Hookworm

Hookworms are tiny worms, about half an inch long, that live in a cat's small intestine. They fasten to the gut lining with hook-like mouthparts and feed on blood. The species that affects cats is mainly Ancylostoma tubaeforme. Cats pick them up by swallowing larvae from soil or contaminated surfaces, by larvae burrowing through the skin, or by eating infected prey such as rodents.

Mild infections can go unnoticed. In kittens and underweight or ill cats, a heavy burden can cause pale gums, weakness, poor growth, weight loss and dark, tarry diarrhea from blood loss, leading to anemia. Hookworm eggs are microscopic, so vets diagnose it from a stool sample under the microscope.

A vet prescribes a deworming medicine suited to the cat and often repeats it to catch worms that mature later. Do not buy a dewormer without asking, since the wrong product may not work against hookworm. Larvae can burrow into human skin, particularly from bare feet or hands in soil that cats have fouled, causing an itchy, winding rash called cutaneous larva migrans. Scoop litter promptly, wash hands, and see a doctor if a rash appears. Ask your vet how often to check stool samples.