Newcastle disease outbreaks in recent years in Western Europe were caused by an old (VI) and a novel genotype (VII)

Abstract

Newcastle disease virus (NDV) strains, isolated from outbreaks during epizootics between 1992 and 1996 in Western European countries, were compared by restriction enzyme cleavage site mapping of the fusion (F) protein gene between nucleotides 334 and 1682 and by sequence analysis between nucleotides 47 and 435. Both methods revealed that NDV strains responsible for these epizootics belong to two distinct genotypes. Strains derived from sporadic cases in Denmark, Sweden, Switzerland and Austria were classified into genotype VI [6], the same group which caused outbreaks in the Middle East and Greece in the late 1960's and in Hungary in the early 1980's. In contrast, viruses that caused epizootics in Germany, Belgium, The Netherlands, Spain and Italy could be classified into a novel genotype (provisionally termed VII), hitherto undetected in Europe. It is possible that the genotype VII viruses originated in the Far East because they showed a high genetic similarity (97%) to NDV strains isolated from Indonesia in the late 1980's.

Restriction Fragment Length Polymorphism Analysis of the F Gene of Newcastle Disease Viruses Isolated from Chickens and an Owl in Taiwan.

“…The restriction sites of the F gene of each strain are summarized in Table 2. None of the RFLP patterns was the same as those reported previously [4] and they could be grouped into Group VII [8]. Ck/Tw/ 2066/94, isolated before the 1995 outbreak, had the same restriction sites as Ck/Tw/2137/95, Ck/Tw/2164/95 and Ck/ Tw/2174/95.…”

“…Molecular epidemiology has been employed to explore the sequence variation and phylogenic relationship of NDV isolates [6][7][8][9]. However, investigation of the nucleotide sequence is time-consuming when the number of samples is large, and a relatively simple way of grouping different isolates with epizootiological relatedness has been demonstrated [4].…”

“…In order to identify viruses of high and low pathogenicity in the laboratory, three pathogenicity tests, the mean death time (MDT), the intracerebral pathogenicity index (ICPI), and the intravenous pathogenicity index (IVPI), are performed [1]. These pathogenicity tests can distinguish viruses according to the degree of severity of ND caused by different isolates, but do not give much epizootiological information.Molecular epidemiology has been employed to explore the sequence variation and phylogenic relationship of NDV isolates [6][7][8][9]. However, investigation of the nucleotide sequence is time-consuming when the number of samples is large, and a relatively simple way of grouping different isolates with epizootiological relatedness has been demonstrated [4].…”

“…However, investigation of the nucleotide sequence is time-consuming when the number of samples is large, and a relatively simple way of grouping different isolates with epizootiological relatedness has been demonstrated [4]. After amplifying a 75% region of the F gene by reverse transcription-polymerase chain reaction (RT-PCR) and restriction endonuclease digestion, restriction site analysis established seven major groups of NDV isolates in the world [4,8].In Taiwan, there was an epidemic outbreak of ND in 1995. The origin of the causative virus for this outbreak was still unknown.…”

Isolation of a Recent Korean Epizootic Strain of Newcastle Disease Virus from Eurasian Scops Owls Affected with Severe Diarrhea

“…Class I viruses are not commonly reported and are found in waterfowl, live bird markets, and domestic poultry (Alexander et al, 1992;Aldous et al, 2003;Seal et al, 2005;Kim et al, 2007). The class II viruses are categorized into genotypes I to IX (Ballagi-Pordany et al, 1996;Lomniczi et al, 1998;Herczeg et al, 1999;Yang et al, 1999;Liu et al, 2003). In Korea, genotype VII first emerged in 1984 and then reemerged in 1995 (Lee et al, 2004).…”