AVIAN INFLUENZA & NEWCASTLE DISEASE ACTIVITIES

M I A K I M T O R C H E T T I , D V M M S P H D

S E C T I O N H E A D - AV I A N , D I A G N O S T I C V I R O LO G Y L A B O R ATO R YU . S . D E PA R T M E N T O F A G R I C U LT U R EA N I M A L A N D P L A N T H E A LT H I N S P E C T I O N S E R V I C EV E T E R I N A R Y S E R V I C E S

O C TO B E R 2 0 1 7

Part I – Year in Review◦ H5/H7 status

◦ Test protocol and reporting

Part II – Update◦ IAV and APMV-1 activity

◦ Test workflow

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Overview

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Historic global HPAI reports by subtype/year 1934-2017 (n=419; count by subtype and country)

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Predominated by gsGD H5

• HPAI reported at low frequency• Aquatic migratory birds found

to be natural hosts of low pathogenic strains

• HPAI not observed in natural hosts

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H5 H5 gsGD

H5 HPAI BY REGION N=375

Africa Americas Asia Australia Europe

What do we know about the genesis of HPAIV from LPAIV?

E R I C A S PA C K M A N , M A R Y PA N T I N - J A C K W O O D , D A V I D

S W AY N E , D A V I D S U A R E Z , D A R R E L K A P C Z Y N S K I

U S N AT I O N A L P O U LT R Y R E S E A R C H C E N T E R

U S D A - A R S , AT H E N S , G A

COURTESY OF E. SPACKMAN, ET AL, USDA NPRC, ATHENS, GA

Technically only applies to gallinaceous poultry

Highly pathogenic (HP) has always been an H5 or H7 subtype◦ Other subtypes?

◦ Some H4, H6 and H10 isolates (Brugh and Beck 1992; Capua et al.; Swayne et al. 1994; Wood et al. 1996) met the definition based on a IV lethality study, but not by a natural route of exposure

◦ LPAIV can also cause disease, low rates of mortality, and decreases in production

COURTESY OF E. SPACKMAN, ET AL, USDA NPRC, ATHENS, GA

First, what do we mean by highly pathogenic and low pathogenic?

Highly pathogenic: Systemic infection

Low pathogenic: Localized infection

What determines if the infection will become systemic?

– A very short protein sequence in the HA protein → the proteolytic cleavage site (PCS) – as defined for chickens

Chen, et al., Cell 95

(409-17). 1998

COURTESY OF E. SPACKMAN, ET AL, USDA NPRC, ATHENS, GA

The HA protein must be cut by an enzyme in the host cell so that the virus can replicate.

COURTESY OF E. SPACKMAN, ET AL, USDA NPRC, ATHENS, GA

Where cleavage occurs by enzymes only in the respiratory tract or intestinal tract = LPAI

Where cleavage occurs by enzymes available in many tissues = HPAI

HPAIVLPAIV

H5 or H7

The mutation from LPAIV to HPAIV occurs when LPAIV

circulates in chickens and turkeys

Selection pressure

Why does LPAIV mutate to HPAIV in chickens and turkeys?

COURTESY OF E. SPACKMAN, ET AL, USDA NPRC, ATHENS, GA

LPAIVH5 or H7

HPAIV

Can we predict which viruses will mutate?

COURTESY OF E. SPACKMAN, ET AL, USDA NPRC, ATHENS, GA

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The most sensitive and specific tools target conserved regions of the influenza Type A (IAV) protein or genome (e.g. matrix, nucleoprotein).

The virus pathotype is ‘presumptive’ based upon the clinical presentation of the flock compared to the USDA HPAI case definition and ‘confirmed’ based upon the HA cleavage site sequence.

What do the other tests tell us?

Diagnostic considerations

Target HA subtype NA subtype pathotype

IAV AGID/ELISA NP-Antibody W W W

IAV HI/NI HA-Antibody ✓ ✓ W

IAV-M PCR M-RNA W W W

H5/H7 PCR HA-RNA ✓ W W

Sequencing genome ✓ ✓ ✓

In vivo pathogenicty test in vivo W W ✓

✓ = test can determine

W = test cannot determine

NPIP AGID/ELISA

• Detect antibody to NP

NVSL HI

• H1-H16

• Confirm antibody to HA

NVSL NI

• N1-N9

• Confirm antibody to NA

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Serologic Test ProtocolEstablishes prior exposure

Test cannot determine pathotypeTest cannot determine virus status

How is the finding confirmed?

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Molecular Test Protocol

Establishes virus statusPCR cannot determine pathotype

Requires sequence or in vivo testing

NAHLN lab rRT-PCR

•FluA (M)

•Subtype (H)

NVSL rRT-PCR

•FluA (M)

•Subtype (H)

NVSL Sequence

•Pan HA (H)

•Pan NA (N)

•Full genome

NVSL Virus Isolation

• In vivo test

•Gen/ant.char

How is the finding confirmed?

How Test Results Contribute to Flock Status*

*Avian influenza-affected flock based upon non-negative antigen results or antibody detection at a NAHLN or NPIP lab.

Subtype: H5 or H7

Clinical presentation

NAHLN lab

NVSL

Presumptive by rRT-PCR

Cannot determine

Confirmed by molecular test orserology (HI/NI)

Pathotype: Low or highly

pathogenic

Clinical presentation

NAHLN/NPIP lab

NVSL

Presumptive (see case definition)

Test cannot determine

Confirmed by virus sequence and/or in vivo testing

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Reporting…simplified

Test confirmed SectorInternational

Reporting

HPAI or LPAI as confirmed by virus sequence

&/or isolation

HPAI – any LPAI – all except

BYDImmediate

H5/H7 PCR +/- antibody,no virus or sequence+ follow-up negative

Commercial Immediate

LBM and BYD6-month

+ bilateral trading partners

H5/H7 Antibody only, no PCR, virus or sequence

+ follow-up negativeAll

Only bilateral trading partners

2016-17 Poultry Events

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Date State Surv stream

Subtype

(AM=North American) Outcome

Jan-16 IN Commercial turkeysHPAI/LPAI H7N8, first H7N8

HPAI detection

Limited spread, mutation to

HPAI occurred at a single site

Apr-16 MO Commercial turkeys LPAI H5N1 Single premises with

no further spread

Jun-16 NJ, NY, PALBM - primarily

MuscovysLPAI H5N2

Traced to single

distributor/source flock

Mar-17 TN, AL, KY, GACommercial chickens

and backyards

LPAI AM H7N9

HPAI in TN only

Multiple point source LPAI

introductions; HPAI mutation

occurred at a single location

with lateral spread to one site

Mar-17 WI Commercial turkeys LPAI H5N2

Single premises with

no further spread; unrelated to

H5N2 from LBM

Apr-17 ID Backyard duck LPAI H5N2

Single premises with

no further spread;

unrelated to other recent H5N2

• Turkeys in Indiana – initial detection in response to clinical signs.

• LPAI>HPAI mutation occurred in a single flock.

• Data from a highly similar wild bird virus collected in KY 11/2015 (6/8 genes) allows estimate for both the timing and likely location of introduction, and is supported by epidemiologic data.

2016 January: AM H7N8

Virology, Volume 507, July 2017, Pages 216-219Dong-Hun Lee, Mia Kim Torchetti, Mary Lea Killian, David E. Swayne

2017 March: AM H7N9• Commercial chickens and backyard

flocks – initial detection in response to clinical signs.

• LPAI>HPAI mutation occurred once (later during circulation) with a single event of secondary spread.

• Data from a highly similar wild bird virus collected in WY 9/2016 (8/8 genes) allows estimate for timing andfrequency of introductions, and is supported by epidemiologic data.

• More than one independent introduction.

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HPAI

USDA-APHIS (2017). Epidemiologic and other analyses of avian influenza: April 27, 2017 Report. USDA:APHIS:VS:STAS:Center for

Epidemiology and Animal Health. Fort Collins, CO. April 2017. Doc #391.0317.

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H2N2 in Northeast LBMS since 2014LBM H2N2 2015 2016 2017

CT 3 4 8

MA 0 1 0

NJ 7 13 6

NY 8 5 80

PA 3 0 21

RI 0 1 0

H7N2 in Cats at NYC Shelter

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