How to prevent and control coccidiosis in nutria? Farmers need to master the methods

Pathogen 1 The pathogen of coccidiosis (C. ccidiosis) is the coccidium of the class Sporozoa, a parasitic single-celled protozoan. Coccidia parasitize the epithelial cells of the small intestinal mucosa, and through asexual reproduction (schizogony) for many generations, they produce many new individuals. After several schizogonic reproductions, they carry out sexual reproduction (gametogony), forming many macrogametes (female) and microgametes (male); the macro- and microgametes enter the intestinal tract, where fusion occurs, and after fertilization the macrogamete is covered with a double-layered membrane and becomes an oocyst, which is excreted from the body with the feces. Oocysts have strong resistance to disinfectants, but die within a few days in dry air. At a temperature of 55C they are killed after 15 minutes; at a water temperature of 80C they are killed after 10 seconds; at 100C they die after 5 seconds. (Epidemiology) Nutria of all ages are susceptible to coccidiosis, but 1-2 month old pups are the most susceptible and also have the highest mortality rate. Adult female nutria often become carriers of coccidiosis and are the main source of infection for the disease in pups.

This disease is often transmitted through contaminated feed, drinking water, pens and equipment. Wild rats, house mice and flies may also become transmission vectors. (Clinical symptoms) The body temperature of sick nutria drops from 37—38~C to 35.5—36C, with poor appetite, depression, diarrhea, blood-tinged mucus in the feces, dull coat, abdominal distension, gas production in the intestines, and reluctance to move. Due to the mechanical, toxic and bacterial involvement, the sick nutria develop disorders of the nervous system, resulting in a series of disturbances, such as liver dysfunction, impaired material metabolism, indigestion, cerebral anemia, vascular fragility and increased permeability. In cases of mild coccidial infection and in most adult nutria, the clinical symptoms are not obvious, while pups die 10—15 days after the appearance of clinical symptoms. (Pathological necropsy changes) The carcass is highly emaciated, anemic, with ascites and an empty stomach. The liver, spleen and kidneys are congested. The small intestinal mucosa shows catarrhal inflammation, and the affected areas are often covered with erosive patches. In chronic cases? There are grayish-white nodules in the mucosal layer of the small intestine, filled with coccidial oocysts. In those suffering from the hepatic type of coccidiosis, the liver shows symptoms of jaundice.

Factors such as an incomplete nutritional value of the diet, lack of vitamins and minerals, insufficient drinking water, and poor sanitation of the water pool and pens can all aggravate this disease. (Diagnosis) Finding coccidial oocysts in the feces of sick nutria is the main basis for diagnosing this disease. Based on pathological anatomical changes such as inflammatory lesions, erosions, ulcers and nodules, as well as microscopic examination of scrapings from the small intestinal mucosa revealing large numbers of coccidia at different developmental stages, a definitive diagnosis can be made. (Prevention and control measures) For affected young nutria, orally administer phthalylsulfathiazole 0.1 g per animal per dose, twice daily; for adult nutria, 0.2 g, for 5—7 consecutive days. This drug can also be dissolved in drinking water for the sick nutria to drink on their own, at a dose of 0.4-0.5 g per animal per day. Orally administer sulfadimethoxine 0.5 g per kg body weight per day for 5 consecutive days. To prevent this disease, a 0.1% iodine tincture solution can be used as drinking water for 10 consecutive days, then discontinued for 5 days, and then given again. The most ideal measure for preventing coccidiosis in nutria is: keep the pens clean and dry at ordinary times, replace the bedding at any time, regularly disinfect the nest chambers with a flame torch or hot cresol solution, and frequently disinfect feeding utensils with a 2—3% creolin solution. The feces of sick nutria contain large numbers of coccidial oocysts, so the feces must be properly handled, and only after biological fermentation treatment can they be used as farmyard manure.