|Dimitrov, Kiril - Consultant|
|Ferreira, Helena - Orise Fellow|
|Goraichuk, Iryna - Consultant|
|Crossley, Beate - Uc Davis Medical Center|
|Killian, Mary Lea - Animal And Plant Health Inspection Service (APHIS)|
|Bergeson, Nichole Hines - Animal And Plant Health Inspection Service (APHIS)|
|Torchetti, Mia Kim - Animal And Plant Health Inspection Service (APHIS)|
Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2019
Publication Date: 3/22/2019
Citation: Dimitrov, K.M., Ferreira, H.L., Pantin Jackwood, M.J., Taylor, T.L., Goraichuk, I.V., Crossley, B.M., Killian, M., Bergeson, N., Torchetti, M., Afonso, C.L., Suarez, D.L. 2019. Pathogenicity and transmission of virulent Newcastle disease virus from the 2018-2019 California outbreak and related viruses in young and adult chickens. Virology. 531:203-218. https://doi.org/10.1016/j.virol.2019.03.010.
DOI: https://doi.org/10.1016/j.virol.2019.03.010 Interpretive Summary: Newcastle disease virus (NDV) is a deadly disease in poultry, including chickens and turkeys, that is considered a foreign animal disease in the United States. Unfortunately an outbreak in May 2018 occurred in California that continues to infect backyard chickens in Southern California in spite of a major effort to eradicate the virus. Studies with the virus were initiated in the laboratory to compare the California 2018 virus with two similar NDV viruses from Belize (2008) and an earlier California virus from 2002 in both young and adult chickens. The viruses caused similar disease and high mortality and easily transmitted to contact control chickens. These studies provided important data on the virus including incubation period, common clinical signs, and sequence analysis. This data is valuable to understand the virus to aid in control efforts.
Technical Abstract: In May of 2018, virulent Newcastle disease virus was detected in sick, backyard, exhibition chickens in southern California. Since, the virus has affected 401 backyard and four commercial flocks, and one live bird market in California, and one backyard flock in Utah. The pathogenesis and transmission potential of this virus, along with two genetically related and widely studied viruses, chicken/California/2002 and chicken/Belize/2008, were evaluated in both 3-week- and 62-week-old chickens given a low, medium, or high challenge dose. All three viruses were highly virulent causing clinical signs, killing all the chickens in the medium and high dose groups, and efficiently transmitting to contacts. The three viruses also replicated in the reproductive tract of the adult hens. Virus shedding for all viruses was detected 24'hours after challenge, peaking with high titers at day 4 post challenge. Although not genetically identical, the studied isolates were shown to be phenotypically very similar, which allows the utilization of the available literature in the control of the current outbreak.