Zoonotic hookworms are hookworms that live in animals but can be transmitted to humans. Dogs and cats can become infected with several hookworm species, including Ancylostoma brazilense, A. caninum, A. ceylanicum, and Uncinaria stenocephala. The eggs of these parasites are shed in the feces of infected animals and can end up in the environment, contaminating the ground where the animal defecated. People become infected when the zoonotic hookworm larvae penetrate unprotected skin, especially when walking barefoot or sitting on contaminated soil or sand. This can result in a disease called cutaneous larva migrans (CLM), when the larvae migrate through the skin and cause inflammation.
People are infected when animal hookworm larvae penetrate the skin, causing a local reaction that is red and itchy. Raised, red tracks appear in the skin where the larvae have been and these tracks may move in the skin day to day, following the larvae’s movements. The symptoms of itching and pain can last several weeks before the larvae die and the reaction to the larvae resolves. In rare cases, certain types of animal hookworm may infect the intestine and cause abdominal pain, discomfort, and diarrhea.
The animal hookworm larvae that cause cutaneous larva migrans (CLM) usually do not survive more than 5 – 6 weeks in the human host. In most patients with CLM, the signs and symptoms resolve without medical treatment. However, treatment may help control symptoms and help prevent secondary bacterial infections. Antiparasitic treatments may be prescribed by your health care provider.
Wearing shoes and taking other protective measures to avoid skin contact with sand or soil will prevent infection with zoonotic hookworms. Travelers to tropical and subtropical climates, especially where beach exposures are likely, should be advised to wear shoes and use protective mats or other coverings to prevent direct skin contact with sand or soil.
Routine veterinary care of dogs and cats, including regular deworming, will reduce environmental contamination with zoonotic hookworm eggs and larvae. Prompt disposal of animal feces prevents eggs from hatching and contaminating soil -- which makes it important for control of this parasitic infection.