Hookworms, which can affect both cats and dogs, live off the animal’s blood. Though they are not very big (around 70mm and 10mm respectively) they can be very damaging, particularly in young animals, where they can cause diarrhoea, anaemia, weight loss and lethargy.
Hookworms, incidentally, are a growing threat, largely because so many foxes are infected. Studies have shown infection levels of almost 70%, and with an ever-growing urban fox population, even city-dwelling cats and dogs are at risk.
