37.4  Lymphatic filariasis

In this final section, you will learn about the definition, mode of transmission, clinical manifestations, and methods of prevention and control of lymphatic filariasis. It is also known as elephantiasis because of its effects on the legs of infected people. Lymphatic filariasis is a parasitic disease caused by a worm that invades the lymphatic system – the network of vessels that exists throughout the body, connecting the lymph nodes, spleen and other organs, and where white blood cells are primarily found (Figure 37.18).

The human lymphatic system
Figure 37.18  The human lymphatic system. (Diagram: The Open University, SXR376 Preparatory Reading, Figure 1.2)

The WHO estimates that over 120 million people worldwide are currently infected with the worm (species name Wuchereria bancrofti, Figure 37.19) which is responsible for 90% of all cases.

A Wuchereria bancrofti worm
Figure 37.19  A Wuchereria bancrofti worm, stained blue and magnified by a microscope. (Photo: CDC Image Library, image 3009)

37.3.4  Prevention and control of onchocerciasis

37.4.1  Where is lymphatic filariasis common in Ethiopia?