Symptoms and Prevention and Treatment Methods of Swine Trichinosis
It is caused by the adult trichina parasitizing the intestinal tract and its larvae parasitizing striated muscle. This disease is mainly seen in pigs, and rats, dogs, cats, etc. are also susceptible to infection. It is also a zoonotic parasitic disease that is highly harmful to humans.
1. Pathogen The adult trichina is a slender nematode. The male is 1.4-1.6 mm long, and the female is 3-4 mm long. The larvae parasitizing in the muscles can be up to 1.15 mm long, curling between muscle fibers to form cysts. The two ends of the cyst are bluntly spindle-shaped, about 0.5-0.8 mm long.
Pigs are infected mainly after eating rats and scraps of diseased pork containing trichinae. The larvae become mature intestinal trichinae in the duodenum and jejunum within 2 days. After fertilization, the female begins to produce large numbers of larvae on the 5th-6th day, and the male dies after mating. The female's life span is 25-45 days, and 1 female can produce 1500-10000 larvae. The larvae enter the blood through the lymph, then enter the striated muscle to grow and develop and form cysts. Therefore, animals suffering from trichinosis are both the final host and the intermediate host of trichinae.
2. Symptoms Clinical symptoms appear only in severe infections. After infection, body temperature rises on days 3-7, with diarrhea and sometimes vomiting. Affected pigs become emaciated, and afterward show muscle stiffness and pain, difficulty breathing, hoarse vocalization, and sometimes facial edema, difficulty swallowing, and other symptoms.
3. Necropsy The sites where muscle trichinae are commonly parasitic are the diaphragm, tongue muscle, laryngeal muscle, intercostal muscle, and costal pleura, etc. The cysts are not easy to see with the naked eye. After calcification, the cysts are gray small nodules about 1 mm long.
4. Diagnosis Take a small piece of muscle from a site prone to parasitism, cut it into wheat-grain-sized pieces, press it thin with a glass slide, and examine it under a low-power microscope.
5. Prevention Strengthen sanitation inspection at slaughter. Diseased pork should be used only after high-temperature treatment. Exterminate rats around the breeding farm, and burn the carcasses of diseased rats. Do not graze pigs, and prevent contact with animal carcasses and some insects. Do not feed raw meat scraps to pigs.
6. Treatment Albendazole, 80-100 mg per kg of body weight, mixed into feed and fed, once in the morning and once in the evening, for 6 consecutive days, is effective.