Virulent Newcastles Disease

July 9  Update:

Thank you to everyone who took the time to participate in the ZAHP Chat discussing the ongoing VND outbreak in Southern California on Tuesday, June 26th, and a huge thank you to our speakers: Dr. Marvistine Y. Briggs-Fisher, Dr. Sarah Mize, Dr. Darrel Styles, Dr. Kevin Dennison, and Rose Massengill.  The biosecurity resources mentioned on the call can be viewed at, and the ZAHP HPAI checklist which may be adapted for use can be found at  If you have any questions please let us know and we will forward them along to our speakers.

Call Notes: ZAHP Chat: A Discussion on the Ongoing Virulent Newcastle Disease Outbreak in Southern California


Marvirstine Y. Briggs-Fisher, DVM – Veterinarian, USDA-AHPIS Veterinary Services (Incident Management Team)

Sarah Mize, DVM, MPVH – Avian Specialist, CDFA

Darrel K. Styles, DVM, PHD –  Senior Staff Veterinarian, USDA-APHIS Veterinary Services

Kevin M. Dennison, DVM – National Emergency Management Staff Veterinarian, USDA-APHIS Animal Care

Rose Massengill – Public Information Officer, USDA-APHIS (Incident Management Team)


  • Situational/IMT UpdateMarvirstine Y. Briggs-Fisher, DVM

o   On May 17 USDA-APHIS confirmed a case of VND in a small flock of backyard exhibition chickens in Los Angeles County, CA

  • Since then additional 19 cases confirmed in backyard ex flocks in San Bernadino County.  Full list of cases available on APHIS website
    • Note: Additional cases have been identified since this call, click here for an up to date list.

o   No cases have been found in commercial poultry

o   APHIS working closely with CDFA to investigate findings and conduct an epidemiological investigation

o   APHIS and CDFA are working together on outreach to ensure info about the disease is reaching throughout the community and the goal is to make sure all sick birds are reported and tested in order to keep the disease from spreading.

o   Questions

  • Q: Within San Bernadino County, what is the radius of the current identified premises?  Is it all within 10km quarantine zone or are there multiple separate quarantine zones?
  • A : Complicated as some surveillance zones overlap.. there are multiple zones and each go out 10 km for the surveillance zone from each infected premises
  • Q: On APHIS site it lists the birds as  backyard exhibition chickens. Is this a broad generalization? Are some of these cockfighting industry or just private collections?
  • A: Just know that they are chickens. When doing surveillance they are listed  as “poultry” on forms and don’t have other designation beside backyard poultry.  Some are shown at exhibitions which is why they have the exhibition/backyard category.


  • CDFA UpdateSarah Mize, DVM, MPVH

o   USDA working with us.

o   Currently the disease is just in backyards not commercial.

  • Working cooperatively to eliminate the disease. Has devastating symptoms when it hits chickens and they are doing everything in their power to get it out of the area  so other birds do not contract it.


  • VND Virology/VaccinesDarrel K. Styles, DVM, PhD

o   There are a number of different paramyxoviruses that affect avian species . Some are more species specific, others are more generalists.

o   APMV1 to which Newcastle disease belongs is more of a generalist. It can affect a wide variety of avian genera as well as mammals in some cases

  • Speaking on APMV1 specifically,  virulent Newcastle disease (formerly known as exotic Newcastle disease) is determined by the virulence in poultry. Classifying it as virulent relates back to the number of cleavage points within the fusion protein region as well as a pathogenicity index in poultry (similar to HPAI).
    • Analogous to HPAI, where the cleavage region within the hemagglutinin and proto-protein contains multiple basic amino acids, it conveys to the virus the ability to be cleaved by a multiple enzymes in different organ systems making it more of a systemic infection.
  • While VND does contain a hemagglutinin-neuraminidase protein, it is the number of basic amino acids found at the cleavage point of the fusion protein that determines the virus as “virulent”
    • The old designation used to be lentogenic for sub-clinical or very low virulence, mesogenic for somewhat of a middle range and , and velogenic that would sometimes go with viscerotropic velogenic (depending on tissue tropism) for highly virulent strains.
    • OIE reclassified Newcastle, lumping the mesogenic and velogenic strains into what they classify as Virulent Newcastle Disease (VND)

o   There are a number of different domestically available vaccine products for NDV vaccination including lentogenic modified live strains, inactivated vaccines, as well as other viral vectored vaccines.

o   Newcastle disease, APMV1, impacts different birds species in different ways.  It can range from sub-clinical to highly virulent which makes its movement in subclinical birds a problem, as people don’t realize the birds are shedding.

  • While birds can carry this virus, the genotypes are somewhat different.
    • Double Crested Cormorants can carry a strain of VND that could potentially bleed over into domestic poultry compartment.
    • Pigeons are known to carry pigeon paramyxovirus 1, a different variant of APMV1 uniquely adapted to pigeons that can carry over into domestic poultry.
    • The 1974 outbreak in the US was linked to the importation of psittacines that were infected prior to the institution of the quarantine system which now prevents that from happening. However pscittacines are not necessarily a host species for this virus.  Often times what happened was that birds would be captured, caged, and stored until there was a sufficient load to ship to the US; kept with poultry and other birds, so it is believed the crossover into psittacines comes from poultry because there is not a lot of evidence that ND would circulate naturally within psittaciformes.
      • However, smuggling remains a concern for all species of birds.  Case in point, in 2006 two presumably smuggled red-lored amazon parrot chicks were found to be infected with HPAI H5N2 derived from a Mexican lineage virus but most similar to viruses circulating in Central America.  The birds were reportedly purchased in California, displayed clinical illness, and diagnosed at UC Davis.  One chick died and the other recovered with supportive care and home quarantine.


  • Animal Care UpdateKevin M. Dennison, DVM; Emergency Program Manager and Veterinarian, USDA-APHIS Animal Care

o   Foreign Animal Disease incidents are managed under USDA-APHIS VS and with the authority of SAHOS.  Typically management starts at the state level and then becomes unified command with APHIS and the State as is happening now.

o   Animal Care does not have any statutory authority related to disease outbreaks, but manage cooperative agreement with ZAHP and support VS through personnel deployed to assist VS with incident.

  • Kevin currently on Zoo Unit of National Incident Coordination group
  • Couple of people deployed to southern CA to assist VS.

o   Inspection process continues but the inspection force is well aware of issues in SoCal and would work with any zoos on biosecurity precautions, as they would any day.  Local SoCal folks are involved in the incident as boots on ground.


Q & A

  • Do poultry producers vaccinate for VND? What are the mechanisms for VND to get into commercial poultry?

o   In CA the egg producers vaccinate.  Usually do two lives and one dead vaccine.  The mechanism of entry we’ve seen in the past have been employees with birds at home or elsewhere that have brought it in. Once (the virus is) gets in the method has been going to the processer and exchanging crates, and going out to other farms – in our last outbreak that was a method of spread.  Usually introduction will be by an employee or sometimes neighbors ( producers at rural urban interface where neighbors have poultry in close proximity).  So employees, neighbors, or equipment used in processing. (Dr. Mize)

o   Usually Broilers do not vaccinate (don’t live that long) but almost all layers in SoCal do.(Dr. Mize)  

  • Is the vaccine considered protective? Are producers better protected now than they were during the 2003 outbreak?  Really wondering if flocks are less susceptible now than they were back then due to improved vaccination products and protocols.

o   Even in private sector there is a lot more vaccination than there used to be. It is protective for this strain. Its estimated that because of its virulence factor it may be a little bit less protective than the one they had in 2003.  (Dr. Mize)

o   In 02-03 the egg producers saw maybe a 1% increase in death loss, but the birds that die are usually shedding virus so there was sampling outside perimeter where they would put dead birds in the barrel. Found at least a couple of positives that way where the farmer hadn’t known he was infected.  (Dr. Mize)

  • Is the vaccine that is currently being used among egg laying community well match for the strains circulating? Is it more effective against a wider range of strains or fussier like AI

o   Not like AI vaccine, core proteins are very stable. One of the reasons they can use a live lentogenic strain is because the core proteins are conserved.  Have different strains so they do change and mutate but since the core is the same they do not need to change to a new vaccine every time. However, there is less protection with some strains than others

  • Pigeons have their own vaccine used in their industry that matches the pigeon strain more closely.
  • These vaccines currently are protective ( no vaccine is 100%) there will always be a few birds left susceptible in a flock. May be slightly more in this case as it is not quite as good a match as 2002 was, but still offers fairly good protection. (Dr. Mize)

o   Only a single serotype for Newcastle for APMV1, so a number of vaccines can be used.  The issue is their immunogenicity varies as well as there are some minor epitopic changes in the major  neutralizing proteins. So some vaccines prepare the birds for more virulent strains, others are really targeted at endemic lentogenic strains that circulate naturally in poultry. (Dr. Styles)

  • Is there any indication that vaccine was applied in any of the positive cases and there was shedding, or did the birds just get sick and die because there was no protection?

o   Majority of what they are responding to are sick bird calls.  At least the large majority of those have not reported vaccination (do not have completed data so need to check to see if it was all or most). Usually when we get the call the birds are dying and not usually vaccinated. (Dr. Mize)

  • Can anyone share information on Wildlife Surveillance?

o   Believe wildlife services has been engaged. If you are asking specifically about the characteristics of the virus that is currently circulating and if there is a wildlife component, the answer is no. This virus is very well adapted to poultry. It does not share those characteristics we would see in the double crested cormorants.

  • Could Darrel follow up more?  Assumption would be that, aside from being a potential fomite, our concerns would be for non-gallinaceous migratory birds carrying the virus?

o   Don’t think that would be a great concern… remember there are VND strains circulating in Central America constantly and do have migratory birds circulating between Central, South, and North America. There is not a lot of evidence to suggest that wild birds, at least with exception of double crested cormorants and feral pigeons, can play a role in the dissemination of this virus. Not to say it is outside the realm of  possibility, but guess is that it would be remote. (Dr. Styles)

  • Any indication that has been passing on to ducks or geese?

o   No. Have had one positive pea fowl but that is it. Last time there was some Guinea fowl and other species in 2002 but so far only the pea fowl this time. (Dr. Mize)

  • Are there materials available for staff to share with birds at home

o   Lots of information on the website –  (Dr. Briggs-Fisher)

o   Important to remember that the same precautions mentioned in HPAI apply to VND, especially exhibition facilities.  If you have free-roaming fowl that puts you at a higher risk factor.. if peafowl or pheasants are roaming on grounds, caging or removing lowers risk considerably. Having a perimeter fence and the ability to meter traffic onto premises also lowers risk. These and common sense measures from HPAI apply equally well here. (Dr. Styles)

o   Need to be very conscious on where food supplies are coming from. Know there are zoos that buy live  quail, frozen chickens, grasshoppers in egg crates (make sure crates are clean) sources of food very important.  Need to be aware of sources (Dr. Mize)

  • Is there any way of telling, from the pattern or epidemiology so far, how long this outbreak may have been going on before it was first detected?

o   Have a number of epidemiologists  still working on the investigation trying to determine an answer to that question (Rose Massengill)

  • Is anyone doing any changes in messaging for patrons?

o   Do have signs at  lorikeet exhibit aviary (where they encourage contact with guests) that said hand sanitizer and footbath was “for the safety of the collection”  but does not mention Newcastle specifically (zoo representative)

  • Comment: One thing in this incident that sticks  in my mind  is that a veterinary hospital was really responsible for getting samples in to identify the first case. Highlights the importance of private practitioners and zoo vets to be on the lookout for anything that doesn’t look typical and to get reports in for anything that looks like a reportable disease.  This was a crucial element for response. (Dr. Dennison)
  • How many doors knocked on to understand poultry in community?

o   Have knocked on over 50,000 doors (actual door to door contact with CDFA and USDA staff).  (Dr. Mize)

  • If the situation got worse would we need to vaccinate within the nondomestic avian species compartment?

o   No reason to believe it will get worse, but products available to do that we would recommend would be inactivated.  The issue is that most poultry inactivated vaccines are combination of other poultry pathogens. There are some in the US that are Newcastle specific, but we don’t know how  well they perform in non-domestic species (same as in AI). Some expectation to believe they may be protective but not guaranteed and they don’t know the duration of immunity in non-domestic species.  (Dr. Styles)


June 2 Update: 

Additional cases of Virulent Newcastle’s disease (VND, formerly known as Exotic Newcastle’s Disease) have been confirmed in Southern California.  As of May 30th, VND has only been detected in backyard poultry and exhibition flocks, primarily in San Bernardino County.  The investigation into the outbreak continues, and quarantines have been established.  For current information about detections please see USDA is on-site working with Wildlife Services to come up with a wild bird surveillance plan.

Multiple species can become infected and display a variety of clinical signs, so it is important to remind staff to be vigilant in observing collections.

The ZAHP Fusion Center is planning on having an industry call as soon as we can arrange a time for subject matter experts to participate.  We have provided some links below for further information on biosecurity for your collections.

May 21, 2018:

On Friday, May 18,  Dr. Jack Shere of USDA Veterinary Services held a conference call with the poultry industry to confirm the detection of virulent Newcastles Disease in a backyard chicken flock in central Los Angeles, California.  While the epidemiological investigation is on-going, as of Friday, there did not seem to be an epidemiological link to commercial poultry.

Anytime there is a Foreign Animal Disease (FAD) detection in a state, your best source of information is that State Veterinarian’s webpage.  This link to information was sent out this morning by the United States Animal Health Association: . Another great source for information on Newcastles is on Iowa State’s Center for Food Security and Public Health.

As this investigation is ongoing, we will update the community on information as it becomes available.