The symptoms and epidemiology of giardiasis.
Giardia is a parasite which can grow in the intestines of infected humans or animals and cause giardiasis. Diarrhoea is the most common symptom of giardiasis. Other symptoms include abdominal cramps, bloating and flatulence.
More information about giardiasis is available on NHS choices.
Giardiasis can be transmitted by direct contact with infected animals or humans, or by consumption of water, food or beverages contaminated by the faeces of infected animals or humans. People may also be infected by swimming in contaminated water (for example in lakes or rivers). Many cases are associated with foreign travel.
The incubation period - the delay between infection and the appearance of symptoms - is 5 to 25 days.
Giardia lamblia Laboratory reports: all identifications reported to the Health Protection Agency (now Public Health England) in England and Wales from 2000 to 2013.
Data source: 2000 to 2013 Labbase2