Overview
Schizothoracic tapeworm is a disease caused by the parasitization of the human intestinal tract by the broad-jointed Schizothoracic tapeworm. It is mostly found in the lakes and water areas in the sub-frigid and temperate zones, and is prevalent in Europe, North America and some Asian countries, such as Japan, Korea and the Philippines, and a few cases have been reported in Northeastern China.
Etiology
Adult tapeworms are very similar in appearance and structure to the Mannheimer’s tapeworm, with a narrow and deeply concave suction groove on the dorsal and ventral sides of the head joints, and the male genital pore and the vaginal opening together in the genital cavity on the ventral surface of the anterior part of the joints. It is the largest parasite among the tapeworms. The length of 4-6m, the body of the worm sometimes up to 10m, the widest place 20mm, with 3000-4000 segments. The eggs are nearly ovoid, 55-76µm long and 41-56µm wide, light grayish brown, with a thick shell, a distinct egg cap at one end and a small spine at the other; when the eggs are discharged, the embryo inside the egg has begun to develop.
Symptoms
In general, patients do not show any particularly obvious symptoms after infection. In severe cases, digestive disorders and anemia are the main symptoms. Occasionally, there will be fatigue, weakness of the limbs, diarrhea or intermittent constipation, or symptoms such as hunger and salt craving. When the number of parasites in the body is large, some of the worms can be twisted into a ball, resulting in obstruction of the intestines and bile ducts, and even intestinal perforation may occur. Vitamin B12 deficiency and megaloblastic anemia can occur. Half of the patients without anemia also have low serum levels of vitamin B12. Migration may occur leading to bile or cholangitis.
Examination
1. Blood picture
The white blood cell count is mostly normal, and the eosinophil count is mildly elevated.
2. Bone marrow picture and special tests
Such as vitamin B12 and folic acid measurement, vitamin B12 absorption test, etc., can confirm the diagnosis of megaloblastic anemia.
3. Biopsy
Biopsy of subcutaneous mass and eyelid nodule can find worms. Pathological examination shows eosinophilic granuloma, and the center of the lesion is a cross section of the worm.
4. Fecal examination
Eggs or nodules are detected in the feces of patients.
Diagnosis
Diagnosis is made when eggs or segments are detected in the feces.
Differential diagnosis
1. Ocular schistosomiasis, especially postbulbar infection leading to convex eyes, should be differentiated from retinoblastoma.
2. It should be differentiated from cysticercosis and schistosomiasis.
Complications
Biliary tract obstruction and intestinal perforation may occur.
Treatment
Praziquantel is taken at once. Clonidine (tapeworm), mebendazole (mebendazole), and albendazole (propylthioimidazole) have anthelmintic effects. After the worms are expelled, the anemia can be self-cured. If the anemia is severe, vitamin B12 can be injected into the muscle.
Prevention
The main thing is to publicize and educate. Change the unhygienic habit of eating fish, like to eat raw fish and fish fillets, or with a small amount of salt, smoked fish or fish eggs, fruit juice soaked fish and taste in the process of cooking fish are very susceptible to infection. Strengthen the management of dogs, cats and other animals to avoid fecal contamination of rivers and lakes, and proper disposal of sewage may reduce the risk of infection by fish.