Schistosomiasis

Introduction

Schistosomiasis (also known as bilharzia) is a vector-borne parasitic disease caused by trematode flatworms of the genus Schistosoma.

Freshwater snails act as the vector, releasing larval forms of the parasite into water. These larvae subsequently penetrate the skin of people who are in that water (e.g. fishermen). The larvae develop into adult schistosomes in the body, and are either released through urine or cause an immune reaction (if they remain in the body).

There are two main forms of schistosomiasis:

• urinary schistosomiasis – which mainly affects the bladder, ureters and kidneys
• intestinal schistosomiasis – which mainly affects the liver and spleen and causes intestinal damage and hypertension of the abdominal blood vessels.

The disease can be treated with drugs, while control efforts include those that target the vector.