Exotic Newcastle disease is sometimes referred to as Asiatic or Doyle's form of Newcastle disease.

According to USDA APHIS Exotic Newcastle Disease: Clinical Signs and Disease Description, "END is the most virulent strain of the Newcastle disease virus and is probably the most serious disease of chickens throughout the world. This pathotype of Newcastle disease is characterized by the lesions it produces in the gastrointestinal tract. In susceptible chickens, morbidity rates approach 100% and mortality rates may exceed 95%.

It is caused by a virus of the Paramyxoviridae family, it is very resistant and it will remain viable at a pH of between 2 and 12, and for 3 hours at 56 degrees centigrade, or for 30 minutes at 60 degrees centigrade. Antigenically similar strains differ in pathogenicity and are classified as lentogenic, mesogenic, and velogenic on that basis."

All birds, both domestic and wild, are susceptible to END. The mortality varies significantly by species and the strain of virus. Cockatiels, budgies, amazons, and cockatoos are highly susceptible to the disease. Other species such as lorys, macaws, canaries, finches, mynahs, and African greys may not show signs but may act as carriers. Mortality rates in psittacine birds have ranged from zero up to 75% prior.

Symptoms

Symptoms of disease are highly variable and non-specific in caged birds. One of the classical signs of Exotic Newcastle Disease is tremors and involuntary shaking of head and body when the bird tries to move. Other signs may include anorexia, depression, diarrhea, paralysis, twisted neck, respiratory difficulty, eye discharge, weight loss, etc.

In some cases, lesions occur. However, these are not as common in pet birds or, if present, are not as evident.

Incubation varies from two to 17 days depending on the species of the bird, management factors, concurrent infections, etc.

Diagnosis

Since similar signs may be seen with other bird diseases, laboratory testing is necessary to confirm a diagnosis of Exotic Newcastle Disease. The best method is identification of the virus in the body.

Treatment

There is no treatment for END. There is a vaccination, but in prior outbreaks, it has not proved effective. Use biosecurity measures to prevent diseases from affecting your birds.

More information can be found in the following articles:

USDA APHIS Exotic Newcastle Disease: Clinical Signs and Disease Description
Exotic Newcastle Disease
Velogenic Newcastle Disease - GrayBook
Brochures and Fact Sheets concerning Caged Birds and Disease Prevention from USDA & CDFA
USDA END Fact Sheet January 2003
Fact Sheet: Exotic Newcastle Disease in Caged (Exotic) Birds - Information for Bird Owners - 01/07/03 CDFA
Exotic Newcastle Disease in Game Fowl, United States Impact Worksheet 10/09/02 - APHIS
Pigeons and Exotic Newcastle Disease - UCDavis