Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 9(11): 1995-2004
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Shady M. Shalaby1*, Walaa F. Awadin1, Mohamed F. Hamed1, Mohamed El-Tholoth2, Iman Ibrahim1, Ahmed F. El- Shaieb1

1Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Egypt; 2Department of Virology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt.

Abstract | During 2019-2021, a total of 456 and 320 pigeons showed clinical signs suspected to be infected with Newcastle disease (ND) and pox disease (PD), respectively at El Gharbia and El Dakahlia Provinces causing several losses to pigeons fanciers despite of culling and vaccination strategies. Confirmative diagnosis of infections was carried out by the molecular detection of both viruses by quantitative real time-polymerase chain reaction (qPCR). Histopathological examination, immunohistochemistry (IHC) staining and transmission electron microscopy (TEM) were conducted on PCR positive specimens. Histopathologically, meningoencephalitis, tracheitis, necrotizing pneumonia, tubulointerstitial nephritis and hyperplasia of gut associated lymphoid tissue were seen in pigeons infected with NDV. Meanwhile hypertrophy and hyperplasia of epidermal stratified squamous epithelium with dense eosinophilic intracytoplasmic inclusion bodies (ICIB) were observed in PD infected pigeons. IHC showed immunopositive staining for Newcastle disease virus (NDV) in brain, lung, heart, intestine, liver, and kidney while immunopositive avipoxviral staining were seen in epidermis and dermis. TEM of infected brain tissue with NDV showed hypertrophied neuron with numerous electron dense granules, dilated mitochondria, and rough endoplasmic reticulum. Intracytoplasmic and intranuclear electron dense inclusion bodies and degenerated axon were also seen. TEM of infected epidermal cells with avipoxvirus showed swollen cells with intracytoplasmic electron lucent inclusion bodies containing cellular debris. In conclusion, this study presented histopathological, immunohistochemical and ultrastructural changes in pigeons molecularly confirmed to be naturally infected with ND and PD.

Keywords | Newcastle disease virus, Pox disease virus, Pigeons, Histopathology, Immunohistochemistry, Transmission electron microscopy