Giardiasis - Symptoms of giardiasis

The symptoms of giardiasis usually begin 4-10 days after a giardiasis infection has occurred, but they can appear up to three weeks later.

They can begin suddenly or they can develop slowly over a number of days.

Common symptoms include:

watery diarrhoea, which can be foul-smelling
abdominal cramps
foul-smelling flatulence and belching
nausea (feeling sick)
bloating
indigestion
fatigue (extreme tiredness)
dehydration
loss of appetite
weight loss, due to malnutrition

You may also experience vomiting and a mild fever of 37-38ºC (98.6-100.4ºF), although these symptoms are less common.

If left untreated, the symptoms can persist for around one or two months before gradually improving.

A small number of people develop long-term (chronic) giardiasis, which causes persistent or repeated bouts of diarrhoea that can last for up to two years. In children, long-term giardiasis can result in a failure to grow at the expected rate. The medical term for this is failure to thrive.

However, long-term giardiasis is rare among people who have been treated for the condition.

When to seek medical advice

Visit your GP if you have symptoms of diarrhoea, cramps, bloating and nausea that last for more than a week.

If your baby or child has diarrhoea that has lasted for more than two or three days, or they have had six or more episodes of diarrhoea in the last 24 hours, you should take them to see your GP.