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.UK.
Transmission
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.
Epidemiology
The Giardia data for 2007 to 2016 includes annual laboratory reports of Giardia in England and Wales, plus regional, age/sex and seasonal breakdowns of data for 2016.
Giardia data 2007 to 2016 (PDF, 353 KB, 9 pages)
Travel-associated infections
Travel-associated Giardia infection: 2014 (PDF, 165 KB, 9 pages)