Just one US employee has examined constructive for H5N1 to this point
26 April 2024
3 minute learn
US officers have strengthened measures to include the additional unfold of the primary identified outbreak of H5N1 or hen flu in dairy cows, which has now unfold to 33 herds in eight states and bled over into the nation’s milk provide, reported Reuters.Â
To this point, just one particular person – a Texas farm employee – has examined constructive for H5N1, and whereas well being officers and scientists say the chance to folks stays low, many questions stay.
Why is H5N1 or hen flu a priority?
The unfold of hen flu amongst dairy cattle displays an enlargement of the vary of mammals that may be sickened by the virus that usually infects birds.
Scientists are on alert for adjustments in H5N1 that would sign the virus is adapting to unfold simply amongst people. The virus has precipitated severe or deadly infections amongst folks in shut contact with wild birds or poultry. It has lengthy been on the record of viruses with pandemic potential, and any enlargement to a brand new mammal species is regarding.
The infections in cattle are from the identical subtype of avian influenza that has been infecting wild birds and poultry flocks globally for greater than two years, additionally killing a number of mammal species that seemingly contracted the virus from consuming sick or useless birds.
How widespread is the avian influenza outbreak in cattle?
The complete extent stays unknown, however a number of latest developments recommend it might be in additional herds than documented.
On April 23, the US Meals and Drug Administration mentioned it has detected particles of H5N1 within the milk provide. Checks recommend they’re remnants of virus killed throughout the pasteurization course of, and that the milk is protected. Early testing has not detected any stay virus in milk samples, and U.S. well being officers imagine folks can not get sick from consuming pasteurized milk and warn to not drink unpasteurized milk.
Officers have realized the virus could be current in cows that present no indicators of an infection, and milk from these cows doesn’t present indicators of an infection reminiscent of being thicker and yellow.
To include the outbreak, the US authorities is requiring dairy cattle shifting between states to be examined for avian influenza.
When did this avian influenza outbreak begin?
US officers had thought the outbreak was latest, however new info suggests it might have began late final 12 months.
After the US Division of Agriculture launched some uncooked genetic information onto a public database on April 21, a crew of evolutionary biologists led by Michael Worobey of the College of Arizona pieced collectively the viral genetic codes.
The crew mapped the outbreak by monitoring adjustments within the virus because it unfold amongst herds. Primarily based on their evaluation, Worobey mentioned in an April 24 interview that the outbreak in dairy cattle occurred by a single transmission occasion from a hen to a cow in late 2023, seemingly in December.
How is H5N1 spreading?
It’s nonetheless unclear how the virus is spreading, however there’s proof of untamed bird-to-cow, cow-to-cow, cow-to-poultry, and one case of cow-to-human transmission. There is no such thing as a proof of human-to-human transmission.
Due to the heavy viral load in milk and mammary glands, scientists suspect the virus is being unfold to animals throughout the milking course of, both by contact with contaminated gear or with virus that turns into aerosolized throughout cleansing procedures.
Whether or not the virus can unfold by respiratory droplets that infect the airway, as flu viruses usually unfold in people, stays unclear.
Is there an avian influenza vaccine for people?
The US has a stockpile of avian influenza vaccines matched with the pressure at present circulating, in addition to antivirals that could possibly be used to deal with human infections. For a serious epidemic or a pandemic, the US must scale up significantly.
Flu vaccine suppliers Sanofi, GlaxoSmithKline and CSL Seqirus have mentioned they’re monitoring avian flu and stand prepared.
