Here’s what you need to know about the US bird flu outbreak

Colombia has restricted the import of beef and beef products coming from US states where dairy cows have tested positive for avian influenza (H5N1) as of April 15, according the US Department of Agriculture.

It is the first country to officially limit trade in beef due to bird flu in cows, in a sign of a broadening economic impact of the virus that has restricted poultry trade globally. Colombia imports a small amount of beef from the US annually, according to government data and market analysts.

In a notice this week on the USDA’s Food Safety and Inspection Service website, which was last updated on April 22, the agency said the ban includes beef products derived from cattle slaughtered in Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota and Texas.

Colombia imposed temporary restrictions on raw bovine meat products, the notice said. If exporters have a valid import permit, shipments may still be held at the port.

What measures has the US implemented to contain H5N1?

The restrictions come as the US government said it will require dairy cattle moving between states to be tested for bird flu starting on Monday, as federal officials ramp up their response to an outbreak that has bled over into the US milk supply.

The measures aim to contain the spread of bird flu, which has been reported in eight states and 33 dairy herds since it was first detected in late March in Texas. A person exposed to cattle tested positive for the disease and suffered conjunctivitis.

To date, no US beef cattle have tested positive for bird flu, government officials said.

Colombia is the only country that has officially imposed restrictions on US beef exports over the H5N1 outbreak, said Joe Schuele, spokesman for the US Meat Export Federation, an industry group.

“We don’t feel that import restrictions related to the avian flu outbreak have any scientific basis,” he said, adding: “It’s certainly a big deal for exporters who are doing business in Colombia and for their customers.”

USDA officials are talking with Colombia about the issue, Schuele said.

Trading partners have requested additional information on the government’s epidemiology, Rosemary Sifford, USDA’s chief veterinary officer, said in a webinar on Thursday.

“We are responding to their requests for information as we receive them, to provide information that assists them in mitigating any trade impacts,” Sifford said.

USDA officials did not say which trading partners asked for such information.

Which countries have reported an outbreak of bird flu?

The Philippines has reported an outbreak of highly pathogenic H5N1 avian influenza, commonly called bird flu, on a poultry farm in the centre of the country, the World Organisation for Animal Health (WOAH) said on Thursday.

The virus killed 4,475 birds out of a flock of 60,529 on a farm in the province of Leyte, the Paris-based WOAH said in a report, citing local authorities.

“The affected farm is surrounded by rice field paddies and a river which are frequented by wild waterfowl. These free-flying wild birds could have introduced the virus via their droppings, as the first building to be affected was at the back of the farm nearest to the rice paddies,” the authorities said in the report.

Bird flu is carried by migrating wild birds and can then be transmitted between farms. It has ravaged flocks around the world in recent years, disrupting supply and pushing up food prices.

The Philippines’ farm ministry in January temporarily banned poultry imports from several countries including Japan, Belgium and France due to outbreaks.

Risk to humans

The US CDC on Friday issued a health alert to inform clinicians, state health departments and the public of a case of avian influenza in a person who had contact with dairy cows presumed to be infected with the virus.

The farm worker from Texas was reported to be infected on April 1, making it the second case of the H5N1 strain of avian influenza, commonly known as bird flu, identified in a person in the United States.

It follows a 2022 case in Colorado, and comes as the virus is spreading to new mammals, including dairy cattle for the first time.

To prevent infection from the virus, the CDC recommends the use of personal protective equipment (PPE), testing, antiviral treatment, patient investigations and monitoring of persons exposed to sick or dead, wild and domesticated animals and livestock that may have been infected with the virus.

Earlier this week, the CDC said the infection does not change the risk assessment for the US general public from H5N1 bird flu, which it considers to be low.

The Texas patient’s only symptom was eye inflammation, according to the state’s health department.

Bird flu, officially called highly pathogenic avian influenza, has increasingly spread to mammals, raising concern of human transmission, with foxes the most affected species and the US reporting the widest number of mammals infected.

Cases of the disease in mammals have mostly been detected in Europe and the Americas.

Here is a list of the type of mammals in which the virus – which has also infected hundreds of wild and captive bird species – has been detected between 2016 and 2024, according to data gathered by the European Food Safety Authority (EFSA).