Abstract

Aspergillus fumigatus infection might predispose birds to other respiratory infections with other pathogens such as Newcastle Disease Virus (NDV). This study aimed to investigate the incidence of Aspergillus fumigatus in commercial farms and its histopathological effects on respiratory organs and to evaluate the immunosuppressive effect of aspergillosis on NDV vaccinated birds. Aspergillus fumigatus was isolated from feedstuff and broilers in farms with respiratory manifestation. Twenty NDV-vaccinated broiler chickens of 10 days old were experimentally infected by feeding on feedstuff contaminated with Aspergillus fumigatus. Twenty vaccinated broilers but not fed the contaminated diet were used as the control group. Clinical signs, histopathological changes, NDV antibody levels in infected birds were recorded. Clinically, infected birds showed respiratory distress, dyspnea, gasping, ruffled feathers, green watery diarrhea, anorexia, lethargy, and unilateral drooping of wing. Histopathological changes were observed as disseminated granulomatous foci in the affected lungs, with caseous necrosis and leukocytes infiltration. The antibody immune response against NDV significantly reduced in infected birds compared with that of non-infected broilers. It is concluded, that Aspergillus fumigatus infection suppresses the immune responses and predisposes the broilers to other microbial infections, leading to considerable economic losses in the poultry industry.