Newcastle disease

Newcastle disease is a viral disease of birds caused by avian paramyxovirus 1 (APMV-1). For official control purposes, this disease is currently defined as the most severe form of the illness, which is caused only by certain viral strains.

Newcastle disease is considered to be one of the most important poultry diseases in the world. Chickens are particularly susceptible, and may experience morbidity and mortality rates up to 100%.

A highly contagious and severe form of the disease, called exotic Newcastle disease (END), is so deadly that many
birds die suddenly without showing any signs of disease.

Animal Transmission

• Direct contact with feces, respiratory secretions.
• Indirect contact:

– Feed, water

– Equipment

– Human clothing

• Contaminated or incompletely inactivated vaccines.

• Survives for long periods in the environment
• Incubation period

– 2 to 15 days

– 5 to 6 days average

• Migratory birds, feral pigeons

– Contamination of poultry feed

Human Transmission

• Mild conjunctivitis

– Virus shed in ocular secretions

– Avoid contact with avian species

• Lab workers and vaccination crews most at risk
• No cases from handling or consuming poultry products
• No human-to-human spread

Newcastle disease in birds can vary from no signs of illness to sudden death. Affected birds may have coughing, sneezing, nasal discharge, depression, and diarrhea. Chicken flocks may have a sudden decrease in egg production or produce thin shelled eggs.

Clinical Signs

• Drop in egg production
• Numerous deaths within 24 to 48 hours
• Deaths continue for 7 to 10 days
• Surviving birds may have neurological or reproductive damage
• Edema of head, especially around eyes

• Greenish, dark watery diarrhea
• Respiratory and neurological signs
• Signs vary with species and virulence

Lesions
Signs of severe illness include swelling of the tissues of the head, muscle tremors, drooping wings, twisted head, circling, paralysis or sudden death.

 

Tracheal and laryngeal mucosa contain many foci of hemorrhage and small clumps of fibrinonecrotic exudate.

 

 

 

 

 

Hyperemic, necrotic cecal tonsils are visible from the serosal surface.

 

 

 

 

 

The mucosa contains multiple sharply demarcated foci of hemorrhage and necrosis.

 

 

 

Segmental intestinal necrosis, mucosal.

 

 

Prevention

Prevent your poultry from becoming exposed to infected poultry. Biosecurity measures, such as cleaning and disinfection of bird-housing facilities and equipment is very important.
New introductions or poultry returning to the farm should be isolated for several weeks before being placed into the flock.
A vaccine is available for poultry and is routinely used in poultry flocks. While this can reduce the severity of the disease, it does not completely prevent infection.

According to The Center for Food Security & Public Health