The California Department of Public Health (CDPH) today reported one more human infection involving H5 avian influenza, raising its total to 27. The US Centers for Disease Control and Prevention (CDC) added the case to its confirmed list today, which notes that all of California's cases are related to dairy cattle exposure.

The case lifts the nation's number of human infections this year to 53 in seven states.

California's outbreaks in dairy cattle began in late August, and since then the virus has hit 335 farms. The state is also battling a recent surge in outbreaks on commercial poultry farms (see related CIDRAP News story today).

Sequencing finds susceptibility changes, but no clinical concerns

In other developments, the CDC, in an update on human cases today, reported new findings from genetic sequencing of samples from 11 human cases from poultry farms in Washington. It noted that some workers in Washington had mild upper respiratory symptoms, but none were hospitalized.

Sequencing found no changes in the hemagglutinin (the "H5" part of the virus name) associated with increased infectivity or transmissibility in people. In three specimens, however, scientists identified a change known as NA-S247N that may slightly reduce susceptibility to neuraminidase inhibitor antiviral drugs, based on lab tests. 

"It is important to note that this change is not spreading in H5 viruses. Additionally, this change is not expected to have an impact on the ability of influenza viruses to replicate or spread more easily," the CDC said, adding that the change isn't likely to have a meaningful impact on the clinical benefit of oseltamivir (Tamiflu).

Meanwhile, the CDC found a different change (PA-I38M) in the polymerase acidic protein of a virus from a recently confirmed case in California that has been associated with reduced susceptibility to the antiviral medication baloxavir marboxil. The change had been seen sporadically in a few avian flu viruses. The agency emphasized that the drug hasn't been recommended for treatment or post-exposure prophylaxis (prevention) of H5N1 infection.

The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) announced last week that it's awarding $5 million to six partners to boost surveillance of antimicrobial resistance (AMR) in livestock, poultry, and pets.

The money will be used to maintain and expand previously developed AMR dashboards and advance scientific knowledge around AMR, APHIS said in a news release. The dashboards will focus on tracking the emergence and spread of drug-resistant microbes in domesticated animals, monitoring trends in AMR patterns, and developing a better understanding of the relationship between antibiotic use, animal health management, and AMR.

The recipients of the funding are Cornell University, Iowa State University, Texas Tech University, the University of Minnesota, the University of Washington, and the National Association of State Departments of Agriculture.

APHIS says the dashboard development efforts will inform strategies for responsible antibiotic use in animals and complement its ongoing work on AMR.

"With its extensive animal health expertise and strong federal, state, tribal and industry partnerships, APHIS plays a critical leadership role in identifying AMR in diseases found in animals, such as livestock and poultry, while protecting the nation's food supply," the agency said.

Louisiana and Washington have reported new chronic wasting disease (CWD) detections in white-tailed deer, the former in a captive animal found dead in Jefferson Davis Parish and the latter in a hunter-harvested deer in Spokane County.

The Louisiana detection, the first case of the fatal neurodegenerative disease in Jefferson Davis Parish in the southwest part of the state, was confirmed on November 7, the Louisiana Department of Agriculture & Forestry said in a press release late last week. The farm participates in the US Department of Agriculture's CWD Voluntary Herd Certification Program.

All deer farms in the surveillance zone are under restricted movement until further notice.

The farm has been quarantined and a 25-mile surveillance zone activated. "The Office of the State Veterinarian has established a surveillance zone for herds near the affected deer farm and is diligently reviewing recent movement records," the release said. "All deer farms in the surveillance zone are under restricted movement until further notice." 

The Louisiana Department of Wildlife and Fisheries has been performing statewide CWD surveillance of wild deer since 2002. Nineteen confirmed cases have been reported in Tensas, Concordia, East Carroll, Madison, and Franklin parishes in the northeast and east-central parts of the state.

Washington's second case, near its first

Also late last week, the Washington Department of Fish and Wildlife (WDFW) announced the state's second case of CWD in a buck harvested during the opening weekend of the modern firearms hunting season in Spokane County. 

The identification occurred about 5 miles north of the Fairwood area of the county, where the first CWD case was confirmed in August. Since then, the state has changed rules that affect hunters, game salvagers, and people who feed wildlife to slow the spread of the disease, the WDFW news release said.

CWD is a fatal neurodegenerative disease in cervids such as deer, elk, and moose caused by infectious misfolded proteins called prions. The disease can spread among cervids and through environmental contamination. While CWD isn't known to infect people, the World Health Organization and the US Centers for Disease Control and Prevention recommend against eating meat from infected animals.