How your pug gets worms depends on the worm type, but generally speaking he gets them just as other dogs do, from various sources in his environment. Even if your dog never goes outside, he could get worms from something on your shoes or from a visiting mosquito.
Heartworm is transmitted by mosquitoes, so transmission to your dog is something that’s almost impossible for you to control. If an infected mosquito bites your dog, it injects heartworm larvae into him. These can eventually develop into a potentially deadly adult heartworm infestation in his heart and lungs. By giving your pup his heartworm medication on time every month, the larvae die before they can mature and your pug avoids the agony of this parasite. Mosquito repellant products designed for dogs can also help to minimize his risk, but only heartworm preventive will stop an infection. Don't give monthly heartworm treatment to a dog that has heartworm or is undergoing treatment for it.
Dogs get roundworms when they swallow infected feces. As gross as that sounds, it can come from something as simple as your dog picking up a ball at the park. When he ingests the yucky stuff, roundworm eggs end up in his intestines, where they will grow to maturity. While roundworms aren’t usually a serious problem for adult dogs, they can cause real trouble for puppies. Fortunately, it’s easy to treat your pug if he has roundworms. Keep him away from places where stray dogs and cats defecate to help minimize his chances of getting infected in the first place.
Hookworms are nasty little creatures that literally hook their mouths into your pug’s intestines and hang on. They may infect him if he swallows hookworm eggs from contaminated feces or soil. He can also become infected with hookworms by direct contact with larvae in the soil. They can make their way through his skin and into his body from there. According to the Baker Institute of Animal Health at Cornell University, pug puppies can get hookworms from their moms, either when they nurse or earlier, before the pups are born, but only if she is infected.
Tapeworms require fleas as an intermediate host, and your pug must actually swallow an infected flea to get the worms. This typically happens when he’s biting at an itchy spot. It helps to keep your buddy as flea-free as possible, but he can still pick up a flea or two anytime he goes outside, especially if he leaves your yard. If you spot little wiggling grains of rice on your pug’s rear, you’ll know for sure he has tapeworms. You’ll need to get wormer from the vet to get rid of them.