The symptoms of schistosomiasis depend on the type of infection and where the parasites are in the body.
The symptoms can follow one of two patterns:
- acute schistosomiasis – symptoms develop a few weeks after infection with the parasites
- chronic schistosomiasis – symptoms develop months, or possibly years, after infection with the parasites
Chronic schistosomiasis is the most common type of infection. Some people have acute schistosomiasis followed by chronic schistosomiasis, but most people will only have one or the other.
The symptoms of acute schistosomiasis are not directly caused by the parasites, but by your immune system (the body's defence against infection) reacting to the parasites.
- a high temperature (fever) above 38ºC (100.4ºF)
- joint and muscle pain
- bloody diarrhoea
- a dark red, blotchy, raised skin rash
- pain in the abdomen
- a general sense of feeling unwell
In many cases, the symptoms usually get better by themselves within a few weeks. However, it is still important to seek treatment as the parasites will stay in your body and chronic schistosomiasis will develop. This does not always lead to symptoms, but the infection will remain and problems may develop at a later date.
If schistosomiasis is not treated, the parasites remain in your body and will go on to cause further symptoms. The immune system reacting to the eggs may damage your organs, but fails to kill the parasites.
The symptoms of chronic schistosomiasis depend on where in the body the parasites have travelled to.
If the parasites travel to the digestive system, they can cause the following symptoms:
- feeling tired all the time (fatigue)
- abdominal pain
- bowel problems – such as mild or severe watery diarrhoea that contains blood and mucus
If the parasites travel to the urinary system, they can cause the following symptoms:
- symptoms of cystitis – such as pain when urinating
- frequent need to urinate
- blood in your urine
If the parasites travel to the heart or lungs, they can cause the following symptoms:
- persistent cough – in some cases, people cough up blood
- feeling breathless and very tired after physical activity
If the parasites travel to the central nervous system or brain, they can cause the following symptoms:
- seizures (fits)
- back pain
- urinary incontinence
- weakness and numbness in your legs
- feeling sick
The parasites can also sometimes travel to the female genitals, where they can cause the following symptoms:
- bleeding after sex
- genital ulcers
- irregular menstruation
- pelvic pain
When to seek medical advice
Contact your GP if you develop any of the symptoms above and you have travelled in parts of the world where schistosomiasis is widespread, particularly countries in sub-Saharan Africa, such as East Africa, Malawi or South Africa.