After reports of new cases of virulent Newcastle disease (vND) had appeared to be slowing down, six new cases of the disease were reported in California during the week beginning December 13 and ending December 19.
According to a report from the U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), five new cases were found in San Bernardino County and one new case was confirmed in Riverside County. All six cases were in "backyard exhibition chickens," according to APHIS.
Samples from the flocks were tested at the California Animal Health & Food Safety Laboratory System (CAHFS) and were confirmed at the APHIS National Veterinary Services laboratories in Ames, Iowa.
The affected flocks were quickly euthanized, according to a notice from APHIS.
Prior to these six cases, there had only been two cases of vND in California in December. There were four cases confirmed in November and none in October.
Federal and state agencies are conducting additional surveillance in the area.
As of December 20, USDA has confirmed 464 premises as infected with vND, with most of those in California. Of those cases, 261 have been in Riverside County, 154 have been in San Bernardino County, 45 have been in Los Angeles County, and there has been one case each in Ventura County, Alameda County and San Diego County, California. Outside of California, the virus has been detected in Utah County, Utah, and Coconino County, Arizona.
The current vND outbreak began in May 2018, when vND was confirmed in Los Angeles County.
The disease has also been detected and confirmed in three commercial layer operations. Other premises where vND has been detected include a research facility, backyard poultry flocks and retail feed stores.
Before 2018, the last time vND, formerly known as exotic Newcastle disease, had been detected in the United States was in 2003.