logging in or signing up AVIAN ENCEPHALOMYELITIS kedarkarki Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 672 Category: Education License: All Rights Reserved Like it (1) Dislike it (0) Added: June 02, 2009 This Presentation is Public Favorites: 0 Presentation Description AE as an enteric disease that can spread to the brain and reproductive tract of susceptible birds. The progression of AE depends on the age at which the bird is infected, the strain of virus and the bird's immune competence. Comments Posting comment... Premium member Presentation Transcript AVIAN ENCEPHALOMYELITIS : AVIAN ENCEPHALOMYELITIS Dr.Kedar Karki AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE AE as an enteric disease that can spread to the brain and reproductive tract of susceptible birds. The progression of AE depends on the age at which the bird is infected, the strain of virus and the bird's immune competence. Transmission : Transmission Egg transmission is the major route of transmission of Avian Encephalomyelitis virus. Infected breeders will transmit the A.E. virus for several weeks and cause a decrease in egg hatchability. Transmission : Transmission Infected chicks that hatch will show clinical signs of the disease and spread the infection in the incubator to other new hatched susceptible chicks. Young chicks can also be infected on the farm. The incubation period varies from 5 to 14 days depending on the route of infection. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE When birds over three to four weeks of age are infected, the virus is ingested and grows in intestinal tissues. As it multiplies, it causes an immune response. The bird produces enough antibodies in time to keep the virus from spreading to the brain and causing clinical disease. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE The virus can, however, spread to the reproductive tract of the hen and cause a temporary drop in egg production. The incubation period from infection to egg production drop is at least 11 days. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE In breeders, AE virus may be transmitted through the egg to the progeny. The virus is also shed from the gut into the cloaca where it may contaminate the egg shell and infect the young as they hatch. Virus shedding occurs from the gut and lasts only five days. There is probably no carrier state. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE When birds under four weeks of age are infected, the virus replicates in the gut, but the birds are not yet fully immune competent. Because they lack immune development, pathogenic strains enter the blood stream and move to the brain, causing neurologic symptoms. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE The incubation period from infection to neurologic signs is 11 days, unless birds were infected as embryos. If infected as an embryo, the incubation period varies from one to seven days. Pathogenic field strains do not affect or kill the embryo. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE It is necessary to hatch birds and observe them to see if they are infected. Young birds shed virus from the gut for up to two weeks. This longer shedding period in the young greatly increases spread of virus to pen mates. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE There are no obvious clinical signs of AE in adult birds. Laying flocks often experience a temporary decline in egg production, but it may be only slight (5-10% decrease). The eggs that are set during the period of decreased production, will have a decreased hatchability. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE An enlarging and bluing of the eye may occur in the adult birds. In the young (under four weeks of age) clinical signs begin with a dullness and reduced activity. Affected birds soon become uncoordinated and have difficulty moving around. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE A tremor of the head and neck develops that resembles shivering. Keep in mind that birds do not shiver when cold stressed, but instead fluff their feathers up. Shivering, or tremors, is a sign of neurologic disease. Affected birds eventually become immobile, lie on their sides and 60 to 90 percent will die. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE In a typical outbreak in young birds, 40 to 60 percent of the flock will be affected and overall mortality will be 25 to 50 percent. In the average outbreak, there are no easily visible gross lesions caused by the AE virus. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Lack of easily visible gross lesions is an important part of the history. There are microscopic lesions in the gut and brain that confirm the diagnosis. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Immunity to AE virus begins developing in immune competent birds (3 to 4 week old chicks) within four days. Breeders begin passing AE maternal antibodies to progeny within eleven days post-exposure. Detectable antibody levels protect birds against clinical disease and reduce shedding from feces. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Bursectomizing young birds results in their inability to make antibodies. Birds which are bursectomized are susceptible to AE neurological disease. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Therefore, antibodies (humoral immunity) are what is important in protection against clinical disease from AE and cell mediated immunity (CMI) plays a minor role. Immunity does not prevent infection of the gut, but stops spread of virus to the brain. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Actively acquired antibodies (post-infection) or passively acquired antibodies (maternal antibodies) both protect well. The decay rate of antibodies in progeny is slow, and protective maternal antibody lasts four to six weeks. This is ample time for young birds to become immune competent. Diagnosis : Diagnosis The following methods may help in making a diagnosis for Avian Encephalomyelitis. 1. Virus Neutralization test.* 2. Agar Gel test.* 3. Elisa test.* 4. Embryo Susceptibility test. Slide 34: The above tests are only indicative of antibody present but not necessarily disease. The final diagnosis can be achieved either by histopathology or by virus isolation. Classic diagnosis is typically made by the presence of brain lesions shown histologically. VACCINATION : VACCINATION There is no specific treatment for AE. Cull affected chicks to reduce virus spread. Once clinical signs are over, the disease will not reoccur in the same flock. VACCINATION : VACCINATION Live AE vaccines are derived from a mild, but immunogenic field strain of AE. The vaccine virus is not attenuated and can cause disease in young susceptible birds and egg production losses in mature hens. Lyophilized vaccine is available for use in turkey breeders and chickens. VACCINATION : VACCINATION The vaccine should be stored refrigerated (not over 45°F, 7°C). Vaccines are available for administration in the drinking water and the wing web injection method. Combination products with AE and Pox are available for the wing web injection method. Slide 38: THANKS TO ALL POULTRY VETS You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
AVIAN ENCEPHALOMYELITIS kedarkarki Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 672 Category: Education License: All Rights Reserved Like it (1) Dislike it (0) Added: June 02, 2009 This Presentation is Public Favorites: 0 Presentation Description AE as an enteric disease that can spread to the brain and reproductive tract of susceptible birds. The progression of AE depends on the age at which the bird is infected, the strain of virus and the bird's immune competence. Comments Posting comment... Premium member Presentation Transcript AVIAN ENCEPHALOMYELITIS : AVIAN ENCEPHALOMYELITIS Dr.Kedar Karki AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE AE as an enteric disease that can spread to the brain and reproductive tract of susceptible birds. The progression of AE depends on the age at which the bird is infected, the strain of virus and the bird's immune competence. Transmission : Transmission Egg transmission is the major route of transmission of Avian Encephalomyelitis virus. Infected breeders will transmit the A.E. virus for several weeks and cause a decrease in egg hatchability. Transmission : Transmission Infected chicks that hatch will show clinical signs of the disease and spread the infection in the incubator to other new hatched susceptible chicks. Young chicks can also be infected on the farm. The incubation period varies from 5 to 14 days depending on the route of infection. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE When birds over three to four weeks of age are infected, the virus is ingested and grows in intestinal tissues. As it multiplies, it causes an immune response. The bird produces enough antibodies in time to keep the virus from spreading to the brain and causing clinical disease. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE The virus can, however, spread to the reproductive tract of the hen and cause a temporary drop in egg production. The incubation period from infection to egg production drop is at least 11 days. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE In breeders, AE virus may be transmitted through the egg to the progeny. The virus is also shed from the gut into the cloaca where it may contaminate the egg shell and infect the young as they hatch. Virus shedding occurs from the gut and lasts only five days. There is probably no carrier state. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE When birds under four weeks of age are infected, the virus replicates in the gut, but the birds are not yet fully immune competent. Because they lack immune development, pathogenic strains enter the blood stream and move to the brain, causing neurologic symptoms. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE The incubation period from infection to neurologic signs is 11 days, unless birds were infected as embryos. If infected as an embryo, the incubation period varies from one to seven days. Pathogenic field strains do not affect or kill the embryo. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE It is necessary to hatch birds and observe them to see if they are infected. Young birds shed virus from the gut for up to two weeks. This longer shedding period in the young greatly increases spread of virus to pen mates. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE There are no obvious clinical signs of AE in adult birds. Laying flocks often experience a temporary decline in egg production, but it may be only slight (5-10% decrease). The eggs that are set during the period of decreased production, will have a decreased hatchability. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE An enlarging and bluing of the eye may occur in the adult birds. In the young (under four weeks of age) clinical signs begin with a dullness and reduced activity. Affected birds soon become uncoordinated and have difficulty moving around. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE A tremor of the head and neck develops that resembles shivering. Keep in mind that birds do not shiver when cold stressed, but instead fluff their feathers up. Shivering, or tremors, is a sign of neurologic disease. Affected birds eventually become immobile, lie on their sides and 60 to 90 percent will die. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE In a typical outbreak in young birds, 40 to 60 percent of the flock will be affected and overall mortality will be 25 to 50 percent. In the average outbreak, there are no easily visible gross lesions caused by the AE virus. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Lack of easily visible gross lesions is an important part of the history. There are microscopic lesions in the gut and brain that confirm the diagnosis. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Immunity to AE virus begins developing in immune competent birds (3 to 4 week old chicks) within four days. Breeders begin passing AE maternal antibodies to progeny within eleven days post-exposure. Detectable antibody levels protect birds against clinical disease and reduce shedding from feces. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Bursectomizing young birds results in their inability to make antibodies. Birds which are bursectomized are susceptible to AE neurological disease. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Therefore, antibodies (humoral immunity) are what is important in protection against clinical disease from AE and cell mediated immunity (CMI) plays a minor role. Immunity does not prevent infection of the gut, but stops spread of virus to the brain. AVIAN ENCEPHALOMYELITIS (AE) DISEASE : AVIAN ENCEPHALOMYELITIS (AE) DISEASE Actively acquired antibodies (post-infection) or passively acquired antibodies (maternal antibodies) both protect well. The decay rate of antibodies in progeny is slow, and protective maternal antibody lasts four to six weeks. This is ample time for young birds to become immune competent. Diagnosis : Diagnosis The following methods may help in making a diagnosis for Avian Encephalomyelitis. 1. Virus Neutralization test.* 2. Agar Gel test.* 3. Elisa test.* 4. Embryo Susceptibility test. Slide 34: The above tests are only indicative of antibody present but not necessarily disease. The final diagnosis can be achieved either by histopathology or by virus isolation. Classic diagnosis is typically made by the presence of brain lesions shown histologically. VACCINATION : VACCINATION There is no specific treatment for AE. Cull affected chicks to reduce virus spread. Once clinical signs are over, the disease will not reoccur in the same flock. VACCINATION : VACCINATION Live AE vaccines are derived from a mild, but immunogenic field strain of AE. The vaccine virus is not attenuated and can cause disease in young susceptible birds and egg production losses in mature hens. Lyophilized vaccine is available for use in turkey breeders and chickens. VACCINATION : VACCINATION The vaccine should be stored refrigerated (not over 45°F, 7°C). Vaccines are available for administration in the drinking water and the wing web injection method. Combination products with AE and Pox are available for the wing web injection method. Slide 38: THANKS TO ALL POULTRY VETS