Schistosomiasis (Bilharzia): Causes, Symptoms, Diagnosis, Treatment, and Prevention
Overview
Schistosomiasis, also known as bilharzia, is an acute and chronic parasitic disease caused by flatworms called Schistosoma. Infection occurs when people come into contact with freshwater contaminated with larval forms of the parasite. These larvae penetrate the skin and migrate through the body, potentially causing long-term damage to vital organs.
Although serious, schistosomiasis can be effectively treated using safe and reliable medications.
What Is Schistosomiasis?
Schistosomiasis is a parasitic infection caused by Schistosoma worms. Most people do not show symptoms immediately after infection. However, the parasite can remain in the body for years, leading to progressive damage to the liver, intestines, urinary system, or even the nervous system.
Types of Schistosomiasis
There are two main forms affecting humans:
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Intestinal schistosomiasis: Affects the intestines and liver.
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Urinary schistosomiasis: Affects the urinary tract and bladder.
Causes: How the Infection Spreads
Infection begins when human waste (urine or feces) containing parasite eggs contaminates freshwater sources. The eggs hatch in the water, releasing larvae that infect specific types of freshwater snails.
The snails then release infectious larvae (cercariae), which can penetrate human skin upon contact.
Inside the human body:
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Larvae migrate through the bloodstream.
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They mature into adult worms.
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Female worms lay eggs—some pass out of the body through urine or stool, while others remain trapped in tissues, causing inflammation and organ damage.
Risk Factors
You are at higher risk of schistosomiasis if you:
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Live in or travel to areas where the disease is common.
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Swim, bathe, or work in contaminated freshwater.
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Are in regions with poor sanitation services.
Who Is Most at Risk?
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School-aged children who frequently swim or play in freshwater sources.
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Farmers and fishermen who are in regular contact with rivers or irrigation water.
Symptoms of Schistosomiasis
Early Symptoms (hours to days after exposure)
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Skin rash
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Itching at the site of larval penetration
Acute Symptoms (within 1–2 months)
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Fever
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Chills
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Cough
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Muscle aches
Chronic Symptoms (long-term disease)
Digestive system:
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Abdominal pain
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Diarrhea, sometimes with blood
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Anemia
Urinary system:
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Painful urination
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Frequent urge to urinate
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Blood in urine
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Bladder irritation
Respiratory system:
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Cough
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Shortness of breath
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In advanced cases: coughing up blood
Nervous system involvement:
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Seizures
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Severe headaches
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Dizziness
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Weakness or numbness in the legs
When to See a Doctor
Seek medical care if:
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You develop symptoms after visiting a country where schistosomiasis is present.
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You have been in contact with contaminated freshwater.
Complications
If left untreated, schistosomiasis may cause:
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Chronic anemia
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Liver fibrosis
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Intestinal and urinary tract damage
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Enlarged spleen
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Lung damage
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Neurological complications, including paralysis or seizures
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In severe cases, it can lead to death
Diagnosis
Diagnosis involves:
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Testing urine and stool samples for parasite eggs
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Blood tests to detect antibodies or antigens
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Ultrasound imaging to evaluate organ damage
Treatment
The primary treatment is Praziquantel, a safe and effective prescription medication that kills adult worms.
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It works best after the worms have matured slightly.
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In some cases, the doctor may repeat the dose after a few weeks to ensure complete eradication.
Prevention
There is currently no vaccine for schistosomiasis. Prevention is based on avoiding contact with contaminated water:
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Avoid swimming or wading in freshwater in endemic locations.
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Drink only boiled, filtered, or bottled water.
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Boil water for at least one minute before using it for bathing, then let it cool.
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Maintain good hygiene and avoid contact with potentially contaminated environments.
Frequently Asked Questions
Is schistosomiasis contagious from person to person?
No. It spreads only through direct contact with contaminated freshwater.
Does drinking contaminated water cause infection?
No, the disease does not spread through drinking. However, contaminated water can cause infection if it touches your lips or skin.
Is there a vaccine for schistosomiasis?
No. The best protection is avoiding exposure to contaminated water.
Common Misconceptions
❌ “Schistosomiasis spreads through drinking dirty water.”
✔ Truth: It spreads when larvae penetrate the skin, not through drinking.
Keywords
schistosomiasis, bilharzia, schistosoma infection, parasitic diseases, freshwater parasites, bilharzia symptoms, urinary schistosomiasis, intestinal schistosomiasis, praziquantel treatment, tropical diseases, parasite prevention, waterborne infections
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