The growing small scale poultry production in most developing countries is challenged by several factors including diseases of varied etiologies.This study aimed to describe the first outbreak of infectious Laryngotracheitis (AILT) in exotic layer chickens managed under semi-intensive production systems in Ethiopia. Outbreak investigations were made between June and July, 2018 following a report of a severe disease outbreak in three small scale poultry farms located at Dore Bafano kebele, Sidama zone. A team of veterinarians then traveled to the area to undertake physical examinations, collect the history and circumstantial evidences and representative chickens for further examinations.To characterize the lesions, systematic postmortem examinationsand histopathology were carried out on eight critically sick and four recently dead chickens.The dominant clinical signs were extension of the neck, long-drawn-out gasps, gurgling, rattling, coughing and death after 5 to 8 days of illness. The morbidityand mortality rates were about 98% and 80%, respectively. The mortality rate reached a peak within two days of onset and then gradually declined but continued for 2 weeks.The gross lesions were restricted to the upper respiratory tracts and ranged from hemorrhagic tracheitis, mucoid rhinitis, and blood-stained mucus along the length of the trachea of critically sick chickens to diphtheritic or caseous necrotic plaques and plugs in the trachea, larynx and mouth of recently dead chickens.The hallmark microscopic lesions were erosion and ulceration of the tracheal mucosa, lymphohistocytic and heterophilic inflammatory infiltrates of the submucoso and eosinophilic intranuclear inclusion bodies in most of the tracheal epithelial cells forming syncytia. Based on the collected information at different levels and while awaiting the results of virus isolation and molecular investigation, the current investigation discovered the outbreak of Avian Infectious Laryngotracheitis for the first time in Ethiopia.The virus/disease may have entered the country through contaminated crates along with the importation of day old chicks and remained undetected or misinterpreted because of the poor veterinary services and reporting systems.
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