Bird flu updates: 4.2M infected chickens to be culled in Iowa, cases detected in alpacas

• Bird flu outbreaks have continued across the U.S. as officials work to keep the spread at bay.
• The virus has been detected in alpacas for the first time.
• The CDC has documented two cases of human bird flu infections in 2024.

Bird flu outbreaks have continued across the U.S. as officials work to keep the spread at bay.

While the outbreak likely began amongst chicken flocks and spread to dairy cows, reports of the virus infecting other animals have come out of several states. Two cases of the virus appearing in people have been reported despite ongoing testing, said the Centers for Disease Control (CDC), and their symptoms were relieved by simple over-the-counter flu medication.

Commercial farming facilities have taken to destroying infected flocks in an attempt to quell the ongoing spread. Even so, a new large-scale infection was reported in Iowa this week, impacting millions of egg-laying chickens.

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More than 4 million chickens set to be killed

An outbreak of bird flu was detected in Iowa on Tuesday in a commercial flock of 4.2 million chickens, according to the state Department of Agriculture.

The egg-laying flock, located in Sioux County, will be culled to prevent further spread. Since 2022, about 22.9 million birds from backyard flocks and commercial facilities have been destroyed to keep the virus at bay in Iowa, the nation's top egg producer, according to USDA data.

Bird flu infection found in alpacas for first time

Besides the unusual spread to dairy cows in recent months, bird flu has been detected in other animals, including barn cats that were found dead at infected facilities. And now it's been found in alpacas.

The US Department of Agriculture’s National Veterinary Services Laboratories said Tuesday that a group of alpacas tested positive on May 16 on a farm in Idaho where poultry had previously tested positive and been destroyed.

This is the first known infection in alpacas, said the USDA.

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What is bird flu?

Bird flu, or avian flu, is a contagious infection that spreads among wild birds and can infect domestic poultry and other animal species. The virus does not often spread to humans but sporadic infections have been reported. There are several strains all belonging to influenza A-type viruses.

The most common subtypes that may affect humans are A (H5N1), A (H7N9) and A (H9N2), according to the Cleveland Clinic. In humans, symptoms can resemble a typical flu but may advance into more serious respiratory symptoms.

In birds, avian flu is highly contagious and cases can range in severity from mild to highly deadly. Infected birds shed the viruses in their saliva, nasal secretions and feces, meaning other birds can contract the virus through contact with those fluids directly or via contact with a contaminated surface.

The CDC has documented two cases of human bird flu infections in 2024, one in a Michigan dairy farm worker and one in a dairy farm worker from Texas. Both infected people showed only symptoms of conjunctivitis, or pink eye.

Bird flu virus outbreak in dairy cows

The current multi-state outbreak of bird flu in cattle likely began late last year.

At least 67 dairy cattle herds in nine states have been confirmed infected in nine states, including Colorado, Idaho, Michigan, New Mexico, North Carolina, Ohio and South Dakota.

In late April, the U.S. Food and Drug Administration announced that dairy product testing had found remnants of the virus in one out of five commercial dairy samples but none that contained a live virus capable of transmitting the disease.

As long as people consume pasteurized dairy products and cook poultry products to a proper temperature, mass-produced products continue to be safe, the agency said.