First bird flu cases in wildfowl reported in Los Angeles County this year
More than 30 wildfowl species in Los Angeles County are infected with a highly contagious bird flu virus, according to biologists who study birds.
The virus was identified in nine species of birds in Los Angeles County this year and was associated with wild geese, migratory ducks, pintails, and swans, according to a report in Science ( http://www.sciencemag.org/content/365/6468/315.abstract) on May 1.
Birds carrying the virus were found in six counties in the Los Angeles region, with the lone confirmed wildfowl case occurring in Ventura County.
The virus is almost certainly the highly pathogenic H5N1 strain that has devastated poultry farms around the United States and that was found in nearly all 50 chicken-poultry industries that were in operation at the time in April, according to the report on May 1. The virus was also found in wildfowl this year.
The virus has a low mortality rate of about 50 percent, but can cause a severe illness that can cause sudden death or neurological complications, according to the report on May 1. Other factors that may contribute to the lethality of the disease are the timing of exposure, the size of the birds and the lack of any protective immunity to the virus.
Only one of the nine cases of the highly pathogenic swine influenza virus detected in wildfowl in Los Angeles County in April was associated with a dead or dying individual.
The outbreak of avian influenza in wildfowl in the San Joaquin Valley this year was first reported to local authorities in March and is likely connected to a single wildfowl mortality event in April.
While the virus in question is most likely to be a highly pathogenic virus, the report on May 1 did not comment on whether the virus in question caused a disease in the wildfowl. It did say that the virus that caused the outbreak was similar to the highly pathogenic virus in poultry.
“The virus may have been circulating in California long before this year,” researchers wrote in the May 1 report on wildfowl health. “That may explain why we have not seen disease in wild mammals before.”
Poultry-associated influenza can be transmitted to humans, but the risk of human infection with the virus is very low, said Dr. Mark Gubler, a vi