The disease is a trematodiasis caused by anterior and posterior disc fluke parasitism on the rumen and bile duct walls of cattle. The pathogenicity of the adult stage is not strong, and when the number of parasites in the larvae is large, it can cause serious disease. In the southern region of China, the epidemic is serious, perennial infection, the infection in the northern region is mainly in May to October, the disease mostly occurs in the rainy summer and autumn, the general young adult cattle due to large feeding, swallow more infectious cysticers, the disease is serious.
(1) The etiological insect body is conical or spindle-shaped, milky white, and the size is (8.8~9.6) mm × (4.0~4.4) mm. Adult worms parasitized in the rumen of end-host cattle lay eggs, the eggs are excreted with feces, under suitable conditions in the outside world, the eggs hatch in water to produce hairy cymbals, hairy worms drill into the snail, through the cytocys, thunderturgy stage into tail cymbals, after maturity escape from the snail, forming cysticers on aquatic weeds. When cattle swallow aquatic weeds containing cysticers, the cysticers reach the intestine and descapsulate and become larvae, the larvae first parasitize in the small intestine, bile ducts, gallbladder and wrinkled stomach for 3 to 8 weeks, and finally reach the rumen to develop adults.
(2) Key points of diagnosis 1. Epidemiology in the southern region of China is serious, perennial infection, the northern region infection is mainly in May to October, the disease mostly occurs in the rainy summer and autumn, the general young adult cattle due to large feeding, swallow more infectious cysticer, the disease is serious. 2. Symptoms The main symptoms of larval infection are stubborn thinning, porridge or watery stool, often fishy odor. Body temperature sometimes rises, appetite loss, emaciation in sick cattle, submandibular edema, and in severe cases progresses to the entire head and the whole body. After a long course of illness, a malignant state appeared, the sick cattle gradually lost weight, high anemia, pale mucous membranes, thin blood, and in the later stage, the sick cattle were extremely emaciated, lying on the ground, and finally died of exhaustion. Adult infections cause mild symptoms and can sometimes be emaciated, anemic, and edematous. 3. Pathological changes Autopsy can show the edema of the small intestine and wrinkle gastric mucosa caused by the migration of larvae, the formation of bleeding spots and hemorrhagic enteritis, in severe cases, necrosis and fibrous inflammation of the intestinal mucosa, the intestine is full of smelly thin feces; the cecum and colon lymphatic follicles are swollen, necrotic, and some ulcers are formed; the bile ducts and gallbladder are expanded; the small intestine, the stomach and the bile ducts and gallbladder can be seen in different numbers of larvae. 4. Laboratory tests for larvae can be used for diagnostic treatment with larval repellent drugs. Stool egg examination Eggs can be examined by fecal wash and precipitate method or direct smear method.
(3) Prevention and treatment 1 Treatment can be treated with the following methods. (1) The dose of niclosamide is 60 to 70 mg per kilogram of body weight, orally once. (2) The dose of thiobidichlorophenol is 40 to 50 mg per kilogram of body weight, once taken orally, the drug has a diarrhea effect, and severe diarrhea and weak sick cattle are banned or used with caution. (3) Bromohydroxyteaniline dosage at 65 mg per kilogram of body weight, made into a suspension, once taken orally. 2. Prevention Regular deworming to prevent pollution. Elimination of intermediate hosts, feces must be treated, etc. Editor: Zhao Lin Review Expert: Zhang Yuanqing, Associate Researcher, Institute of Animal Husbandry and Veterinary Medicine, Shanxi Academy of Agricultural Sciences
【Source: Popular Science China Network】
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