The outbreak of H5N1 bird flu virus has spread to dairy cows for the first time in the United States, raising concerns about it spreading to humans through the nation's milk supply.
Since 2022, bird flu in the United States has infected over 90 million chickens, more than 9,000 wild birds, 34 dairy herds, one person in Texas who came in close contact with infected cattle and another after exposure to poultry.
The following is a timeline of the current outbreak in the country:
April 26
Colorado became the ninth US state to report an infected dairy herd.
April 25
Colombia became the first country to restrict the import of beef and beef products coming from US states due to bird flu in dairy cows.
April 24
The US government said it will require dairy cattle moving between states to be tested for bird flu.
April 23
The US Food and Drug administration said it had found bird flu virus particles in some samples of pasteurised milk, but said the commercial milk supply remains safe due to pasteurisation.
April 11
South Dakota became the eighth US state to find avian influenza in a dairy herd, after the US Department of Agriculture (USDA) reported infections in North Carolina, Texas, Kansas, Ohio, Michigan, Idaho and New Mexico.
April 4
Bird flu dairy cow outbreak widened to a dairy herd in Ohio.
April 2
Mexico's agriculture ministry said it was taking preventative measures to increase surveillance and reinforce inspections of US livestock imports after bird flu was found in dairy cattle there.
April 1
The second known human case of bird flu in the United States is reported in a person from Texas who had contact with dairy cows presumed to be infected with the virus.
The virus was detected in dairy cattle in New Mexico, Michigan and Idaho, along with Texas and Kansas.
March 25
The USDA said samples of milk collected from sick cattle in Kansas and Texas tested positive for avian flu, but the nation's milk supply was safe.
Dec 12, 2023
Egg producer Cal-Maine Foods said it had temporarily ceased production at a facility in Kansas after some of the flock tested positive for avian flu.
Nov 3, 2023
Arkansas, a major US chicken producer, reported its first outbreak of lethal avian flu in a commercial poultry flock in a year.
Oct 6, 2023
The United States detected its first case of avian flu on a commercial poultry farm since April, in a flock of 47,300 turkeys in Jerauld County, South Dakota.
April 14, 2023
The US government said it was testing four potential bird flu vaccines for poultry, after more than 58 million chickens, turkeys and other birds had died in the nation's worst outbreak ever.
March 20, 2023
Some of the world's leading makers of flu vaccines say they could make hundreds of millions of bird flu shots for humans within months if a new strain of avian influenza ever jumps across the species divide.
Oct 7, 2022
Avian flu infected a commercial flock of breeding chickens in Arkansas, widening an outbreak of the disease in the southern region.
Nationwide, more than 47 million birds have been killed by avian flu or culled to control its spread this year in the nation's worst outbreak since a record 50 million birds were wiped out in 2015.
April 29, 2022
The first known human case of H5N1 bird flu in the United States appeared in a person in Colorado, who was involved in culling birds at a commercial poultry facility.
March 7, 2022
More than 22 million commercially raised US chickens and turkeys have been killed since February 2022 due to outbreaks of a highly lethal type of bird flu.
March 4, 2022
A bird flu outbreak is reported in a commercial flock of chickens being raised for meat in Stoddard County, Missouri, taking the spread of the virus to 10 commercial chicken and turkey farms in four states.
Feb 9, 2022
The USDA reported an outbreak of highly pathogenic avian flu in an Indiana turkey flock, the nation's first case in a commercial poultry operation since 2020.