Communicable Diseases
Bilharzia (Schistosomiasis)

​​Overview:

  • Bilharzia is an acute and chronic parasitic disease caused by a kind of parasitic worms.
  • Care should be taken when traveling to areas where bilharzia is endemic.
  • The infection occurs when infected individuals contaminate fresh water sources with feces or urine carrying the eggs of this parasite.
  • Symptoms result from the body’s reaction to the worms' eggs, which may result in a rash or itch.
  • The infection can be treated with some medications and methods of prevention.

What is bilharzia? 
Bilharzia is an acute and chronic parasitic disease caused by a kind of parasitic worms known as “cercariae”. Usually, no symptoms appear when a person is first infected; however, this parasite can live in a person’s body for years and causes damage to his internal organs. 

Types:
  • Intestinal schistosomiasis
  • Urinary schistosomiasis

Cause:
The infection occurs when infected individuals contaminate fresh water sources with excreta (feces or urine) that carry the eggs of this parasite. The eggs hatch in the water, releasing tiny larvae. When another person comes in contact with this contaminated water, the larvae penetrate his skin. This could happen while a person is diving, swimming, washing, or paddling in contaminated water. In the body, the larvae develop into adult schistosomes. Adult worms live in the blood vessels where the females release eggs. Some of the eggs are passed out of the body in the feces or urine to continue the parasite’s lifecycle. Others become trapped in body tissues, causing immune progressive damage to organs.

Risk Factors:
  • Living in or traveling to areas where schistosomiasis exists
  • Coming in contact with fresh contaminated water
  • Living in areas with poor sanitation

Who is at the high risk?
School-age children living in these areas are more vulnerable to infection; because they tend to spend some time swimming or bathing in contaminated water.

Symptoms:
Symptoms result from the body’s reaction to the worms' eggs, not the worms. So symptoms could vary from a person to another:
  • Within days, you may develop a rash or itch.
  • Within 1-2 months, you may develop a fever, chills, cough, and muscle aches.
  • Children may frequently suffer from anemia, poor nutrition, stunted growth and a reduced capability to learn.

Long-term symptoms:
  • Some people with bilharzia (regardless of whether they showed initial symptoms or not) eventually develop more serious problems in the parts of the body where the eggs were present.
  • Digestive system: infection in the digestive system could cause anemia, stomachache, swelling, diarrhea, and blood in stool.
  • As for the urinary system, the infection could cause cystitis, pain when passing urine, a frequent need to urinate, and blood in the urine.
  • A cough resulting in blood and shortness of breath.
  • If the nervous system is affected, seizures, headache, dizziness, and weakness and numbness in the legs can occur.

When to see a doctor?
When you experience the aforementioned symptoms, travel to countries where schistosomiasis exists, or if you come into contact with contaminated water.

Complications:
  • Anemia
  • Fibrosis of intestinal veins and the liver
  • Lung and bladder damage
  • Splenomegaly
  • In severe cases, the infection may lead to neurological complications causing death.
Diagnosis:
To diagnose schistosomiasis, the doctor will ask about the symptoms you are experiencing. Medical tests will also be necessary to examine stool and urine samples, alongside with a blood test to check for the presence of this parasite.

Treatment:
A safe and effective prescription drug is available for treating schistosomiasis and killing worms caused by all types of bilharzia. This drug is more effective once the worms grow slightly; therefore, treatment may be delayed for a few weeks after the infection. The doctor may also repeat the treatment a few weeks after you take the first dose.

Prevention:
There is no vaccine against schistosomiasis; so it is important to be aware of its danger and take the necessary precautions. If you are traveling to countries where schistosomiasis exists, it is necessary to take the following into consideration:
  • Avoid swimming or playing in fresh water.
  • Drink filtered or boiled, cooled water that is free of parasites. Although schistosomiasis is not transmitted by drinking contaminated water, if this water comes into contact with the lips, the person may become infected. 
  • Prepare the water you use for bathing by boiling it for one minute to kill the parasites and avoid infection, and then cool it before your bath.

FAQs:
  • Can bilharzia be transmitted directly from one person to another?
    • Infection occurs only as a result of direct exposure to water contaminated by parasites that penetrate a person's skin.
  • Is there a vaccine to protect me from bilharzia? 
    • There is no vaccine for bilharzia; however, adhering to prevention methods greatly contributes to preventing infection.

Myths & Truths:
  • Myth: Schistosomiasis can be transmitted through drinking water carrying the parasite.
    • Truth: Schistosomiasis is not transmitted by drinking contaminated water; however, if this water comes into contact with the lips, the person may become infected as the parasite penetrates the skin.

Clinical Education General Department
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