Giardiasis is a diarrheal disease caused by the microscopic parasite Giardia duodenalis or simply “Giardia”. Once a person or animal is infected with Giardia, the parasite lives in the intestines and is passed in the feces (poop). Once outside the body, Giardia can sometimes live for weeks or months. Giardia can be found in every region of the United States and worldwide.
Giardia infections are spreading throughout the world, especially in areas with poor sanitation. Waterborne transmission is the major source of infection (1), but transmission can also occur by eating contaminated food or by direct person-to-person contact.
Giardia cysts remain viable in surface water and are resistant to normal levels of chlorination in drinking water. Thus, mountain streams, as well as chlorinated but poorly filtered municipal water supply systems, are implicated in waterborne epidemics. Infections are also associated with child care, particularly involving diaper-age children. close contact with family or household members who have giardiasis; discharge of water or ice from untreated or improperly treated water from lakes, streams, or wells; Backpackers, hikers, and Campers who drink contaminated water or fail to practice good hand hygiene. drinking water while swimming or playing in lakes, ponds, rivers, or streams; or exposure to feces through sexual contact.
How common is giardiasis?
Giardia parasites live worldwide, in most countries and continents. This is a major problem in developing countries such as countries with poor sanitation.
In the United States, giardiasis is the most common parasitic infection affecting the intestines.
What are the causes of giardiasis?
G. lamblia is found in animal and human feces. These parasites also thrive in contaminated food, water, and soil and can survive for long periods outside the host. Accidental ingestion of these parasites can lead to infection.
The most common way to get giardiasis is by drinking water that contains G. lamblia. Contaminated water can be found in swimming pools, spas, and water bodies, such as lakes. Contamination sources include animal feces, diapers, and agricultural runoff.
Contraction of giardiasis from food is less common because heat kills the parasites. Poor hygiene when handling food or eating products washed in contaminated water can allow the parasite to spread.
Giardiasis is also spread by personal contact. For example, unprotected anal sex can transmit infections from one person to another.
Changing a baby’s diaper or picking up a parasite while working in a daycare center are also common ways to get infected. Babies are at higher risk of giardiasis because they are exposed to their feces while wearing diapers or potty training.
Prevention
You can’t prevent giardiasis, but you can reduce your risk of getting it by washing your hands thoroughly, especially if you work in places where germs spread easily, such as daycare centers.
Pools, streams, rivers, and other water bodies can all be sources of giardia. If you swim in one of these, do not swallow the water. Avoid drinking surface water unless it has been boiled, iodized, or filtered. When you go hiking or camping, bring bottled water with you.
When traveling to an area where giardiasis occurs, do not drink tap water. You should also avoid brushing with tap water. Keep in mind that tap water can also be in ice and other drinks. Avoid eating raw local produce.
Be careful about sexual practices associated with the spread of this infection, such as anal sex. Use condoms to reduce the chance of contracting giardiasis.
Complications
Giardiasis can cause complications such as weight loss and dehydration from diarrhea. Infections can also cause lactose intolerance in some people. Children under 5 years of age who have giardiasis are at risk of malnutrition, which can impair their physical and mental development.
Symptoms of Giardiasis
Some people with Giardia infections never develop signs or symptoms, but they still carry the parasite and can spread it to others through their stool. For those who do become ill, signs and symptoms usually appear one to three weeks after exposure and may include:
- Watery, sometimes foul-smelling diarrhea that may alternate with soft, greasy stools
- Fatigue
- Abdominal pain and bloating
- Gas
- Nausea
- Weight loss
Signs and symptoms of Giardia infection can last two to six weeks, but in some people, they last longer or come back.
When to see a doctor
Call your doctor if you have loose stools, abdominal pain and bloating, and nausea for more than a week, or if you become dehydrated. Be sure to tell your doctor if you’re at risk for giardia infection — that is, your child is in childcare, you’ve recently traveled to an area where the infection is common, or you’ve been to a lake. Swallowed water. or stream.
Diagnosis
The parasite may not be visible in every stool sample. For this reason, your provider may need more than one sample to confirm the diagnosis.
If you have severe symptoms, your provider may examine your bowel using a thin, flexible tube. This procedure is called an upper endoscopy. Parasites are often seen when small pieces of a biopsy obtained during endoscopy are laboratory stained. Your provider may also take a sample of your intestinal contents to look for parasites.
Treatment
Children and adults who have asymptomatic giardia infections usually do not need treatment unless they are likely to spread the parasites. Many people who develop anxiety get better on their own within a few weeks.
When signs and symptoms are severe or the infection persists, doctors usually treat giardia infections with medications such as:
- Metronidazole (Flagel). Metronidazole is the most commonly used antibiotic for Giardia infections. Side effects can include nausea and a metallic taste in the mouth.
- Tinidazole (Tindamax). Tinidazole works as well as metronidazole and has many of the same side effects, but can be given at the same dose.
- Nitazoxanide (Alenia). Because it comes in liquid form, nitazoxanide may be easier for children to swallow. Side effects may include nausea, gas, yellow eyes, and bright yellow urine.
There are no consistently prescribed drugs for giardia infection in pregnancy because of the potential for harmful effects of drugs on the fetus. If your symptoms are mild, your doctor may recommend delaying treatment beyond the first trimester or longer. If treatment is necessary, discuss the best treatment option with your doctor.