National Agricultural Biosecurity Center

Synopsis of Exotic Newcastle Disease

Exotic Newcastle Disease (END), also known as velogenic viscerotropic Newcastle disease, is a fatal, highly contagious viral disease that affects all species of birds. Newcastle disease is caused by a paramyxovirus, which has nine serotypes. END is probably one of the most infectious and fatal diseases of poultry in the world with many birds dieing before showing any clinical signs of illness and death rates approaching 100 percent (unvaccinated poultry flocks; death may even occur in vaccinated flocks). Infection is most severe in chickens, peafowl, guineas, pheasants, quail, and pigeons and mild in turkeys, finches, and canaries. Carrier states can exist in psittacine and other wild birds; these carriers are capable of shedding virus for more than 400 days. END is endemic in many countries of Asia, the Middle East, Africa, and Central and South Asia and has been found in Europe, Australia, Canada, and the United States. Smuggled pet birds, especially Amazon parrots from Latin America, pose a great risk of introducing END into U.S. poultry flocks. There are three pathotypes: lentogenic, mesogenic, and velogenic. The velogenic pathotype, often referred to as Exotic Newcastle Disease since it is not commonly found in the U.S., is the most pathogenic pathotype. Often, however, birds are simultaneously infected with multiple strains.

• Transmission occurs through direct contact between healthy birds and the bodily discharges of infected birds, specifically feces and secretions from the nose, mouth, and eyes. Newcastle Disease can also be spread by mechanical means, including contaminated shoes, clothing, implements, and premises (Note: END is often spread by vaccination and debeaking crews, manure haulers, rendering-truck drivers, feed-delivery personnel, poultry buyers, egg-service workers, and poultry farm owners and employees) or by ingestion of contaminated feed or water.
• Due to the close confinement of commercially raised birds, the disease is able to spread rapidly.
• The most common source of exposure for humans in contact with contaminated animals or animal products.

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Clinical Signs and Symptoms

Birds:

• Incubation: 5 to 6 days, but can vary from 2 to 15 days
• Infection with multiple strains is common
• Clinical signs and symptoms:
  • Respiratory: sneezing, gasping for air, nasal discharge, coughing, increased respiration
  • Digestive: greenish, watery diarrhea 2 to 3 days after onset of illness
  • Nervous: depression, muscular tremors, drooping wings, dragging legs, lack of appetite, twisting of head and neck, circling, complete paralysis; Note: survivors often exhibit permanent neurological signs
  • Egg changes: partial to complete drop in production; eggs produces are thin-shelled, misshapen, rough-shelled, and contain water albumen; Note: in those that survive, egg production may never reach its former capacity
  • Swelling of tissues around eyes and in the neck
  • Sudden death within 24 to 48 hours; Note: mortality depends on the virulence of the virus strain, the degree of immunity from previous vaccinations, environmental conditions, and the condition of the flock
• Characteristic lesions seen on necropsy:
  • Petechial and small ecchymotic hemorrhages on the mucosa of the proventriculus, usually near the base of the papillae around the posterior and anterior orifices,
  • Edematous, hemorrhagic, necrotic, and ulcerative areas on Peyer's patches, cecal tonsils, and other aggregations of lymphoid tissues in the gut wall, and
  • Edematous, hemorrhagic, or degenerated ovaries
• Pathotypes:
  • Viscerotropic velogenic (END):
    • Hemorrhagic intestinal lesions
    • Highly pathogenic
  • Neurotropic velogenic (END):
    • High rate of mortality following respiratory and nervous symptoms
  • Mesogenic (ND):
    • Respiratory signs
    • Rare nervous signs
    • Low mortality
  • Lentogenic (ND):
    • Subclinical respiratory infection
  • Asymptomatic enteric (ND):
    • Subclinical enteric infection

Humans:

• Infection generally causes conjunctivitis and generally occurs in those persons working in the poultry industry, veterinarians, or laboratory technicians.

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Diagnosis and Treatment

Diagnostic Samples:

• Samples for diagnostic purposes collected from live birds:
  • Tracheal swabs
  • Cloacal swabs
  • Feces
• Samples for diagnostic purposes collected from dead birds:
  • Pooled organ samples, including oronasal swabs and samples from the lung, kidneys, intestine (including contents), spleen, brain, liver, and heart tissues
  • Feces

Differential Diagnosis:

• In animals, the differential diagnoses include highly pathogenic avian influenza, fowl cholera, infectious laryngotracheitis, fowl pox, coryza, psittacosis, mycoplasmosis, infectious bronchitis, Pacheco's parrot disease, and management errors such as deprivation of water, air, or feed.
• In humans, the differential diagnosis includes conjunctivitis.

Clinical Diagnosis:

• Clinical diagnosis (birds) can be made based on the following signs and symptoms:
  • Respiratory and/or nervous signs: gasping, coughing, drooping winds, dragging legs, twisting of the head and neck, circling, depression, inappetence, complete paralysis
  • Partial to complete cessation of egg production; eggs produced are misshapen, rough-shelled, thin-shelled and contain watery albumen
  • Greenish, water diarrhea
  • Swelling of the tissues around the eyes and in the neck
  • Note: Due to similarities to other diseases, such as fowl cholera and highly pathogenic avian influenza, confirmation requires virus isolation and identification
• Clinical diagnosis (humans) can be made based on the following signs and symptoms:
  • Conjunctivitis during an animal outbreak (with signs and symptoms consistent with those above)

Laboratory Tests:

• Diagnostic tests in birds:
  • Identification of the agent:
    • Inoculation of 9- to 11-day old embryonating chicken eggs followed by examination of hemagglutination (HA) activity and inhibition of hemagglutination by ND virus-specific antiserum
  • Pathogenicity assessment:
    • Plaque test in chicken embryo fibroblast cultures
    • Mean death time of embryonated chicken eggs
    • Intracerebral pathogenicity index in 1-day-old chickens
    • Intravenous pathogenicity index in 6-week-old chickens
  • Serological tests:
    • Hemagglutination inhibition test
    • ELISA

Treatment:

• In animals:
  • No effective treatment
  • Vaccination are generally administered at 2- to 4-weeks-of-age when they become susceptible or at 1 day of age via conjunctival instillation. The latter birds are revaccinated 3 to 4 weeks later. The duration of immunity depends on the vaccination program and, regardless, of the initial treatment, must be continued throughout the life of the bird to maintain efficacy.
    • Live vaccine is administered via ingestion from drinking water, as well as intranasally or intraocularly by aerosol
    • Inactivated vaccine (considerably more expensive) is administered via intramuscular or subcutaneous injection
    • Newplex (a proprietary virus antibody complex vaccine) is delivered into eggs prior to hatching and can be administered automatically by machine
• In humans:
  • Supportive care

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Economic Consequences and Disease Eradication

Economic Consequences

• Loss of livestock
• Costs associated with eradication efforts
• International trade embargoes
• Increased costs to consumers

Disease Eradication:

• Immediate notification of state and federal health officials
  • NOTE: USDA operates a toll-free hotline, 1-800-536-7593
• Good management principles and biosecurity measures:
  • Permit only essential workers and vehicles on premises
  • Clean clothing and disinfection facilities should be provided for employees
  • Clean and disinfect vehicles (including tires and undercarriages) entering and leaving the premises
  • Other poultry operations should not be visited
  • Clean poultry houses between each lot of birds
  • Do not keep pet birds on the premises or hire employees with pet birds
  • Protect flock from wild birds by cleaning up spilled feed and removing wetlands near the barn
  • Maintain an "all-in all-out" policy for flock management:
    • Single age flock
    • Control movement of all poultry and poultry products in and out of farm
    • Do not "skim" mature birds from a flock for sale to a live-poultry market
    • Clean and disinfect poultry houses between each lot of birds
  • Take diseased birds to a diagnostic laboratory for examination
  • Keep the tops of feed bins closed
  • Chlorinate water taken from dugouts or ponds
  • For pet bird enthusiast:
    • Ensure that birds are legally imported (i.e., request documentation of the bird's health and safe transportation)
    • Isolate new purchases for 30 days, including the restriction of personnel movement between new and old birds
    • Click on one of the following links for more information on biosecurity guidelines for bird owners, 1, 2, 3, or 4 published by the USDA.^{7, 8, 9, 10}
• Eradication:
  • Strict quarantine and destruction of all infected birds is mandatory to eradicated the virus from an area
  • Insects and mice, which can act as potential vectors, should be destroyed prior to the destruction of birds
  • Clean and disinfect area thoroughly since the virus can survive well in some environmental conditions
  • Cresylics or phenolic disinfectants should be used after thorough cleaning of all surfaces and equipment
  • Contaminated manure must be safely removed by burying it at least 5 feet deep or by composting
  • No birds should be reintroduced into the depopulated facility for at least 30 days
• Viability:
  • Able to survive for several weeks in a warm, humid environment, such as on birds' feathers, manure, and other materials
  • Able to survive indefinitely in frozen materials
• Inactivation:
  • 56°C for three hours
  • 60°C for 30 minutes
  • Minimum core temperature of 80°C for one minute will destroy the virus in meat products
  • Ether sensitive and inactivated by formalin, phenol, and acid pH
  • Destroyed rapidly by dehydration and ultraviolet rays

END and Bioterrorism:

• END is of concern as a biological weapon for the following reasons:
  • Extremely high morbidity and mortality rates, especially in chickens (approaches 100%)
  • No effective treatment
  • No fully effective vaccination

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Outbreaks

• Newcastle disease derives its name from an outbreak near Newcastle upon Tyne, England, 1927, which is the 1st recorded instance of the disease.

Animal outbreaks

• 2003: Outbreak in Texas and New Mexico, outbreak originated in a backyard flock near El Paso and resulted in the culling of about 1,900 birds from 31 flocks. Click here for more information on this outbreak published by the Texas Animal Health Commission.¹³
• 2003: Outbreaks in Nevada and Arizona, outbreak was quickly contained with minimum loss. Click here for more information on this outbreak published by the Nevada Department of Agriculture or here or here for information published by the USDA.^{11, 12, 14}
• 2002-2003: Outbreak in California which included more than 3.5 million birds in over 2,100 sites, including 22 commercial poultry farms at a cost of more than $160 million. Click here for more information on this outbreak published by the USDA.¹⁵
• 1999-2000: Major outbreak in northern and central Italy which resulted in the culling of more than 13 million birds.
• 1973: Outbreak in Northern Ireland which affected 26 locations in all but one county and resulted in a policy of compulsory vaccination.
• 1971: Major outbreak in California which infected more than 1,300 flocks and resulted in the culling of 12 million birds. Eradication costs totaled $56 million and took three years. Click here for more information on this outbreak published by the California Veterinary Diagnostic Laboratory System.⁶

• Click on the following hyperlink for the most recent outbreak information located at the Office International des Epizooties Website. http://www.oie.int/eng/info/hebdo/A_DSUM.htm.⁵

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Sources and Related Articles

Sources

1. Animal and Plant Health and Inspection Service, USDA. January 2003. Exotic Newcastle Disease. Available at http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahend.pdf.
2. Center for Infectious Disease Research and Policy at the University of Minnesota, September 19, 2003. Exotic Newcastle Disease. Available at http://www.cidrap.umn.edu/cidrap/content/biosecurity/ag-biosec/anim-disease/exnewcastle.html.
3. Georgia Department of Agriculture May 2003. Exotic Newcastle Disease. Available at http://agr.georgia.gov/vgn/images/portal/cit_1210/21/37/.
4. Office International des Epizooties, April 22, 2002. Animal Disease Data: Newcastle Disease. Available at http://www.oie.int/eng/maladies/fiches/a_A160.htm.
5. Office International des Epizooties, Most recent outbreak information (worldwide). Available at http://www.oie.int/eng/info/hebdo/A_DSUM.htm.←

Related Articles:

6. Anonymous, Fall 1998. Exotic Newcastle Disease Detected in Fresno. Published in Lab Notes, 11(3):1; 5 by the California Veterinary Diagnostic Laboratory System at the University of California, Davis. Available at http://cahfs.ucdavis.edu/lab_notes/ln11-3-98.pdf.←
7. Anonymous, December 2002. Biosecurity Guidelines to Prevent the Spread of Exotic Newcastle Disease - Information for Bird Owners. Published by the California Department of Food and Agriculture. Available at http://www.cdfa.ca.gov/ahfss/ah/pdfs/Biosecu_long_Dec_%202002.pdf.←
8. Anonymous, December 2002. Biosecurity Footbaths for Exotic Newcastle Disease: Information for Bird Owners. Published by the California Department of Food and Agriculture. Available at http://www.cdfa.ca.gov/ahfss/ah/pdfs/Footbaths_owner_Dec02.pdf.←
9. Anonymous, January 2003. Exotic Newcastle Disease in Caged (Exotic) Birds: Information for Bird Owners. Published by the California Department of Food and Agriculture. Available at http://www.cdfa.ca.gov/ahfss/ah/END_TEST/pdfs/.←
10. Anonymous, July 2003. Newcastle Disease: A Penny's Worth of Prevention. The Cultivator. 22:1-2. Available at http://www.dol.state.nc.us/ash/cultivator_july03.pdf.←
11. Fernandez. P., February 14, 2003. Exotic Newcastle Disease: Additions to Quarantined Area, Docket No. 02-117-4. Published by the USDA Office of the Secretary in the Federal Register, 68(31):7412-7413. Available at http://www.cdfa.ca.gov/ahfss/ah/END_TEST/pdfs/02-117-4FedRegister.pdf.←
12. Foster, E. Statement Regarding Exotic Newcastle Disease in Nevada. Published by the Nevada Department of Agriculture. Available at http://agri.state.nv.us/ENDPR.pdf.←
13. Hillman, B. and C. Everett, April 10, 2003. Exotic Newcastle Disease Confirmed in Texas; Five Counties Quarantined in Texas and New Mexico. News release published by the Texas Animal Health Commission. Available at http://www.tahc.state.tx.us/news/pr/2003/2003Apr_END_confirmation.pdf.←
14. Shea, K., January 24, 2003. Exotic Newcastle Disease: Additions to Quarantined Area, Docket No. 02-117-3. Published by the USDA Office of the Secretary in the Federal Register, 68(16):3375-3376. Available at http://www.cdfa.ca.gov/ahfss/ah/END_TEST/pdfs/03-1608_FedRegister.pdf.←
15. Veneman, A. M., January 10, 2003. Declaration of Extraordinary Emergency Because of Exotic Newcastle Disease, Docket No. 03-001-1. Published by the USDA Office of the Secretary in the Federal Register, 68(7):1432. Available at http://www.cdfa.ca.gov/ahfss/ah/END_TEST/pdfs/03-001-1FedRegister.pdf.←

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