What are the obvious symptoms of schistosomiasis?

Schistosomiasis is a chronic parasitic disease that is particularly prevalent in Asian, African and Latin American countries. Common symptoms of the disease are fever, sometimes as high as 39 to 40 degrees Celsius. Some patients will show gastrointestinal symptoms, such as congestion and edema of the intestinal mucosa, or necrosis of the surface mucosa, forming ulcers, etc. Some patients will also have symptoms of enlarged liver and spleen and congestion.

1. Fever: It is the main symptom of this period. The degree, duration and type of fever vary depending on the severity of the infection. The fever pattern is irregular and may be intermittent or remittent, with the temperature mostly between 39 and 40°C, accompanied by chills and night sweats. The fever can last for weeks to months. The fever of mild patients is lower, generally not exceeding 38°C, and it will subside automatically after only a few days.

2. Gastrointestinal symptoms: Worm eggs are deposited in large quantities in the intestine, especially in the descending colon, sigmoid colon and rectum, causing acute inflammation, and the patient experiences abdominal pain and diarrhea. Due to intestinal eosinophilic abscesses, the surface mucosa may necrotize and form ulcers, so the stool often presents as dysentery, which may contain blood and mucus. If a sigmoidoscopy is performed at this time, congestion and edema of the mucosa can be seen, and small yellow particles (worm egg nodules) and a few ulcers can be found. In patients with severe infection, due to the large deposition of worm eggs in the colon serosa and mesentery, peritoneal irritation symptoms may occur, abdominal distension, flexibility and tenderness, which may be misdiagnosed as tuberculous peritonitis. In a small number of patients, the inflammatory exudation caused by the worm egg nodules and the worm eggs may cause extensive liver lesions, resulting in poor blood flow in the liver, increased lymph leakage into the abdominal cavity and the formation of ascites.

3. Hepatosplenomegaly: The vast majority of patients in the acute phase have an enlarged liver due to the formation of a large number of worm egg nodules, which cause congestion and edema of the surrounding tissues, resulting in a rapid enlargement of the liver, which is soft and painful to percussion. Both the left and right lobes were enlarged, with the right lobe being more obvious, which may be related to the fact that the inferior mesenteric venous blood flow mainly returns to the right lobe of the liver. The spleen becomes congested and swollen due to the stimulation of the worm egg toxins and can be clearly felt.

4. Lung symptoms: Cough is quite common, and there may be symptoms such as chest pain and bloody sputum. There are no obvious lung signs, but X-rays may show increased lung striae, flake-like shadows, and miliary changes.