Bird Flu in US Dairy Herds: It’s Emergence, What’s Being Done About It & How To Spot It
Since avian influenza, or bird flu, first appeared in Hong Kong in 1997, it has hit the headlines at various times over the last three decades with varying degrees of alarm.
The latest outbreak in the US is also generating worrying headlines, but with good reason. The highly pathogenic avian influenza (HPAI) virus H5N1 has been detected amongst dairy cows and has spread to two humans.
The strain affecting the US dairy herds was originally an outbreak that drastically affected wild birds and poultry in Europe in 2020, before spreading to North America and having a similar devastating effect on the bird species found there. It is dead, infected birds being found on farms that are the cause of the recent outbreak. The statistics of infected wild birds and poultry are big – ver 82 million cases of poultry being infected have been reported as of March 2024, including commercial birds and those kept as pets.
The new outbreak, spread between cows via contaminated surfaces, is being investigated by the U.S Department of Agriculture (USDA) and has been found in cattle in Texas, Kansas, South Dakota, North Carolina, Michigan, Ohio, and New Mexico so far. The cows symptoms have included decreased lactation and reduced appetite, among others.
It’s not all bad news
Even though it has spread to two humans since 2022, the Centers for Disease Control and Prevention have deemed the risk to the general public to be low as testing has detected no genetic changes in the strain that makes transition to humans easier. The latest person infected was found to work closely with cattle, making infection more likely, and they have been successfully treated with antiviral flu medicines and advised to isolate.
There is also little risk to the public when it comes to consumption of commercial dairy products, as milk from affected cows is being destroyed and the act of legally required pasteurization kills any pathogens in the produce.
For dairy farmers the news is good too as there is reported to be little loss in earnings from affected cows. This is because milk levels appear to be unaffected by the symptomatic low milk supplies, and there are low infection numbers amongst cattle populations, and a zero mortality rate.
However caution should be taken
Due to the constantly evolving nature of the pathogen and the fact that this is a changing situation, a cautious approach should be taken by farmers, backyard bird keepers, and the public alike.
The USDA, U.S. Fish & Wildlife Service, and other government departments are constantly monitoring the biosecurity situation and are carrying out rigorous testing of biological samples from birds and cattle. When it comes to the bird part of the problem, some areas of wildlife refuges may have limited public access, to prevent infection in humans or their pets.
Guidelines have also been published to help prevent further spread of the virus, which includes the reporting of bird deaths for testing, not allowing captive birds – pets or commercial – to mix with wild birds, and to avoid the handling of dead birds with bare hands. Additionally, game hunters are advised to not eat sick game, prepare any game outdoors, and pay strict attention to hygiene when preparing or cooking game.
Photo by Stijn te Strake on Unsplash
How to spot avian flu symptoms in cattle
Decreased milk production
Thicker consistency of milk
Loose stools
Dehydration
Lethargy
Fever
If a herd is affected then the best course of action for the owner is to isolate the animals displaying symptoms before calling their usual veterinarian and State Veterinarian in order to submit samples for testing. Currently, cattle can be expected to make a full recovery.
How to spot avian flu symptoms in birds
Reduced appetite
Lethargy
Decreased production and quality of eggs
Swelling and discoloration of eyes, wattles, combs, and legs
Coughing and sneezing
Loose stools
Sudden death
Flock owners should follow strict biosecurity measures daily and report any sick or dead birds to their usual veterinarian or State Veterinarian for advice and testing.
Symptoms in humans
Fever
Cough
Sore throat
Runny nose
Muscle aches
Headaches
Shortness of breath
Loose stools
Irritated eyes
While H5N1 is rare in humans, it is possible to catch it from close interaction with dairy herds or birds, and the appropriate PPE and strict hygiene measures are advised for those working with such animals.
Symptoms can be mild for some but extremely severe for others and can even lead to respiratory failure and sepsis. If a person suffering the above symptoms has cause to think they may have contracted avian flu it is important to seek the appropriate medical help.
Moving forward
Although this latest outbreak is concerning, the public can be well assured that the risk to their health is vanishingly small and that they can continue to enjoy the dairy products, eggs, and poultry that the farmers across America strive to produce.
The USDA and other departments are working with farmers and the public to ensure biosecurity measures are adhered to in order to preserve the health and safety of the people and animals involved.
Commercial farmers and backyard keepers of chickens can play their part by remaining vigilant and sticking to the government guidelines when it comes to the rearing of their animals. The general public can also help prevent contracting the virus by taking sensible measures if they come across dead wildlife.
Prevention is always easier than the cure.
https://www.cdc.gov/media/releases/2024/p0401-avian-flu.html
https://www.cdc.gov/flu/avianflu/avian-flu-summary.htm
https://www.fws.gov/avian-influenza
https://www.aphis.usda.gov/sites/default/files/hpai-dairy-faqs.pdf
https://www.aphis.usda.gov/livestock-poultry-disease/avian/defend-the-flock