Infested by Toxoplasma gondii
Michael Mosley from 'Infested' describes the infection of household cats with Toxoplasma gondii. This infection starts with growing cysts in an infected cat. These are excreted and can survive for a long period outside a host. They are eventually accidentally eaten by mice. To complete its life-cycle the parasite must return to a cat. Michael Mosley interviews a scientist called Joanne Webster who describes her experiment which showed that infected rats have drastically altered behaviours. This includes being attracted to cat urine (not repelled by it). This makes it easier for the rat to be caught and the parasite to complete its life-cycle. Amazingly about a quarter of the UK population is infected with this disease. Evidence suggests that infection may also affect our behaviour.