Infectious Laryngotracheitis & Avian Encphalomyelitis Flashcards
1
Q
What type of animal is primarily affected by Infectious Laryngotracheitis?
A
Chickens
2
Q
In what year was Infectious Laryngotracheitis first reported in the USA?
A
1924
3
Q
What is the economic significance of Infectious Laryngotracheitis, particularly in commercial poultry?
A
It is an economically significant disease in commercial egg-producing flocks with a global distribution.
4
Q
What type of virus family does the causative agent of ILT belong to?
A
Herpesviridae
5
Q
Under what environmental conditions can ILTV survive away from the host for an extended period?
A
Under farm conditions for several weeks and longer when very cold, especially with organic material (mucus, blood, feces).
6
Q
On which part of the chicken embryo does ILTV grow well, producing lesions?
A
Chorioallantoic membrane
7
Q
Besides chickens, what other avian species is occasionally naturally infected by ILTV?
A
Pheasants
8
Q
What age range of fowl is most commonly seen with ILT in field conditions?
A
3-9 months old
9
Q
Which sex and type of chicken breed are generally more susceptible to ILT?
A
Males and heavier breeds
10
Q
True or False. Infectious Laryngotracheitis only affects chickens in the USA and the UK.
A
False
11
Q
True or False. The virus that causes ILT is a type of retrovirus.
A
False
12
Q
True or False. ILTV survives longer in warm, dry environments.
A
false
13
Q
True or False. ILTV can grow in cell cultures derived from chick embryos.
A
True
14
Q
True or False. Only very young fowl are susceptible to ILT.
A
False
15
Q
True or False. Infection with fowl pox virus can exacerbate the signs of ILT.
A
True
16
Q
The primary route of entry for the ILT virus into a bird is via:
a) The digestive tract through contaminated feed.
b) The skin through abrasions.
c) The upper respiratory tract and conjunctiva through infective droplets or mucus.
d) The cloaca through fecal contamination.
A
The upper respiratory tract and conjunctiva through infective droplets or mucus.
17
Q
ILT virus is mainly shed from an infected bird through exudates originating from the?
A
Nares, oropharynx, trachea, and conjunctiva.
18
Q
The form in which ILT virus is primarily transmitted between birds is:
A
In aerosol or expectorant form (blood and mucus)
19
Q
Birds that have recovered from ILT or have been given attenuated live vaccines can become?
A
Latent carriers of the virus
20
Q
Inanimate objects that can transmit ILT virus are known as:
A
Fomites
21
Q
Examples of mechanical carriers that can spread ILT virus
A
Personnel, wild birds, vermin, cats, and dogs
22
Q
Distinguishing the mild form of ILT from other mild respiratory diseases based solely on clinical signs or necropsy findings can be:
a) Always straightforward.
b) Relatively easy with careful observation.
c) Very difficult or impossible.
d) Reliably done by examining feather condition.
A
Very difficult or impossible
23
Q
Which of the following is a diagnostic method specifically mentioned for infectious laryngotracheitis?
a) Culture of bacteria from tracheal swabs.
b) Histological examination of the trachea.
c) Analysis of air sac fluid.
d) Complete blood count.
A
Histological examination of the trachea.
24
Q
Besides histopathology, other diagnostic methods for ILT include?
A
Virus detection and antibody detection.
25
Typical incubation period for ILT is approximately?
6–12 days
26
Infection with ILT can result in forms of the disease ranging from peracute to:
a) Chronic severe pneumonia.
b) Subclinical bacteremia.
c) Mild disease or asymptomatic infection.
d) Fatal neurological signs.
Mild disease or asymptomatic infection.
27
The peracute form of ILT is characterized by?
Death without prodromal signs or sudden acute dyspnea with severe coughing and expectoration of blood-stained mucus, often leading to death within 1–3 days.
28
A key feature of the acute form of ILT
Dyspnea, which is not as sudden as in the peracute form, and often moist rales
29
In severely dyspneic birds with acute ILT, what physical sign might be observed on the face and wattles?
Cyanosis
30
In some birds with the acute form of ILT, the dyspnea may increase over several days and then:
a) Lead to rapid death within 24 hours.
b) Persist indefinitely without change.
c) Subside, with recovery occurring in 2–3 weeks.
d) Transition into the peracute form
Subside, with recovery occurring in 2–3 weeks.
31
What are some signs associated with the mild form of ILT?
Moist rales, slight coughing, head shaking, nasal exudate, and conjunctivitis.
32
The characteristic tracheal lesion in the peracute form of ILT
Hemorrhagic tracheitis with blood casts.
33
In the acute form of ILT, the trachea typically contains?
Caseous diphtheritic exudate, mucus, and some hemorrhage.
34
The most common ocular lesion observed in mild forms of ILT
Conjunctivitis.
35
Histological examination of the respiratory tract in ILT-infected birds reveals:
a) A lack of inflammatory response.
b) An inflammatory response and necrosis, with or without hemorrhage, mirroring disease severity.
c) Predominantly bacterial colonies.
d) Granulomatous lesions.
An inflammatory response and necrosis, with or without hemorrhage, mirroring disease severity.
36
A pathognomonic (specifically diagnostic) histological feature of ILT is the presence of?
Cowdry type A intranuclear inclusion bodies in some epithelial cells.
37
Cowdry type A intranuclear inclusion bodies characteristic of ILT are:
a) Basophilic and located in the cytoplasm.
b) Eosinophilic and characterized by a condensed nucleus surrounded by a halo and chromatin margination.
c) Found primarily in lymphoid tissues.
d) Easily visible on gross necropsy.
Eosinophilic and characterized by a condensed nucleus surrounded by a halo and chromatin margination
38
The simplest method for initial virus identification in clinical material for ILTV is?
Agar Gel Immune Diffusion (AGID) tests
39
Isolation of ILTV can be performed using?
Embryonated eggs or cell cultures.
40
Give some clinical samples suitable for ILTV isolation
Exudate and epithelial scrapings or tracheal swabs taken early in the disease
41
After inoculating clinical material for ILTV isolation, the virus can be identified using techniques such as:
Immunofluorescence, virus neutralization, or electron microscopy
42
Enumerate some more rapid methods for detecting ILTV antigen or genetic material
Immunofluorescence staining of tracheal sections, antigen capture ELISA, PCR, and DNA hybridization
43
A commonly used method for ILT control is:
Vaccination with live vaccines.
44
What are some methods of applying live ILT vaccines?
Eye drop application, coarse spray, drinking water inclusion, or cloacal scarification
45
Besides vaccination, what are the other control strategies for ILT?
Destocking & disinfection and eradication.
46
True or False. Hemorrhagic tracheitis with blood casts is characteristic of the mild form of ILT.
False
47
True or False. The presence of caseous diphtheritic exudate in the trachea is typically seen in the acute form of ILT.
True.
48
True or False. Conjunctivitis is a rare ocular finding in birds with ILT.
False
49
True or False. Isolation of ILTV is typically performed on bacterial growth media.
False
50
True or False. Tracheal swabs for virus isolation should be taken late in the course of the disease for optimal results.
False
51
Avian Encephalomyelitis is caused by a?
Picornavirus
52
Avian Encephalomyelitis primarily affects young poultry, usually between?
1-3 weeks old
53
Based on recent genomic characterization, the Avian Encephalomyelitis virus is most closely related to?
Hepatitis A virus
54
Field strains of Avian Encephalomyelitis virus are mainly:
a) Neurotropic
b) Dermatropic
c) Enterotropic
d) Pneumotropic
Enterotropic
55
Fowl-embryo-adapted strains like the Van Roekel (VR) strain are mainly:
a) Enterotropic
b) Nephrotropic
c) Neurotropic
d) Viscerotropic
Neurotropic
56
Young chicks typically become infected with Avian Encephalomyelitis virus through which route?
Oral ingestion
57
Avian Encephalomyelitis virus primary site of initial infection in the alimentary tract is the?
Duodenum
58
Favored sites for Avian Encephalomyelitis virus replication in the central nervous system are the?
Purkinje cells and the molecular layer of the cerebellum
59
Persistence of Avian Encephalomyelitis virus infection is common in the:
CNS, alimentary tract, and pancreas
60
Natural infection with Avian Encephalomyelitis virus can cause disease in which animals?
Chicks, turkey poults, Japanese quail, pheasants, and pigeons
61
Avian Encephalomyelitis virus is transmitted through?
Both vertical and horizontal transmission
62
Vertical transmission of Avian Encephalomyelitis virus occurs when a breeder flock is infected:
a) Before the onset of egg production
b) During egg production
c) After the cessation of egg production
d) Only with specific breeds
During egg production
63
Chicks infected via vertical transmission may start showing clinical signs as early as?
1 day after hatching
64
Chicks infected horizontally shed the virus through their:
a) Respiratory secretions
b) Urine
c) Feces
d) Saliva
Feces
65
Horizontal shedding of the virus by infected chicks typically lasts for up to?
2 weeks
66
The main clinical signs of Avian Encephalomyelitis involve:
a) Respiratory distress
b) Gastrointestinal upset
c) Ataxia and leg weakness
d) Ocular lesions
Ataxia and leg weakness
67
Severely affected birds with Avian Encephalomyelitis may lie on their side and exhibit?
Intermittent fine tremors of the head, neck, and legs
68
The fine tremors of the head and neck due to Avian Encephalomyelitis are responsible for the common name?
Epidemic tremor
69
The incubation period of Avian Encephalomyelitis in chicks that hatch from infected eggs is typically
1-7 days
70
The incubation period of Avian Encephalomyelitis in chicks infected after hatching is approximately?
11 days
71
In laying hens infected with Avian Encephalomyelitis virus, a significant clinical sign is?
Drop of egg production
72
Along with a drop in egg production, Avian Encephalomyelitis infected layers may also experience reduced:
a) Feed conversion ratio
b) Body weight
c) Hatchability
d) Water intake
Hatchability
73
The reduction in hatchability in Avian Encephalomyelitis infected layers is typically around:
5-10%
74
True or False. Avian Encephalomyelitis is primarily a respiratory disease.
False
75
True or False. The Avian Encephalomyelitis virus is now classified in the genus Hepatovirus.
True
76
True or False. Fowl-embryo-adapted strains of the virus are less likely to kill embryos than field strains.
False
77
True or False. The pancreas is one of the visceral organs infected by the Avian Encephalomyelitis virus.
True
78
True or False. Virus replication in the CNS mainly targets neurons in the cerebrum.
False
79
True or False. Pigeons are not susceptible to natural infection with Avian Encephalomyelitis virus.
False
80
True or False. Fine tremors are most commonly observed in the wings of affected birds.
False
81
True or False. The incubation period of Avian Encephalomyelitis is shorter for chicks infected after hatching compared to those infected vertically
False
82
True or False. Laying hens infected with Avian Encephalomyelitis typically show neurological signs along with a drop in egg production.
True
83
Pale or whitish areas are sometimes observed in the __________ muscle of chicks with Avian Encephalomyelitis.
Gizzard
84
In a small proportion of Avian Encephalomyelitis survivors, what ocular lesion might be observed?
Opacity and fixation of the lens
85
Microscopic lesions in the central nervous system (CNS) of birds with AE include?
Degeneration and necrosis of neurons, perivascular lymphocytic cuffing, and gliosis
86
Gliosis in the CNS of birds with AE involves the formation of:
a) Bacterial colonies
b) Glial nodules
c) Viral plaques
d) Mineral deposits
Glial nodules
87
A common microscopic lesion outside the CNS in birds with AE is:
Diffuse or nodular lymphocytic infiltrates in various organs
88
Lymphocytic infiltrates outside the CNS are typically found in the?
Gizzard muscle, esophagus, proventriculus, myocardium, and pancreas
89
The diagnosis of Avian Encephalomyelitis is best confirmed by:
Isolation and identification of the virus
90
What are the tissues that must be collected for Avian Encephalomyelitis virus isolation?
Brain and duodenum with the pancreas
91
A reliable method for demonstrating Avian Encephalomyelitis virus antigen in tissues is?
Immunofluorescent and immunohistochemical staining
92
What are the major differential diagnosis for neurologic signs in very young chicks infected with Avian Encephalomyelitis virus?
Bacterial or mycotic encephalitis and neurotropic virulent Newcastle disease
93
Non-infectious differential diagnoses to consider for Avian Encephalomyelitis
Rickets and nutritional encephalomalacia
94
What is the recommended course of action for chicks showing neurologic signs of Avian Encephalomyelitis?
Euthanasia because they rarely recover
95
Vaccination of broiler breeder pullets aims to prevent?
Vertical transmission of the AEV to the progeny
96
Avian Encephalomyelitis vaccine is administered to broiler breeders at what age or time frame?
8 weeks or older but at least 4 weeks before the start of lay
97
Avian Encephalomyelitis vaccine is often combined with which other poultry vaccine?
Fowlpox vaccine
98
The typical route of administration for the combined Avian Encephalomyelitis and Fowlpox vaccine in chickens is?
Wing-web stab
99
True or False. Pale areas in the heart muscle are a common lesion in chicks with Avian Encephalomyelitis.
False
100
True or False. Opacity and fixation of the lens can occur in some surviving birds with Avian Encephalomyelitis.
True
101
True or False. There is an effective antiviral treatment available for Avian Encephalomyelitis.
False
102
True or False. Nutritional deficiencies can sometimes mimic the neurological signs of Avian Encephalomyelitis.
True
103
Avian encephalomyelitis primarily affects which age group of chickens?
Young chicks (under 4 weeks)
104
The causative agent of Avian Encephalomyelitis belongs to which viral family?
Picornaviridae
105
What are the primary routes of transmission for Avian Encephalomyelitis?
Vertical (breeder to offspring) and horizontal (fecal-oral)
106
A characteristic clinical sign of Avian Encephalomyelitis, leading to its common name.
Fine tremors of the head and neck
107
In Avian Encephalomyelitis, a biphasic mortality pattern is typically associated with?
Vertical infection followed by horizontal infection
108
After what age are chickens generally considered resistant to developing clinical disease from Avian Encephalomyelitis infection?
4 weeks
109
In laying hens infected with Avian Encephalomyelitis, what is a typical effect on egg production?
A sudden 5-10% drop lasting less than 2 weeks
110
What is a potential effect on hatchability in eggs laid by hens infected with Avian Encephalomyelitis?
A drop of up to 5% due to late embryonic mortality
111
A notable gross lesion observed in the brain of birds infected with Avian Encephalomyelitis
No gross lesions are typically seen
112
Weeks after infection with Avian Encephalomyelitis, some surviving chickens may develop _____
Opacity of eye lenses (cataracts)
113
The characteristic microscopic lesions in the central nervous system of birds with Avian Encephalomyelitis
Degeneration and necrosis of neurons, perivascular lymphocytic cuffing, and gliosis
114
In the cerebellum of birds with Avian Encephalomyelitis, a key microscopic finding is ______________________
Areas of necrosis or loss of Purkinje cells and replacement by glial nodules
115
A common microscopic lesion outside the CNS in birds with Avian Encephalomyelitis
Diffuse or nodular lymphocytic infiltrates in the gizzard muscle, muscular layer of esophagus, proventriculus, myocardium, pancreas
116
What are the characteristic clinical signs of the acute form of Infectious Laryngotracheitis?
Gasping, coughing, rattling, and extension of the neck during inspiration
