Los Angeles County health officials announced that the H5N1 avian influenza virus was detected in wastewater collected from the AK Warren Water Resources Facility in Carson.
The viral “hit” was detected on October 28 by WastewaterSCAN, an infectious disease surveillance network run by researchers at Emory University, Stanford University and Verily, Alphabet’s life sciences organization.
Hits were also seen in San Jose, Redwood City, San Francisco, Palo Alto, Sacramento, Santa Cruz, Marina and Turlock last week.
The Carson plant treats wastewater from about 50% of Los Angeles County’s population, said Annabelle de St. Maurice, director of community outbreak and syndrome surveillance for the Los Angeles County Department of Public Health.
Officials have not determined the source of the virus, but have suggested several possibilities, including discarded contaminated animal products and infected wild bird feces. They are also “actively engaging with key risk groups” including nearby dairy and meat processing plants.
“It seems likely that the source is animal rather than wild birds,” de Saint-Maurice said.
He said the risk to the public remained low.
H5N1 avian influenza has been detected in 203 dairy herds in California since August. 17 dairy workers were also infected. Nationwide, 41 people have been infected, including 21 infected with dairy cows, 19 infected with poultry, and one unknown. USDA reported 404 dairy herds in 14 states tested positive. This number does not include a herd of eight spotted in Utah earlier this week.
It was also definitively detected in pigs in Oregon.
De St. Maurice said the county regularly monitors and tests symptomatic birds, pets and wild mammals.
In addition, the county is working locally on subtyping influenza specimens collected at clinics and hospital specimens “to determine if there are potential H5N1 human cases,” he said. .
He said the county public health department is also providing “support and education to at-risk communities,” but so far there have been no cases of human infection.
De St. Maurice said this kind of work, subtyping influenza samples, allowed Missouri health officials to identify human H5N1 cases that had no reported contact with dairy products or poultry. He said it was thanks to The source of the person’s infection has not yet been determined.
The wastewater findings suggest that the virus is spreading in dairy cows in California (which currently accounts for more than half of the cattle infections reported nationwide) and that wild birds from the Arctic are moving along the Pacific Flyway in the fall. This became clear as we headed south.
There are currently two strains of H5N1 avian influenza circulating in California. This form circulating in dairy cows is known by scientists as B3.13. A new version of Wild Bird has emerged recently and is known as D1.1 or D1.2.
The genetic sequence of the H5 virus found in Los Angeles County sewage has not yet been studied. De St. Maurice said the way the samples were collected and identified made sequencing impossible.
The H5 virus originates from birds. They are not human viruses.
Officials said in a statement that the risk of infection can be reduced by avoiding raw milk, raw cheese and undercooked meat. Pasteurization and proper cooking inactivate the virus.
It also recommends avoiding unprotected contact with sick or dead animals and avoiding items contaminated with bird feces. Pets can also become infected in these ways. And officials are asking people to report sick or dead birds to their local animal control agency.
We also recommend getting a flu shot every year. Seasonal influenza vaccination does not prevent avian influenza infection, but it reduces the chance that avian influenza will combine with human influenza, potentially creating new viruses that can spread more easily between people. there is.
