oes your skin start crawling when someone talks about parasites? Do you hesitate when a dog comes in with ticks or a cat has fleas? Most of us would rather not deal with them; however, in the pet care industry, exposure is part of the job. Avoiding the subject doesn’t reduce the risk—education, awareness and consistent prevention do.

Parasites come from two primary sources: the environment and direct or indirect contact with an infected animal. In our field, we commonly divide them into internal and external parasites. Internal parasites include roundworms, hookworms, whipworms, tapeworms, Giardia and heartworms. External parasites include fleas, ticks, lice and mites such as demodectic, sarcoptic, cheyletiella and otodectes (ear mites). As groomers and pet professionals, we are routinely exposed to both types.

Most internal parasites, with the exception of heartworms, are transmitted through the fecal-oral route. That means parasite eggs are shed in feces and ingested by another host through contaminated surfaces, soil, water or grooming behavior.

Some people believe they are protected because they wear gloves when cleaning feces. However, exposure doesn’t stop there. Bathing a pet’s rear, trimming sanitary areas, expressing anal glands or simply handling a coat that has been licked can all present risks. Cross-contamination can occur through towels, grooming tools, tables, kennels, clothing and even our phones.

Roundworms are one of the most concerning internal parasites. In dogs, they migrate through the body before settling in the intestines. In humans, however, we are abnormal hosts. If eggs are accidentally ingested—often by young children—the larvae can migrate through tissues rather than remain in the digestive tract. In rare but serious cases, they may affect the eyes or brain, potentially leading to blindness or neurological complications. While these cases are not common, they highlight the importance of strict hygiene. Thorough handwashing, avoiding face-touching and changing clothes before going home are simple but powerful precautions.

Hookworms present another risk because some species can penetrate human skin, especially through bare feet in contaminated environments. Giardia, a microscopic parasite, spreads easily in moist environments and group settings like boarding and daycare facilities, causing gastrointestinal illness. Even when parasites are not visible, environmental contamination can persist.

External parasites are often easier to spot but no less important. Fleas and ticks are the most common. With fleas, what you see on the pet represents only about 5% of the infestation. The other 95%—eggs, larvae and pupae—are in the environment. Flea eggs fall off into carpets, cracks, bedding and grooming areas. Pupae can remain dormant and hatch in response to vibration, heat or carbon dioxide—such as when someone walks across a room. This is why environmental control (at home and in the salon) is just as important as treating the pet.

Modern monthly flea preventatives are effective, but most work by killing fleas after they bite. That means fleas can still jump onto a treated pet—and sometimes onto us. Many pets have an allergic reaction to the bite/saliva and can still react even though they are on a preventative. Regular vacuuming, laundering bedding, disinfecting grooming areas and educating clients about complete flea control are critical.

Ticks are commonly found in wooded areas, tall grass and even suburban yards. They latch onto animals as they brush past vegetation. Many tick preventatives also kill ticks after attachment rather than prevent bites. Ticks can transmit serious diseases to pets and humans, making routine checks important. A single female tick can lay thousands of eggs, and some species can survive months without feeding. Therefore, vigilance matters.

Lice are less common but do appear in certain regions. They are similar in size to fleas but flatter and unable to jump. Fortunately, lice are host-specific—dog lice stay on dogs, and human head lice stay on humans. They may crawl onto us temporarily but cannot reproduce. Simple tools, like placing debris on white paper and using a phone camera to zoom in, can help distinguish parasites from dander or skin flakes.