Tucked off the Miracle Mile exit of Interstate 10, a lab most pet owners have never heard of has been testing for rabies, avian flu and a growing list of zoonotic diseases since 1957, offering walk-in appointments and results for as little as $51.

The Arizona Veterinary Diagnostic Laboratory is a state-operated laboratory at the University of Arizona College of Veterinary Medicine. It tests samples from pets, livestock and wildlife to diagnose diseases, investigate outbreaks and protect public health, sending samples to the U.S. Department of Agriculture.

It also helps train student interns from the University of Arizona.

The lab tests for a range of animal diseases, from avian influenza to zoonotic diseases like rabies, and also screens for Heterobilharzia americana, or HA, a parasite carried by snails in the Colorado River that causes infections in dogs.

The lab prides itself on serving as Tucson's first line of defense as pandemics and changing climates make zoonotic diseases more likely to spread. It accepts specimen shipments from across Southeastern Arizona, the greater Phoenix area and even other states.

The lab accepts walk-ins and same-day appointments, following standard identification procedures based on morphological diagnosis. Samples can take many forms, from swabs and feces to fetuses and full animal bodies.

The lab's website offers fillable submission forms for convenience, including a dedicated page for valley fever. A generic canine test costs as little as $51, though prices vary by scan, and results can be sent directly to a pet's veterinarian.

"Our mission is to provide diagnostic service to producers and animal owners in Arizona to support the animal industry," said lab director Dr. Yan Zhang. "Our second mission is to provide surveillance testing for animals and foreign animal diseases as well."

Zhang specializes in biology and molecular diagnostics and has published more than 40 scientific papers.

The lab covers a broad set of disciplines, including pathology, mycology, histology and serology, but specializes in microbiology, cytology, histopathology, molecular diagnostics and necropsy.

It helps keep small businesses running by improving food safety and working closely with livestock and wildlife. Samples can come from virtually anywhere, including, perhaps surprisingly, local zoos.

"We actually do testing for elephants, as well," Zhang said.

Many pet owners come to the lab to diagnose infections, where staff run bacterial cultures and offer treatment guidance, though Zhang stressed the importance of keeping animals up to date on general vaccinations, especially rabies.

Zhang, who came to Arizona four years ago from Ohio and, before that, Washington, said most of the animals the lab tests are companion animals, a reflection of its close ties to the University of Arizona. The lab is federally funded by the USDA and FDA and assists the CDC.

The lab currently hosts five student interns from the UA as part of a work-study program. Students help staff the front office and are able to gain experience in their field by assisting pathologists or technicians.

The lab is accredited by the American Association of Veterinary Laboratory Diagnostics and is a member of the USDA's National Animal Health Laboratory Network and the FDA's Veterinary Laboratory Investigation and Response Network.

For Tucson pet owners like Celina Santa Cruz, that credibility translates into everyday peace of mind.

Santa Cruz, owner of Tucson dog parlor and boutique Bark 'N Berry, learned about the lab while working at Banfield Pet Hospital, where she now has a wellness plan for her three dogs, Bella, Pablo and Xena.

After noticing one of her dogs limping, she had her veterinarian draw blood and took the sample on ice to the diagnostic lab to be tested for valley fever, a fungal infection specific to the Southwest that dogs contract by digging in the dirt and inhaling spores.

"They're fast, they're efficient, they're professional," Santa Cruz said.

Testing for valley fever can cost upward of $175 at a vet's office, and for dogs that test positive, most vets recommend retesting every 180 days, since the infection never fully goes away.

"Because valley fever is pretty much lifelong, (many) owners won't get their dogs properly treated because they can't afford a $200 dollar test," Santa Cruz said. "It's very unfortunate because if valley fever goes untreated, it can kill."

At just $51 for a test, the UA lab's pricing offers a different path.

"It surprised me that it's not known how easy it was," Santa Cruz said. "You simply fill out a form and write what test you want from hundreds of different types."

For Santa Cruz, who posted about her experience with the UA lab on Instagram, that accessibility has become part of how she cares for her own dogs, and something she now recommends to other pet owners navigating the cost of veterinary care.

Lily Cottam is a journalism major at the University of Arizona and intern at Tucson Spotlight.

Tucson Spotlight is a community-based newsroom that provides paid opportunities for students and rising journalists in Southern Arizona. Please consider supporting our work with a tax-deductible donation.