News briefing： Rabbit coccidiosis is a disease of rabbits caused by several coccidiosis of the genus Eimeria in the family Eimeria. The symptoms of rabbit coccidiosis can be divided into intestinal type, hepatic type and mixed type according to the different species and

Rabbit coccidiosis is a disease of rabbits caused by several coccidiosis of the genus Eimeria in the family Eimeria. The symptoms of rabbit coccidiosis can be divided into intestinal type, hepatic type and mixed type according to the different species and parasitic sites of coccidiosis, but the clinical findings are mostly mixed type. Its typical symptoms are coarse hair disorder, loss of appetite or abandoned, depression, slow movement, lying still, eyes, nose secretions increase, the mouth around the hair damp, diarrhea or diarrhea and constipation alternately. The sick rabbits were weak and emaciated, the conjunctiva was pale, and the visible mucosa was slightly yellow-stained. Rabbit coccidiosis is a common disease in rabbits, which is widely distributed in the world. Especially the young rabbits within 3 months of age, often cause a large number of deaths, to bring huge losses to the rabbit industry. The prevention and treatment of rabbit coccidiosis are often combined with the comprehensive prevention and control measures. Rabbit coccidiosis was listed in the list of quarantine diseases of entry animals of the People's Republic of China, which was issued on July 3,2020. It was classified as a second class infectious disease.

The pathogen of rabbit coccidiosis is a variety of coccidiosis of the genus Eimeria in the family Eimeria. One of the common Eimeria stephensi, medium-sized eimeria, large eimeria, Eimeria residue-free eimeria, intestinal Eimeria and so on. Eimeria stephensi is one of the most virulent coccidiosis in rabbits. It infects the epithelial cells of the hepatic bile duct and causes severe hepatic coccidiosis. The egg is large, oblong, yellowish, (26-40) μm × (16-25) μm in size. The egg membrane foramen one end is more flat, has the sporangium remnant body, assumes the granule shape. The sporangium is ovoid and steely. Sporulation time 41-51 hours. Eimeria medium Eimeria is parasitic on the jejunum and duodenum and can cause severe coccidiosis. Oocysts are of medium size, short elliptic, yellowish, with membranous foramen. The size is (18.6-33.3) μm × (13.3-21.3) μm, and the sporulation time is 42-72. Large Eimeria parasitic in the small and large intestine, the pathogenicity is very strong. The oocysts are large, ovoid, yellowish, and have prominent membranous foramina (figs. 6-17,6-18) . The size is (26.6-41.3) μm × (17.3-29.3) μm. The sporulation time was 32-48 hours. Eimeria invulnerable parasitic in the middle of the small intestine, the pathogenicity is strong. Oocysts are long oval or ovoid, yellowish. The egg membrane foramen is obvious, inside the egg sac does not have the remnant body. The size is (25.3-47.8) μm × (15.9-27.9) μm, and the sporulation time is 72-96. Eimeria enterocolitica is a highly pathogenic parasite of the small intestine (except the duodenum) . The oocyst was pear-shaped, with a prominent membranous foramen at the narrow end. There was an obvious remnant in the sporulated oocyst. The size is (24.7-31.0) μm × (17.8-23.3) μm, and the sporulation time is 24-48.

The development of Rabbit Eimeria necatrix with folding life habit all goes through 3 stages: merozoites, gametophytes and spores. The first two stages were carried out in bile duct epithelial cells or intestinal epithelial cells, and sporulation was carried out in the external environment. The mature sporulated oocysts are swallowed by the rabbits when they drink water or eat. The sporozoites escape into the intestine and develop into enterocytes or cholangiocytes, which then develop into merozoites. The merozoites in the merozoites invade the epithelial cells of the intestine or hepatobiliary duct for the second, third, even the fourth and fifth generation merozoites, and seriously destroy the epithelial cells, causes the rabbit to appear the serious enteritis or the hepatitis. After merogenesis, some merozoites become large gametes or small gametes, large and small gametes combined to form zygotes and oocysts. The oocysts were excreted in feces and sporulated to form sporulated oocysts under suitable external conditions.

Because of the different species and parasitic sites of coccidiosis, the symptoms can be divided into hepatic coccidiosis and intestinal coccidiosis clinically, but in fact, the mixed infection is the most common. The parasite, which lives in the epithelial cells of hepatic bile duct and intestinal epithelial cells, destroys a large number of epithelial cells and destroys the integrity of bile duct and intestinal mucosa, the animal's central nervous system function is disrupted, resulting in chronic starvation, edema, and the occurrence of hemodilution and leukopenia. Due to the collapse of intestinal epithelial cells, the environment conducive to the proliferation of spoilage bacteria, resulting in a large number of toxic substances in intestinal contents, after being absorbed, poisoning, clinical manifestations of spasticity, collapse, intestinal distention and cerebral anemia. Can also cause loss of appetite or waste, depression, lying on the ground, eyes, eyes and nose secretion increase, anemia, diarrhea, growth arrest of young rabbits. The anus is often polluted by feces, abdominal distention. When the liver was damaged, palpation of the liver area was painful, and the visual mucosa was slightly yellow. At the later stage of the disease, the young rabbits developed neurologic symptoms, limb spasms, paralysis, and died of high degree of failure. The mortality rate is 50-60% , sometimes more than 80% . Course of disease more than 10 days to several weeks, long-term weight loss after recovery, poor growth and development.

All kinds of rabbits were susceptible to coccidiosis in epidemic situation. Young rabbits within 3 months old after weaning were most susceptible to coccidiosis, and the condition of the disease was serious. Adult rabbits with mild disease often take the chronic pass or become carriers. Infection is caused by oral ingestion of mature oocysts. Because of poor nutrition and sanitary condition of rabbit house, the feed and drinking water are polluted by rabbit feces, which is easy to cause the occurrence and spread of the disease. Mice and flies can mechanically transmit oocysts. The disease usually prevails in warm, rainy seasons. The pathological changes of hepatic coccidiosis in rabbit coccidiosis were mainly in the liver: there were many white or yellowish nodules in the liver parenchyma and the surface of the liver, which were round like Millet to pea, distributed along the small bile duct. Taking the tubercle to press the slice examination, may see the different development stage coccidia. The contents of the old lesions became thick and calcified. In chronic hepatic coccidiosis, partial desmoplasia around the bile ducts and between the lobules atrophy the liver cells and reduce the size of the liver. The mucosa of the bile duct is characterized by catarrhal inflammation, thick bile, and many collapsed epithelial cells. Enterococcidiosis is characterized by congestion of blood vessels in the intestinal wall, duodenum dilatation and hypertrophy, catarrhal inflammation of the mucosa, gas and mucus filling the small intestine, and sometimes congestion and sometimes bleeding spots in the mucosa. In the chronic course, the intestinal mucosa was light gray, there are many small white scleroma and purulent foci, necrotic foci, small scleroma in coccidia.

Diagnostic methods fecal examination: in the feces of coccidial oocysts detected after the diagnosis. Compression film examination: according to the liver and intestinal lesions, and lesions with nodules and intestinal mucosa smears, find oocysts or merozoites can be diagnosed. The prevention of coccidiosis is to clean and disinfect the rabbit house regularly and to keep the rabbit house clean and dry. The key to prevent coccidiosis is to use anticoccidial drugs in a planned way. The effective anticoccidial drugs suitable for rabbit farms should be selected. Young rabbits were fed with medicine and drinking water every 15 days for 5-7 days, and adult rabbits were fed with medicine and drinking water every 30 days for 5-7 days. Treatment measures once the outbreak of coccidiosis in rabbit farm was confirmed, comprehensive treatment measures should be taken. Coccidiosis can be controlled well by drinking water in proportion with Diclazuril and strengthening feeding management. Sulfamethoxidine has strong anti-coccidiosis effect and is often used to treat fulminant coccidiosis. According to 0.1% concentration of mixed feed, 5 days for a course of treatment, 10 days after stopping using a course of treatment.