Infectious Laryngotracheitis & Avian Encephalomyelitis Flashcards
(18 cards)
What is infectious laryngotracheitis?
A viral respiratory disease that affects chickens, first reported in the USA in 1924 and recognized worldwide.
It is economically significant in commercial egg-producing flocks and has global distribution.
What is the causative agent of infectious laryngotracheitis?
A virus of the family Herpesviridae, designated Gallid herpesvirus 1 (ILTV).
ILTV is known to survive outside the host for several weeks, especially in cold environments.
Which species are primarily affected by the infectious laryngotracheitis virus?
Domestic fowl, occasionally pheasants.
All ages of fowl are susceptible, with the greatest susceptibility in very young birds.
How does infectious laryngotracheitis spread?
Through infective droplets or mucus via the upper respiratory tract and conjunctiva.
Transmission can also occur through aerosol or expectorant forms.
What are the clinical signs of the peracute form of infectious laryngotracheitis?
Death without prodromal signs or sudden acute dyspnea with severe coughing and bloodstained exudate.
Death typically occurs within 1–3 days.
What diagnostic methods are available for infectious laryngotracheitis?
Histological examination, virus detection, and antibody detection.
The mild form may be difficult to distinguish from other mild respiratory diseases.
What lesions are associated with the acute form of infectious laryngotracheitis?
Caseous diphtheritic exudate, mucus, and some hemorrhage in the trachea.
Hemorrhagic tracheitis is noted in the peracute form.
What is a diagnostic feature of infectious laryngotracheitis?
Presence of Cowdry type A intranuclear inclusion bodies in epithelial cells.
These inclusions are pathognomonic for the disease.
What are common vaccination methods for infectious laryngotracheitis?
Eye drop application, coarse spray, drinking water inclusion, or cloacal scarification.
Live vaccines are commonly used.
What is avian encephalomyelitis also known as?
Epidemic tremor.
It is caused by a picornavirus and affects young birds.
What is the primary route of infection for avian encephalomyelitis?
Oral infection, primarily affecting the alimentary tract.
Viremia follows, leading to infection of other organs.
How is avian encephalomyelitis transmitted?
Through vertical and horizontal transmission.
Infected breeder flocks can pass the virus to offspring via eggs.
What are the main clinical signs of avian encephalomyelitis?
Ataxia, leg weakness, and fine tremors of the head and neck.
Severe cases can lead to paralysis and recumbency.
What lesions are associated with avian encephalomyelitis?
Degeneration and necrosis of neurons in the CNS, and lymphocytic infiltrates in various organs.
Microscopic lesions are found in the brain and spinal cord.
What is the best method for diagnosing avian encephalomyelitis?
Isolation and identification of the virus from tissues.
Brain and duodenum tissues are critical for virus isolation.
What is the treatment for avian encephalomyelitis?
No treatment is available; control relies on removal of affected birds and vaccination.
Vaccination prevents vertical transmission and provides maternal immunity.
Fill in the blank: The incubation period for chicks infected with avian encephalomyelitis after hatching is _______ days.
11
True or False: Vaccination of broiler breeder pullets with a commercial vaccine can prevent vertical transmission of avian encephalomyelitis.
True
