Vets Say This Hidden Outdoor Risk Can Make Dogs Seriously Sick

Our pets are family, and much like our own health, we try to do everything we can to keep them safe. That's why a Chicago man is sharing the heartbreaking story of his beloved dog, Casper, who contracted blastomycosis-a serious and potentially fatal infection.

In a recent TikTok, NBC Chicago shared Casper's story, along with insight from a local veterinarian to help other pet parents recognize the risks and warning signs, and hopefully avoid such a tragedy.

@nbcchicago

Pet owners, listen up! Vets are warning of a potentially life-threatening infection that can be contracted just by taking your dog on a walk outside. NBC Chicago's Regina Waldroup shares the story of Casper, a dog who lost his life to blastomycosis. #blastomycosis#ticks#tick#fungalinfection#dogs#dogowner

original sound - NBC Chicago - NBC Chicago

What Is Blastomycosis?

Blastomycosis is a fungus that lives in soil. The risk of infection begins when dogs inhale spores from contaminated soil, allowing the virus to enter the lungs. Dogs who spend a lot of time digging in moist soil or dirt are most susceptible, as the tiny organisms can easily enter a dog's respiratory tract this way. Once inhaled, the fungus can grow in the lungs and spread throughout the body, leading to a potentially life-threatening illness.

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Symptoms of Blastomycosis

In the video, Dr. Abby Ostronic from the Veterinary Specialty Center in Chicago explains that while some animals (and humans) may be exposed, not all will become infected. Unfortunately, there's no vaccine or proven preventative measures, so recognizing symptoms early is key.

According to PetMD, symptoms of blastomycosis in dogs can include:

• Persistent coughing, especially dry or harsh-sounding
• Lethargy
• Loss of appetite
• Fever
• Limping or lameness
• Changes to the eyes, such as inflammation, vision loss, or swelling
• Skin lesions or wounds with discharge

"It happened so quickly. It's a steep decline. It's really awful, and I never could have imagined something like this happening to our loved one," Casper's grieving dog dad shared.

Pet parents who are concerned should contact their veterinarian right away. Blastomycosis is often diagnosed through a urine test, and early detection can make a critical difference. For Casper's family, a hidden danger turned into a devastating loss-and a warning that other pet parents won't want to ignore.

Related: If Your Dog Licks Their Paws, a Vet Wants You to Know This

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This story was originally published May 3, 2026 at 12:26 PM.