Phylogenetic and Histopathological Characterization of Newcastle Disease Virus (VII.1.1) Recently Isolated from Naturally Infected Quails in Egypt
Phylogenetic and Histopathological Characterization of Newcastle Disease Virus (VII.1.1) Recently Isolated from Naturally Infected Quails in Egypt
Mohamed Lebdah1, Sahar Abd El Rahman2*, Ahmed Attia3, Reham Karam2, Naglaa Fathy Saeed Awad1, Mohamed Ibrahim El Bagoury1
ABSTRACT
Newcastle disease (ND) as a devastating disease is a challenge of poultry industry not only in developing countries, but also all over the world. The pathogenesis of ND in quails is still poorly understood. The present study aimed to investigate the natural occurrence and pathological changes of ND in quails in Egypt. The diseased quails were collected from eleven flocks in Egypt exhibited respiratory, nervous signs and whitish green diarrhea in addition to egg abnormalities and lower production with mortalities. No characteristic gross lesions were observed except heamorrhages in brain, congested liver, spleen, brain and muscles besides greenish content of the gizzard. The histopathological examination of lung, brain, liver, and trachea of these diseased quails revealed non-suppurative encephalitis, perivascular cuffing, congestion of hepatic sinusoids, degenerative changes in the hepatic cells and interstitial lymphocytic aggregations in the liver and focal pneumonic areas in the lung. Pooled samples from the investigated quails were inoculated in specific pathogen free embryonated chicken eggs (SPF-ECEs). The dead embryos showed hemorrhages, congestion and dwarfism. The collected allantoic fluids were examined later by haemagglutination (HA) and haemagglutination inhibition (HAI) test. The allantoic fluids of 5 pooled samples expressed positive using specific Newcastle disease virus (NDV) antiserum. The NDV field isolates were confirmed by reverse transcription polymerase chain reaction (RT-PCR) and partial sequencing targeting F gene of amplicon size (362) bp containing the region 112RRQKRF117 motif, which is the determinant part of virus virulence. The sequenced isolate was grouped in class II genotype VII.1.1 with small distance from NDV strains in chickens and turkeys which is alarming for the potential transmission of NDVs from quails to other poultry species.
Keywords | Newcastle disease, Quails, RT-PCR, F gene, Pathological changes, Class II genotype VII.1.1
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July 2022
Vol. 10, Iss. 7, Pages 1423-1658
