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. Intestinal blood loss secondary is the major clinical manifestation of hookworm infection. In fact, hookworm disease historically refers to the childhood syndrome of iron deficiency anemia, protein malnutrition, growth and mental retardation with lethargy resulting from chronic intestinal blood loss secondary to hookworm infection in the face of an iron deficient diet.
Zoonotic hookworm infections usually result in a skin condition called cutaneous larva migrans, or CLM. When people walk or sit on beach sand or soil where infected dogs or cats have defecated, the dog or cat hookworm larva can penetrate the skin of the foot or body and migrate in the top layers of the skin. This migration causes severe itchiness and raised red lines can form as part of the reaction to the larva in the skin. The larva will die in the skin after several weeks without developing any further, and the itchiness and red lines will go away. Scratching at the lines can cause a bacterial infection.
Regular dosage of Anti parasitic drugs is the best treatment for this disease. 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. Adults carry larger worm burdens than children do and are generally more subject to disease, the relationship is nonlinear and depends on diet and activity thresholds. The increasing prevalence of hookworm disease and higher worm burden among adults in many infected communities, especially in Japan, suggests that hookworm is immunosuppressive. Studies from China and Brazil indicate a consistently increasing prevalence, from 15% at age 10 years to 60% at age 70 years and older. Egg counts in stool also increase in a similar pattern.