You can get worms from a dog in three main ways: swallowing microscopic parasite eggs (usually from contaminated soil or unwashed hands), having hookworm larvae burrow through your skin, or accidentally ingesting an infected flea. Each type of worm has its own transmission route, and understanding them makes prevention straightforward.
Roundworms: The Most Common Route
Roundworms are the parasite you’re most likely to pick up from a dog. Studies of canine populations have found roundworm infection rates as high as 46%, making it the most prevalent intestinal parasite in dogs. An infected dog sheds millions of microscopic eggs in its feces. Those eggs don’t become infectious immediately, but once they mature in soil over a few weeks, they can survive and remain infectious for years.
You get infected by swallowing these eggs. That happens more easily than you’d think. Gardening in contaminated soil, then touching your mouth. A child playing in a sandbox or park where a dog once defecated. Eating unwashed vegetables grown in contaminated ground. The eggs are invisible to the naked eye, so there’s no way to spot them on your hands or food. Roundworm eggs are commonly found in soil samples collected from playgrounds and public parks.
Once swallowed, the eggs hatch inside your intestine. Unlike in dogs, the larvae don’t settle down and grow into adult worms. Instead, they migrate through your body, traveling through the bloodstream to the liver, lungs, heart, eyes, and sometimes the brain. This condition is called visceral larva migrans. It can cause fever, fatigue, coughing, and abdominal pain. When larvae reach the eyes, they can cause vision problems or permanent damage, a form known as ocular larva migrans. Many mild infections produce no obvious symptoms at all, which means people can carry the larvae without realizing it.
Hookworms: Infection Through Bare Skin
Hookworms take a completely different path into your body. You don’t need to swallow anything. The larvae hatch from eggs deposited in soil through dog feces, and when your bare skin touches contaminated ground, they burrow in. They do this by secreting an enzyme that breaks down the outer layer of your skin.
This typically happens when you walk barefoot on contaminated beaches, lawns, or soil, or sit or lie directly on the ground. The larvae create visible, winding red tracks just beneath the skin surface as they migrate, a condition called cutaneous larva migrans. It’s intensely itchy and usually appears on the feet, legs, or buttocks. Hookworm larvae thrive in warm, moist environments, so this type of infection is most common in tropical and subtropical climates, including the southeastern United States, Latin America, the Caribbean, and Southeast Asia.
In most cases, the larvae can’t penetrate deep enough to reach your intestines the way they would in a dog. They wander under the skin for weeks or months before dying off, but the itching and skin irritation can be significant during that time.
Tapeworms: The Flea Connection
Dog tapeworms reach humans through an unexpected middleman: fleas. A flea larva eats tapeworm eggs from the environment, and the tapeworm develops inside the flea as it matures. You get infected by accidentally swallowing one of these infected fleas. That sounds unlikely, but it happens, especially to young children who have close face-to-face contact with flea-infested pets. A child petting a dog, then putting their fingers in their mouth, could ingest a flea without noticing.
The CDC notes that children are the most frequently infected group for exactly this reason. Tapeworm infections from dogs are generally mild, often causing no symptoms beyond occasionally noticing small, rice-like segments in stool. But they’re easily preventable by keeping your dog on flea prevention.
Hydatid Disease: Rare but Serious
One lesser-known parasite worth mentioning is the type that causes hydatid disease. Dogs pick it up by eating raw organs from infected livestock, and they shed microscopic eggs in their feces. Humans swallow the eggs through the same contaminated-soil-to-mouth pathway as roundworms. Inside the body, the parasite forms slow-growing cysts, most often in the liver and lungs, but occasionally in the bones, kidneys, or central nervous system. These cysts can take years to grow large enough to cause symptoms.
This infection is rare in the United States but more common in rural livestock-raising regions worldwide. The World Health Organization identifies the dog-sheep-dog cycle as the primary transmission route, with humans acting as accidental hosts who pick up the infection the same way sheep do but play no role in spreading it further.
Why Children Face Higher Risk
Kids are disproportionately affected by every type of dog-related worm infection. They play on the ground, put their hands and objects in their mouths more frequently, and have closer physical contact with pets. Behaviors like eating dirt (pica) dramatically increase exposure to roundworm eggs in soil. Their immune systems are also still developing, which can make infections more consequential.
How to Reduce Your Risk
The single most effective thing you can do is keep your dog on a regular deworming schedule. The American Animal Hospital Association recommends starting puppies on deworming as early as two weeks of age, repeating every two weeks until monthly prevention begins, then continuing monthly treatment year-round for the dog’s entire life. This breaks the cycle by preventing your dog from shedding eggs into the environment in the first place. Flea prevention is equally important for blocking tapeworm transmission.
Beyond treating your dog, basic hygiene matters more than you might expect. Washing your hands with soap and water after handling your dog, cleaning up after yard work, or playing in soil is highly effective at removing parasite eggs. One study quantifying parasite egg removal from hands found that detergent-based washing removed over 95% of eggs, while even plain water rinsing removed about 83%. The physical action of scrubbing with soap dislodges eggs that cling to skin.
Other practical steps that lower your risk:
- Pick up dog feces promptly. Removing waste before eggs have time to mature in soil (usually a few weeks) prevents the ground from becoming a long-term source of infection.
- Wear shoes outdoors in areas where dogs frequent, especially in warm climates, to block hookworm larvae from reaching your skin.
- Wash produce thoroughly if you grow vegetables in soil that dogs could access.
- Cover sandboxes when not in use to keep dogs and cats from using them as litter boxes.
Stray and untreated dogs pose the greatest risk. Research shows that stray dogs carry intestinal parasites at rates exceeding 80%, compared to about 48% in pet dogs receiving some level of care. A dog that looks healthy can still be shedding parasite eggs, since many worm infections cause no visible symptoms in adult dogs.