Summary This report outlines pathomorphological findings of a study involving commercial mule ducks with confirmed influenza A(H5N8) infections after a series of outbreaks in Bulgaria. Examinations were carried out after performing necropsy on dead birds from three different age groups (up to 15; 20 to 30; and 40+ days of age) fattened in different farms. Among birds of all ages, gross lesions were present in form of lesions affecting the heart. Histologically, the myocardium exhibited severe intermyofibrillar oedema, moderate to massive haemorrhages, and degenerative changes. All lesions resulted in single or multiple, small to massive, myocardial infarctions. Other affected organs included brain, lungs, liver, spleen and pancreas. Nonpurulent lymphocytic encephalitis was found post mortem in ducks that had priorly shown clinical nervous signs. Among ducks of all ages, a viral antigen in the cardiomyocytes and the epithelium of air capillaries was found through immunohistochemical detection methods. The results of the present study allowed us to conclude that the HPAI А(H5N8) viral infection may manifest itself as a systemic illness in commercial mule ducks with septicaemic lesions, resulting in high morbidity and mortality rates of up to 100%. Pathomorphological lesions were somewhat different from those previously reported in wild waterfowl.

This content is only available as a PDF.
You do not currently have access to this content.