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Molecular epidemiological investigation of Newcastle disease virus from domestic ducks in Korea

Lee, Eun-Kyoung, Jeon, Woo-Jin, Kwon, Jun-Hun, Yang, Chang-Bum, Choi, Kang-Seuk
Veterinary microbiology 2009 v.134 no.3-4 pp. 241-248
ducks, Newcastle disease, Newcastle disease virus, disease detection, strains, pathotypes, microbial genetics, virulence, disease reservoirs, epidemiological studies, disease surveillance, hemagglutination tests, molecular epidemiology, molecular genetics, sequence analysis, reverse transcriptase polymerase chain reaction, viral proteins, genetic variation, genotype, phylogeny, geographical variation, South Korea
To expand the epidemiological understanding of Newcastle disease virus (NDV) found in domestic ducks in Korea, 14 NDV isolates from apparently healthy domestic ducks were biologically and genetically characterized. Thirteen and 1 isolates of NDV were categorized into lentogenic and velogenic viruses, respectively, based on in vivo pathogenicity tests. Twelve lentogenic viruses showed HA activity to horse RBCs, while 1 lentogenic virus and the velogenic virus were negative. Lentogenic viruses (n =13) had sequence motifs of ¹¹²ERQERL¹¹⁷ (n =1) or ¹¹²GRQGRL¹¹⁷ (n =12) at the F0 cleavage site, while the velogenic virus (n =1) had a sequence motif of ¹¹²RRQKRF¹¹⁷ at the same site. Phylogenetic analysis revealed that at least three distinct genotypes may exist in domestic ducks in Korea; one class I genotype (genotype 2), and two class II (genotypes I and VII) genotypes. The class I virus was most closely related to strains of genotype 2 which were isolated in birds from the USA, Germany and Denmark. Twelve lentogenic class II viruses were grouped together in genotype I, and were then divided into at least three clusters, namely Aomori-like, Ulster2C-like, and V4-like. The velogenic class II virus was assigned to genotype VII which represents viruses responsible for recent epidemics in many Asian countries including Korea. The epidemiological importance of domestic duck isolates of NDV in Korea is discussed.