Abstract

Exotic Newcastle disease (END) is classified as an Office International des Epizooties (OIE) List A disease and is a foreign animal disease in the United States.¹ It is caused by a highly contagious and pathogenic paramyxovirus strain that affects many species of birds. In domestic poultry, the mortality rate is high, though there is variable mortality in other species of birds. A carrier state may exist in psittacine and some wild birds. Southern California had an extensive outbreak in commercial poultry in the early 1970s that lasted 2 yr and resulted in 12 million birds being destroyed.

In October 2002, END was diagnosed in southern California backyard poultry flocks that spread to commercial poultry flocks in early December 2002. On December 30, 2002, END was confirmed in a commercial egg-laying facility in San Diego County within 10 miles of the San Diego Wild Animal Park. As of April 1, 2003, 22 commercial poultry premises were affected, seven of which were in San Diego County within a 15 mile radius of the San Diego Wild Animal Park.²

The consequences would be catastrophic if our premises at the San Diego Zoo or Wild Animal Park became infected. Those consequences could include partial or complete depopulation of the avian collections, closing of all or part of the public facilities, and loss of genetic diversity for key conservation programs, including the California condor (Gymnogyps californianus). It was recognized early on that prevention, through stringent biosecurity measures, was essential. Close communications were established with the multi-agency END Task Force including critical protocol reviews, site visits, and outreach presentations to employees. The following is a summary of the biosecurity measures, based on recommendations for domestic poultry,³ put into place in response to the threat of END occurring in our region. Since many of these measures are generally a good practice, some will likely stay in place once the quarantine is lifted. These biosecurity measures are categorized by the potential source of infection to the avian collection.

Employees

1.  Employees working in bird areas were required to wear footwear that did not leave the workplace and was cleaned and disinfected before entering to or exiting from bird areas.

2.  Employees entering bird areas were required to wear uniforms that were supplied and laundered. Uniforms were not permitted to go home with the employee.

3.  All employees working in bird areas were required to disinfect their shoes when first coming to work.

4.  Informational signage was placed at the entrance to all bird areas identifying them as a site for END biosecurity precautions.

5.  Employees were instructed not to come to work and to call their supervisors if they have a bird at home that was sick or died.

6.  Employee education efforts included the following measures:

a.  General employee biosecurity briefings were held numerous times.

b.  Members of the END Task Force provided outreach presentations.

c.  An "Open Forum" summary publication was provided to all employees.

d.  Periodic (three to five times weekly) email updates were sent to all employees with latest update on END situation.

e.  A document listing biosecurity measures was written and distributed to employees at both facilities through their supervisors.

f.  An information letter was sent to all employees describing the disease outbreak and precautions that they could take as individuals.

g.  Employees were discouraged from visiting other bird or bird product facilities (e.g., pet stores, feed stores, etc.).

7.  A protocol was written for employees leaving grounds and returning same day.

8.  A protocol was developed for proper footbath preparation, maintenance, and disposal techniques.

Collection Birds

1.  Movement of birds into and out of the collections, including transfers between facilities, was discontinued. Exceptions occurred only in accord with the multi-agency END Task Force.

2.  All free-flight bird programs were discontinued.

3.  Laboratory samples from collection birds could not be sent outside the quarantine area without permission from the receiving state veterinary office and with a permit granted from the END Task Force.

4.  Transport cages, feed trays, and any equipment used with birds were required to be cleaned and disinfected after each use and, where possible, were restricted for use within a specific group of birds.

5.  Birds that die are placed in closed, leak-proof containers and transported to the necropsy room through an outside entrance. Dead birds from the Wild Animal Park were transported to the San Diego Zoo for necropsy.

6.  If five or more birds died in 1 day at the Wild Animal Park, suspicion of END would be assessed. If indicated, necropsies would be performed in a biosecure location at the Wild Animal Park.

7.  Collection birds that escape and are recaptured were quarantined under certain circumstances.

Public Guests and Visitors

1.  Direct public contact with collection birds was discontinued.

2.  Collection birds were no longer allowed to go off premises for any reason.

3.  Walk-through aviaries were closed to the public.

4.  The chick hatching display at the Children's Zoo was closed.

5.  Behind-the-scenes tours of animal forage warehouses and areas housing birds were discontinued.

6.  Neighbors were notified of the disease outbreak and were given educational materials to encourage the use of biosecurity measures in poultry husbandry.⁴

Foods and Feeds

1.  The use of poultry as an animal food item was discontinued (except for commercially processed and disinfected eggs).

2.  Bulk poultry feed, though never used, was formally banned from entering facilities.

3.  Fresh or frozen poultry used for human consumption at catering events was obtained only from vendors outside the quarantine area.

4.  Bird toys used for enrichment were disinfected before being given to birds.

5.  Feed sources were scrutinized for possible exposure to poultry (e.g., cricket and rabbit vendors).

6.  General biosecurity was reviewed at animal food warehouses.

Vendors, Contractors, Volunteers, and Consultants

1.  All noncompany vehicles had tires and wheel-wells sprayed with a disinfectant when entering the service entrances. Drivers were queried regarding their recent bird contact and required to step in footbaths.

2.  Those needing to go into bird areas were provided shoe disinfection and protective outerwear.

Wild and Feral Birds

1.  Protocols were updated and revised for handling sick and injured native birds brought to our facilities or found within our facilities.

2.  Protocols were developed for short-term treatment of sick and injured native bird species before release to rehabilitation facilities.

3.  Free-roaming birds (e.g., peafowl and guinea fowl) were confined or removed where feasible.

4.  Surveillance of wild birds for END in the vicinity of our facilities was performed by the END Task Force.

Other Measures

1.  Members of the END Task Force made site visits to both facilities to critically evaluate biosecurity measures in place and to familiarize themselves with the facilities.

Neither the Zoological Society of San Diego, nor any of its directors, trustees, employees or agents warrants the accuracy, reliability, or timeliness of the information provided and shall not be liable for any losses caused by reliance on the accuracy, reliability, or timeliness of such information.

Literature Cited

1.  OIE Newcastle Disease Technical Card: Newcastle Disease: http://www.oie.int/eng/maladies/fiches/a_A160.htm. (VIN editor: link could not be accessed on 2/10/21)

2.  California Department of Food and Agriculture, Newcastle Disease website: http://www.cdfa.ca.gov/ahfss/ah/Newcastle_info.htm. (VIN editor: the updated link is www.cdfa.ca.gov/AHFSS/Animal_Health/Newcastle_Disease_Info.html)

3.  University of California Recommendations to Prevent the Spread of Exotic Newcastle Disease: http://animalscience.ucdavis.edu/avian/shortENDcontroldocenglish.pdf. (VIN editor: link could not be accessed on 2/10/21)

4.  Biosecurity Guidelines to Prevent the Spread of Exotic Newcastle Disease - Information for Bird Owners. October 2002: http://www.cdfa.ca.gov/ahfss/ah/pdfs/Biosecu_long_Dec_%202002.pdf. (VIN editor: link could not be accessed on 2/10/21)