Preparation in the United States for a possible avian influenza outbreak

The avian influenza virus continues to spread among dairy cows in the United States, and the country’s health authorities are actively preparing for possible spread to humans.

“risk [of bird flu] “While the current rate remains low, we continue to be strongly prepared as new data becomes available,” Vivian Dugan of the Centers for Disease Control and Prevention (CDC) said at a meeting of health officials on April 25. Stated.

The first priority is tracking the spread of the virus. So far, the U.S. Department of Agriculture (USDA) has confirmed the H5N1 avian influenza virus subtype in dairy cows. 33 farms across 8 statessix cats on farms in three of those states.

Genetic sequencing has shown that out of 260 samples taken from sick dairy cows, only one has a mutation that suggests H5N1 is adapted to infect mammals, he said. Rosemary Chiffod At the Department of Agriculture during a meeting. However, this marker has been previously observed in other diseased mammals and did not affect the ability of the virus to transmit between mammals. Furthermore, her other 10 samples from the same herd from which this sample was collected did not have the same mutation.

“It hasn’t changed much and remains an avian virus…in other words, it hasn’t become an avian virus. [cow] It’s a virus,” Sifford said.

According to data presented at the meeting, the CDC tested 23 people who had close contact with the animals for the virus. Only one person tested positive, a dairy worker in Texas whose only symptom was bloodshot eyes. To increase testing capacity, the CDC recently increased funding to genetic sequencing centers in six states, Dugan said.

Another important measure being taken is to ensure the security of the milk supply in the United States. Milk from infected cows contains large amounts of the virus. Although milk from sick animals should not enter the milk supply, initial testing by the U.S. Food and Drug Administration (FDA) found that: 1 in 5 milk samples Contains genetic signatures of avian influenza.

“Importantly, this does not mean the sample contains intact infectious virus.” donald prater At the FDA. The test method used detects any genetic material, including dead virus.

Most milk sold in the United States is pasteurized, a process that uses high heat to kill pathogens. Although no studies have evaluated the effectiveness of pasteurization against H5N1, research on similar influenza viruses suggests it may be effective, Prater said. This is why people should avoid consuming or touching raw dairy products.

Two vaccine candidates against H5N1 are also under development. Initial testing by the CDC showed both to be effective in laboratory tests on current strains of cattle, Dugan said.

As part of pre-established procedures, the US Office of Strategic Preparedness and Response (ASPR) said it is stockpiling supplies for the avian influenza vaccine. david boucher At the ASPR conference. This involves producing a part of the vaccine called an antigen that triggers an immune response to the virus. He said ASPR and its commercial partners have already filled hundreds of thousands of bottles of H5N1 vaccine and can quickly supply it for clinical trials or emergency use if needed.

“Based on the CDC’s current situational risks, vaccination is not a necessary tool at this time. But we want to be prepared in case the situation changes,” Boucher said. Enough material is also stockpiled to produce 10 million more doses. And ASPR has contracts with vaccine manufacturers to further increase production as needed.

“If we need to pull any of these levers, we are ready to do so,” Boucher said.