Chicken histomoniasis is a disease that frequently occurs in free-range chickens raised under forest cover. It is caused by chickens accidentally ingesting earthworms containing nematode eggs. The symptoms are relatively obvious after infection and may include liver hemorrhage or necrosis, affecting the healthy development of the chicken farming industry and causing considerable losses to farmers. Therefore, attention should be paid to the prevention and control of chicken histomoniasis to reduce its impact.
1, Disease Occurrence
At a large-scale chicken farm in a certain area, chickens were raised under forest cover to improve farming quality. However, hygiene management was neglected during rearing, and sanitary conditions were poor. The flock density was relatively low, and there was a large amount of manure and other contaminants in the poultry houses. These were not cleaned up in a timely manner, and lighting conditions under the forest cover were poor. In 2020, in the month of 9, chickens at the farm began to develop diarrhea, passing yellow or light-green feces with a pronounced foul odor. Some chickens also died. To treat the disease, the farmer administered florfenicol and compound sulfamethoxazole powder to the affected chickens, but the treatment was not noticeably effective. In the first ten days of 10, the number of chicken deaths increased, and the farmer began to take the situation seriously.
2, Clinical Symptoms
On arriving at the farm, clear clinical symptoms were observed. Affected chickens were lethargic, had ruffled feathers, appeared drowsy, and held their wings drooping. In addition, some affected chickens showed obvious lesions on the head and comb. Affected chickens also had diarrhea, passing yellow or golden-yellow feces with a foul odor; some feces also contained blood clots. Without treatment over an extended period, affected chickens gradually became emaciated and eventually died of exhaustion.
3, Necropsy Findings
Necropsy of dead chickens revealed a series of clear symptoms. The liver was enlarged and had irregular necrotic lesions that were white or yellow, clearly distinguishable from the surrounding tissue. In addition, the ceca of affected chickens showed changes: the cecum on the 1 side or the 2 side was enlarged and firm, hard to the touch, and accompanied by hemorrhagic inflammation. There was also a large amount of blood in the intestinal lumen.
4, laboratory diagnosis
After a dead chicken is brought back to the laboratory for necropsy, obvious lesions can be found in the liver and cecum. Select liver tissue, as well as mucus and feces from the surface of the cecum, and dilute them in physiological saline at approximately 35℃. Then place a small amount of the diluted solution on a microscope slide. Microscopic examination reveals flagellated organisms moving rhythmically. Based on the clinical symptoms, necropsy lesions, and laboratory tests, histomoniasis in chickens can be provisionally diagnosed.
5, prevention and control measures
5.1 Strengthen routine husbandry management. During chicken farming, maintaining a clean and hygienic environment is important for reducing disease occurrence. Therefore, the poultry house should be kept clean and hygienic, with good ventilation and lighting. In addition, under the forest-based rearing system, there is a large amount of debris and decomposing leaves in the forest. To reduce the presence of pests and parasites, fallen leaves and other debris beneath the trees should be cleared regularly. Heterakis worms are the main transmission vector for histomoniasis and should be controlled. In addition, use albendazole and ivermectin premix regularly to eliminate Heterakis worms in the ceca. Finally, the area around the woodland should also be thoroughly disinfected. Quicklime can be used to disinfect the ground and kill earthworms.
5.2 Treatment measures. Timely and effective treatment can reduce the spread of the disease. First, a certain amount of metronidazole can be added to the feed and mixed in at an appropriate ratio, or a certain amount of dimetridazole premix can be added. Administer it for 5d, discontinue for 3d, and then administer it again for 5d. In addition, to prevent other diseases, preventive measures can be taken by adding a certain amount of Pulsatilla powder or a certain amount of florfenicol powder to the feed; use continuously for 3d. After the above treatment measures were taken, no new cases or deaths were observed after 1 weeks of treatment, and the treatment effect was relatively clear.
6, summary and discussion
First, after histomoniasis in chickens is diagnosed, targeted prevention and control measures should be taken to address its cause. In addition, histomoniasis in chickens can be confused with other diseases, as they have a high degree of similarity. Histomoniasis in chickens has clear similarities to coccidiosis, Heterakis infection in chickens, fowl cholera, and fowl paratyphoid, among other diseases, so scientific differential diagnosis is needed. Second, the occurrence of histomoniasis in chickens is directly affected by earthworms and Heterakis worms, which are the main transmission vectors. Therefore, routine husbandry management should be strengthened, droppings should be cleaned up promptly, and the rearing environment should be kept clean and hygienic. Droppings should also be composted by fermentation, which can destroy parasite eggs in the droppings while reducing impacts on the surrounding ecological environment. In addition, regularly deworming against Heterakis worms and preventing chickens from eating earthworms can effectively prevent the disease. Third, histomoniasis in chickens causes necrosis and lesions in the liver and intestinal tract. The liver should be protected, or medications that aid liver recovery should be selected. The disease also causes cecal inflammation, leading to cecal damage and bleeding. Therefore, during treatment, medications that enhance blood clotting should be used in combination to improve hemostasis and reduce blood loss. If the disease develops into a chronic condition, care should be taken to supplement the chickens with a certain amount of VC and various minerals, thereby increasing their resistance and immunity and reducing disease occurrence. Fourth, adopt a scientific husbandry management system. Keep stocking density under reasonable control to prevent overcrowding and poor air circulation. Provide chickens with clean, sufficient drinking water. Maintain hygiene and disinfection at the farm, and establish a disinfection management system to ensure that disinfection is carried out properly; only then can the likelihood of this disease occurring be genuinely reduced.
Author: Kou Bingtao / Agricultural Comprehensive Administrative Law Enforcement Brigade of Shangcai County, Henan Province
Source: Veterinary Guide magazine