A particularly concerning form of bird flu has now decimated poultry and spread to wild birds in many different parts of the world.

The current clade of H5N1 virus, called clade 2.3.4.4b, appears well-adapted to spread efficiently among wild birds and poultry in many regions of the world and was first identified in wild birds in the United States in January 2022. Since then, this current clade 2.3.4.4b HPAI A(H5N1) virus has been detected in wild birds in all 50 states and has caused bird outbreaks in 47 states affecting more than 58 million commercial poultry and backyard flocks.

CDC

The current strain is contagious to humans only when they have very close contact with live birds, according to CDC. However, there is concern now that it may have mutated and developed an ability to spread in mammals, including farmed mink in Spain and possibly wild sea otters in Peru.

The CDC says the mink are particularly susceptible and the spread of the virus in mink does not indicate an increased likelihood of spread among humans. They say a candidate vaccine has already been developed and could be produced quickly if needed.

I don’t trust the CDC as much as I did before Covid-19. However, this flu virus seems to be exactly what they were preparing for when they got blind-sided by Covid, so hopefully they would be better prepared for this.

This editorial in Science also takes aim at USDA and the Fish and Wildlife Service.

More zoonotic diseases originated in the United States than in any other country during the second half of the 20th century… The ongoing H5N1 avian influenza outbreak has left 58 million animals dead in backyard chicken coops and industrial farms. It has infected animals in one of the dozens of live poultry markets in New York City (elsewhere called “wet markets”)…

Since 2011, the US has recorded more swine-origin influenza infections than any other country. Most occurred at state and county fairs, where an estimated 18% of swine have tested positive. These fairs attract 150 million visitors each year. In 2012, H3N2v influenza jumped from pigs to humans at livestock exhibitions and infected 306 people across 10 states, with suspected human-to-human transmission…

Each year, the US consumes an estimated 1 billion pounds of “game” (elsewhere called “bushmeat”). Yet, most hunter-harvested meat is not inspected, and no sanitary measures are required. Avian influenza has spread from wild birds to hunters and also appeared in captive game farms, where 40 million birds are raised annually. Three million mink live on US fur farms in long rows of wire cages where their waste falls onto the floor or onto other animals below…

The US is the largest importer of wildlife in the world. More than 200 million live wild animals enter the US each year, most undergoing no health and safety checks when they arrive.

Science

These facts and figures surprised me. Routine contact between people and domestic and wild animals is not just something that happens outside the U.S., it is happening here every day.