Medical expert of the article
New publications
Schistosomiasis - Symptoms
Last reviewed: 04.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
[ Symptoms of urogenital schistosomiasis
Urogenital schistosomiasis is caused by Schistosoma haematobium. The male is 12-14 x 1 mm, the female is 18-20 x 0.25 mm. The eggs are elongated, oval, with a spine at one pole. The size of the eggs is 120-160 x 40-60 µm. The female lays eggs in small vessels of the bladder and genitals.
In the clinical course, three stages are distinguished: acute, chronic and the outcome stage.
Symptoms of urogenital schistosomiasis associated with the introduction of cercariae in the form of allergic dermatitis in non-immune individuals are rarely recorded. After 3-12 weeks of latent period, acute schistosomiasis may develop. Headaches, weakness, widespread pain in the back and limbs, loss of appetite, increased body temperature, especially in the evening, often with chills and heavy sweating, urticarial rash (inconstant) are observed; hypereosinophilia is characteristic (up to 50% and higher). The liver and spleen are often enlarged. Disorders of the cardiovascular system and respiratory organs are revealed.
The earliest symptoms of chronic urogenital schistosomiasis are hematuria, which is often terminal (drops of blood appear in the urine at the end of urination). Pain in the suprapubic region and perineum is noted. These symptoms of urogenital schistosomiasis are caused by the reaction of the bladder and genital tissues to the introduction of schistosome eggs. In later stages, cystitis caused by a secondary infection may occur. Cystoscopy reveals tubercles on the mucous membrane of the bladder (histologically, a conglomerate of specific granulomas) - whitish-yellow formations the size of a pinhead, as well as infiltrates, papillomatous growths, erosions, ulcers, "sand spots" - clusters of calcified schistosome eggs visible through the thinned mucous membrane. Stenosis of the ureters and fibrosis of the bladder neck create conditions for urine stagnation, formation of stones, and subsequently hydronephrosis and pyelonephritis. Damage to the genitals is also noted: in men - fibrosis of the spermatic cords, orchitis, prostatitis, in women - formation of papillomas and ulceration of the mucous membranes of the vagina and cervix. In the late period, formation of bladder fistulas and neoplasms of the genitourinary system is possible. Damage to the lungs and their vessels leads to hypertension in the pulmonary circulation: patients experience shortness of breath, a feeling of palpitations, signs of hypertrophy of the right ventricle of the heart.
Symptoms of intestinal schistosomiasis
Intestinal schistosomiasis is caused by S. mansoni. The male measures 10-12 x 1.2 mm, the female - 12-16 x 0.17 mm. The eggs (130-180 x 60-80 µm) are somewhat elongated, on the lateral surface of the shell, closer to one pole, there is a large spine curved toward the pole.
Soon after infection, dermatitis may also develop, followed by fever, weakness, headache. These symptoms of intestinal schistosomiasis last from 1 to 7-10 days.
Acute intestinal schistosomiasis is characterized by fever (remitting, intermittent, irregular), loss of appetite, nausea, vomiting, frequent loose stools, sometimes with dehydration; possible blood in the stool, abdominal pain, in some cases resembling the picture of "acute abdomen", cough with sputum, often tachycardia, arterial hypotension. Weakness, adynamia, less often - agitation are noted. In the blood - hypereosinophilia, leukocytosis. Sometimes hepatitis develops. Symptoms of acute intestinal schistosomiasis are observed during the first 3 months after infection.
In the chronic period of the disease, the main symptoms of intestinal schistosomiasis are associated with damage to the colon, especially its distal sections. Intestinal dysfunction occurs in the form of loose stools, alternating loose stools and constipation, or chronic constipation. Aching pains along the colon are noted. During exacerbations, a dysentery-like syndrome develops: stools are frequent, mucous-bloody: cramping pains in the abdomen, tenesmus, fever, as a rule, is absent. A fading exacerbation is replaced by constipation; anal fissures and hemorrhoids often form. During colonoscopy, hyperemia, edema of the mucous membrane, multiple point hemorrhages are recorded mainly in its distal sections; sometimes intestinal polyposis, infiltrates in the intestinal wall resembling a tumor are detected.
In schistosomiasis liver damage (hepatosplenomegaly), the outcome of the process is periportal fibrosis and cirrhosis of the liver. Regardless of intestinal symptoms, patients note the appearance of a "tumor" in the upper half of the abdomen. The pain is minor, a feeling of heaviness and discomfort is disturbing. The liver is enlarged, dense, its surface is lumpy. Biochemical parameters do not undergo significant changes until signs of decompensation of liver function appear. With the development of portal hypertension, the veins of the esophagus and stomach expand, and bleeding may occur as a result of their rupture. Decompensation of portal circulation is manifested by ascites. In this case, the spleen is also enlarged. With S. mansoni invasion, glomerulonephritis is recorded, which is caused by the formation and deposition of immune complexes.
Lung damage, if blood circulation is not impaired, does not produce noticeable clinical manifestations. If the pressure in the pulmonary artery exceeds 60 mm Hg, then typical signs of chronic "pulmonary" heart appear: shortness of breath, palpitations, increased fatigue, cough, cyanosis of the lips, epigastric pulsation, accent and bifurcation of the second tone over the pulmonary artery.
Intestinal intercalate schistosomiasis is caused by parasitism of S. intercalatum in the veins of the intestine, mesentery, and portal vein system. The disease occurs in limited foci in Africa and is pathogenetically and clinically similar to intestinal schistosomiasis caused by S. mansoni. The course of the disease is benign; cases of portal fibrosis have not been reported.
Symptoms of Japanese schistosomiasis
Japanese schistosomiasis is caused by S.japonicum. The male measures 9.5-17.8 x 0.55-0.97 mm, the female - 15-20 x 0.31-0.36 mm. The eggs (70-100 x 50-65 µm) are round, on the side closer to one pole there is a small spine.
The acute phase of the disease, known as Katayama disease, is much more common in Japanese schistosomiasis than in S. mansoni and S. haematobium infections. It can occur in different forms, from mild, asymptomatic to fulminant, with sudden onset, severe progression and death.
Chronic Japanese schistosomiasis primarily affects the intestines, liver and mesentery. Recent studies show that even among the most susceptible age group (children aged 10-14), gastrointestinal disorders are observed in only 44% of patients. Symptoms of Japanese schistosomiasis include diarrhea, constipation or alternation of the two; mucus and blood may be present in the stool; abdominal pain and flatulence are common. Appendicitis is sometimes detected. The introduction of eggs into the portal system leads to the development of periportal fibrosis 1-2 years after the invasion, followed by liver cirrhosis, all manifestations of portal hypertension and splenomegaly, with the spleen being able to increase to large sizes and become very dense. A severe and frequent complication of Japanese schistosomiasis is bleeding from the dilated veins of the esophagus. Lung lesions are of the same nature as in other forms of schistosomiasis, but with S.japonicum invasion they develop less frequently than with intestinal and urogenital schistosomiasis.
CNS damage may develop in 2-4% of those infected. Neurological symptoms of Japanese schistosomiasis appear as early as 6 weeks after infection, i.e. after the parasites begin to lay eggs; in most cases, these symptoms become noticeable during the first year of the disease. The most common symptom is Jacksonian epilepsy. Signs of encephalitis, meningoencephalitis, hemiplegia, and paralysis also develop. In advanced cases, bleeding from dilated veins of the esophagus, increasing cachexia, and secondary infection lead to the death of the patient.
Schistosomiasis caused by S. mekongi is registered in the Mekong River basin in Laos, Cambodia, Thailand. The eggs of its pathogen are similar to those of S. japonicum, but smaller. The pathogenesis and symptoms of S. mekongi schistosomiasis are identical to those of Japanese schistosomiasis.