Newcastle Disease is a disease caused by a group of RNA viruses. These viruses are highly contagious, with varying degrees of severity between strains. Some strains, like virulent Newcastle disease (VVND), can cause high mortality rates in domestic poultry and some wild bird species. The strains of this virus that have caused the highest amounts of mortality among wild North American bird populations are largely associated with parrots from the pet trade. Most strains of Newcastle disease are largely innocuous.
Transmission of Newcastle disease happens mostly through direct contact with secretions and aerosols from infected birds. Newcastle disease can also persist in the carcass of some animals that have died from it. Transmission can also occur through clothing or equipment, or through rodents, which act as carriers.
In cormorants, Newcastle disease can cause dehydration, emaciation, diarrhea, paralysis of limbs, incoordination and twisted or drooping necks. Signs of Newcastle disease in other birds can include sneezing, gasping for air, nasal discharge, coughing, greenish diarrhea, tremors, circling drooping wings, and swelling around the eyes and neck.
Wildlife Management Implications
Some strains of Newcastle disease like VVND can have high mortality for some wild birds like cormorants. Breakouts of deadly strains of Newcastle disease are rare in North America. Newcastle disease is often linked to parrots from the pet trade. The best way to prevent outbreaks of VVND is to ensure separation of wild birds, domestic poultry, and psittacine birds.
Human Health Significance
Transmission of Newcastle disease virus from birds to people is rare. When it occurs, it is usually accompanied by flu-like illness and irritation of the eyes. People who have close contact with infected birds or their environments are more likely to be infected. Most human illness with Newcastle disease is mild and self-limiting, but infections can be severe in people with compromised immune systems.