What could virulent Newcastle disease mean for layer industry?

Learn what professionals are doing at ground zero to manage Virulent Newcastle disease.

Before the recent outbreak of virulent Newcastle disease occurred, the last time there was a confirmed case of the disease in a United States commercial poultry flock was in 2003. (Elly Kellner | Freeimages.com)
Before the recent outbreak of virulent Newcastle disease occurred, the last time there was a confirmed case of the disease in a United States commercial poultry flock was in 2003. (Elly Kellner | Freeimages.com)

Since May 18, the United States Department of Agriculture (USDA) has confirmed virulent Newcastle disease (vND) cases in California, including San Bernardino County, Riverside County, Los Angeles County and one in Ventura County. USDA also confirmed one case in Utah County, Utah.

Deven King, managing Editor of Egg Industry magazine, spoke with Annette Jones, director and state veterinarian with the California Department of Food and Agriculture, to get insight from ground zero.

Annette Jones Dvm

Annette Jones, director and state veterinarian for the California Department of Food and Agriculture, gives insight on what virulent Newcastle disease could mean for layer and egg production. (Courtesy California Department of Food and Agriculture)

KING: What could the spread of this disease mean for the commercial layer industry?

JONES: Our observation is that well-vaccinated layer flocks show minimal signs of disease, at least initially, but they can become infected and, once introduced, the virus spreads to other houses on the premises. Pullets show earlier and more severe signs of disease. So, from an animal health standpoint, disease caused by this virus would undermine production despite vaccine status, threaten the ability to move eggs, and potentially decimate unvaccinated or young flocks, like pullet flocks and broiler flocks.

Another major impact relates to the cost of enhanced biosecurity. The producers in Southern California currently maintain biosecurity well above (U.S. Food and Drug Administration Salmonella enteritidis) or (National Poultry Improvement Plan) requirements. Besides the day-to-day expense of supplies, additional time to do a task, training and supervision, they also have made capital investments in things like concrete pads, fencing, security gates, vehicle wash stations, and upgraded employee facilities. Depending on the ranch, we can be talking about $10,000 to $120,000 investments.

Finally, if the virus load in backyard poultry remains high, it is a continual disease threat. One strong wind, wayward run-off after a rainstorm, or slip in biosecurity can lead to infection. Even with USDA recovery support through indemnity and virus elimination, producers can lose millions of dollars related to down time, lost contracts, feed premiums -- the list goes on.

KING: What do consumers need to know about the disease?

JONES: vND is not a food safety concern and no human cases of the virus have occurred from eating poultry products. Properly cooked poultry products are safe to eat.

For people working directly with sick birds, vND can cause conjunctivitis or flu-like symptoms. Human infection is easily prevented by using standard personal protective equipment such as gloves and eye protection and washing and disinfecting hands thoroughly after handling birds.

KING: What is the industry doing to contain the problem?

JONES: Since May 2018, every commercial poultry company in Southern California has implemented some form of enhanced biosecurity, and almost all companies have been submitting regular vND samples to the California Animal Health and Food Safety (CAHFS) laboratory, using their own labor but under state oversight. In fact, this proactive surveillance is what led to the immediate detection last December of the first spillover into commercial poultry. Disease was detected in a pullet flock even before they started experiencing increased mortality. Thanks to company cooperation, the flock was euthanized within 24 hours of confirmation.

Not only have companies enhanced biosecurity on their own, but they have been working with us and other biosecurity experts to identify and reduce biosecurity gaps. After our review, many did not need to make further modifications, but some built fences, added security cameras, added locking gates, added concrete aprons, moved doors, added truck washes, added or moved employee parking areas and changing stations, etc. Ongoing enhanced biosecurity and testing costs can total about $120,000 per premises annually.

In all cases, employee education and reiteration of company policies stating, “no ownership and no contact with poultry outside of work” were reinforced. Currently, our staff are working with producers to further reinforce employee education efforts through a new biosecurity education and certification program. This support is particularly important for the small, boutique egg producers in the area that do not have access to poultry veterinarians.

Virulent Newcastle Reported Usda

The U.S. Department of Agriculture has been announcing confirmed cases of virulent Newcastle disease weekly since May 2018. Cases are still being tested and confirmed as they are identified.

KING: What is California doing specifically to manage the issue?

JONES: Though experience, we have found that successful eradication in this environment depends on a multi-pronged approach. The failure of any one aspect may lead to disease eradication failure. We have also found that success lies in working cooperatively, in “unified command” with the USDA, so that we avoid “us against them” and most efficiently use resources around shared objectives.

Stop the movement of virus: California is using state veterinarian quarantine authority to establish “no movement” areas, but the challenge is placing restrictions before birds are moved. The only way to get ahead of disease instead of chasing it is through strategic surveillance. We have implemented several successful tactics to identify higher risk areas for surveillance, including the use of zoning maps, intelligence from local communities, satellite maps and historical data. With thousands of homes under quarantine, enforcement of stop-movement orders adds an additional challenge. To address enforcement, we send dedicated teams to re-check quarantined homes at prescribed intervals as resources allow, and we send investigators to follow up on tips. We have found that almost all residents comply and are very cooperative. The few who do not comply require significant additional time and effort on our behalf and delay eradication. If non-compliant, our actions include entry with law enforcement and warrants, euthanasia of poultry without compensation and fines.

Generate community assistance: Usually, bird owners must fully understand this disease and its negative impacts before they take the often difficult and costly steps needed to help us eradicate the virus. We work to build trust and find the best ways to engage each community. They are all different.  Local employees have been instrumental in developing a myriad of outreach opportunities. We engage at Sunday mass, during community events and celebrations, at feed stores, through town hall meetings -- the list goes on. 

Seek and eliminate: Finding and eliminating poultry that are infected or exposed to vND is the only way to reduce virus load in a dense semi-urban community. Without significant surveillance and euthanasia of affected flocks, the virus will just move back and forth between neighborhoods as new birds are introduced. We are working hard to reduce the population of backyard poultry in highly infected areas and then hold the properties empty until no more virus can be detected.

Commercial poultry biosecure barriers – While producers and service providers invest in and maintain biosecurity designed to keep the virus out and minimize spread, the state reviews and approves these plans to ensure they meet our elevated standards, and conducts audits to ensure they are activated and followed. If a company is in a control area or linked to a company in a control area, they are placed under state quarantine and are required to implement specific biosecurity, have permits for movements, and test for disease. When virus was first detected last May, we also collaborated with all companies in the area to gather information needed to establish epidemiologic links so we could immediately work together to minimize spread if one ranch became infected.

Mitigation: The state is investigating mitigation and intends to implement strategies that have worked in the past, including introduction pathway analysis, ongoing community engagement, targeted surveillance, audited commercial producer biosecurity, and capacity to immediately eliminate virus if reintroduced. We also are interested in new strategies like network analysis and the use of social media tools.

KING: What has the industry learned from these outbreaks, i.e., symptoms, treatment, vaccination, biosecurity tactics?

JONES: In pullets, mortality is significant, but in well-vaccinated adults, mortality and reduced production is less significant and delayed. We have, however, documented virus spread through vaccinated flocks. Refer to USDA (Agricultural Research Service) for more information on recent studies looking at this virus strain in poultry.

Given that the virus has been in California backyard poultry since before May 2018, we believe that enhanced biosecurity does successfully prevent introduction. Enhanced biosecurity also has effectively reduced spread from farm to farm. During the prior outbreak in 2003, after just a couple of months, 22 commercial ranches became infected. While producers did implement biosecurity during that outbreak, things like egg flats and rendering routes were linked to spread. Also, state biosecurity standards were not as rigorous and were not actively audited by state employees. Our standards for enhanced biosecurity can be found on our website.

Epidemiologic studies to better understand why particular commercial flocks became infected are ongoing, but some early considerations are rain runoff from infected neighborhoods and high levels of virus load in backyard poultry near commercial facilities.

KING: If the disease is found on a producer’s operation, how should they react?

JONES: Stop all movement of poultry, products and other things that may spread disease, and reduce people on the farm to the greatest extent possible. Be ready to work with the USDA case manager on indemnity and virus elimination. Manage feed to ensure appropriate animal care until the birds can be euthanized. Start gathering information that will assist government officials to trace potential spread onto and off of your ranch. 

KING: How do you believe the disease started in the U.S.?

JONES: In the past, smuggled psittacines (parrots) were implicated, but at this point relative to the 2018 introduction, we have no such evidence. We support further investigation.

KING: Since the first outbreak, have control methods changed?

JONES: Primarily, changes in control methods reflect resource availability, but we do adjust our approach to each area, as they are all different. When we are short resources, we minimize surveillance and focus on known disease, usually picked up through calls to our hotline. We have found that self-reporting is by far the most efficient way to find neighborhoods with disease, but we are concerned it can result in delayed detection. Ideally, we combine active, targeted surveillance with outreach and hotline-generated passive surveillance and carry out immediate euthanasia of positive and exposed flocks in the area. When we find a new area with disease, we gear the response to the area – density of birds, level of confirmed infection, degree of connectivity of flocks, etc.  When there is a high level of disease in epidemiologically connected backyards, we consider all poultry in the area as part of the same “flock,” and euthanize all as infected or exposed poultry. On the other hand, in areas with more isolation and less disease, we have a smaller euthanasia footprint and increase diagnostics.

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