Yes, Cows Can Get Bird Flu – Here's What You Need to Know

Yes, cows can get bird flu—specifically, certain strains of avian influenza such as H5N1 have recently been detected in dairy cattle herds across the United States. While birds remain the primary natural hosts for avian influenza viruses, emerging evidence from 2024 shows that the H5N1 strain has crossed species barriers and infected cows, primarily through indirect contact with infected wild birds or contaminated environments. This development marks a significant shift in our understanding of can cows get bird flu and highlights growing concerns about interspecies transmission and agricultural biosecurity.

Understanding Avian Influenza: Origins and Natural Hosts

Avian influenza, commonly known as bird flu, is caused by type A influenza viruses that naturally circulate among wild aquatic birds, particularly ducks, geese, swans, and shorebirds. These birds often carry the virus without showing symptoms, allowing them to spread it over long distances during migration. The virus belongs to the Orthomyxoviridae family and is classified based on two surface proteins: hemagglutinin (H) and neuraminidase (N). There are 18 known H subtypes and 11 N subtypes, but H5 and H7 are of particular concern due to their potential to become highly pathogenic.

The term 'bird flu' reflects the disease’s origin, but it does not mean the virus is limited exclusively to birds. In fact, influenza A viruses are notorious for their ability to jump between species under the right conditions. Historically, outbreaks have occasionally affected poultry farms, leading to mass culling to prevent further spread. However, recent surveillance data from early 2024 revealed something unprecedented: the detection of H5N1 in dairy cattle across multiple U.S. states, including Texas, Kansas, and Michigan.

How Did Bird Flu Reach Cows? Transmission Pathways

The transmission of bird flu to cows represents a rare but increasingly documented case of zoonotic spillover. Research suggests that cows likely contracted the virus through environmental exposure rather than direct bird-to-cow contact. Infected wild birds may have shed the virus in their feces, saliva, or nasal secretions, contaminating pastures, feed, water sources, or milking equipment. Because many dairy operations use open-air barns or shared grazing lands, this creates opportunities for cross-species contamination.

One key factor facilitating this transmission is the presence of the virus in high concentrations in raw milk from infected cows. In March 2024, federal health authorities confirmed that H5N1 was detectable in unpasteurized milk samples from affected herds. While pasteurization effectively kills the virus, the discovery raised alarms about on-farm hygiene practices and worker safety. It also prompted new questions about whether livestock could act as intermediate hosts, potentially enabling further viral adaptation.

Biological Susceptibility of Cows to Avian Influenza

Cattle are not typical hosts for avian influenza viruses. Their respiratory and digestive tracts differ significantly from those of birds, which usually serve as reservoirs. However, studies indicate that bovine cells express some receptors that allow limited binding of avian influenza strains, especially when viral loads are high or immune defenses are compromised.

In infected cows, clinical signs have been relatively mild compared to birds. Symptoms include decreased milk production, lethargy, reduced appetite, and sometimes a temporary drop in body temperature. Notably, most affected cows recover within days without specific treatment, suggesting a self-limiting infection. Still, the economic impact on dairy farms can be substantial due to lost productivity and movement restrictions imposed by animal health agencies.

Virologists emphasize that while cows can become infected, they do not appear to efficiently transmit the virus to other cows—or to humans—under normal conditions. This contrasts sharply with poultry outbreaks, where rapid horizontal transmission leads to devastating losses. Ongoing research aims to determine whether prolonged viral shedding occurs in cattle and whether mutations enhancing mammalian adaptation are emerging.

Public Health Implications and Human Risk

A major concern arising from can cows get bird flu is the potential risk to human health. In April 2024, the Centers for Disease Control and Prevention (CDC) reported the first known case of H5N1 infection in a U.S. dairy worker who had direct contact with infected cows. The individual developed conjunctivitis (eye infection), a symptom previously seen in poultry workers exposed to bird flu.

This incident underscores the importance of occupational safety measures. Farmers, veterinarians, and farmworkers handling sick animals should wear personal protective equipment (PPE), including gloves, masks, and eye protection. Additionally, avoiding contact with raw milk and ensuring proper sanitation of tools and clothing can reduce transmission risks.

To date, there is no evidence of sustained human-to-human transmission of H5N1. However, public health experts warn that every new mammalian infection increases the chances of the virus acquiring mutations that could make it more transmissible among people. Therefore, monitoring infections in cows is not just an agricultural issue—it's a critical component of pandemic preparedness.

Regulatory Response and Farm Management Practices

Following the confirmation of bird flu in cows, the U.S. Department of Agriculture (USDA) and state veterinary offices implemented enhanced surveillance protocols. Dairy farms reporting unusual drops in milk yield or animal illness are now required to submit samples for testing. Positive cases trigger quarantine measures, movement restrictions, and traceback investigations to identify possible sources of contamination.

Farmers are encouraged to adopt biosecurity improvements, such as:

• Preventing wild bird access to feed storage areas
• Using covered water troughs
• Disinfecting milking equipment regularly
• Isolating new or sick animals promptly
• Limiting visitor access to livestock zones

While no vaccine is currently approved specifically for cattle against H5N1, researchers are exploring options. Meanwhile, routine monitoring and rapid reporting remain the most effective strategies for controlling outbreaks.

Geographic Spread and Seasonal Patterns

As of mid-2024, bird flu in cows has been confirmed in at least nine U.S. states, predominantly in the central and northern regions where large dairy operations overlap with migratory bird flyways. The timing of outbreaks aligns with spring and fall migrations, when wild birds travel across North America and interact with local ecosystems.

States vary in their reporting requirements and response speed. For example, Texas and Idaho moved quickly to test suspect herds after initial alerts, while others relied on voluntary farmer participation. This inconsistency highlights the need for standardized national guidelines. International comparisons show similar patterns: in Europe, avian flu has occasionally been found in pigs and minks, but widespread cattle infections have not yet been reported.

State	First Detection in Cows	Number of Affected Herds	Primary Source Suspected
Texas	March 2024	6	Wild bird contamination of feed
Kansas	April 2024	3	Shared pasture exposure
Michigan	May 2024	2	Contaminated milking equipment
New Mexico	April 2024	1	Unknown (under investigation)

Debunking Common Misconceptions About Cows and Bird Flu

Several myths have emerged since news of bird flu in cows became public. One widespread belief is that drinking milk causes bird flu infection. This is false—commercial milk is pasteurized, a process that destroys all known pathogens, including H5N1. Only raw, unpasteurized milk poses any theoretical risk, and even then, documented cases are lacking.

Another misconception is that cows can spread bird flu easily to humans. Current evidence shows only isolated cases linked to close, unprotected contact with infected animals. There is no indication that casual contact or consumption of properly handled dairy products poses a threat.

Some fear that bird flu in cows signals an imminent pandemic. While vigilance is warranted, experts stress that the current situation does not meet criteria for widespread human transmission. Continuous genomic sequencing of virus samples helps track mutations and assess evolving risks.

What This Means for Consumers and the Dairy Industry

For consumers, the bottom line is simple: store-bought milk and dairy products remain safe. Regulatory agencies continue to affirm that pasteurization eliminates the H5N1 virus. People concerned about food safety should avoid raw milk and ensure all dairy items come from licensed producers.

For the dairy industry, the emergence of bird flu in cows presents both operational and reputational challenges. Producers must invest in stronger biosecurity, train staff on infection control, and maintain transparent communication with regulators and buyers. Export markets may impose temporary restrictions, affecting international trade until disease status is clarified.

Future Outlook and Research Needs

The discovery that cows can get bird flu opens new frontiers in virology and animal health. Scientists are now investigating how the virus replicates in bovine tissues, whether cattle can amplify the virus, and if ongoing circulation might lead to novel variants. Long-term surveillance programs are being expanded to include routine testing of livestock near wetlands or migratory routes.

Collaboration between ornithologists, veterinarians, and public health officials will be essential. Understanding the interplay between wild bird populations, climate change, farming practices, and viral evolution will help predict and prevent future spillovers.

Frequently Asked Questions (FAQs)

Can you get bird flu from drinking milk?

No, you cannot get bird flu from commercially sold milk. All legal milk products are pasteurized, which destroys the H5N1 virus. Raw milk may carry risks and should be avoided.

Are cows dying from bird flu?

Most infected cows show mild symptoms and recover fully. Mortality rates in cattle are extremely low compared to poultry.

Is bird flu in cows contagious to other animals?

Limited evidence suggests transmission between cows is inefficient. However, cats that consumed raw milk from infected cows tested positive in experimental settings, indicating some risk to other mammals.

Should I stop eating eggs or chicken if cows have bird flu?

No. There is no connection between cow infections and poultry safety. Eggs and chicken are safe when cooked properly.

How can farmers protect their herds from bird flu?

Farmers should prevent wild bird access to feed and water, practice strict hygiene, isolate sick animals, and report unusual symptoms to veterinary authorities immediately.