GIARDIASIS (GIARDIA INFECTION)

What is giardiasis?

Giardiasis is a diarrhoeal illness caused by a one-celled, microscopic parasite, Giardia intestinalis (also known as Giardia lamblia). Once an animal or person has been infected with Giardia intestinalis, the parasite lives in the intestine and is passed in the stool. Because the parasite is protected by an outer shell, it can survive outside the body and in the environment for long periods of time.

During the past 2 decades, Giardiainfection has become recognised as one of the most common causes of waterborne disease (found in both drinking and recreational water) in humans in the United States. Giardia are found worldwide and within every region of the United States.

The Giardia parasite lives in the intestine of infected humans or animals. Millions of germs can be released in a bowel movement from an infected human or animal. Giardia is found in soil, food, water, or surfaces that have been contaminated with the feces from infected humans or animals. You can become infected after accidentally swallowing the parasite; you cannot become infected through contact with blood. Giardia can be spread by:

• Accidentally putting something into your mouth or swallowing something that has come into contact with feces of a person or animal infected with Giardia.
• Swallowing recreational water contaminated with Giardia. Recreational water includes water in swimming pools, hot tubs, jacuzzis, fountains, lakes, rivers, springs, ponds, or streams that can be contaminated with sewage or feces from humans or animals.
• Eating uncooked food contaminated with Giardia.
• Accidentally swallowing Giardia picked up from surfaces (such as bathroom fixtures, changing tables, diaper pails, or toys) contaminated with feces from an infected person.

Giardia infection can cause a variety of intestinal symptoms, which include

• Diarrhoea
• Gas or flatulence
• Greasy stools that tend to float
• Stomach cramps
• Upset stomach or nausea.

These symptoms may lead to weight loss and dehydration. Some people with giardiasis have no symptoms at all.

Symptoms of giardiasis normally begin 1 to 2 weeks (average 7 days) after becoming infected.

In otherwise healthy persons, symptoms of giardiasis may last 2 to 6 weeks. Occasionally, symptoms last longer.

Anyone can get giardiasis. Persons more likely to become infected include

• Children who attend day care centers, including diaper-aged children
• Child care workers
• Parents of infected children
• International travelers
• People who swallow water from contaminated sources
• Backpackers, hikers, and campers who drink unfiltered, untreated water
• Swimmers who swallow water while swimming in lakes, rivers, ponds, and streams
• People who drink from shallow wells

Contaminated water includes water that has not been boiled, filtered, or disinfected with chemicals. Several community-wide outbreaks of giardiasis have been linked to drinking municipal water or recreational water contaminated with Giardia .

See your health care provider.

Your health care provider will likely ask you to submit stool samples to check for the parasite. Because Giardia can be difficult to diagnose, your provider may ask you to submit several stool specimens over several days.

Several prescription drugs are available to treat Giardia . Although Giardia can infect all people, young children and pregnant women may be more susceptible to dehydration resulting from diarrhoea and should, therefore, drink plenty of fluids while ill.

Treatment is not necessary when the child has no symptoms. However, there are a few exceptions. If your child does not have diarrhoea, but is having nausea, fatigue (very tired), weight loss, or a poor appetite, you and your health care provider may wish to consider treatment. If your child attends a day care center where an outbreak is continuing to occur despite efforts to control it, screening and treating children who have no obvious symptoms may be a good idea. The same is true if several family members are ill, or if a family member is pregnant and therefore not able to take the most effective anti- Giardia medications.

Yes, a Giardia infection can be very contagious. Follow these guidelines to avoid spreading giardiasis to others:

1. Wash your hands with soap and water after using the toilet, changing nappies (diapers), and before eating or preparing food.
2. Do not swim in recreational water (pools, hot tubs, lakes or rivers, the ocean, etc.) if you have Giardia and for at least 2 weeks after diarrhoea stops. You can pass Giardia in your stool and contaminate water for several weeks after your symptoms have ended. This has resulted in outbreaks of Giardia among recreational water users.
3. Avoid faecal exposure during sexual activity.

Practice good hygiene.

1. Wash hands thoroughly with soap and water.
   1. Wash hands after using the toilet and before handling or eating food (especially for persons with diarrhoea).
   2. Wash hands after every diaper change, especially if you work with diaper-aged children, even if you are wearing gloves.
2. Protect others by not swimming if you are experiencing diarrhoea (essential for children in nappies (diapers)). 

Avoid water that might be contaminated.

1. Do not swallow recreational water
2. Do not drink untreated water from shallow wells, lakes, rivers, springs, ponds, and streams.
3. Do not drink untreated water during community-wide outbreaks of disease caused by contaminated drinking water.
4. Do not use untreated ice or drinking water when travelling in countries where the water supply might be unsafe.

If you are unable to avoid using or drinking water that might be contaminated, then you can make the water safe to drink by doing one of the following:

• Heat the water to a rolling boil for at least 1 minute.
  OR
• Use a filter that has an absolute pore size of at least 1 micron or one that has been NSF rated for "cyst removal."
• If you cannot heat the water to a rolling boil or use a recommended filter, then try chemically treating the water by chlorination or iodination. Using chemicals may be less effective than boiling or filtering because the amount of chemical required to make the water safe is highly dependent on the temperature, pH, and cloudiness of the water.

Avoid food that might be contaminated.

1. Wash and/or peel all raw vegetables and fruits before eating.
2. Use safe, uncontaminated water to wash all food that is to be eaten raw.
3. Avoid eating uncooked foods when travelling in countries with minimal water treatment and sanitation systems. 

Avoid faecal exposure during sexual activity.

It depends. You should consider having your well water tested if you can answer “yes” to any of the following questions:

• Are members of your family or others who use your well water becoming ill? If yes, your well may be the source of infection.

• Is your well located at the bottom of a hill or is it considered shallow? If so, runoff from rain or flood water may be draining directly into your well causing contamination.

• Is your well in a rural area where animals graze? Well water can become contaminated with feces if animal waste seepage contaminates the ground water. This can occur if your well has cracked casings, is poorly constructed, or is too shallow.