Infectious Laryngotracheitis (ILT)
TL;DR: ILT is a herpesvirus of the upper airway — the most dramatic respiratory presentation in poultry, with gasping, extended neck and sometimes blood-stained discharge. Two things set it apart from CRD and coryza: it is viral, so antibiotics do not address it, and recovered birds can remain carriers for life, shedding under stress. That makes an apparently healthy incoming bird a real route of entry, and quarantine the thing that matters most.
The respiratory disease where “the bird got better” is not the end of the story.
What It Is
A viral disease of chickens caused by a herpesvirus, affecting the larynx and trachea — the upper airway rather than the deep respiratory tract.
That places it in a different category from the other respiratory problems on this site:
| Disease | Cause |
|---|---|
| CRD | Mycoplasma |
| Infectious coryza | Bacterial |
| Infectious bronchitis | Virus (coronavirus) |
| Newcastle disease | Virus (paramyxovirus) |
| ILT | Virus (herpesvirus) |
The distinction is not academic. A bacterial or mycoplasmal disease may respond to treatment prescribed by a vet; a viral one does not, and the care is supportive. Which is why the diagnosis matters rather than treating “a respiratory problem” generically — see gamot sa halak ng manok and mga sakit ng manok at gamot.
What It Looks Like
The presentation is severe and hard to mistake for a mild problem:
- Marked respiratory distress — open-beak gasping, neck extended.
- Upper airway involvement, so the sounds come from the throat rather than deep in the chest.
- Blood-stained discharge in serious cases, which is the sign that most distinguishes it.
- Birds visibly struggling, not merely snuffly.
This is not the sniffle you monitor for a day. Birds gasping with extended necks need veterinary attention, and if there is blood involved that is urgent.
Do not attempt to diagnose from a list. Several serious diseases produce respiratory distress, including Newcastle and avian influenza, and some of them are reportable. Describe what you are seeing to a veterinarian or your municipal agriculture office.
The Carrier Problem
The part that changes management, and the reason this entry exists separately.
Herpesviruses establish latency. A bird that recovers from the acute illness can remain a carrier, and can shed virus later — typically when stressed.
Consequences a keeper actually has to plan around:
An apparently healthy bird can introduce it. There is no way to look at a chicken and see a latent carrier. This is the strongest possible argument for quarantining new chickens, and quarantine alone will not reveal a latent carrier either — which is why sourcing from flocks with known health status matters.
Stress can trigger shedding. Which means the flock’s stress load is a disease-control variable, not just a welfare one: heat (summer, heat stress), crowding (coop space per bird), transport, mixing birds (pecking order), and molt.
A flock that has had it may carry it indefinitely. Decisions about what to do with such a flock — whether to keep breeding from it, whether to sell birds on, whether to close the flock — are veterinary and ethical decisions, not something to settle from an article. If you sell birds from a flock with a history, say so.
Vaccination
Vaccines for ILT exist and are used in some circumstances.
Whether they are appropriate for your flock is a veterinary decision, and it is not a routine backyard measure everywhere. There are real considerations around vaccine type and the implications for a flock’s carrier status that need a vet’s judgement rather than a general recommendation.
Ask a veterinarian, your agrivet or your municipal agriculture office what applies in your area and at your scale. See bakuna sa manok for how vaccination decisions are approached on this site generally.
Prevention
The same discipline that works for every infectious disease, and it carries more weight here because of latency:
- Quarantine everything incoming. No exceptions, no matter the source.
- Know where your birds come from. Ask about flock health history — see where to buy day-old chicks and gamefowl for sale.
- Biosecurity — footwear, visitors, shared equipment, and birds returning from events.
- Reduce stress, because stress is the trigger.
- Ventilation and dry litter. Ammonia damages the airway lining and opens the door — see chickens in the rainy season.
- Clean and disinfect between batches.
Birds attending events or moving between yards are a specific exposure route worth thinking about deliberately.
The Honest Limits Here
That infectious laryngotracheitis is caused by a herpesvirus affecting the larynx and trachea, that severe cases can involve blood-stained discharge, that there is no specific antiviral treatment, and that recovered birds can remain latent carriers and shed under stress, is established veterinary knowledge. This guide gives no treatment protocol, no drug names, no dosages and no vaccination schedule — the diagnosis needs confirming, the response is a veterinary matter, and vaccination decisions depend on circumstances a general guide cannot assess. Severe respiratory distress, and any blood, warrants immediate veterinary attention. Some diseases producing similar signs are reportable to the authorities.
Related: CRD, infectious coryza, infectious bronchitis, quarantine new chickens.
Frequently Asked Questions
What is infectious laryngotracheitis?
A viral respiratory disease of chickens caused by a herpesvirus, affecting the larynx and trachea. It is distinct from the bacterial and mycoplasmal respiratory diseases and can be considerably more severe.
What are the signs of ILT?
Severe respiratory distress affecting the upper airway — gasping, extended neck, and in serious cases blood-stained discharge. It is one of the most dramatic respiratory presentations in poultry.
How is ILT different from CRD or coryza?
It is viral rather than bacterial or mycoplasmal, it tends to be more severe, and being a herpesvirus, recovered birds can remain carriers for life. That last point changes how a flock has to be managed afterwards.
Do birds recover from ILT?
Birds can recover from the acute illness. Recovered birds may remain carriers and can shed virus later, particularly under stress, which is the central management problem.
Is there a treatment for ILT?
There is no specific treatment for the virus. Veterinary care is supportive, and confirming the diagnosis matters because the response differs from bacterial respiratory disease.
Is there a vaccine for ILT?
Vaccines exist and are used in some circumstances. Whether vaccination is appropriate for a given flock is a veterinary decision, and it is not a routine backyard measure everywhere.
How do I stop ILT getting into my flock?
Biosecurity and quarantine. Because recovered birds carry the virus, an apparently healthy new bird can introduce it, which makes quarantining incoming stock especially important here.