Identification and pathotypical analysis of a novel VIk sub-genotype Newcastle disease virus obtained from pigeon in China

•This is the first description of a novel sub-genotype of NDV (VIk).•Genotype VIk strains are present in China and Europe, calling for strict control strategies.•Inconsistencies exist in pathogenicity indexes in chickens in comparison to other pigeon viruses.•Genotype VIk strains are pathogenic to pigeons.

Newcastle disease virus (NDV) can lead to a devastating disease to various avian species including pigeons. Genotype VI NDV is a major cause of Newcastle disease (ND) in Columbiformes (i.e. pigeons and doves). Here, we analyzed the genetic diversity of genotype VI based on the complete F gene sequences of 2 pigeon-origin isolates in northeastern China in 2015, along with 238 genotype VI strains available in GenBank. The phylogenetic tree and evolutionary distances revealed that the 2 new isolates were clustered into a new sub-genotype herein proposed as VIk. Although the 2 isolates contain the 113RQKRF117 cleavage site, a feature generally associated with virulent NDV strains, the values of ICPI and MDT showed lentogenic characteristics. The challenge experiment demonstrated that the isolate Pigeon/China/Jilin/NG05/2015 was pathogenic to pigeons, causing lesions in multiple tissues and organs. The emergence and spread of the sub-genotype VIk viruses illustrated that the genotype VI NDV was undergoing evolutionary changes. It is necessary to pay close attention and carry out epidemiological surveillance in pigeons.