Molecular identification of inclusion body hepatitis in broiler chickens in Egypt

Objective: Isolation and molecular identification of fowl adenovirus (FAdV) in broilers at different farms in EI.Dakahlia and EL.Gharbia, Egypt.

Design: Experimental study

Animals: Fifty chicken flocks (250 broiler chickens)

Procedures: A total of 250 diseased chickens were collected from fifty different farms in El.Dakahlia and El.Gharbia, Egypt. Chickens were suffered from ruffled feathers, diarrhea, melena, dehydration and crouching position. These chickens were euthanized and samples were collected and pooled (liver, lung, kidney, spleen, heart fluid and the cloacal swabs were pooled separately). Histopathology was performed for liver samples. Molecular diagnosis by using polymerase chain reaction based on hexon gene has performed on all 50 collected pooled samples. Viral isolation was done for PCR positive cases in ECE via CAM. Isolates were retested post isolation in embryos by PCR and sequence analysis was done.

Results: Four positive samples (El-Dakahlia and El-Gharbia) from fifty flocks were detected by PCR according to the hexon gene with expected product size of 890 bp. Phylogenetic analysis based on partial nucleotide sequence of hexon gene revealed that the Egyptian virus in this work FAdVs was placed with the same group of Adenoviruses D serotype 11. Histopathology showed basophilic intranuclear inclusion bodies in hepatocytes. Congestion, hemorrhage and death of embryo were a sequel of egg inoculation with 4 isolates. Liver of embryo appeared swollen with focal necrosis and petechial & ecchymotic hemorrhage. CAM was opaque, congested and/or hemorrhagic. This study shows molecular identification and characterization of inclusion body hepatitis (IBH) viruses in Egyptian poultry farms.