Schistosomiasis (Bilharzia) Clinical Presentation

Updated: Mar 08, 2023
  • Author: Shadab Hussain Ahmed, MD, FACP, FIDSA, AAHIVS; Chief Editor: Michael Stuart Bronze, MD  more...
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Acute manifestations

Individuals who have been exposed to fresh or salt water may develop a pruritic rash due to cercarial dermatitis (also called swimmer's itch). This has been described in North America as occurring via nonhuman avian schistosomes.

Patients with acute schistosomiasis (Katayama fever) present usually 4-8 weeks after contact with infested water. It occurs 2-8 weeks after exposure to S japonicum or S mansoni. Katayama fever is common in heavily infested areas where there is S japonicum. Wading and swimming in fresh water in tropical regions causes schistosomal trematodes to enter the body. Fever, lethargy, malaise, and myalgia are the most common symptoms of Katayama syndrome. Less common symptoms include cough, headache, anorexia, and rash (urticarial or papular). Right upper quadrant pain and bloody diarrhea also may occur. [45]

These symptoms mimic any acute viral, bacterial, or malarial illness. The distinguishing features from malaria include generalized urticaria, pruritic rash at the site of cercarial penetration (often the legs), eosinophilia, and lymphadenopathy. Consequently, acute illness often is missed unless schistosomiasis is suspected.

In acute schistosomiasis, patients may present with focal neurologic deficits.

Obtaining a careful travel history, including drinking water sources and recreational activities, is important. Symptoms are likely secondary to immune complex formation following egg deposition in tissues; the illness resembles serum sickness.

Chronic manifestations

Patients with symptomatic chronic schistosomiasis may present months to years after primary exposure. A complete lifelong travel history often is essential for diagnosis. Many patients do not have a clear history of acute schistosomiasis and many individuals have few or mild symptoms. Individuals with symptoms may present with nonspecific complaints reflecting their level of infection, the immune response to the eggs, the primary location of egg production for the schistosomal species involved (eg, mesenteric, bladder wall), the extent of hepatosplenic involvement, the extent of cardiopulmonary involvement, and the presence of ectopic sites (eg, CNS). Typically, disease onset is insidious.

S mansoni, S mekongi, S intercalatum, and S japonicum cause intestinal tract and liver disease. S haematobium only rarely causes intestinal or liver disease but characteristically causes urinary tract disease. [46] S hematobium also can cause genital involvement. In men, schistosomiasis can cause involvement of the epididymis, spermatic cord, testicles, and prostate.

In the early stage of hepatic schistosomiasis, dyspepsia, flatulence, and pain are present in the left hypochondrium due to spleen enlargement. Anemia or cor pulmonale may cause generalized pain, weakness, and shortness of breath. In the later stages, abdominal distention, lower limb edema, hematemesis, and melena can occur. Symptoms of liver failure are rare unless other infectious, toxic, or malignant causes of hepatitis are present. [47]

In patients with intestinal schistosomiasis, the following symptoms may occur:

  • Fatigue

  • Abdominal pain

  • Diarrhea

  • Dysentery

In patients with urinary schistosomiasis, the following symptoms may occur:

  • Dysuria

  • Urinary frequency

  • Terminal hematuria

Cardiopulmonary schistosomiasis may cause larval pneumonitis with a cough, mild wheezing, and a low-grade fever, while in schistosomal cor pulmonale, easy fatigability, palpitations, dyspnea on exertion, and hemoptysis are present.

CNS schistosomiasis causes the following:

  • Focal and generalized seizures

  • Headache

  • Myeloradiculopathy with lower limb and back pain, bladder dysfunction, paresthesia, and lower limb weakness

  • Transverse myelitis, back pain, and paraplegia from eggs reaching the conus medullaris and cauda equina

Dizziness, nausea, and increased intracranial pressure can occur with cerebellar schistosomiasis. [43] Visual scintillation from occipital mass has been described. [48]

Female genital schistosomiasis can involve the following symptoms:

  • Postcoital bleeding

  • Genital ulceration

  • Irregular menstruation

  • Pelvic pain


Physical Examination

Physical findings vary with the stage of illness, worm burden, worm location, and end-organ involvement.

Findings with acute schistosomiasis may include the following:

  • Generalized lymphadenopathy

  • Hepatosplenomegaly

  • Rash

  • Fever

  • Right upper quadrant tenderness

  • Urticaria

  • Bloody stool

Findings with chronic schistosomiasis may include the following:

  • Portal hypertension with abdominal distention, hepatosplenomegaly, pedal edema, pallor, distended abdominal veins, and ascites

  • Intestinal polyposis with heme-positive stool, pallor, and signs of malnutrition

  • CNS symptoms, including focal neurologic findings, seizures, and spinal cord lesions

  • Renal failure with anemia and hypertension

  • Cor pulmonale with signs of right heart failure

  • Genital lesions, including ulceration, hypertrophic lesions, or nodular lesions of the cervix, vulva, or vagina or vesicovaginal fistula (external vulvar or perianal) lesions develop in 30% of women; women develop uterine enlargement, menstrual disorders, cervicitis, and infertility [6] Such genital lesions increase vulnerability to HIV infection. [49]