Auburn researcher aims to help prevent, control avian influenza

Since 2022, avian flu — a rapidly circulating Influenza Type A virus — has affected over 81 million poultry, as well as the industries that depend on them. In Alabama alone, poultry generates more than 80,000 jobs and $15 billion in revenue.

In the past two years, a disease-causing strain of avian flu, known as H5N1, has impacted 1,046 flocks across the United States. Miria Criado, an assistant professor in Auburn’s College of Veterinary Medicine, is tackling this timely topic by investigating how these influenza viruses evolve and examining approaches to reducing their deadly impact on poultry.

“This work is focused on understanding how avian influenza circulates between species, how the virus evolves to continue circulating and how the bird’s immune system responds to the virus,” Criado said. “We are especially interested in how we can use some currently available tools or vaccines to help control these outbreaks.” 

To advance this avian flu research, Criado received a grant from the U.S. Department of Agriculture (USDA), U.S. National Poultry Research Center for approximately $644,000 per year. This non-assistance cooperative agreement, which is a renewable grant for up to four years and $2.5 million, is a collaboration between the USDA and Auburn University. Criado, the lead principal investigator, is collaborating with Auburn Assistant Professor Constantinos Kyriakis, Erica Spackman, acting research lead within the USDA’s Exotic & Emerging Avian Viral Diseases Research and David Suarez, acting USDA laboratory director.

Criado prepares materials to perform research. Photo credit: Molly Bartels

The basics of bird flu

Poultry are susceptible to two different kinds of avian flu: low-pathogenicity (LPAI) and high-pathogenicity (HPAI). LPAI can cause a variety of mild symptoms or none at all, said Criado. In contrast, HPAI strains typically lead to the death of the birds within two days.

In all of Criado’s research at Auburn, she is working with LPAI.

“There’s so many questions that we can answer using LPAI strains,” she said. “It’s a great opportunity to study avian flu in a very safe way.”

Criado’s research will allow her to better understand how LPAI strains are circulating among poultry and provide insights for future studies involving HPAI: a key goal given that HPAI is spreading rapidly.

“Two years ago, we only had around 40 HPAIV outbreaks reported,” Criado said. “In the last few years, we have had thousands of outbreaks. Almost all continents around the world had detections.”

This high transmission of HPAI can quickly decimate a flock, and several biosecurity measures and quarantine need to be in place for the affected poultry premise.

“One of the reasons this new strain is concerning is because the amount of virus you need to infect a bird is really, really low compared to previous strains that were circulating,” Criado said.

The virus has a surprisingly simple structure for its detrimental impacts. Criado said a virus is genetic material surrounded by a protein coat and an additional layer with surface proteins.

“If you think about a virus as a ball, then imagine there are all of these surface proteins attached to the outside of the ball,” she said. “You may have one influenza virus strain with a square green protein or a rounded red one.”

These surface proteins seek to bind to a bird’s cells. Once the protein latches onto the cell, the virus releases its genetic material into the cell and hijacks its normal operations. The virus’ genetic material — RNA in the case of bird flu — becomes the cell’s instruction guide, causing it to produce more of the virus.

The bird’s body may respond by producing certain proteins, known as antibodies, which adopt different tactics depending on the situation. For example, an antibody may block one of the virus’s surface proteins from latching to the bird’s cell.

But this tactic may only ward the virus off for so long; viruses are adept at adapting.

“This virus mutates a lot, especially in these surface proteins,” Criado said. “When this evolution happens, it can be difficult for the antibody to defend the bird from the virus.”  

Criado is candling eggs to observe the growth and development of a chicken embryo. Photo credit: Molly Bartels

Criado is pictured with her research team. From left to right: Postdoctoral Researcher Rocio Gerez, Lab Manager James Krehling, Postdoctoral Researcher Mariana Andrioli Pinheiro, Principal Investigator Miria Ferreira Criado, Research Assistant Diego E. Ventura Urbina and Doctoral Candidate Thais de Lima.

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Bridging basic, applied science at Auburn

Criado is churning out basic science insights in the laboratory that can lead to improved approaches for reducing the impact of avian flu. She is studying poultry cells in a flask to better understand how the virus evolves and interacts with poultry immune cells, known as host cells.

“You can look at the genome of the virus and compare it to old or current strains to try to figure out if there is evolution,” she said. “We are especially interested in understanding how the surface proteins may change and interact with the host.”

For example, perhaps a certain segment of the virus’ genetic information is more susceptible to mutations. If Criado can pinpoint this segment of genetic material and determine what it encodes, she would be armed with more insight when developing applied solutions.

“Our work could help explain a pattern where a specific protein tends to evolve,” she said. “Maybe we can use a vaccine later to target that surface protein that can be more effective than what we’ve been using nowadays.”

Moving forward, Criado plans to conduct poultry studies using LPAI virus and vaccines through extensively vetted protocols. Through this work, she aims to develop recommendations that can help curb the deadly impact and spread of avian flu, as well as provide insights about counter-measures that can be implemented at facilities and farms to help control the spread of avian flu.

As Criado conducts her grant-funded research, she is leveraging her extensive expertise. She has previously investigated how LPAI and HPAI viruses replicate and transmit in different avian species. She also has studied vaccines for avian flu, including a recent peer-reviewed publication where she and her coauthors found that multivalent vaccines could protect chickens against avian flu and other important viral infections that affect poultry.

Across her basic and applied work, Criado’s multi-pronged research has the potential to positively impact poultry, humans and the environment. While avian flu is rare in humans, Criado hopes her research can help the scientific community be ahead of the curve if the disease were to become widespread beyond birds.

“My work is rooted in the OneHealth concept that the health of people is closely connected to the health of animals and our shared environment,” Criado said. “Long-term, we hope our research leads to practical tools, recommendations and intervention strategies to reduce avian flu’s impact, especially in poultry.”