Leading The Flock: Texas A&M Epidemiologist Studies Zoonotic Diseases’ Impact On Animals, People

Story by Megan Bennett

February 3, 2026

A passionate researcher and educator, Dr. Sarah Hamer has established herself as a global leader in veterinary medicine, public health, and epidemiology.

Her expertise centers around zoonotic diseases, or those that can spread between people and animals. By dedicating her career to studying West Nile virus, Lyme disease, emerging viruses, avian malaria, Chagas disease, and more, she hopes to help society better prepare for and prevent future outbreaks.

As a professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences (VMBS), Hamer is also dedicated to training and inspiring the next generation of veterinarians, researchers, and epidemiologists.

Catching The Bug

Hamer first developed a passion for zoonotic diseases while studying the American crow as she pursued her master’s degree in Natural Resources & Environmental Sciences at the University of Illinois.

“We sewed radio-transmitters onto the birds’ tail feathers to track their movement and see what habitats they were using,” Hamer said. “By understanding how these birds moved and utilized resources, we could identify critical factors that allow these birds to thrive in the urban environment.”

During the study, she noticed that a large number of birds began getting sick and dying.

“Because we were tracking their movement, we were able to locate and test the birds quickly after their death,” she said. “Nearly all of the dead birds tested positive for the West Nile virus. We also sampled and tested mosquitoes from the exact trees where the crows were roosting at night and found the virus within the mosquitoes as well.”

As they conducted this sampling, people living in those neighborhoods also began getting sick from the virus.

Although West Nile virus was first detected in the United States in 1999, it wasn’t until 2002 — as Hamer was pursuing her master’s degree — that the number of reported cases jumped from dozens to thousands. She suddenly found herself working with a disease that was rapidly spreading across the country, and what began as a young student’s ecology project quickly morphed into research on the relationship between human and animal health.

“That experience as a master’s student really set me on a career path of studying these emerging pathogens that impact animal health but also impact human health,” Hamer said. “I became very interested in studying wildlife populations and disease vectors, such as mosquitoes and ticks, and how the pathogens they transmit are passed to humans.”

Ruling The Roost

Hamer completed both a Ph.D. in Ecology, Evolutionary Biology & Behavior and a Doctor of Veterinary Medicine degree at Michigan State University to better enable her research career in disease ecology at the human/animal interface. She continued to pursue her new interest in zoonotic and vector-borne diseases, this time by studying how invasive ticks spread Lyme disease and other tick-borne pathogens — and how wild animals can provide an early warning system for diseases that may come to affect humans.

After graduation, she joined the VMBS faculty as an epidemiologist, running a broad program to study infectious diseases in animals that can also infect people.  She was later named the Richard Schubot Endowed Chair and director of the Schubot Center for Avian Health, a multidisciplinary academic group dedicated to improving the health of birds and the environments in which they live through research, teaching, and outreach.

“It is awesome to be surrounded by so many people who are united by their passion for bird health,” Hamer said. “Many pressing issues with respect to avian health are complex, requiring expertise from different disciplines. We combine the strengths within the Schubot Center and partner with others to expand our capabilities and solve these complex problems.”

Research at the Schubot Center has covered diseases in captive and wild birds, genomic sequencing of birds, and avian nutrition. 

The center also conducts field studies, hosts outreach projects, and responds to outbreaks. For example, Hamer and the Schubot team are conducting surveillance for highly pathogenic avian influenza and assisting Texas zoos in protecting their birds from vector-borne diseases native to our state, like avian malaria.

One of the most impactful roles of the center is in the education and real-world training opportunities it provides for students.

“There is no shortage of students who want to be involved in avian health research — undergraduates, graduate students, and veterinary students,” Hamer said. “In order to succeed as a research powerhouse, we must serve as a training ground for students of various capabilities.”

Going Viral

When the COVID-19 pandemic hit in early 2020, Hamer found an opportunity to study how the SARS-CoV-2 virus was impacting animals as well as people.

She began collecting samples from local companion animals and soon discovered the first two cats in Texas that tested positive for SARS-CoV-2 while living in a household with a person who was diagnosed with COVID-19.

“Tracking infection in pet dogs and cats was critical work early in the pandemic,” Hamer said. “We learned that pets can become infected in high-risk households and, therefore, should be considered in the way we manage these households as part of the public health response. Fortunately, our work shows that the virus was rarely associated with clinical signs of disease in animals.”

Their work led to new public health guidelines for pet owners diagnosed with COVID-19; it also spurred a series of additional studies about the virus’ impact on animals.

Over the next two years, Hamer’s team also identified the first United Kingdom variant (B.1.1.7) of SARS-CoV-2 in a pet in the world and studied the virus in deer, showing that captive deer can become infected with the SARS-CoV-2 virus under natural conditions. 

In addition, they teamed up with the Austin Humane Society, Austin Animal Center, and Texas Department of State Health Services to conduct a study on coronaviruses in cats and made key contributions to the first national-scale COVID-19 animal surveillance study that analyzed companion animal COVID-19 data from across the United States.

“During our COVID-19 & Pets Project, we detected more than 100 cases in cats and dogs in Texas. In many cases, we showed infected animals didn’t seem to get sick from the virus,” Hamer said. “However,  we felt it was important to study these animal infections because different viral variants can have different health outcomes.”

Battling Bloodsuckers

One of Hamer’s longest ongoing projects is looking at Chagas disease, a tropical illness caused by the parasite Trypanosoma cruzi, most commonly spread by triatomine bugs — also known as “kissing bugs” because they bite their hosts to feed on blood. Chagas disease — which develops in humans and dogs — often goes unnoticed in early stages, but a chronic infection can lead to serious heart and digestive system problems, making early diagnosis important.

Hamer and Dr. Ashley Saunders, a VMBS professor and veterinary cardiologist, have spent years studying the United States Department of Homeland Security’s working dogs, which are often exposed to kissing bugs along the United States-Mexico border.

“Because these working dogs spend lots of time outside where they may be exposed to vectors, they may provide a sensitive indication of the different vector-borne infections across the landscape that are not only important for dog health but also human health,” Hamer said. “Recording health information from such a large population of dogs will hopefully help us understand why the disease develops in different ways.”

Hamer, Saunders, and other collaborators are also using innovative diagnostic and treatment strategies to establish optimal protocols for detection and treatment of the infection, so as to optimally prevent the development of cardiac disease.

“That project is unique because we are studying privately owned hunting dogs in large kennel environments that have, unfortunately, become naturally infected with T. cruzi,” Hamer said. “Many of these owners have had other dogs die from the disease, so they want to help us solve the problem.”

Finally, a third arm of their research involves conducting a clinical trial to treat and monitor individual pet dogs brought to Texas A&M’s Small Animal Teaching Hospital and developing a staging system for Chagas disease in dogs.

Hamer’s team raised awareness of Chagas disease to label it as endemic in the U.S., demonstrating why it’s more important than ever to understand the disease, increase awareness within the general population, and develop new strategies for treatment.

To help achieve these goals, Hamer is also leading a community science project that invites the general public to send kissing bugs to Texas A&M for identification and disease testing. In the 10 years since the project began, they have received kissing bugs from 28 states across the southern U.S. 

“These projects will advance Chagas disease research to understand the process of natural infections, disease, and effect of treatments,” Hamer said. “We’re conducting field and laboratory research, treating dogs, measuring clinical outcomes, and studying ecological factors. It’s truly a ‘One Health’ approach.”

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For more information about the Texas A&M College of Veterinary Medicine & Biomedical Sciences, please visit our website at vetmed.tamu.edu or join us on Facebook, Instagram, and X.

Contact Information: Jennifer Gauntt, Director of VMBS Communications, Texas A&M College of Veterinary Medicine & Biomedical Sciences, jgauntt@cvm.tamu.edu, 979-862-4216

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