Schistosomiasis, also termed as Bilharzia, Snail fever or Katayama fever is an acute and chronic infectious parasitic disease caused by the flatworms of the Schistosoma genus which includes Schistosoma mansoni, Schistosoma japonicum and Schistosoma haematobium. The infection is usually transmitted when humans come in contact with freshwater contaminated with the parasites. Also Read: Swimmer’s Itch: Causes, Symptoms, And Treatment


When an infected person washes urine or faecal matter in the freshwater, the larvae hatched from the eggs present in the faeces infects a specific type of freshwater snail depending upon the genus of the parasite. The parasitic larvae then grow and reproduce within the snail and are again released back into the water. Humans get infected with these parasites during their routine agricultural, occupational, domestic, and recreational activities like bathing, swimming, playing, washing, fishing, or just walking through the water.

The parasite then enters the human body, reaches the maturity stage, mates and produces eggs. These eggs travel through body fluids and enter the intestines and bladder and are excreted through faeces or urine within the water bodies, thus completing the life cycle of the parasite. Eggs unable to pass through the body wastes, often get attached to body tissues leading on to a variety of immunomodulatory reactions which cause the disease.

People who are in the profession of farming, fishing or using unclean water for their daily work activities or children playing in the unhygienic water or women doing their domestic chores in the contaminated water are more at risk of getting infected through the parasite. Also Read: Parasitic Infections Can Affect Kids With Weaker Immunity

In certain cases, the infection if not treated on time can also lead to chronic conditions like katayama fever, neural disease, genitourinary disease, high blood pressure, seizure, paralysis, organ damage and even death.


Signs and symptoms usually develop within days of getting infected and may continue for 1-2 months. The symptoms are usually due to the body’s response towards the eggs that have latched itself with the tissues and not for the worms itself. They mostly include:

  • Rash or itchy skin
  • Fever and chills
  • Cough
  • Muscle pain
  • Headache
  • Abdominal Pain

A more severe form of infection can lead to:

  • Paralysis
  • Spinal cord inflammation
  • Seizures
  • Bloody diarrhoea
  • Chest pain
  • Lesions
  • Liver damage
  • Lung damage
  • Bladder damage
  • Intestine damage

Diagnosis and Treatment

It is strictly advisable to consult a doctor if you notice any of the following above mentioned symptoms. The doctor usually acknowledges the patients past medical history and does a thorough physical check-up followed by blood tests, urine and stool test to analyse the presence of the parasitic eggs in them. Further diagnosis to understand the extent of infection includes:

  • ELISA Test i.e. Enzyme-linked Immunosorbent Assay
  • Alkaline Phosphatase Immunoassay
  • Polymerase Chain Reaction Test
  • Circumoval Precipitation Test
  • Kato Technique
  • Imaging techniques include Ultrasound, CT-Scan, MRI and ECG

Treatment options usually depend on the extent of infection. Depending on that and the type of parasite causing the infection, the doctor generally prescribes for some specific medication to remove the parasitic eggs from the body and neutralise the immunomodulatory reactions.

In chronic conditions, the doctor may also suggest some surgical procedures including removal of the tumour mass, shunt surgery, ligation of oesophageal varices, and removal of granuloma.


Schistosomiasis can also be prevented by avoiding usage of infected water, from unhygienic areas which might be at risk of the infection. People should take proper precautions while bathing and swimming in freshwater, drinking tap water, eating food washed in water etc.

Even addition of chlorine to water doesn’t possibly kill the germs, hence one should always use packaged drinking water or boil the water before using it for any purpose when they are staying an infection-prone surrounding.