Coccidiosis Management in Poultry
Shikha Tamta1 and Megha G.K 2
1Assistant Professor, Department of Veterinary Public Health and Epidemiology, International Institute of Veterinary Education and Research, Rohtak, Haryana,124001, India
2Ph. D Scholar, Department of Veterinary Public Health and Epidemiology
ICAR- Indian Veterinary Research Institute, Izzatnagar, Bareilly, U.P. India
Etiology
The spread of Coccidiosis is world-wide including wild birds. The causative agent for coccidiosis is protozoa of the phylum Apicomplexa and belongs to the family Eimeriidae. consumption of a sizable quantity of sporulated oocysts by vulnerable birds will be leading etiology. The majority of the species that infect different places in the gut of chickens belong to the genus Eimeria. This genus mainly responsible for the disease. The incubation period for the disease is 4-7 days and intestinal mucosa will be the target site. Poultry coccidia are host specific in most of the cases and attack mainly specific part of intestine. But in case of quail, it may infect whole intestine.
Risk Factors
Droppings of the birds which infected with oocyst of Eimeria will be the risk factor for both clinically sick and recovered birds. Besides all these factors, feed contaminating with oocyst, dust, water, litter, and soil heavily contaminated with the causative agent will act as a burden and hazard for public health. equipment, Clothing, insects, farm workers, and other animals will act as the mechanical vectors for transmission of the disease. Fresh oocysts are not infectious until they sporulate, they specially require oxygen and moisture which should be favourable for the growth of oocyst (21°–32°C). oocyst can be persisted for long time depending on the favourable condition of environment all the temperature, humidity etc. Oocysts are destroyed by freezing or high ambient temperatures but are resistant to several disinfectants frequently used around animals.
Pathogenicity
Host genetics, dietary variables, coexisting disorders, host age, and coccidium species all have an impact on pathogenicity. Due to widespread bleeding caused by schizogony, Eimeria necatrix and Eimeria tenella are the most harmful Eimeria in chickens. This occurs in the lamina propria and Lieberkühn crypts of the small intestine and ceca, respectively. The most dangerous pathogens for chukars are E kofoidi and E legionensis, while the most dangerous pathogen for bobwhite quail is E lettyae. Pheasants are susceptible to several Eimeria species, including E phasiani and E colchici. The villi’s epithelial cells are where the majority of species develop.
Clinical sings
Coccidiosis symptoms might include slowed development, a large proportion of obviously ill birds, severe diarrhoea, and significant mortality. The amount of food and water consumed is low. Outbreaks may be accompanied by weight loss, the use of culls, a reduction in egg production, and an increase in mortality. Depigmentation may result from mild intestinal infections that would otherwise be considered subclinical, especially those that are caused by Clostridium spp. Those who survive severe illnesses get well in 10–14 days, although they might never regain lost function. In case of chicken E tenella infections are exclusively present in the ceca, and they are identified by bloody excretions and a build-up of blood in the ceca. Birds who survive the acute stage may have cecal cores, which are collections of clots, tissue fragments, and oocysts. In the anterior and middle regions of the small intestine, E necatrix causes significant damage. On the serosal surface, there are tiny white dots that are typically accompanied by spherical, bright- or dull-red patches of different sizes. “Salt and pepper” are a common description of this look. If aggregates of big schizonts can be seen under a microscope, the white dots are indicative of E necatrix. When the infection is severe, the intestinal wall becomes thicker and the diseased region enlarges to 2-2.5 times its normal size. Blood, mucus, and fluid may all be present in the lumen. The rectum, ceca, cloaca, and lower small intestine all contain E brunetti. The mucosa is pale, disordered, lacking in distinct foci, and maybe thickened in mild infections. In severe infections, the majority of the small intestine experience’s coagulative necrosis and mucosal sloughing. The small intestine is where E maximum develops, and it results in petechial bleeding, a crimson, orange, or pink sticky mucous exudate, and dilatation and thickening of the wall. Numerous white pinpoint foci are frequently seen on the midgut’s exterior, and the region may seem engorged. The lesions contain clearly huge amounts of oocysts and gametocytes, especially macrogametocytes.
Diagnosis
- Diagnosis can be done on the basis of host location, lesions in the host or different site, and the size of oocysts.
- Demonstration of oocysts in feces and by taking intestinal scrapings disease can be diagnosed.
- Diagnosis depends on the severity of the lesions as well as information about the flock’s appearance, illness, daily mortality, feed intake, growth rate, and lay rate.
- Necropsy
- Microscopic diagnosis: Oocysts, merozoites, or schizonts can be seen microscopically.
Control
Coccidial infection cannot be prevented by realistic treatment techniques. There are fewer infections in poultry kept constantly on wire flooring to keep the birds away from droppings; clinical coccidiosis is infrequent in such situations. Vaccination and anticoccidial medication prophylaxis are further strategies of control. A species-specific immunity develops following natural infection, the degree of which mostly relies on the depth of infection and the frequency of reinfections. T-cell response is essentially what causes protective immunity. Live, sporulated oocysts of several coccidial species are given in small quantities as part of commercial vaccinations. At the hatchery or on the farm, day-old chicks should get modern anticoccidial immunizations. Because the vaccine only serves to spread infection, chickens on the farm are reinfected with the vaccine strain. Most commercial vaccines contain live oocysts of coccidia that are not attenuated. Live, sporulated oocysts of several coccidial species are given in small quantities as part of commercial vaccinations. At the hatchery or on the farm, day-old chicks should get modern anticoccidial immunizations. Because the vaccine only serves to spread infection, chickens on the farm are reinfected with the vaccine strain.
