Hookworms

Hookworms are among the smaller intestinal parasites of cats, but they punch well above their size because of how they feed. Rather than simply absorbing nutrients from the gut contents, they bite into the intestinal wall and draw blood, moving from site to site and leaving small bleeding points behind. A modest number may cause few obvious problems in a healthy adult, but a heavy burden steadily drains blood and protein, which is why anaemia and dark, digested-blood stools are the hallmark signs.

The worms complete their life cycle when eggs pass out in the faeces and hatch into larvae in warm, damp soil. A cat can then be reinfected by swallowing those larvae while grooming, or the larvae can bore straight through the skin of the feet and travel to the intestine. Nursing kittens are especially vulnerable because some hookworm species pass to them through their mother's milk, and their small size means even a moderate infection can cause serious blood loss.

Diagnosis is usually made by finding the characteristic eggs on a faecal examination, and treatment with the right dewormer is very effective. The bigger picture, though, is prevention and hygiene: because the larvae live in the environment and can persist for a long time, breaking the cycle means regular worming, prompt removal of faeces, and clean, dry living conditions. Some feline hookworm larvae can also penetrate human skin and cause an itchy rash, so good litter-tray hygiene protects the whole household.