Roundworms in Dog Poop: A Florida Yard Risk Every Owner Should Know

Roundworm eggs shed in dog waste can survive in Florida soil for years — and they pose a real infection risk to children, barefoot adults, and even your other pets.

What Are Roundworms and Why Does Florida Make Them Worse?

Toxocara canis — the common dog roundworm — is one of the most widespread parasites in the United States, and Florida's warm, humid climate gives it an outsized advantage. Adult roundworms live in a dog's intestines and shed millions of microscopic eggs into every bowel movement. Those eggs don't die quickly. In cooler, drier climates they may survive a few months. In Florida's moist, shaded yard soil, roundworm eggs can remain infective for two to four years.

How Dogs Get Roundworms (and Spread Them)

Puppies are the biggest source of yard contamination. Many are born with roundworms passed directly through the placenta or mother's milk — before they ever eat a single bite of food. Adult dogs become infected by sniffing or eating contaminated soil, grass, or the feces of other animals. Once infected, an adult dog can shed roundworm eggs daily without showing any obvious symptoms at all, making it easy to miss.

• A single roundworm can produce up to 200,000 eggs per day
• Eggs are not visible to the naked eye
• Eggs hatch only after two to four weeks in the environment — not immediately when deposited
• Once embryonated (matured in soil), eggs become infectious and can survive for years

The Risk to Humans: Visceral and Ocular Larva Migrans

Roundworm eggs from dog poop cannot develop into adult worms inside a human body — but the larvae that hatch can migrate through tissue, and that migration causes real harm. The two main conditions are Visceral Larva Migrans (VLM), where larvae travel through the liver, lungs, or other organs, and Ocular Larva Migrans (OLM), where a larva reaches the eye and can cause permanent vision damage or blindness. Children are most at risk because they play on the ground, put hands in mouths, and may play in sandboxes or garden soil that cats or dogs have contaminated.

Florida-Specific Risk Factors

Several things about the Port St. Lucie area amplify roundworm risk compared to northern states.

• Year-round warmth — eggs don't get killed off by a hard freeze
• Sandy, well-draining soil that's easily tracked indoors on shoes and paws
• Outdoor living — Floridians spend more time barefoot outdoors than residents of most other states
• Stray cat and wildlife populations that also shed Toxocara eggs in shared outdoor spaces
• High puppy ownership — Port St. Lucie has a fast-growing population with many families getting new dogs

Symptoms to Watch For

Most roundworm infections in humans are mild or produce no symptoms at all — but serious cases do occur. In children, signs may include persistent cough, fever, fatigue, abdominal pain, or unexplained eye problems. Because these symptoms overlap with many common illnesses, roundworm exposure is often not considered until other causes are ruled out. If your child plays regularly in a yard where dog waste isn't promptly removed, mention it to your pediatrician.

What Actually Kills Roundworm Eggs in Your Yard?

This is where many homeowners are surprised. Roundworm eggs are extremely resistant to standard cleaning. Bleach, most disinfectants, and even Florida's UV sunlight won't reliably kill embryonated eggs in soil. The only truly effective control measure is removing the poop — quickly and consistently — before eggs have time to embryonate in the soil (which takes 2–4 weeks). Once eggs are in the soil, they're nearly impossible to eliminate short of replacing the topsoil entirely.

Protect Your Dogs Too

Roundworms are also harmful to dogs themselves. Heavy infections in puppies cause a pot-bellied appearance, poor growth, vomiting, and diarrhea. In adult dogs symptoms are milder but the ongoing egg-shedding means continual yard contamination. Regular veterinary deworming is essential — especially for puppies — and monthly heartworm preventives often include roundworm coverage as well. Ask your vet which product is right for your dog.