Giardia, a protozoan parasite which people typically pick up through drinking infected water or contaminated food, can cause diarrhoea and stomach pains. New research published today in GigaScience , with supporting data in GigaDB, provides insights into the mechanisms that cause the symptoms of giardiasis. Currently more than 200,000 people are ill with giardiasis and there are 500,000 new cases a year.