Giardiasis is an infection in your small intestine. It’s caused by a microscopic parasite called Giardia lamblia. Giardiasis spreads through contact with infected people. Pet dogs and cats also frequently contract giardia. You can also get giardiasis by eating contaminated food or drinking contaminated water. Giardia can be found all over the world, according to the Centers for Disease Control (CDC). However, it’s more common in overcrowded developing countries that lack sanitary conditions and water quality control.
Giardia are found in animal and human feces. They also thrive in contaminated food, water, and soil. They can survive outside a host for long periods of time. Accidentally consuming these parasites can lead to an infection.
The most common way to get giardiasis is to drink water that contains giardia. Contaminated water can be in swimming pools, spas, and bodies of water, such as lakes. Sources of contamination include animal feces, diapers, and agricultural runoff.
Contracting giardiasis from food is less common because heat kills the parasites. Handling food with poor hygiene or eating produce rinsed in contaminated water can allow the parasite to spread.
Giardiasis also spreads through personal contact. Unprotected anal sex is one way that this infection passes from one person to another.
Changing a child’s diaper or picking up the parasite while working in a child care center are also common methods of infection. Children are at high risk for giardiasis because they’re likely to encounter feces when wearing diapers or potty training.
Some people can carry giardia parasites without experiencing any symptoms. Symptoms of giardiasis generally show up one or two weeks after exposure. Common symptoms include:
- diarrhea or greasy stools
- loss of appetite
- bloating and abdominal cramps
- weight loss
- excessive gas
- abdominal pain
You may have to submit one or more stool samples for testing. A technician will check your stool sample for giardia parasites. You might also submit more samples during treatment. Your doctor may also perform an enteroscopy. This procedure runs a flexible tube down your throat and into your small intestine to examine your digestive tract and take a tissue sample.
In most cases, giardiasis eventually clears up on its own. Your doctor might prescribe medication if your infection is severe or prolonged. Most physicians will recommend that you get treated with antiparasitic drugs, rather than leaving it to heal on its own. Certain antibiotics are commonly used to treat giardiasis:
- Metronidazole is an antibiotic that can cause nausea and leave a metallic taste in your mouth.
- Tinidazole often treats giardiasis in a single dose and is as effective as metronidazole.
- Nitazoxanide is a popular option for children because it’s available in liquid form.
- Paromomycin has a lower chance of causing birth defects than other antibiotics, although pregnant women should wait until after delivery before taking any medication for giardiasis.
Giardiasis can lead to complications such as weight loss and dehydration from diarrhea. The infection can also cause lactose intolerance in some people. Children under five years old who have giardiasis are at risk for malnutrition, which can interfere with their physical and mental development.
You can’t prevent giardiasis, but you can lower your risk of getting it by thoroughly washing your hands, especially if you work in places where germs spread easily, such as day care centers.
Ponds, streams, rivers, and other bodies of water are all potential sources of giardia. Don’t swallow water if you go swimming in one of these. Avoid drinking surface water unless it’s been boiled, treated with iodine, or filtered. Bring bottled water with you when you go hiking or camping.
When traveling in a region where giardiasis occurs, don’t drink tap water. Even brushing your teeth with tap water should be avoided. Keep in mind that tap water can also be present in ice and other beverages. Avoid eating uncooked local produce.
Be cautious about sexual practices that are associated with the spread of this infection, such as anal sex. Use a condom to reduce the chance of contracting giardiasis.
Giardiasis infections usually last about six to eight weeks, but problems such as lactose intolerance can persist after the infection clears up.