What are the diagnostic points and prevention and treatment methods for swine paratyphoid?

Swine paratyphoid, also known as swine salmonellosis, is an infectious disease of piglets caused by Salmonella. Acute cases show septicemic changes, while chronic cases show necrotizing inflammation of the large intestine and pneumonia.
(1) Diagnostic points:
This disease mainly occurs in piglets aged 1-4 months, so it is also called piglet paratyphoid. Adult pigs rarely develop the disease. It often occurs sporadically or as a local epidemic, and can occur in all four seasons, but poor feeding and management, rainy and humid conditions, cold, and long-distance transport can promote the occurrence and spread of this disease.
Acute: body temperature rises to about 42°C, loss of appetite, tendency to burrow into bedding straw, sometimes vomiting, first constipation then diarrhea, sometimes blood in the feces, feces grayish-black-green and foul-smelling. The skin of the ears, abdomen, and inner thighs is bright red, later turning purple. Most affected pigs die.
Chronic: slight fever, rough coat, poor appetite, but likes to drink water, diarrhea, foul-smelling feces, affected pigs gradually become emaciated, sometimes they can recover, but growth is poor.
Necropsy lesions: in acute cases, the gastrointestinal mucosa is congested, hemorrhagic, swollen and thickened; there are hemorrhagic spots in the renal cortex, endocardium and epicardium, and pleura; the spleen is enlarged; the liver has grayish-white nodules. In chronic cases, there are relatively large necrotic areas covered with bran-like pseudomembranes, beneath which are sunken ulcerated surfaces; the lymph nodes and lungs show caseous necrosis.
(2) Prevention and treatment methods:
1. Strengthen feeding and management to enhance the body's resistance. In herds where this disease commonly occurs, antibacterial drugs such as oxytetracycline and chlortetracycline can be added to the feed. If drug resistance develops, switch to other drugs. When this disease is found, isolate and disinfect immediately, and deeply bury dead pigs to prevent the spread of the virus and poisoning after human consumption.
2. Vaccinate with live piglet paratyphoid vaccine; the usage and dosage should follow the bottle label instructions.
3. Treatment——Among antibiotic therapies, the most commonly used are oxytetracycline, neomycin, and doxycycline. Oxytetracycline: oral, 50-100 mg per kg body weight per day, divided into 2-3 doses; intramuscular injection, 40 mg per kg body weight once. Neomycin: oral, 5-15 mg per kg body weight per day, divided into 2-3 doses. Doxycycline: oral, 2-5 mg per kg body weight, once daily. Sulfonamide-potentiator combinations have relatively good efficacy. Sulfamethoxazole or sulfadiazine 20-40 mg per kg body weight, plus trimethoprim 4-8 mg per kg body weight, mixed and divided into two oral doses, used continuously for one week. Or use compound sulfamethoxazole, 70 mg per kg body weight, doubled for the first dose, orally twice daily, used continuously for 3-7 days. Furazolidone, 20-40 mg per kg body weight per day, divided into two oral doses. After continuous use for 3-5 days, halve the dose and continue for another 3-5 days. (This content is excerpted from "100 Questions and Answers on Scientific Pig Farming", compiled and printed by the Yingtan City Association of Old Science and Technology Workers, authored by Zhang Genkai.)