Schistosomiasis is caused by a parasitic worm that lives in freshwater snails. A parasite is a creature that benefits from its relationship with its host (in this case, humans) while having a negative impact on the host. Schistosomiasis is also known as snail fever or bilharzia. The worm, also known as a fluke, infects humans by biting them in bodies of freshwater. There are five types of worms that cause schistosomiasis. The worms Schistosoma mansoni and Schistosoma haematobium live in South Africa.
Depending on what type of worm bites you, it can cause intestinal schistosomiasis (these symptoms you’ll experience most in the stomach and digestive system) or urogenital schistosomiasis (this will affect genitalia and the ease through which you urinate).
The worms that cause schistosomiasis do not live in every country. Schistosomiasis is more likely to occur throughout Africa, certain South American countries, Southeast Asia, and parts of the Middle East. Schistosomiasis is a disease that can severely affect quality of life if not treated properly. Since it mainly occurs in tropical regions, it is classified as a neglected tropical disease (NTD). While the exact number of infections each year is unknown, schistosomiasis is considered endemic (specific to a region) to South Africa, with up to 95% of children being affected in some parts of the country as of 2018.
People living with schistosomiasis can have no symptoms at all. However, those that do experience symptoms often have early, late, and chronic (ongoing) symptoms.
Early symptoms occur within days of being infected and include a rash and itchiness.
Late symptoms occur within 1-2 months of being infected and can include a cough, chills, fever, and muscle pains.
If left untreated, people can experience symptoms years after being infected. These are called chronic symptoms and can include:
Long-term schistosomiasis makes people more likely to develop cancer, functioning of organs like the liver, or in some very rare cases, spinal cord irritation or even paralysis due to the presence of the flatworms.
Schistosomiasis is caused by a parasitic flatworm that lives in freshwater snails. The worm bites humans and uses humans as their host. In humans, these worms grow to maturity and lay eggs. Infected humans get rid of these eggs in their urine and faeces. Outside of the human body, the eggs find the snail hosts again. The flatworms that cause schistosomiasis depend on this cycle.
Risk factors for schistosomiasis include:
A medical professional will use a combination of medical history, physical exam findings, and testing blood, urine, or faeces to make a diagnosis. Knowing where you have travelled recently or if you may have been exposed to contaminated water will be very helpful for the doctor. A definitive diagnosis can be made by viewing the flatworms that cause schistosomiasis under a microscope. This can be done with urine or faeces but is most easy to do in the blood.
Complications of schistosomiasis occur when the disease goes untreated, causing long-term health problems. These complications can include paralysis, seizures, spinal cord inflammation, bladder cancer, or scar tissue in the liver. Scar tissue in the liver leads to a decrease in liver function.
Schistosomiasis is treated with a deworming drug called praziquantel. There may be side effects from the drug or from the worms dying that a doctor will discuss with you.
A few measures that can be used to prevent schistosomiasis in areas where it is common are to never drink the freshwater, wash clothes in it, or swim in it.