Phylogenetic assessment reveals continuous evolution and circulation of pigeon-derived virulent avian avulaviruses 1 in Eastern Europe, Asia, and Africa

Authors: SABRA, MAHMOUD - Consultant; DIMITROV, KIRIL - Consultant; GORAICHUK, IRYNA - Consultant; WAJID, ABDUL - University Of Veterinary And Animal Sciences; SHARMA, POONAM - Orise Fellow; REHMANI, SHAFQAT - University Of Veterinary And Animal Sciences; MUZYKA, DENYS - National Scientific Center; Williams Coplin, Tina; Miller, Patti; Afonso, Claudio

Submitted to: BMC Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2017
Publication Date: 9/26/2017
Publication URL: https://handle.nal.usda.gov/10113/5807220
Citation: Sabra, M., Dimitrov, K., Goraichuk, I.V., Wajid, A., Sharma, P., Rehmani, S.F., Muzyka, D.V., Williams Coplin, T.D., Miller, P.J., Afonso, C.L. 2017. Phylogenetic assessment reveals continuous evolution and circulation of pigeon-derived virulent avian avulaviruses 1 in Eastern Europe, Asia, and Africa. BMC Veterinary Research. 13(2017):291. https://doi.org/10.1186/s12917-017-1211-4.
DOI: https://doi.org/10.1186/s12917-017-1211-4

Interpretive Summary: Newcastle disease is a very serious disease of poultry. The virulent forms of this virus are present in Africa, Asia and South America. The viruses of genotype VI are called pigeon paramyxoviruses (PPMV-1) because they are normally isolated and cause clinical disease in pigeons and doves. These species are natural reservoirs of the viruses that may occasionally cause disease in poultry. Here, we describe the isolation and genome sequence analysis of recent viruses genotype VI from Egypt (2015) Ukraine (2007, 2013) and Pakistan (2014-2016). Current rapid assays to determine the virulence of those viruses do not work and for that reason here we have developed a new test function to determine the virulence of two new sub-genotypes of pigeon viruses. These results highlight the importance of conducting active surveillance on pigeons and the need to update existent rapid diagnostic reagents to detect variants that are widely distributed worldwide.

Technical Abstract: Background: The remarkable diversity and mobility of Newcastle disease viruses (NDV) includes virulent viruses of genotype VI. These viruses are often referred to as pigeon paramyxoviruses 1 because they are normally isolated and cause clinical disease in birds from the Columbidae family. Genotype VI viruses occasionally infect, and may also cause clinical disease in poultry. Thus, the evolution, current spread and detection of these viruses are relevant to avian health. Results: Here, we describe the isolation and genomic characterization of six Egyptian (2015), four Pakistani (2015), and two Ukrainian (2007, 2013) recent pigeon-derived NDV isolates of sub-genotype VIg. These viruses are closely related to isolates from Kazakhstan, Nigeria and Russia. In addition, eight genetically related NDV isolates from Pakistan (2014–2016) that define a new sub-genotype (VIm) are described. All of these viruses, and the ancestral Bulgarian (n = 2) and South Korean (n = 2) viruses described here, have predicted virulent cleavage sites of the fusion protein, and those selected for further characterization have intracerebral pathogenicity index assay values characteristic of NDV of genotype VI (1.31 to 1.48). A validated matrix gene real-time RT-PCR (rRT-PCR) NDV test detect all tested isolates. However, the validated rRT-PCR test that is normally used to identify the virulent fusion gene fails to detect the Egyptian and Ukrainian viruses due to mismatches in primers and probe. A new rapid rRTPCR test to determine the presence of virulent cleavage sites for viruses from sub-genotypes VIg was developed and evaluated on these and other viruses. Conclusions: We describe the almost simultaneous circulation and continuous evolution of genotype VI Newcastle disease viruses in distant locations, suggesting epidemiological connections among three continents. As pigeons are not migratory, this study suggests the need to understand the possible role of human activity in the dispersal of these viruses. Complete genomic characterization identified previously unrecognized genetic diversity that contributes to diagnostic failure and will facilitate future evolutionary studies. These results highlight the importance of conducting active surveillance on pigeons worldwide and the need to update existent rapid diagnostic protocols to detect emerging viral variants and help manage the disease in affected regions.