Two-and-one-half months after state agricultural officials optimistically hailed what they thought might be significant process toward the extirpation of Newcastle disease in Southern California, there has been in the last month-and-a-half a flare-up of the poultry-killing virus.
The California Department of Food and Agriculture has intensified a quarantine on all of Los Angeles County and the roughly westernmost halves of San Bernardino and Riverside counties to head off a repeat of the epidemic that between May 2018 and Summer 2019 necessitated the euthanization of 1.2 million birds, most of them chickens.
The quarantine protocol calls for isolating a chicken that has, or chickens that have, been potentially or actually exposed to the contagious illness, preventing it or them from contact with the rest of a flock. That bird is then killed.
Of the 1.2 million fowl killed as a result of the 2018/2019 outbreak, more than 1.1 million were chickens being raised agriculturally for commercial purposes. Close to 100,000 of the birds killed were pets or show birds.
Newcastle disease is a highly contagious viral bird malady affecting many domestic and wild avian species. While it is transmissible to humans, among whom it manifests in relatively mild forms of conjunctivitis, also known as pink eye, and influenza-like symptoms, it seems to pose no other significant hazard to people.
Newcastle’s effects are most notable among farm-raised chickens due to their high susceptibility and the potential for widespread infestation throughout the poultry industry.
Newcastle typically results in swelling around a bird’s eyes, a purplish swelling of the wattle and comb, a large amount of fluid coming from the beak and nasal areas, a twisting of the neck and head, loss of appetite, green diarrhea, and sudden death. No treatment for Newcastle exists.
Transmission occurs by exposure to fecal and other excretions from infected birds, contact with contaminated food and water, as well as through human interaction as when a person moves infected birds, equipment or feed or by coming into contact with unaffected birds while wearing the same clothing or shoes worn when that person had contact with infected areas.
The 2018/19 epidemic, which included cases in Los Angeles, Ventura, San Bernardino and Riverside counties, had significantly declined throughout the summer, and by September had been isolated to four known locations. There were no further outbreaks in October. That cessation in the disease spread did not last.
According to a “virulent Newcastle disease update” issued by State Veterinarian Dr. Annette Jones on December 23, “Over the past month, virulent Newcastle disease cases have increased because people have violated the California Department of Food and Agriculture Virulent Newcastle Disease Regional Quarantine by moving infected birds or contaminated equipment and secondary spread to neighboring flocks. We now have 20 new cases under investigation, all linked to the recent Bloomington area outbreak. Most of the cases are in San Bernardino County, with two in Riverside County and one in Los Angeles County. Backyard flocks as well as retail pet/feed stores are involved.”
Jones’ update continued, “Based on phylogenetic analysis and epidemiologic studies, we understand how the disease spreads in Southern California. This highly contagious virus has been spread when people move exposed birds or equipment, or when people carry the virus to their own unfortunate flock on their hands and feet. It moves long distances as people illegally move birds or equipment. When introduced to a new area, it is amplified as the previously uninfected poultry succumb until the environmental virus load is so great, the outbreak spreads from yard to yard. Exposed poultry around a newly infected flock are the ‘virus amplifiers,’ particularly just before they show signs of disease.”
Speaking directly to bird owners, Jones said, “Put simply, your birds can spread the disease before they show symptoms, so the only way to stop it is to not move birds – period – if you are in the  California Department of Food and Agriculture Regional Quarantine Area.”
In San Bernardino County that quarantine area includes the jurisdiction’s western half, and all of the county’s inland valley’s and mountains, including all municipalities except Yucca Valley, Twentynine Palms and Needles.
The somber tone of Jones’ December 23 update was a stark contrast to the more positive missive she had put out on October 22, which read: “The California Department of Food and Agriculture/U.S. Department of Agriculture Virulent Newcastle Disease response team has started the ‘freedom of disease’ phase in which we continue surveillance and testing of birds to detect and quickly eradicate any small pockets of infection (if present). There have been no new positive detections of virulent Newcastle disease since early September, but the regional quarantine is still in place at this time. A sufficient number of negative virulent Newcastle disease tests from the community will help meet international standards to demonstrate freedom from virulent Newcastle disease and allow the regional quarantine to be lifted. This phase will take place over the next few months, bearing in mind that if any positives are found, it would potentially create a setback to this process. We are sincerely grateful for the continued cooperation and support from the community.”
Twenty-four days later, however, Jones on November 15 reported in an update, “There were new detections of virulent Newcastle disease on November 14 at two neighboring residential properties in western San Bernardino County. These are the first detections of virulent Newcastle disease in Southern California since September 4. These cases were identified when a bird owner at one of the properties contacted a veterinarian.”
That was followed by a November 19 update from Jones, which stated, “A new detection of virulent Newcastle disease was identified on November 18, 2019 at a retail feed and pet store in western San Bernardino County. The store is linked to the two recently confirmed positive premises in western San Bernardino County. This new premises is approximately 1 kilometer outside the boundary of the current control area and control area expansion is being reviewed.”
On December 9, Jones put out another update that informed the agricultural community that “In November and December of 2019, the California Department of Food and Agriculture and the U.S. Department of Agriculture have detected a total of 6 new confirmed cases of virulent Newcastle disease in backyard poultry and at a retail feed store in western San Bernardino County. Information gathered so far indicates that these cases are linked, but we are still working to find additional connections and potentially more cases. As a result of these findings, we have euthanized poultry on confirmed infected and exposed properties in the Bloomington-area and have intensified testing in the neighborhoods surrounding the infected flocks. In an effort to minimize the impact of this new pocket of disease on the entire area, our epidemiologists continue to explore multiple disease response strategies with an eye towards preventing a major outbreak from reoccurring.”
In the December 9 update, Jones said, “All strategies currently under consideration will involve more testing in areas we have already tested at least once, including in Los Angeles and Riverside counties. While these recent cases are in San Bernardino County and our last positive cases in Los Angeles and Riverside counties were in May 2019 and September 2019, significant historical evidence shows that infected birds are moved frequently between these counties, so as long as we have remaining pockets of disease, a substantial risk of spread exists. We are hoping that we can keep moving toward eradication and freedom from disease. Success depends on community efforts. Stay vigilant, report sick birds, and take actions to protect your birds and your community’s birds from disease. Do not move birds and do not allow new poultry on your property.”
Jones was critical of a subset of poultry raisers who are engaging in irresponsible and illegal action that is endangering the region with further contagion.
“While the vast majority of people in affected communities have made the commitment and sacrifice needed to stop this outbreak, some have ignored our quarantine and even encouraged others to ignore the quarantine,” she said. “We all need to work together so we can eliminate this virus entirely from California and return to an environment that supports healthy backyard birds and poultry farms.”
Historically, Southern California has weathered worse Newcastle outbreaks than the one that manifested in 2018 and has persisted now into 2020.
In 2002 and 2003, a Newcastle epidemic resulted in the euthanization of 3.2 million birds. In 1971, a major outbreak occurred among 1,341 commercial poultry flocks in Southern California, necessitating the killing of just under 12 million birds.
The means used to head off the spread of Newcastle disease can be brutal. Public health officials, agricultural inspectors and regulators, as well as farmers have engaged in what are perceived by many members of the public to be ruthless and cruel means when the disease appears to be raging out of control. Flocks of birds, such as egg producing hens in an area where Newcastle has been detected, even if no birds on that particular farm have been confirmed to have the virus, have on occasion been uniformly slaughtered. One of the means of by which this is effectuated involves loading thousands of chickens into an enclosed garbage truck. A hose is then run from the truck’s exhaust pipe into an aperture so the carbon monoxide can be introduced into the enclosure containing the chickens. Those chickens not crushed to death by the weight of the chickens above them succumb to carbon monoxide poisoning.
-Mark Gutglueck