During coughing or sneezing can be ejected masses mucus stained with blood or clotted blood, which temporarily relieves their difficulty breathing. As they exhale, the birds lower their heads, sometimes extending them until their beaks touch the ground.

The accumulation of exudate in the larynx or trachea may determine the sudden death of the bird by suffocation. In chicks attacked, the breath is extremely fast and the mouth is opened widely at each inspiration.

The course of the disease usually last from seven to fifteen days, although symptoms can occur up to a month. Birds that recover from the infection become gradually to apparently normal health, but still carrying the germ and they are carrying.

Gibbs (1932) found that birds can be carriers up to and during two years, found that the virus seems to be confined in any part of the larynx or trachea, and although some birds emit snoring when breathing is not an indication of confidence to recognize the chronic cases.

In summary, the common symptoms of this disease include breathing difficulties, abnormal breathing sounds, and the presence of mucus in the nostrils. The birds adopt an orthopneic posture, with their necks stretched out, heads tilted upward, and beaks open.

The birds gasp for air, often with their beaks open and necks stretched out, while emitting plaintive sounds. This type of dyspnea is often referred to as “staring at the stars”; they periodically make a noise or “whistle,” cough, or wheeze, and their feathers are stained with blood around the head and neck.

It is not uncommon for animals to expel bloody mucus while shaking their heads, sometimes spraying it onto the walls.

Under natural conditions, the incubation period ranges from 2 to 12 days; with intratracheal infection, it is shortened to 2 to 4 days. The acute symptoms are relatively characteristic of this disease: conjunctivitis and mild rhinorrhea are present; very soon, severe dyspnea, particularly during inspiration, becomes apparent.

The reduction in productivity is a factor variable. The disease spreads slowly through the herd and the mortality can be high, depending on the condition of the bird.

In acute cases, the beak, pharynx, larynx, and trachea are filled with bloody mucus. In some cases, the laryngeal and tracheal lumens are completely or partially obstructed by blood or grayish-yellow deposits, which initially cause dyspnea and eventually lead to death by asphyxiation as these secretions accumulate.

After recovery, they are still carriers and will become a source of infection for susceptible birds. In stress conditions, the latent virus can be reactivated.

Prevention and control:

There are two types of live-attenuated vaccines against laryngotracheitis available on the market:

to.— chicken embryo and b.— in cell cultures.

One or two doses of the vaccine (which do not provide lifelong protection) are usually sufficient to provide reasonable protection, provided that proper isolation measures are followed.

It is administered to chickens from 10 to 16 weeks of age or younger in the form of eye drops or as a spray, but also in the drinking water.

Scarification (incisions surface) of the cloaca with an applicator dipped into the vaccine also is used.

In outbreaks, apply the vaccine could control the spread of the virus among poultry and chicken coops, due to the spread is a slow process, and protect those that still have not been infected.