
Lymphatic filariasis (LF), also known as elephantiasis, is an infection caused by filarial parasites. It is transmitted via mosquito bites and is usually acquired during childhood, although the symptoms can take years to fully manifest (1). LF causes damage to the lymphatic system, resulting in pain, swelling, and lymphoedema (the accumulation of lymph fluid due to impaired drainage) that particularly affects the legs and scrotum (Figure 1). The health impacts of living with LF, coupled with social stigma towards a highly disfiguring disease, can lead to permanent physical, social, and financial disability.
Lymphatic filariasis is a severely debilitating condition that is endemic to 15 out of the 22 Pacific Island countries and territories. However, it was often neglected and overlooked as a tropical disease until 1999, when the WHO implemented the Pacific Programme to Eliminate Lymphatic Filariasis (PacELF) as part of a bigger world-wide initiative to eradicate this disease (2). Elimination of LF can be achieved through mass drug administration (MDA), which involves the administration of prophylactic medications* to the entire at-risk population in order to prevent the infection from spreading (1). Importantly, all 15 Pacific Island countries with endemic LF have taken on this programme and are working their way towards the elimination of this disease. Even more heartening is the fact that some of these 15 countries have already achieved their target, and are now undergoing surveillance to prevent relapse (3). For example, Vanuatu, Tonga and Niue were three of the first countries to achieve an LF prevalence of <1% after undergoing 5 cycles of MDA (4).
Happily, the eradication of LF in the Western Pacific region is well underway, and already, many countries have succeeded in meeting their treatment targets. However, in order to fully eliminate this disease in the Pacific Island countries and territories, the MDA programme must be supported and sustained until the very last endemic country has been cleared of disease – only then will we have truly and definitively addressed this regional parasite.
* The medications used are antihelminthics – diethylcarbamazine (DEC) or a combination of ivermectin + albendazole
1. WHO. Lymphatic filariasis fact sheet. 2018.
2. WHO. What is lymphatic filariasis? 2018.
3. WHO. What is PacELF. 2018.
4. Huppatz C, Capuano C, Palmer K, Kelly PM, Durrheim DN. Lessons from the Pacific programme to eliminate lymphatic filariasis: a case study of 5 countries. BMC Infectious Diseases. 2009;9(1):92.