Phylogenetic Analysis of Some Isolates of Newcastle Disease Virus from the Sudan Using the Fusion Protein Gene

Abstract

Seven Newcastle disease virus (NDV) strains and isolates were propagated in chicken embryonated eggs and identified by hemagglutination test (HI). Genomic RNA was extracted from allantoic fluid harvests of the studied viruses. Two reverse transcription-polymerase chain reactions (RT-PCR) were developed, which amplified 984 and 1412 bp of the fusion protein gene (F gene) of NDV strains TY-1/90, DIK-90, DONGOLA, GD.S.1, I 2, LASOTA, CLONE 30 using two sets of gene specific primers. Following sequencing, nucleotide sequences were annotated and 894 bp were compared phylogenetically with those from strains previously reported in the Sudan and reference strains from the Genbank ® . It could be shown that TY-1/90 and DIK-90 strains isolated from Tyba and Dikhainat towns in Sudan in 1990, respectively, belong to the genotype VI subtype (VIb) of NDV genotypes and were in close genetic relationship to earlier Sudanese isolates of the mid-1970s, suggesting thatSudanese genotype VI subtype VIb was genetically stable and circulating over at least 15 years. Earlier Sudanese isolates were in turn genetically related to the European pigeons paramyxovirus type 1 (PPMV-1) responsible for panzootic outbreaks of PPMV-1 in pigeon in the 1980s. It could thus be postulated,based on our findings, that this Sudanese strain of NDV might be the origin of, or share a common ancestor with, the European pigeon’s paramyxovirus type 1 (PPMV-1) in the 1980s. Dongola, GD.S.1 strains and the vaccinal strains (I 2, LASOTA, and CLONE 30) were classified into genotype II that comprises non-pathogenic lentogenic NDV strains. The present genetic classification of NDV isolates of the Sudan provides valuable information, which is fundamental for improving the efficiency of controlling strategies and vaccine development.