Schistosomiasis: Part 3

Clinical Presentation

Symptoms vary with the species of worm and the phase of infection. Itching and rash at site of invasion of the cercariae is often the first sign of infection (commonly known as Swimmer's Itch). Fever, pruritis, localized edema and allergic reactions may occur immediately afterwards 3 . Large invasions may cause fever, chills, and lymph node, liver, and spleen enlargement

After this initial phase one to three months may pass before the acute phase of the disease is manifested. As the mature flukes lay eggs in the mesenteric or vesical venules patients may complain of fever and abdominal pain. Granulomas in the liver and “pipestem fibrosis” of the portal and associated veins may form as well. These granulomas are caused by deposits of eggs lodging in the small hepatic venules (John, Petri). Hepatosplenomegaly and lymphadenopathy are usual.

Chronic Schistosomiasis may present in a wide variety of forms:

Urinary schistosomiasis usually caused by S. haematobium– painful urination (dysuria), and blood in urine (hematuria). Heavy egg deposits can become trapped in the bladder walls, causing papillomas and ulceration. As these eggs burst through the bladder wall they cause the damage that can contribute to hematuria. They are also associated with greatly increased incidence of squamous cell carcinoma of the bladder 3 .

Intestinal Schistosomiasis caused by S. japonicum, S. mansoni – Large intestine is usually the focus of the infection. Victims experience abdominal pain and diarrhea that may be bloody. This is due to eggs lodged in the tissue of the intestine exiting into the lumen and causing tissue damage as they depart. Complications may include kidney and bladder obstruction, chronic renal failure, bladder cancer, chronic liver damage, enlarged spleen, colon inflammation with bloody diarrhea, pulmonary hypertension, right sided heart failure, seizures, recurrent blood infections 3 .

Cerebral Schistosomiasis is most commonly caused by S. japonicum; egg deposits can cause local damage and legions in the CNS, or more severe problems rooted in capillary blockage and subsequent ischemia 3 .

Several other disorders are commonly correlated with chronic schistosomiasis: Colon and liver cancer risk increases with prolonged schistosomiasis infection. Chronic schistosomiasis is sometimes also associated with chronic salmonellosis, and it is probable that the bacteria and the trematodes are more than coincidentally connected 3 .

Case History

“My aunt died in San Jose 1991 of Schistosomiasis infection after moving to the United States in 1980. At that time, most of the Doctors in the area were unaware of Schistosomiasis and its symptoms. My Aunt's symptoms were high fever, a bitter taste in her mouth which prevented her from eating well, and a large painful area on the side of her stomach. She was a healthy person before these symptoms arose, so we were concerned when she began to feel ill and not eat. When her fever was high and she felt awful, so she kept going to her doctor, but her doctor kept telling her that it was nothing serious. When her symptoms worsened, she had to be hospitalized. One of the doctors that saw her suspected that she had an infectious disease, so he contacted a doctor at Stanford who worked with the Asian population. He figured out that she had schistosomiasis, but she had been so sick for a very long time and ended up dying within three months.” 8



3 John, David T and William A. Petri, Jr. Markell and Voge's Medical Parasitology. 9th ed. United States: Saunders Elsevier, 2006. 181-196.

8 Seng Singh. Personal interview. 17 May 2006.

img10 Blankespoor, Harvey B. and Ronald L. Reimink. Swimmer’s Itch. 17 May 2006.