August 30, 2018

US backyard chickens in California hit by Newcastle disease
 

Newcastle disease had impacted about 100 backyard chicken flocks in Southern California, US, by mid-August, the American Veterinary Medical Association reported.

First detected in May 17, the diseases has already infected chickens in Los Angeles, San Bernardino, Riverside, and Ventura counties, according to the USDA. At least one turkey flock also had infections.

Several poultry production facilities were briefly quarantined as they were close to infected birds, but commercial poultry flocks remain free from the disease.

Dr. Annette Jones, California state veterinarian, said the infections have occurred among chickens raised at homes on the outskirts of Los Angeles. Former farms and stables have become extensions of the city, but those areas still have dense pockets of animals, including goats, pigs, and menageries of birds such as chickens, pigeons and peacocks. The outbreak has spread across areas that vary by wealth and culture.

In flocks at homes, most of the Newcastle disease virus replication and transmission is occurring through chickens, Dr. Jones said. Other species that are less susceptible would have more minor roles in spreading the disease.

Newcastle can spread through feces, feathers, eggshells and respiratory secretions, as well as fomites such as clothing or vehicles. It affects at least 250 bird species in 27 orders, according to a 2013 USDA Animal and Plant Health Inspection Service manual on the disease.

"Because of the ND reservoir in wild birds and the ability of this virus to mutate, minimising contact between domestic and wild birds is fundamental to preventing ND infection in the US domestic poultry population," it states.

Infections can kill entire flocks of unvaccinated poultry. Any survivors may have twisted necks, head tremors or other permanent neurologic damage, the APHIS manual elaborates.

Even vaccinated poultry can be affected, laying fewer eggs following infection, and eggs that are laid may be misshapen or lighter in color.

According to Dr. Jones, California is working with commercial poultry producers to review biosecurity plans, while industry members have been performing their own surveillance and testing.

In addition, federal and state employees have been removing carcasses and other materials with the highest potential of transmitting the virus.

- American Veterinary Medical Association