Giardia or giardiasis is caused by a group tiny parasites known as Giardia intestinalis or Giardia lamblia or Giardia duodenalis. Giardia is an infection of the gut. The infection can cause diarrhoea, nausea, and abdominal pain. It is common. It can cause problems even in healthy people.
Giardia does not always cause symptoms. Some people carry the parasite that causes Giardia without ever knowing it. When this happens a person is referred to as being asymptomatic. When symptoms do happen, they can include:
Diarrhoea that comes on suddenly and that can start off watery
Feeling generally unwell
Offensive smelling or fatty bowel movements
Abdominal cramps, wind, and bloating
Nausea or vomiting
These symptoms aren’t specific to giardia though and may occur with other gut infections and in patients with immunodeficiency when they have non-infectious gut involvement.
From person to person – The parasite that causes Giardia lives in bowel movements of people who are infected. You can catch Giardia from another person if they do not wash their hands after a bowel movement and then touch you. The same is true for someone who changes a nappy on a child or an adult and then does not wash his or her hands. It is also possible to catch Giardia through any kind of anal sex (even if you use a condom).
Through food – The parasite that causes Giardia can live on food. Cooking kills it. But if food is not cooked or not handled the right way, it can carry Giardia. Please read our food safety advice.
Through water – The parasite that causes Giardia can live in water sources that people drink from. For instance, Giardia can live in streams or drinking wells. People who camp and hike are at risk of getting Giardia if they drink water from lakes or streams without treating the water properly first.
Yes. If your doctor or nurse thinks you might have Giardia, he or she will ask you for a bowel movement sample. At the lab, the sample can be checked for Giardia and other infections that can cause the same symptoms as Giardia. A fresh stool sample is required though and it is often missed on a poorly kept specimen.
Treatment for Giardia involves taking an antibiotic medicine for several days. In most cases, that gets rid of the infection and its symptoms. In some cases, though, Giardia does not get better with the first round of antibiotics. If that happens, doctors usually suggest changing the type or dose of antibiotic, or increasing the length of time a person is treated. This is particularly true for PID patients. Rehydration with oral rehydration salts following age specific recommendations is very important for individuals with significant symptoms.
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