Giardiasis (Giardia lamblia infection)

What is it about ?

Giardia lamblia is a single-celled parasite that lives inside the small intestine. Giardia lamblia infection (giardiasis) is spread by contact with contaminated stools.

Transmission occurs through consumption of food or drink contaminated with stool or direct person-to-person or animal-to-person transfer. The parasite is thus found, among others, in dogs, cats, pigs and sheep. In Belgium, however, the infection is more often transmitted from person to person. The parasite can survive for up to 2 to 3 months in cold water.

What is its frequency?

This parasite is present all over the world, but it is much more widespread in developing countries. In western countries, 0.5 to 7% of the population is infected with Giardia lamblia; in developing countries, infection affects up to one in two people.

Most infections occur in late summer or fall.

Giardiasis can occur at any age. In young children, the risk of transmission is high.

Lack of personal hygiene increases the risk of infection.

How to recognize it?

The symptoms can be many and varied. Some people are asymptomatic, others have serious gastrointestinal problems and lose weight.

• The most common complaints are cramps and diarrhea.
• The first symptoms usually appear 1 to 3 weeks after infection: cramps, nausea and diarrhea (more firm to watery, smelly, sometimes pale in color). There is sometimes a feeling of false needs.
• If the infection is not diagnosed and treated, it can become chronic:
• Symptoms are the same as in the acute form, but usually milder.
• Periods of intestinal disturbances alternate with asymptomatic periods.
• There is also a higher risk of complications such as lactose intolerance, inflammation of the pancreas, or inflammation of the bile ducts.
• In rare cases, giardiasis can cause growth disturbances in children, skin conditions, eye inflammation or joint inflammation.

How is the diagnosis made?

Your doctor will mainly think about giardiasis if you have diarrhea or abdominal cramps that last for more than a week and / or if you have returned from an area where these infections are more common.

The Giardia lamblia parasite can be detected by a number of tests:

• A stool analysis is usually done first. It can also detect other parasites responsible for similar symptoms.
• In recent infections and in some chronic infections, the parasite does not always pass immediately in the stool. That is why it is advisable to repeat the stool test in case of negative result and persistent symptoms.
• Less common, endoscopy of the small intestine can also be used to detect the parasite Giardia lamblia.

What can you do ?

If you are infected with the parasite Giardia lamblia, drink enough to prevent dehydration. When you have diarrhea, you not only lose fluid, but also salt. You can supplement these losses by adding a oral rehydration solution or ORS in your water. ORS are available in pharmacies without a prescription.

Prevention

• Good hygiene, including washing hands before eating and after using the toilet, is important to limit the risk of contamination.
• You can also filter the water or boil it for a few minutes to avoid contamination.
• Hygiene is particularly important in groups of children (for example in preschools and nurseries): thorough cleaning of toilets, washing of hands before eating and disinfection of games and toys can be useful in the fight against transmission of Giardia lamblia.

What can your doctor do?

• The doctor will prescribe a pest control (metronidazole). This medicine decreases the symptoms and also stops the spread of the disease.
• After 1 and 2 months, a stool control will be ideally carried out to verify the effectiveness of the treatment.
• It is advisable to pass these checks even if you no longer have symptoms.
• If the parasite is still present, the doctor will prescribe a longer course of treatment. In this situation, it is also advisable to re-screen the close entourage.
• Symptoms may persist for a few weeks or even months, even after successful treatment. The infection may indeed have damaged the inside of the small intestine.

Want to know more?

• Healthy travel – IMT – Institute of Tropical Medicine
• Hand hygiene – SPF Public health, food chain safety and the environment
• Metronidazole – CBIP – Belgian Center for Pharmacotherapeutic Information

Source

Foreign clinical practice guide ‘Giardiasis’ (2000), updated on 11.17.2016 and adapted to the Belgian context on 06.28.2018 – ebpracticenet