Giardiasis

Overview

Giardiasis (also called giardia infection, traveler's diarrhea, beaver fever or lambliasis) is an infection of the small bowel by a single-celled organism called Giardia lamblia. People become infected with the Giardia parasite after swallowing Giardia cyst often found in water contaminated by raw sewage or animal waste.

  • Giardiasis can be found among 2-5% of people in industrialized nations such as the United States. In developing countries, 20-30% of the population may have giardiasis.
  • Travelers to foreign countries may develop diarrhea often caused by Giardia.

source: eMedicine

Symptoms

Giardiasis was initially regarded as non-pathogenic and often found in asymptomatic patients. However, there is now copious evidence for the pathogenic nature of Giardia lamblia.

The major symptom of acute giardiasis, mainly seen in travelers, is protracted diarrhea. The incubation period for infection is generally 9-15 days. The acute stage usually begins with a feeling of intestinal uneasiness followed by nausea and anorexia. Low grade fever and chills may occur. These symptoms are followed by watery, foul-smelling, explosive diarrhea, abdominal pain, passage of foul gas and belching. This stage lasts for 3-4 days, often resembling other causes of travelers' diarrhea, so giardiasis may go undiagnosed. If left untreated, symptoms may persist for months. Malabsorption due to chronic Giardia infection has also been reported.

Other common symptoms of giardiasis include abdominal pain, flatulence, bloating, vomiting and weight loss. Symptoms vary from person to person, often depending on the inoculum size, duration of infection, and individual host and parasite factors. The diarrhea can be mild and produce semi-solid stools, or it can be intense and debilitating. Children generally become less ill than adults and frequently develop asymptomatic infection. It has been suggested that as many as 50% of infections are asymptomatic.

source: Giardiasis

Causes

Giardia cysts are transmitted to humans in various ways.

  • Contaminated water supplies: Giardia is one of the most common causes of water-borne diarrhea outbreaks. Sources of contaminated water include public facilities that improperly filter and treat water, water in developing countries, or rivers and lakes used by hikers. Overseas travelers and hikers are at a high risk for infection.
  • Contaminated food: Food that may have been washed in contaminated water, exposed to manure, or prepared by an infected person can transmit the disease.
  • Person-to-person contact: Infection may be caused by poor hygiene and most commonly occurs in daycare centers, nursing homes, and in sexually active homosexual males. Up to 50% of children infected with Giardia in daycare centers, and up to 20% of infected sexually active homosexual males, pass cysts in their stool. Family members, daycare workers, and others in contact with infected stool may then themselves become infected.

source: eMedicine

Prevention

Here are some ways to protect your family from giardiasis:

  • Drink only from water supplies that have been approved by local health authorities.
  • Bring your own water when you go camping or hiking, instead of drinking from sources like mountain streams.
  • Wash raw fruits and vegetables well before you eat them.
  • Wash your hands well before you cook food for yourself or for your family.
  • Encourage your kids to wash their hands after every trip to the bathroom and especially before eating. If someone in your family has giardiasis, wash your hands often as you care for him or her.
  • Have your kids wash their hands well after handling anything in "touch tanks" in aquariums, a potential source of giardiasis.
  • Have your water checked on a regular basis if it comes from a well.

Also, it's questionable whether infants and toddlers still in diapers should be sharing public pools. But certainly they should not if they're having diarrhea or loose stools (poop).

Contagiousness

People and animals (mainly dogs and beavers) who have giardiasis can pass the parasite in their stool. The stool can then contaminate public water supplies, community swimming pools, and "natural" water sources like mountain streams. Uncooked foods that have been rinsed in contaminated water may also spread the infection.

In child-care centers or any facility caring for a group of people, giardiasis can easily pass from person to person. At home, an infected family dog with diarrhea may pass the parasite to human family members who take care of the sick animal.

source: KidsHealth

Diagnosis

Doctors confirm the diagnosis of giardiasis by taking stool samples and sending them to the lab to be examined for Giardia parasites. Several samples may be needed before the parasites are found.

For that reason the doctor may order a much more sensitive test called the Enzyme-Linked ImmunoSorbent Assay or ELISA test.

Less often, doctors make the diagnosis by looking at the lining of the small intestine with an instrument called an endoscope and taking samples from inside the intestine to be sent to a laboratory. This is done in more extreme cases, when a definite cause for the diarrhea hasn't been found.

source: KidsHealth

Prognosis

t is common for the infection to go away on its own. However, persistent infections have been reported and need further antibiotic treatment. Some people who have had Giardia infections for a long time continue having symptoms even after the infection has gone.

Possible Complications

  • Dehydration
  • Malabsorption (inadequate absorption of nutrients from the intestinal tract)
  • Weight loss

When to Contact a Medical Professional

Call your health care provider if:

  • Diarrhea or other symptoms last for more than 14 days
  • You have blood in the stoolblood in the stool
  • You are dehydrated

source: MedPlus

Treatment

The most common treatment for giardiasis is metronidazole (Flagyl) for 5-10 days. It eradicates the Giardia more than 85% of the time, but it often causes gastrointestinal side effects such as nausea and a metallic taste as well as dizziness and headache. Despite its effectiveness, metronidazole is not approved by the FDA in the U.S. for treatment of giardiasis.

The only drug approved for treating giardiasis in the U.S. is furazolidone (Furoxone) for 7-10 days. It is approximately as effective as metronidazole. Tinidazole is available outside the U.S. and is highly effective at treating giardiasis(>90%). It also can be given as a single dose and is well tolerated. Quinacrine is very effective for treating giardiasis but is no longer available in the U.S. Paromomycin and albendazole are less effective than other treatments.

Occasionally, treatment fails to eradicate Giardia. In such cases, the drug may be changed or a longer duration or higher dose may be used. Combination therapy also may be effective (e.g., quinacrine and metronidazole).

source: MedicineNet

Resources

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

  • Heat the water to a rolling boil for at least 1 minute (at altitudes greater than 6,562 feet [>2,000 meters], boil water for 3 minutes).

OR

  • Use a filter that has an absolute pore size of 1 micron or smaller, or one that has been NSF rated for "cyst removal." For information on choosing a water filter, see CDC's Fact Sheet A Guide to Water Filters.
  • 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.

Source: CDC