Bird Flu in Arizona Dairy Cattle Milk, What is the Risk to Humans?

A recent detection of bird flu in Arizona dairy cattle milk has people wondering. What is the risk to humans?

What can you do to reduce your risk of infection from dairy cattle milk?

Arizona Department of Agriculture Quarantines Dairy Farm

The Arizona Department of Agriculture (AZDA) has confirmed bird flu found in milk from a dairy herd in Maricopa County.

The results come after routine testing activities. A move initiated after several states have been impacted by bird flu in dairy cows.

“Every dairy in Arizona has been tested at least once since January. Thus far, only a sample from this dairy has tested positive,” officials said. “Milk and other dairy products that have been pasteurized are safe to consume.”

The cows remain asymptomatic, but the farm has been placed under quarantine.

The Specific Genotype of the Observed Bird Flu in Arizona Dairy Cattle Milk Tells a Story

A “genotype” is the genetic makeup of the organism. Scientists use this genetic information to better understand the pathogen. In this case, it helps them track movement of the organism and how it is mutating over time.

Previously, the B3.13 genotype was detected in dairy cattle. This latest sample of bird flu in Arizona dairy cattle contained the D1.1 genotype. A genotype first confirmed in Nevada dairy cattle on January 31, when a dairy farm worker became sick with the virus.

Fortunately, the farm worker did not experience severe illness and did not require hospitalization. They have since recovered.

D1.1 has most often been found in wild birds, mammals, and in spillovers to domestic poultry along the North American flyways.

More than a dozen other people have been infected with the D1.1 bird flu virus. But those were associated with infected poultry. The Nevada dairy was the first cow-to-human case for this genotype.

According to AZDA, this bird flu genotype “bears no feature that would make it more likely to infect humans.”

The Bird Flu Situation

Based on the most recent Centers for Disease Control and Prevention (CDC) data, the risk for that type of transmission is low at this time. There have been no reports of person-to-person spread of bird flu.

There have been 69 cases of bird flu in humans so far in the United States. One case resulted in death. Most of these were the result of occupational exposure. Those working in the poultry or dairy industry. However, some have been transmitted by backyard flocks or wild birds.

Overall, human cases of bird flu seem to be coming from dairy cattle exposure more so than poultry.

Reported human cases include:

• 41 from dairy herd exposure
• 23 from poultry farms and culling operations
• 2 from “other animal exposure”
• 3 cases where the exposure source was unknown

What Does Bird Flu Look Like in Humans?

In birds, bird flu begins with respiratory symptoms and is often fatal. This is why the H5 bird flu is referred to as “highly pathogenic.”

In cows, bird flu looks like reduced milk production. Cows are generally otherwise asymptomatic.

In humans, bird flu has historically been rare and mild. However, there have been a few recent cases of more severe illness and one death. Unfortunately, those have been from the new D1.1 genotype virus.

People get sick with bird flu from touching something contaminated with the virus and then touching their eyes, nose, or mouth.

Most reports of illness have been from close or lengthy unprotected contact with infected birds or places that sick birds (or their saliva, mucous, and feces have touched).

While most of the human cases of bird flu have come from the highly pathogenic H5 version of the virus, there is another form of bird flu in circulation. The H7N2 bird flu virus. This version is referred to as “low pathogenic avian influenza” because it causes mild-to-moderate illness. Four human cases have been reported with H7N2 bird flu.

Bird Flu in Arizona Dairy Cattle Milk Raises Concerns

Previous studies have shown that the risk of bird flu by ingesting contaminated eggs or milk is low. However, as the genetic makeup of the virus changes over time to become more potentially infectious to humans, this could change.

For many, milk and eggs are a dietary staple. They are often paired on breakfast tables across the world. Should we opt for alternatives and avoid these mainstays altogether? Or is there a better way?

Protecting Yourself from Bird Flu in Milk and Eggs

The bird flu virus is not indestructible. Like just about all viruses, a good amount of heat is sufficient to kill it. Or rather, inactivate it. This tidbit of information can be used to protect yourself from becoming infected from potentially contaminated milk and/or eggs.

Drink Pasteurized Milk

Pasteurization is a heat treatment process that has been around for over 100 years. One way to protect yourself from bird flu in milk is to only drink pasteurized milk. This type of milk has been undergone a sufficient heating and cooling process proven to kill lurking germs. Including bird flu.

Avoid drinking raw (unpasteurized) milk that has not undergone such treatment. Raw milk can be potentially contaminated with Listeria, E. coli, or any number of potential pathogens found on a dairy farm.

Completely Cook Eggs

Consuming raw or undercooked eggs leaves the consumer vulnerable to foodborne infection. In addition to bird flu, other harmful germs like Salmonella and E. coli can be present. Completely cooking eggs until both the yolk and the white are completely opaque and solid should be sufficient to kill the bird flu virus and other harmful pathogens potentially present in the egg.

Want to Learn More?

If you’d like to know more about food safety topics in the news, like “Bird Flu in Arizona Dairy Cattle Milk, What is the Risk to Humans?,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!

By: Heather Van Tassell (contributing writer, non-lawyer)