Microbiological and pathological studies of concurrent infections associated with retarded growth in broilers at Behira governorate

Abstract

P arvoviruses cause significant economic losses for domestic waterfowl producers. From June 2020 to January 2022, eight mule and four pekin duck farms were investigated for parvovirus in Al -Beheira governorate, Egypt. The affected ducks exhibited severe growth retardation with atrophied and deformed beak, a protruding tongue, profuse white diarrhea, locomotor dysfunction and lost their feathers, especially on the back, neck, and wing. The mortality rate was 10 %-18% and the morbidity rate was 60%-80% in affected flocks. Histopathological analysis of samples from mule and pekin ducks at different ages revealed multiple pathological alterations in various organs including; heart, liver, spleen, lung, trachea, intestine, kidneys, even tongue and brain and consistent with clinical picture. Six out of twelve duck flocks were positive for parvovirus genome by PCR. These viruses were isolated from pooled fecal swabs and caused a cytopathic effect in duck embryo liver (DEL) cells. Phylogenetic analysis of the partial VP1 gene indicated that five of current Egyptian parvovirus strains belonged to the Novel goose parvovirus (NGPV) group and clustered with both Chinese NGPV strains and previously identified Egyptian NGPV strains and one strain belonged to the duck adeno-assciated virus and clustered with the Australian duck adeno-associated virus DA. To the best of our knowledge, this can be considered the first record of duck adeno-assciated virus infection in mule duck in Al-Beheira governorate.