Lymphatic Filariasis (Elephantiasis or LF)

Defining the Disease

What is Lymphatic Filariasis?

CDC illustration showing the life cycle of the Wuchereria bancrofti mosquito
(click to zoom)

Lymphatic Filariasis: (lim-fat-ik fĭl’ə-rī’ə-sĭs) is a parasitic disease endemic throughout the world, but found primarily in Africa, India, and the Pacific Islands. In Africa, LF is caused by the parasitic, threadlike worm Wuchereria bancrofti, and is transmitted to humans through the bites of mosquitoes. Long-term infection with LF can lead to painful and disfiguring chronic enlargement of the arms, legs, breasts, and genitals of people of all ages. It can cause severe swelling in the testicles, a condition known as hydrocele, which can be reversed surgically. The disease is commonly called “elephantiasis” because of the elephant-like appearance of swollen limbs in those most severely affected. Infection with LF can cause severe physical and psychological disability. In addition, men with hydroceles often suffer from sexual dysfunction. Like river blindness, LF also has a significant economic impact when productivity is reduced due to the disabilities caused by the disease.

LF Disease Burden

The World Health Organization estimates that worldwide there are:

0 M
At Risk for Lymphatic Filriasis Infection
0 M
People Currently Infected with LF
0 M
With Symptoms From LF Infection

Clinical Manifestations

In the first year of infection, a person may experience few or mild symptoms. However, with repeated infections over several years, a person may develop outward manifestations of the disease. Through a variety of mechanisms, the adult worms in the lymphatic system alter the structure and functioning of the lymphatic vessels, resulting in one or more of the following conditions:

Treatment

Treating people in endemic districts eliminates microfilariae from the blood of infected individuals, thereby interrupting transmission of infection by mosquitoes. WHO recommends > 5 years of mass drug administration (MDA) with preventive chemotherapy to reduce microfilariae from the bloodstream and to prevent transmission. The medicines used are albendazole co-administered with Mectizan® in countries co-endemic with river blindness, or diethylcarbamazine (DEC) co-administered with albendazole in other endemic countries. Some countries are eligible for a new treatment strategy, which will accelerate LF elimination through the co-administration of ivermectin (Mectizan) + DEC + albendazole (a “triple therapy” known as IDA). In areas where Loa loa and LF are co-endemic, treatment with albendazole (400 mg) alone should be given, preferably twice per year, to stop the spread of LF.

Status of MDA for Lymphatic Filariasis in 2020

Status of MDA for Lymphatic Filariasis in 2020

Note: Lymphatic filariasis is widespread and different environments call for different medications (see “Treatment” above). Medication(s) used in each region is indicated in parentheses next to the region’s name.

KEY:
I = Mectizan (ivermectin)
D = diethylcarbamazine (DEC)
A = albendazole

MDA Not Started or Not Implemented
MDA Started but Not at Scale
MDA Scaled to All Endemic IUs*
In Post-MDA Surveillance
LF Eliminated as a Health Problem
  • Equatorial Guinea (IA)
  • Gabon (IA)
  • New Caledonia (DA)
  • Angola (IA)
  • Central African Republic (IA)
  • Madagascar (DA, IDA)
  • Nigeria (IA)
  • Papua New Guinea (DA, IDA)
  • South Sudan (IA)
  • Sudan (IA)
  • American Samoa (DA, IDA)
  • Burkina Faso (IA)
  • Cameroon (IA)
  • Chad (IA)
  • Comoros (DA)
  • Congo (IA)
  • Côte d’Ivoire (IA)
  • Democratic Republic of the Congo (IA)
  • Eritrea (DA)
  • Ethiopia (IA)
  • Fiji (DA, IDA)
  • French Polynesia (DA)
  • Ghana (IA)
  • Guinea (IA)
  • Guinea-Bissau (IA)
  • Guyana (DA, IDA)
  • Haiti (DA, IDA)
  • India (DA, IDA)
  • Indonesia (DA, IDA)
  • Kenya (DA, IDA)
  • Liberia (IA)
  • Malaysia (DA, IDA)
  • Federated States of Micronesia (DA)
  • Mozambique (IA)
  • Myanmar (DA)
  • Nepal (DA)
  • Niger (IA)
  • Philippines (DA)
  • Samoa (DA, IDA)
  • São Tomé and Príncipe (DA, IDA)
  • Senegal (IA)
  • Sierra Leone (IA)
  • Tanzania (IA)
  • Timor-Leste (DA, IDA)
  • Tuvalu (DA, IDA)
  • Zambia (DA)
  • Zimbabwe (DA)
  • Bangladesh (DA)
  • Benin (IA)
  • Brazil (DA)
  • Brunei Darussalam (DA)
  • Dominican Republic (DA)
  • Lao PDR (DA)
  • Mali (IA)
  • Uganda (IA)
  • Cambodia (DA)
  • Cook Islands (DA)
  • Egypt (DA, IDA)
  • Kiribati (DA)
  • Malawi (IA)
  • Maldives (DA)
  • Marshall Islands (DA)
  • Niue (DA)
  • Palau (DA)
  • Sri Lanka (DA)
  • Thailand (DA)
  • Togo (IA)
  • Tonga (DA)
  • Vanuatu (DA)
  • Vietnam (DA)
  • Wallis and Futuna (DA)
  • Yemen (IA)

*Implementation Units

Source: World Health Organization