Online Dermatologist > Schistosomiasis (Bilharzia): Causes, Symptoms, Diagnosis & Treatment

Schistosomiasis (Bilharzia): Causes, Symptoms, Diagnosis & Treatment

by | Feb 7, 2024 | Blog, Traveling

children bathing in a water source highlighting the potential health risks associated with schistosomiasis in such environments

Key Takeaways


  • Global Prevalence: Schistosomiasis affects almost 240 million people worldwide, with the highest occurrence in sub-Saharan Africa, highlighting it as a significant public health concern.

  • Transmission Cycle: The disease is contracted through skin contact with contaminated freshwater, where parasitic worms from infected snails penetrate human skin, underscoring the importance of water safety.

  • Symptoms and Stages: Early symptoms include rash or itchy skin, progressing to more severe conditions like anemia, organ damage, and potentially bladder cancer, emphasizing the need for early detection and treatment.

  • Treatment: Praziquantel is the primary treatment, effective across all species of Schistosoma, pointing to the critical role of accessible healthcare in managing the disease.

  • Prevention Strategies: Avoiding contact with contaminated water, using proper hygiene practices, and implementing community-wide health education and preventive treatments are key to controlling schistosomiasis spread.

Schistosomiasis, commonly known as Bilharzia, is a parasitic disease caused by trematode worms of the genus Schistosoma. This neglected tropical disease is a significant public health concern, particularly in regions with poor sanitation and limited access to clean water. Schistosomiasis is prevalent in tropical and subtropical areas, with the majority of cases occurring in sub-Saharan Africa.

The parasitic worms responsible for Schistosomiasis have a complex life cycle involving freshwater snails as intermediate hosts. Human infection occurs when individuals come into contact with contaminated water, often during routine activities such as bathing, swimming, or agricultural work. Once inside the human host, the worms mature and produce eggs that can cause chronic and debilitating health complications.


The Causative Agents: Schistosoma Species

Schistosomiasis, is an acute and chronic parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. It is considered one of the neglected tropical diseases (NTDs) and is second only to malaria as the most devastating parasitic disease.[1]

Schistosomiasis affects almost 240 million people worldwide, and more than 700 million people live in endemic areas.The disease is most commonly found throughout Africa, but also lives in parts of South America, the Caribbean, the Middle East, and Asia.
The parasites that cause schistosomiasis are transmitted through the skin when a person comes into contact with contaminated freshwater.

This  tends to spread in warm regions and places where people lack access to clean water and proper sanitation, especially in impoverished communities. Urogenital schistosomiasis results from the presence of Schistosoma haematobium, while intestinal schistosomiasis can be caused by various organisms, including S. guineensis, S. intercalatum, S. mansoni, S. japonicum, and S. mekongi.[2] Understanding these distinctions is crucial for accurate diagnosis and targeted treatment strategies.


How Schistosomiasis is Contracted

The transmission process involves several steps:

  • Infected individuals: People suffering from schistosomiasis contaminate freshwater sources with faeces or urine containing parasite eggs.
  • Hatching of larvae: The eggs hatch, and if the appropriate species of snails are present in the water, the parasites infect, develop, and multiply inside the snails.
  • Parasite release: The parasite leaves the snail and enters the water, where it can survive for about 48 hoursSkin contact: When a person’s skin comes into contact with contaminated freshwater, the parasites can penetrate the skin and migrate through the host tissue.
  • Development of adult worms: Over several weeks, the parasites develop into adult worms inside the blood vessels of the host, where females release eggs.
  • Eggs in urine or stool: Some of the eggs are passed out of the body in the faeces or urine to continue the parasite’s life cycle.[3]

Schistosomiasis transmission involves a complex life cycle of parasitic worms. Infected individuals release parasite eggs into freshwater, where they hatch into larvae. These larvae find snails to further develop. Infected snails release larvae that can penetrate human skin during water activities. Once inside the host, larvae develop into adult worms, completing the cycle. Activities like swimming and farming increase the risk. Stagnant water bodies, common in endemic regions, favor transmission. Regional variations exist, with poor sanitation correlating to higher prevalence. Understanding the transmission process, identifying risky water bodies, and implementing preventive measures are key to mitigating schistosomiasis impact in endemic regions.


Symptoms and Diagnosis

The symptoms and diagnosis of schistosomiasis vary depending on the stage of the infection and the affected area of the body.


Early Symptoms of Schistosomiasis

Within days: After becoming infected, individuals may experience a rash or itchy skin,redness, and the appearance of small, raised bumps – Swimmer’s Itch (Cercarial Dermatitis)

Within 1-2 months: Fever, chills, cough, and muscle aches can develop. – Katayama Syndrome[4]

Some people may develop:

  • High temperature (fever)
  • Itchy, red, blotchy, and raised rash
  • Diarrhea
  • Muscle and joint pain
  • Abdominal pain
  • Cough
  • Itchy red bumps on the skin where the worms burrowed in


Chronic Symptoms and Long-Term Effects

Chronic schistosomiasis can lead to various symptoms and problems, such as

  • Anemia
  • Tummy pain and swelling
  • Diarrhea with blood
  • Blood in urine
  • Bladder and ureter fibrosis
  • Kidney damage
  • Bladder cancer in later stages
  • Genital lesions, vaginal bleeding, and pain during sexual intercourse in women
  • Persistent cough, wheezing, and shortness of breath in the case of heart and lung involvement


Diagnostic Methods

  • Stool or urine samples: Health care providers may ask for these samples to check for the presence of parasite eggs
  • Blood sample: A blood test can be conducted to detect evidence of infection. It is important to wait 6-8 weeks after the last exposure to contaminated water for accurate results
  • Microscopic examination: Samples are examined under a microscope to identify the presence of the parasite or its eggs

Early diagnosis and treatment are crucial in managing the infection and preventing long-term complications.As Schistosomiasis can present with a wide range of symptoms, and its diagnosis involves various laboratory tests to detect the presence of the parasite or its eggs in the body. Understanding the early and chronic symptoms of the infection is important for timely medical intervention and management.

Treatment and Management

The treatment and management of schistosomiasis involve various aspects, including available treatments, the use of praziquantel and other medications, and the appropriate timing to seek medical advice.

Available Treatments and Their Effectiveness,

  • Praziquantel: This is the recommended treatment for all forms of schistosomiasis. It is effective, safe, and low-cost.Praziquantel is most effective once the worms have grown a bit, so treatment may need to be repeated a few weeks after the first dose.[6]
  • Corticosteroids: In cases of schistosomiasis affecting the central nervous system (CNS), praziquantel is used in combination with glucocorticoids to reduce inflammation and suppress changes resulting from the killing of the parasites.
  • Inpatient Care: Acute schistosomiasis and Katayama fever may require inpatient care, with patients receiving antischistosomal drugs and corticosteroids, especially if acutely ill.

Praziquantel is the preferred and highly effective treatment for all species of schistosomes, playing a pivotal role in reducing the prevalence of schistosomiasis. It is a cornerstone of the World Health Organization’s (WHO) strategy for controlling the disease. In addition to praziquantel, corticosteroids may be utilized to address symptoms of acute schistosomiasis and Katayama fever, particularly when the central nervous system is affected, providing comprehensive management of the infection.


When to Seek Medical Advice

Early Symptoms: If you have been in an area where schistosomiasis is common and experience early symptoms such as fever, rash, abdominal pain, or muscle aches, it is important to seek medical advice for appropriate testing and treatment.

Chronic Symptoms: For individuals experiencing chronic symptoms such as anemia, blood in urine or stool, persistent cough, or other long-term effects associated with schistosomiasis, medical attention should be sought for ongoing management and care.[7]

It is important to seek medical advice promptly if you experience symptoms suggestive of schistosomiasis, as early diagnosis and treatment are essential for a successful outcome.

Prevention and Safety Measures for Schistosomiasis

Prevention and adherence to safety measures are crucial to reduce the risk of infection, particularly for travelers.[8]


Prevention Strategies

  1. Avoidance of Contaminated Water:
    • Schistosoma parasites primarily inhabit freshwater bodies. Avoid swimming, wading, or engaging in water-related activities in ponds, lakes, rivers, or streams in endemic areas.
    • Do not use untreated water for recreational activities, and be cautious when using water from unfamiliar sources.
  2. Proper Hygiene Practices:
    • Ensure good hygiene by washing hands thoroughly with soap and clean water, especially before handling food or after using the bathroom.
    • Avoid contact with potentially contaminated water during personal hygiene routines.
  3. Footwear Use:
    • Wear closed-toe shoes to minimize the risk of skin exposure to contaminated water or soil, which may harbor Schistosoma larvae.
  4. Educational Outreach:
    • Travelers should be educated about the risk of schistosomiasis in specific regions and informed about preventive measures.
    • Local authorities and health organizations can play a crucial role in raising awareness about the disease and promoting preventive behaviors.
  5. Water Treatment:
    • If access to safe water is uncertain, consider using water disinfection methods such as boiling, filtering, or using chemical disinfectants.
  6. Avoidance of Raw Seafood:
    • Certain species of freshwater snails, which are intermediate hosts for Schistosoma larvae, can be found in raw or undercooked freshwater seafood. Avoid consuming these foods in endemic areas.


Safety Measures for Travelers

  1. Pre-Travel Consultation:
    • Seek pre-travel medical advice, especially if visiting areas where schistosomiasis is endemic.
    • Discuss the risk of infection, receive information on preventive measures, and consider taking prophylactic medications if recommended by healthcare professionals.
  2. Avoid High-Risk Areas:
    • Identify and avoid high-risk areas with known schistosomiasis transmission, especially during the peak transmission seasons.
  3. Personal Protective Measures:
    • Use protective clothing, such as long-sleeved shirts and pants, to minimize skin exposure when in potential contact with contaminated water or soil.
  4. Post-Travel Vigilance:
    • Monitor health post-travel and seek medical attention promptly if symptoms such as fever, abdominal pain, or blood in urine occur, as they may indicate schistosomiasis infection.

Preventing schistosomiasis involves a combination of prudent behaviors, hygiene practices, and awareness, particularly for travelers in endemic areas. Adhering to these preventive strategies is essential for minimizing the risk of infection and ensuring the overall well-being of individuals in regions where schistosomiasis is prevalent.


Living with Schistosomiasis

Schistosomiasis, a parasitic infection caused by Schistosoma worms, can have a profound impact on an individual’s quality of life.[10] While treatment is available, some individuals may experience persistent symptoms or long-term consequences,delves into the challenges of living with schistosomiasis and strategies to enhance the overall well-being of affected individuals.

Impact on Quality of Life

  1. Chronic Symptoms:
    • Individuals with chronic schistosomiasis may experience a range of symptoms, including abdominal pain, diarrhea, and fatigue. These symptoms can significantly affect daily activities, work, and overall quality of life.
  2. Organ Damage:
    • Severe or longstanding infections can lead to organ damage, particularly in the liver, spleen, and bladder. This can result in complications such as liver fibrosis, bladder cancer, and impaired organ function, further impacting the quality of life.
  3. Fatigue and Weakness:
    • Chronic infections may contribute to persistent fatigue and weakness, making it challenging for individuals to engage in regular physical activities or work.
  4. Social Stigma:
    • In some communities, there may be a social stigma associated with schistosomiasis. This can lead to feelings of isolation and psychological distress, further impacting the mental well-being of affected individuals.
  5. School and Work:
    • Schistosomiasis can affect school attendance and performance in endemic areas, potentially limiting educational and economic opportunities. In workplaces, individuals may face challenges due to the impact of the disease on their energy levels and overall health.


Strategies for Managing Life with Schistosomiasis:

Managing life with schistosomiasis involves a holistic approach to address physical, social, and psychological well-being. Adhering to prescribed treatments, such as praziquantel, is crucial for preventing disease progression and alleviating symptoms.

Regular medical check-ups enable early intervention and management of potential complications, while adopting a healthy lifestyle, including balanced nutrition, exercise, and adequate rest, contributes to overall well-being and combats fatigue associated with the infection.

Seeking psychosocial support from family, friends, and community networks, along with accessing counseling services and support groups, is essential for managing the emotional impact of schistosomiasis.

Additionally, raising awareness in affected communities reduces stigma and promotes understanding, emphasizing preventive measures and early detection for improved health outcomes.

Combining medical interventions with healthy lifestyle choices and a supportive community enables individuals affected by schistosomiasis to better navigate the challenges and enhance their quality of life.


1.CDC – Schistosomiasis. Published 2024. Accessed January 22, 2024.

2.Cozzi D, Bertelli E, Savi E, et al. Ultrasound findings in urogenital schistosomiasis: a pictorial essay. Journal of Ultrasound. 2019;23(2):195-205. doi:

3.World. Schistosomiasis. Published February 2023. Accessed January 24, 2024.

4.Carbonell C, Rodríguez‐Alonso B, López‐Bernús A, et al. Clinical Spectrum of Schistosomiasis: An Update. Journal of Clinical Medicine. 2021;10(23):5521-5521. doi:

5.Colley DG, Bustinduy AL, W. Evan Secor, King CH. Human schistosomiasis. The Lancet. 2014;383(9936):2253-2264. doi:

6.Tamirat Hailegebriel, Endalkachew Nibret, Abaineh Munshea. Efficacy of Praziquantel for the Treatment of Human Schistosomiasis in Ethiopia: A Systematic Review and Meta-Analysis. Journal of Tropical Medicine. 2021;2021:1-12. doi:

7.CDC – Schistosomiasis – Disease. Published 2024. Accessed January 24, 2024.

8.Inobaya MT, Olveda RM, Thao N.P. Chau, Olveda DU, Ross AG. Prevention and control of schistosomiasis: a current perspective. Research and Reports in Tropical Medicine. Published online October 1, 2014:65-65. doi:

9.CDC – Schistosomiasis – Prevention & Control. Published 2024. Accessed January 24, 2024.

10.Jia TW, Utzinger J, Deng Y, et al. Quantifying Quality of Life and Disability of Patients with Advanced Schistosomiasis Japonica. PLOS Neglected Tropical Diseases. 2011;5(2):e966-e966. doi:

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