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NEWCASTLE DISEASE IN THE U.S.
MI A TORCHET TI , DVM MS PHD
D I A G N O S T I C V I R O LO GY L A B O R ATO R Y - AV I A NN AT I O N A L V E T E R I N A R Y S E R V I C E S L A B O R ATO R I E SU S D A A P H I S V S D B N V S L . D V L . AV I A N @ U S D A .G O VP H . 5 1 5 - 3 3 7 - 7 5 5 1
EU AI/NDJUNE 2019
PADOVA, ITALY
On May 16, 2018, the California Department of Food and Agriculture (CDFA) detected virulent Newcastle
disease in a small flock of backyard exhibition chickens.
Since May 17, USDA has confirmed 445 cases in backyard birds in California, one in Utah, and one in
Arizona.
Since December 18, 4 of the confirmed cases have been from commercial operations.
2
California vND Incident 2018
DEC 2018 EPI REPORT 3
Genetic Analysis CA2018-1The CA 2018 virus (genotype Vb) is related to Mexican-lineage viruses from Central America village poultry (Belize 2008, Honduras 2007), and the U.S. (smuggled parrot 1996, backyard CA 2002).◦ Current analysis supports a single introduction followed
by lateral spread.
◦ Lack of epidemiologic and contemporary sequence data contribute to the uncertainty surrounding the origin of the outbreak.
◦ Evolutionary analysis suggests the early CA2018 virus was actively evolving at an expected rate, however, where and in what population remains unclear.
4DEC 2018 EPI REPORT
Genetic Analysis CA2018-2• Early divergence into two main groups was defined by the
presence of a sustained single nucleotide polymorphism (SNP) in the fusion gene compared to a closely related reference sequence (GenBank: KF767466.1).
• No change in the amino acid profile of the cleavage site has been observed for sequenced viruses (PGGRRQKR/FVGAII).
• The ICPI ranges between 1.6-1.8 (n=11).
• Chickens remain predominantly affected, other species identified include quail, peafowl (peacock) and turkey, as well as duck, goose, parakeet, and pigeon.
DEC 2018 EPI REPORT 5
6
3-week olds: Lethargy/neurologic signs, conjunctivitis, comb hemorrhage and necrosis
Dimitrov et al. 2019. Virology, accepted
Adult birds also had periorbital swelling
Dimitrov et al. 2019. Virology, accepted
Multifocal hemorrhage
Atrophic thymus with gelatinous edema and
perithymic hemorrhages
mottled spleen
Field Case Definition Developed for CA 2002
Hemorrhagic tracheitis
Hemorrhage at junction of
proventriculus
Hemorrhage of cecaltonsils
Diptheritic lesions
Defined as >2 of any 5 birds demonstrating ANY of:
9
Molecular Workflow
NAHLN lab receives swab or tissue for testing
Neg
Screening rRT-PCR (APMV-1)
*may be run in parallel with screening assay for FADI
RNA detection by either assay is forwarded to NVSL
Any Ct>0is tested by
F-gene* assay andforwarded to
NVSL
Molecular (PCR / Sangerdirect from sample where possible)
Virus Isolation
Neg NegHA/NA subtype/
pathotype
Positive
Virus characterization
Received at NVSL for confirmation
10
11
USDA-APHIS (2018). “Epidemiologic Analyses of Virulent Newcastle Disease in Backyard Birds in California, December 2018.” USDA:APHIS:VS:STAS:Center for Epidemiology and Animal Health. Fort Collins, CO. December 2018. M&M Doc #447.0718. 41 pgs.
DEC 2018 EPI REPORT
California vND weekly case detection curve May 17 to November 9, 2018
DEC 2018 EPI REPORT 12
By the date the case definition was met for a presumptive positive flock
Predicted Population at Risk
DEC 2018 EPI REPORT 13
Data analyzed for 912 premises• 137 confirmed/presumptive positive premises• 68 dangerous contacts• 712 uninfected premises
DEC 2018 EPI REPORT 14
Disease Spread and Control Simulations• Time to detect vND in an unvaccinated, 50-bird backyard
flock based on observation of increased mortality (e.g. two or more dead birds within a 3-day period) was estimated to be from 4 to 7 days. • Estimates for the mean latent period (0.40 days) and the
mean infectious period (4.33 days) were used.
• Rapid and targeted surveillance, depopulation, and disposal were estimated to be the most effective at minimizing outbreak size and severity.
• The likelihood of disease spillover into commercial flocks was estimated to be low, but spillover was observed in 7 percent of simulated outbreaks.
15DEC 2018 EPI REPORT
16
Special Thanks to:
• USDA partners: Center for Epidemiology and
Animal Health, ARS SEPRL, Wildlife Services
• USGS National Wildlife Health Center
• State Animal Health Officials, and network
laboratories participating under the National
Poultry Improvement Program, and the
National Animal Health Laboratory Network
• Team Avian, Diagnostic Virology Lab