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.

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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

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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:

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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

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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

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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