Humans can contract certain types of worms from cats. While not common, cat owners should understand the potential for transmission and how to minimize risks. This article covers the types of cat worms that can infect humans, how transmission occurs, potential symptoms, and prevention strategies.
Types of Cat Worms Transmissible to Humans
Several intestinal worms found in cats can infect humans. The most common are roundworms (Toxocara cati), hookworms (Ancylostoma braziliense and Uncinaria stenocephala), and tapeworms (Dipylidium caninum).
Toxocara cati roundworms live in a cat’s intestines and shed microscopic eggs in feces. If ingested, larvae can migrate through the body, potentially causing visceral larva migrans (affecting organs) or ocular larva migrans (affecting eyes). Hookworms latch onto the intestinal lining. Their larvae can penetrate human skin, causing cutaneous larva migrans. Tapeworms, resembling small grains of rice, are often found in a cat’s feces or around their rear. Humans typically contract Dipylidium caninum by ingesting an infected flea, which is an intermediate host.
How Humans Contract Cat Worms
Humans primarily contract worms from cats through accidental ingestion of microscopic worm eggs or larvae. This often occurs via the fecal-oral route, where contact with contaminated cat feces, soil, or litter boxes transfers eggs to the mouth. Children playing in contaminated sandboxes or dirt are at higher risk.
Direct skin contact with contaminated environments can also lead to infection, particularly with hookworms. Hookworm larvae in soil can penetrate bare skin, causing localized infections. For tapeworms like Dipylidium caninum, humans usually become infected by accidentally ingesting an infected flea. This is more common in young children who might swallow a flea during play or close contact with a flea-infested cat.
Symptoms of Infection in Humans
Symptoms of worm infections in humans vary widely, often being mild or asymptomatic. When symptoms occur, they depend on the worm type and its migration location in the body.
Roundworm infections (toxocariasis) can cause fever, cough, wheezing, and an enlarged liver if larvae migrate to organs (visceral larva migrans); if larvae reach the eye (ocular larva migrans), symptoms may include eye inflammation, redness, vision loss, or seeing spots/flashes of light, typically affecting one eye. Hookworm infection (cutaneous larva migrans) typically presents as an intensely itchy, red, raised rash on the skin where larvae have burrowed. Less commonly, some hookworm species can cause abdominal pain, diarrhea, or anemia if they establish an intestinal infection. Tapeworm infections from Dipylidium caninum are often asymptomatic, but some individuals may notice worm segments resembling small rice grains in their stool or around the anal area. Other potential symptoms include mild abdominal pain, diarrhea, or anal itching.
Prevention Strategies
Preventing the transmission of cat worms to humans involves several practical hygiene measures. Regular handwashing is among the most effective steps, particularly after handling cats, cleaning litter boxes, or engaging in outdoor activities involving soil contact.
Proper litter box maintenance is important; this includes daily scooping of feces and regular disinfection. Wearing gloves while cleaning the litter box further reduces accidental exposure to worm eggs.
Regular deworming of cats, as recommended by a veterinarian, significantly reduces worm eggs shed into the environment. The frequency may vary based on a cat’s lifestyle, with outdoor cats or those that hunt often requiring more frequent treatment. Controlling fleas on cats is also important, as fleas are intermediate hosts for tapeworms. Using veterinarian-approved flea treatments breaks the Dipylidium caninum transmission cycle. Preventing children from playing in areas potentially contaminated with cat feces, such as uncovered sandboxes, and teaching them not to eat dirt, helps minimize exposure to worm eggs.
Diagnosis and Treatment
If a human infection with cat worms is suspected, consulting a medical professional is the first step. Diagnosis typically involves various methods depending on the suspected worm type. For intestinal worms, a doctor may request a stool sample to examine for worm eggs or segments.
In cases of larval migration to organs or the eyes, blood tests might be performed to detect antibodies to the parasites. Skin biopsies can confirm cutaneous larva migrans if skin lesions are present.
Treatment usually involves prescription antiparasitic medications, such as albendazole or praziquantel, which are effective in eliminating the worms. The specific medication and dosage will be determined by the medical professional based on the type of worm identified. Prognosis for human worm infections from cats is generally good with appropriate medical intervention.