USDA shares recent H5N1 avian influenza sequence, more dairy herd outbreaks

The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) announced last night that it has shared the latest genetic sequences of 239 H5N1 avian influenza viruses from poultry, wild birds and dairy cows, which will help scientists find new information about the spread of the virus. clue.

In related developments over the past three days, APHIS reported the detection of four more cases of H5N1 in dairy herds, along with additional positive results in game birds and poultry. Additionally, the U.S. Centers for Disease Control and Prevention (CDC) released the latest update on its actions to search for new human infections.

Long-awaited genetic sequence

As the outbreak approaches one month, it remains unclear how the 2.3.4.4b H5N1 clade is able to infect dairy cows and how it spreads within the dairy herd. As the virus continues to spread in many parts of the world, veterinary experts are looking for answers to protect the health of dairy cows and humans.

Some scientists have expressed frustration at the slow pace of sharing genetic sequences and other details of the investigation.Until yesterday, only a few genetic sequences from the recent outbreak were available, including those from several cows and cats detailed in a recent preprint Paper A team from Iowa State University.

APHIS said in a statement that it normally publishes sequences on GISAID, the Global Initiative for Sharing All Influenza Data, but for the sake of transparency and speed of research, it is sharing raw sequence data through the National Center for Biotechnology Information at the National Institutes of Health. It added that the sequences were from cows, cats, chickens, skunks, raccoons, wrens, blackbirds and geese, and data would continue to be provided on a rolling basis.

Dr. Louise Moncla, Assistant Professor of Pathology, University of Pennsylvania College of Veterinary Medicine, Today It welcomed the release of the original genetic sequencing but said analysis steps such as downloading and mapping take time and it will be some time before scientists can show how the viruses are related to each other.

More detected in cattle, poultry, wild birds

Meanwhile, in updates over the past few days, APHIS reported the detection of four more cases of the H5N1 virus in the dairy herd, bringing the total to 32 cases. .

Additionally, APHIS reports the detection of two additional H5N1 viruses in poultry flocks, including an earlier-announced outbreak at a commercial turkey farm in Newaygo County, Michigan, and a third hatchery in Roosevelt County, New Mexico . The agency also reported about 30 cases of the H5N1 virus detected in wild birds, including waterfowl, shorebirds, crows and birds of prey. Most come from the eastern region of the country.

Neuraminidase inhibitor-sensitive viruses

In other related developments, the CDC released its latest response on April 19, which included laboratory studies to better elucidate the impact of antiviral drugs and vaccine candidate viruses.

The agency said it had just completed susceptibility testing of seasonal influenza antiviral drugs. Testing of the H5N1 virus in recent human cases in Texas confirmed that it is sensitive to all commercially available neuraminidase inhibitors. “Testing to confirm sensitivity to another antiviral drug, baloxavir marboxil, will take longer and is ongoing,” it said.

Tests to confirm sensitivity to baloxavir, a different antiviral drug, take longer.

The CDC said it is studying blood samples from people vaccinated against H5 avian influenza to confirm that existing candidate vaccine viruses (CVVs) can protect against the H5N1 virus isolated from Texas patients. Early genetic analysis suggests that two of the CDC’s existing CVVs protect against the subtype found in the Texas patients.

Among other actions, the CDC said it is designing an epidemiological field study to better understand the outbreak. So far, surveillance of emergency room and influenza testing data in areas where H5N1 has been found in dairy cows or other animals has not shown unusual trends.