【Pathogen】 Chicken coccidiosis is a protozoal disease of the family Emmelidae, a variety of coccidioides of the genus Emmel that parasitize in the epithelial cells of the mucosa of the small intestine and the cecum.
【Epidemiological characteristics】 1. The source of infection of this disease is sick chickens and worm-carrying chickens, which are mainly infected by eating coccidioidal oocysts.
2. Feed, drinking water, utensils and feeding managers contaminated with feces from sick chickens or chickens with insects are all vectors of transmission of the disease.
3. Age of onset: 7 to 40 days old, high mortality rate; Less common onset at age of more than 3 months; Adult chickens rarely develop diseases, but occasionally occur sporadically. 4. Coccidiosis is mostly prevalent in the warm season: april to September in the north, and the most serious in July to August; In the south, it is peaked from March to September and may to August. In addition, warm, humid, crowded environment, ground free range, poor sanitary conditions all cause the disease.
【Pathogenic effect】 When coccidiosis proliferates in the epithelial cells of the intestinal mucosa, it destroys the intestinal mucosa, causing a large number of intestinal epithelial cells to disintegrate and intestinal inflammation, intestinal inflammatory changes and capillary rupture, resulting in a large amount of body fluids and blood flowing into the intestinal lumen, resulting in anemia, emaciation, and blood diarrhea. 【Clinical Symptoms】
1. Sick chickens are depressed, fluffy feathers, shrunken heads, loss of appetite, full of fluid in the sac, anemia and pallor of the crown and visible mucosa, gradually emaciated, sick chickens often drain red radish-like feces.
2. If infected with tender Amy's coccidiosis, the feces are brown at the beginning, and then become complete blood feces, if not taken in time, the fatality rate can reach more than 50%. If multiple coccidiosis are mixed with infection, the stool carries blood and contains a large amount of shedding intestinal mucosa.
3. Chronic coccidiosis such as giant Amy's coccidioides discharge orange soft stools, some contain foam; Some stools have a small amount of blood.
【Autopsy lesions】 1. Tender Amy's coccidioides mainly invade the cecum, the two cecal colons are significantly enlarged, which can be 3 to 5 times normal, the intestinal lumen is filled with coagulated or fresh dark red blood, the cecum epithelium becomes thicker, and there is serious erosion.
2. Poisoning Amy's coccidiosis damages the middle part of the small intestine, causing the intestinal wall to expand, thicken, and have severe necrosis. At the site of the schizoite reproduction, there are obvious pale white spots, and there are many small bleeding spots on the mucous membrane. There is coagulated blood or radish-colored jelly-like contents in the intestinal tube.
3. Giant Amy's coccidiosis damages the middle section of the small intestine, which can dilate the intestinal canal and thicken the intestinal wall; The contents are viscous and pale grey, light brown or reddish.
4. Heap-type Amy's coccidiosis mostly develops in the epithelial surface, and the insects at the same stage of development often gather together, and a large number of pale white spots appear in the damaged intestinal segment.
5. Americles Hastellois damages the anterior section of the small intestine, and bleeding spots the size of large needles appear on the intestinal wall, and there is serious bleeding in the mucous membrane.
6. If a variety of coccidiosis are mixed infection, the intestinal tract is enlarged, there are a large number of bleeding spots on the intestinal mucosa, and there is a large amount of purple-black blood with exfoliated intestinal epithelial cells in the intestinal tube.
7. Chronic coccidiosis chicken intestinal wall thickening, pale, with purulent contents inside.
【Diagnosis】 According to the epidemiological characteristics, clinical symptoms and changes in autopsy, the preliminary diagnosis can be confirmed.
【Control measures】 Adult chickens are fed separately from chicks to avoid the spread of pathogens in adult chickens with insects, resulting in outbreaks of coccidiosis in chicks.
Strengthen feeding management: keep the chicken coop dry, ventilated and hygienic, regularly remove feces, pile up; Fermentation to kill the egg sacs. Keep the feed and drinking water clean, cages, feeding tanks, sinks are disinfected regularly, generally once a week, and can be treated with boiling water, hot steam or 3% to 5% hot alkaline water. Second, the high temperature season provides favorable conditions for the reproduction of coccidiosis, once the humidity also reaches the needs of coccidiosis, the chicken flock does not run away from coccidiosis, and if you want to treat coccidiosis, the environment should also be improved.
Causes of recurrent coccidiosis in chickens
The life history of coccidiosis is generally 4 to 7 days, the asexual reproduction period is 3 to 5 days, the sexual reproduction period is 2 days, and it takes only about 1 day to form spore-shaped oocysts in vitro. The sac wall of the coccidioidal oocyst has 2 layers, the outer layer is a protective membrane, strong, has a large elasticity, and the chemical composition is like keratin; The inner chemical composition is lipid-like, and the protoplasm is granular.
Because of such a special protective structure, the resistance of the coccidioid oocyst is very strong, and it can survive in the soil for 4-9 months. The oocyst is extremely resistant to common disinfectants.
Oocysts are present in all feces contaminated with feces from sick chickens or chickens with worms, such as overage feed, drinking water, soil, utensils, etc. Birds, poultry and certain insects, as well as foragers, can all be propagators of coccidiosis.
Writing these today, I hope to help the majority of farmers and friends.