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|species = GHV-1
|species = GHV-1
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Also Known As — '''''Infectious laryngotracheitis''''' — '''''ILT''''' — '''''Avian Infectious Laryngotracheitis''''' — AILT
Caused By — ''Gallid Herpesvirus I'' — ''GHV-1'' — ''Infectious Laryngotracheitis Virus'' — ''ILTV'' — ''LTV''
==Introduction==
Gallid Herpes virus causes '''respiratory disease''' in '''chickens''' and pheasants.
This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]
Disease varies from mild to peracute, with mortality in peracute outbreaks exceeding 50%.
As with all herpesviruses, GHV-1 can remain '''latent''' in carriers after infection and then be shed intermittently, '''recrudescing with stress'''.
==Signalment==
Only chickens, pheasants and peafowl are naturally infected.
==Distribution==
Transmission is via '''direct contact''' and contaminated people and equipment. Vermin and wild bords and dogs may aid mechanical transmission.
==Clinical Signs==
Respiratory signs – '''Nasal discharge''' which is often '''bloody''', '''Coughing''' which may include blood, '''Sneezing''', Dyspnoea, '''Gasping''', Upper respiratory tract pain, Abnormal lung sounds.
Decreased egg production, Thin egg shells, Lack of growth
Neurological and ophthalmologic signs may develop
Death may occur rapidly and with '''high mortality''' in peracute and acute disease, or in subacute cases respiratory signs may be present for several days before death and more birds will recover.
==Diagnosis==
On '''post-mortem, haemorrhagic tracheitis''' and bloodstained mucus are evident. Pneumonia and sacculitis may also be seen. '''Caseous diptheritic membranes''' may be present on the mucosae of the upper respiratory tract.
Histopathology reveals loss of cilia, mucosal gland atrophy, intranuclear inclusion bodies and epithelial cell sloughing. Characteristic syncytia develop. A fibrinonecrotic membrane may develop in more chronic disease cases.
'''Antigen [[ELISA testing | ELISA]]''' is both straightforward, quick and sensitive.
Immunofluorescent or Immunoperoxidase staining can also be performed and is more rapid but less sensitive.
Virus isolation can be performed on a variety pf tissues including tracheal swabs or tissue samples.
Agar Gel Immunodiffusion can detect virus in tracheal samples.
Electron microscopy can be used to demonstrate viral particles in tracheal scrapings or exudates but is insensitive.
Measuring viral antibody measures infection indirectly as serum anibodies peak around 2 weeks after infection and wane slowly afterwards.
==Treatment==
Where early diagnosis is made, '''vaccination''' can be administered '''in the face of infection''' to help reduce further morbidity and mortality.
==Control==
ILT can be effectively controlled by '''vaccination'''. Vaccinated and unvaccinated birds should '''not be mixed''' due to the possibility of reversion to virulence. Most are modified live isolates and are administered by '''eye drop'''.
Adequate biosecuriy, quarantine and disinfection is also essential.
Wild birds and vermin should be prevented from accessing poultry and their food/water sources.
==References==
<references/>
Animal Health & Production Compendium, '''Gallid Herpesvirus datasheet''', accessed 05/06/2011 @ http://www.cabi.org/ahpc/
[[Category:To Do - Steph]]
[[Category:To Do - Steph]]