infectious laryngiotrachitis ILT https://www.udemy.com/course/poultry-farming-viral-diseases-threaten-poultry-industry/?referralCode=EAFBDC5B623DADAAFD25

1. ILT infectious laryngotracheitis
DEFINITION
Infectious laryngotracheitis (ILT) is an acute viral disease of
chickens, and, rarely, pheasants and peafowl characterized
by marked dyspnea, coughing, gasping, and expectoration
of bloody exudate.

2. occurrence
•
Most outbreaks in chickens
•
occur in broilers more than 4 weeks of age
ILT is caused by a DNA virus belonging the
family Herpesviridae.
ETIOLOGY

3. CLINICAL SIGNS
Signs of markedly pathogenic ILT
There is marked dyspnea
Expectoration of bloody mucus may occur
High morbidity.
Morbidity as high as 50-70%
mortality usually is 10-20%

4. Signs of ILT of low pathogenicity
Signs often include
hemorrhagic conjunctivitis with
watery eyes
lacrimation
persistent nasal discharge,
swollen infraorbital sinuses
generalized unthriftiness
and lowered egg production

5. LESIONS
Infected birds often have blood exuding from
the nostrils, mouth or staining the feathers of
the face and neck.
With milder strains of ILT virus, only swollen
eyelids and ocular and nasal discharge may
be seen.

6. Lesions are most common in the nasal turbinates
sinuses, conjunctiva, larynx and trachea

7. more pathogenic strains of ILT virus,
the tracheal mucosa will be
congested hemorrhagic
roughened with mucoid
mucohemorrhagic
Fibrinonecrotic exudates

8. sloughed syncytia of epithelial cells
bearing intranuclear herpesvirus inclusions

9. DIAGNOSIS
The signs and lesions of the pathogenic type of
ILT are
distinctive enough to incite suspicion of ILT
ILT of low pathogenicity.
ILT can usually be confirmed by one or more of
the following
steps:
Demonstration of the characteristic multinucleated
epithelial syncytial cells bearing eosinophilic
intranuclear herpesvirus inclusions in tissues
Growth of the virus on the chorioallantoic membrane
of embryonating chicken eggs. Typical plaques are produced
Exposure of known-immune and known-susceptible
chickens to virus

10. CONTROL
Avoid adding vaccinated, recovered, or exposed birds
to a susceptible flock because these birds may include
recovered carrier birds
Premises contaminated with laryngotracheitis virus
should be depopulated, cleaned, disinfected,
vaccination of layers is
frequently practiced and is quite effective. Attenuated
vaccines are available and can be administered by
eyedrop, in the drinking water, or by aerosol spray.
Birds vaccinated prior
to 10 weeks of age should be revaccinated at 10 weeks
of age or older to confer lifelong immunity
Vaccination
of broilers, when indicated, should be done before 4
weeks of age to minimize losses from severe vaccine