It is estimated that a quarter of cats in the UK are currently infected! Picked up from contaminated faeces, or even from the soil, roundworms can cause diarrhoea and poor growth, and also have human health risks.
Cat roundworms are brownish-yellow, round-bodied worms, and can get up to 10cm long! These worms spend most of their life within the gut of cats, feeding on intestinal contents.
Roundworms reproduce by laying eggs within the intestine – these eggs are tiny, and aren’t visible to the naked eye. These eggs are passed out with faeces, mature for up to a month, and then become infectious. Cats then ingest these infectious eggs, which hatch into larvae. Importantly, larval roundworms can travel out of the gut to a wider range of tissues, including multiple organs such as the liver and lungs, skeletal muscle and the gut wall, where they may form cysts. This allows cats to maintain a level of infection, and females can pass on infections to their kittens via the placenta or milk.
Sadly, toxocara can also infect humans, and while usually harmless in adults, can cause serious damage to children’s eyesight.