title: Atypical velogenic Newcastle disease in a commercial layer flock in Japan.
abstract: In 2002, a commercial layer flock in Japan was initially diagnosed as being infected with infectious bronchitis (IB) based on clinical signs, virus isolation, and serological analysis but was later found to be atypically infected with velogenic Newcastle disease virus (NDV) following molecular diagnosis. The flock had slightly decreased egg production and an increased occurrence of soft-shelled eggs without significant mortality. IB-like viruses were isolated, which caused dwarfing and curling in 12-day-old chicken embryos. Ten years after this case, retrospective genetic analyses showed that apart from IB virus (IBV), the flock was also infected with NDV. Mean death time (MDT), intracerebral pathogenicity index (ICPI), and deduced amino acid sequence of the cleavage site of the fusion (F)-protein gene revealed that the NDV isolate was velogenic ((112)RRQKR(116)). These results indicate that poultry clinicians should look out for atypical velogenic ND, especially in vaccinated commercial chicken flocks, which may harbor hidden NDV infection.
authors: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of the Philippines Los Baños, College, Laguna 4031, Philippines United Graduate School of Veterinary Sciences, Yamaguchi University, Yamaguchi 753-8515, Japan Poultry Products Quality Control (PPQC Co. Ltd.), 125-7 Daiwa Dakeonsen, Nihonmatsu, Fukushima 964-0062, Japan.
authors: Dennis V
authors: DV
authors: Umali
authors: Avian Zoonoses Research Center, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8553, Japan United Graduate School of Veterinary Sciences, Yamaguchi University, Yamaguchi 753-8515, Japan.
authors: Hiroshi
authors: H
authors: Ito
authors: Poultry Products Quality Control (PPQC Co. Ltd.), 125-7 Daiwa Dakeonsen, Nihonmatsu, Fukushima 964-0062, Japan.
authors: Kazutoshi
authors: K
authors: Shirota
authors: Avian Zoonoses Research Center, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8553, Japan United Graduate School of Veterinary Sciences, Yamaguchi University, Yamaguchi 753-8515, Japan.
authors: Toshihiro
authors: T
authors: Ito
authors: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of the Philippines Los Baños, College, Laguna 4031, Philippines Poultry Products Quality Control (PPQC Co. Ltd.), 125-7 Daiwa Dakeonsen, Nihonmatsu, Fukushima 964-0062, Japan h_katoh@ppqc.co.jp.
authors: Hiromitsu
authors: H
authors: Katoh
mesh_terms: D000818:Animals; D002645:Chickens; D005260:Female; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D007564:Japan / Q000453:epidemiology; D008969:Molecular Sequence Data; D009521:Newcastle Disease / Q000453:epidemiology / Q000473:pathology*; D009522:Newcastle disease virus / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins
keywords: avian infectious bronchitis; commercial layer flock; silent infection; velogenic Newcastle disease