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- Patient Comments: Schistosomiasis - Symptoms
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- Schistosomiasis facts
- What is schistosomiasis?
- What causes schistosomiasis?
- What are the symptoms and signs of schistosomiasis?
- How is schistosomiasis diagnosed?
- What is the treatment for schistosomiasis?
- When should people with schistosomiasis seek medical care?
- What are the complications of schistosomiasis?
- Can schistosomiasis be prevented?
- What is the prognosis (outcome) for schistosomiasis?
How is schistosomiasis diagnosed?
The presumptive diagnosis of schistosomiasis is based on the medical caregiver's history and physical examination of the patient. It is important to know that a person has inhabited or visited areas of the world where the disease is endemic, especially if the person has had skin exposure to freshwater lakes and streams. If the patient has that history and has symptoms that are described above, a presumptive diagnosis may be made. However, because symptoms of schistosomiasis resemble those of serum sickness and other diseases, definitive diagnostic tests are usually required. Thick fecal smears and urine concentration tests are used to determine if any Schistosoma spp. eggs are present. If eggs are found, the patient is definitively diagnosed with schistosomiasis. In addition, most eggs from each species are shaped differently so it is possible to determine which Schistosoma spp. is infecting the patient. Sometimes the definitive diagnosis is made by examination of biopsy samples of tissue, when the eggs are visualized in the infected tissue.
Blood tests and, more recently, polymerase chain reaction (PCR) tests can help confirm the diagnosis, but positive results may only indicate past exposure. However, these tests are not usually positive until the patient has been infected for about six to eight weeks because it takes time for the eggs to develop and stimulate the human immune response. The PCR test is available from the U.S. Centers for Disease Control and Prevention.
Many other tests and procedures may be necessary to establish the diagnosis, especially if no eggs are found in the feces or urine, which is often the situation in chronic schistosomiasis. Colonoscopy, cystoscopy, endoscopy, and liver biopsy are all methods that can be used to obtain tissue biopsy material. In addition, ultrasound, chest X-rays, CT scan, MRI, and echocardiograms may be used to determine the extent of the infection in various organ systems. Most physicians will run additional blood tests (complete blood count [CBC], liver function tests, renal function tests) to determine if organs have been damaged by the parasites.