A highly contagious infectious Herpes viral disease of chickens and pheasants.
Characterized by SEVERE respiratory distress and bloody tracheal exudates. Chickens 14 weeks and older are more susceptible than young chicken.
Most LT outbreaks occur in mature hens. Can become a problem within an endemic or localised area.
Chickens that recover carry the virus, so farms tend to stay infected for a while after outbreaks.
Transmission is direct bird-to-bird contact, or bird contact with bird-tissue, dead infected birds, infected buildings or unattentuated vaccines. Can be spread on clothing, shoes, tires.
Chickens that recover remain carrier for as long as 24 months. Clinical signs first noticed are water eyes, then the birds remain quiet because breathing is difficult, coughing, sneezing, and shaking of the head to dislodge exudate plugs in the windpipe.
Birds extend head and neck to attempt open mouth breaking (gasp), and inhalation produces a wheezing sound. These birds are called "callers". Blood tinged exudates and serum clots are expelled from the trachea of affect birds.
Many birds die of asphyxiation. No nervous symptoms as in NewCastle Disease. Egg production drops sharply. Gross lesions are usually confined to the respiratory tract. Tracheal hemorrhage is common, including blood clots. Treatment is difficult at best.
Quarantine the farm, tighten farm security and have separate caretaker for sick birds, stop cross traffic to other poultry buildings. Administer antibiotics and vaccinate the remaining flock. Administer vaccine by eye or nose drop methods. Delay vaccination until birds are at least 6 weeks old. Vaccination with LT is not as successful as for other diseases, but is an excellent preventative measure for use in outbreaks and in epidemic areas.