What are the other Names for this Condition? (Also known as/Synonyms)

• Giardia Infection

What is Giardiasis? (Definition/Background Information)

• Giardiasis is an infection of the intestines, caused by a microscopic protozoan parasite called Giardia. This organism lives in soil, food, and water
• The parasite is found worldwide, but is specifically known to affect humans and animals in places with poor sanitation or untreated water. Giardiasis is a very common waterborne disease in the United States
• The parasite can infect humans and animals, such as cats, dogs, cattle, deer, and other wild animals. Giardiasis is chiefly transmitted through contaminated water, person-to-person contact, and contact with infected animals or human feces
• Once the parasite infects a human or an animal, it lives inside their intestines causing associated symptoms. Some common symptoms of Giardiasis are bloating, diarrhea, stomach or abdominal cramps, and fatigue
• The chief mode of diagnosis of Giardiasis is via the microscopic examination of stool samples. If treatment is delayed, it may result in complications such as weight loss, dehydration, and chronic diarrhea
• Giardiasis usually resolves within a few weeks of infection; medications may be prescribed, if the healthcare provider deems it necessary to treat the infection

Who gets Giardiasis? (Age and Sex Distribution)

• Giardiasis is more often observed in developing countries than the developed countries, due to a lack of better sanitation facilities
• Any individual, who is exposed to unsanitary conditions, can develop Giardiasis. However, children are more likely to contract the disease, due to a higher probability of they being exposed to feces
• Both men and women are equally vulnerable to Giardiasis
• No racial or ethnic predilection is generally reported

This parasitic infection is the most common intestinal disease affecting humans in the United States.

What are the Risk Factors for Giardiasis? (Predisposing Factors)

The risk factors for Giardiasis include the following:

• Not having access to safe drinking water; drinking or swallowing contaminated water
• Traveling to a country/region where Giardiasis is known to be common
• Having close contact with infected individuals without taking the appropriate preventive measures (such as washing hands)
• Contact with animals or feces of animals that are infected
• Changing diapers of children and not washing one’s hands thoroughly
• Childcare centers
• Hiking to the endemic regions; drinking from contaminated lakes or rivers
• Engaging in anal sex, especially without using a condom
• Children playing outdoors

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Giardiasis? (Etiology)

Giardiasis is caused by the protozoan parasite Giardia, which may be present in the soil, food, and water. The parasite exists in the form of a microscopic hard shell, called a cyst, which protects it from the outside environment.

The chief mode of transmission is ingestion of Giardia cysts via contaminated water. Once a cyst has been ingested, the outer shell dissolves, releasing the parasite in the intestine. This results in an infection. The sources of contaminated water may include:

• Untreated water supplies
• Swimming pools
• Water parks
• Spas
• Waterbodies such as ponds, streams, lakes, and rivers 

Other modes of transmission include:

• Direct contact with an infected animal or individual, especially contact with contaminated feces 
• Eating contaminated food, especially if the food ingredients are not washed or cooked thoroughly

What are the Signs and Symptoms of Giardiasis?

The symptoms of Giardiasis typically start within 1 to 3 weeks of the parasitic infection. However, it is possible to be infected and not present with symptoms. The signs and symptoms of Giardiasis may vary from one individual to another and may include:

• Diarrhea or soft, greasy stools that float
• Passing gas or flatulence
• Stomach or abdominal cramps
• Upset stomach that can cause nausea and/or vomiting
• Dehydration
• Fatigue
• Some of the less common symptoms include:
  • Itchy skin
  • Hives
  • Swelling of the eye and joints  

The symptoms can vary between individuals and last for 1 to 2 weeks, or even longer. In some cases, the symptoms of Giardiasis may go away, but then return after several days.

How is Giardiasis Diagnosed?

The diagnosis of Giardiasis is made through the following tools:

• A complete physical examination and review of any medical and travel history
• Assessment of symptoms
• Analysis of stool samples for the presence of Giardia. Submission of several samples of stool for testing by a healthcare professional over several days may be needed to procure accurate results

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Giardiasis?

Children and infants are the most susceptible to developing complications from Giardiasis. Some complications of Giardiasis include:

• Weight loss, along with failure to absorb fat, vitamin A, and vitamin B12
• Lactose intolerance: It is the inability to digest milk sugar properly. It may persist for a long time, even after the infection has been treated and cleared
• Dehydration, from loss of water through severe diarrhea. This can affect the normal functions of the body
• The mental and physical development of a child may be severely affected from malnutrition, as a result of chronic diarrhea

Giardiasis is rarely ever fatal in developed countries; but, the symptoms may persist for long periods and other complications may develop.

How is Giardiasis Treated?

Many individuals, who do not present significant symptoms, may not require treatment for Giardiasis. The affected individuals often get better without treatment within a few weeks. However, the healthcare provider may opt to treat the patient, in order to prevent the infection from spreading to others.

The treatment options for severe cases of Giardiasis may include:

• Administration of medications, including 
  • Antibiotics
  • Anti-parasitic medications
• The entire family may be treated, as Giardiasis can easily spread from one individual to another
• Analyzing stool samples to monitor how effective the treatment is

It is important to note that pregnant women (in the first trimester) may be told not to use medication to treat Giardiasis, because of potential adverse drug effects to the developing fetus.

How can Giardiasis be Prevented?

Giardiasis may be prevented by considering the following measures:

• Practicing proper hygiene: It is the most efficient method of preventing Giardiasis infection. This includes washing hands thoroughly before and after preparing/eating food, after caring for individuals who are ill, treating a cut, using the bathroom, changing diapers, coughing, sneezing, touching an animal or its waste products, handling pets, pet foods or treats, and after handling trash
• Keeping infected children at home until their symptoms subside; before sending them to school/daycare centers
• Avoiding swimming in public pools or waterparks, if one has recently experienced diarrhea. Avoiding swimming for at least a week after being diagnosed with Giardiasis
• Showering before and after using a public pool; ensuring that children with diapers are constantly monitored and changed before they enter the pool water
• Washing hands and feet after gardening, even if wearing suitable hand gloves
• Avoiding drinking water that may be contaminated with Giardia; boiling water that may be possibly contaminated, for at least 10 minutes
• When traveling to countries/region where Giardia is endemic, drink bottled or boiled water
• Using approved water filters (such as those approved and rated by the US National Safety Foundation; Standard 53 or NSF Standard 58)
• Using clean water to prepare and wash food items. Washing fruits and vegetables before consumption; preferably peeling them, if they are to be eaten raw
• Avoiding anal sex; using condoms, washing hands after sex. Washing hands after touching the anus or rectal area. Using a barrier, if engaging in oral-anal sex
• Cleaning up after pets and keeping a clean living environment in homes

What is the Prognosis of Giardiasis? (Outcomes/Resolutions)

The prognosis of Giardiasis is generally positive with adequate treatment.

• In many cases, the condition resolves spontaneously after a few weeks
• In some individuals, there may be persistent intestinal problems, well after the parasite has been eliminated from the body

Additional and Relevant Useful Information for Giardiasis:

• The various forms of Giardia species causing the infection include Giardia intestinalis, Giardia lamblia, and Giardia duodenalis
• Generally, contracting Giardiasis from cats and dogs is unlikely, as the type of parasite that causes infection in cats and dogs is not the type causing infection in humans. Individuals may more often contract the infection from infected cattle, deer, or other wild animals
• The infection rate of Giardia has been shown to go up during late summer months, with reported cases of Giardiasis being twice as high in June through October, when compared to the period January through March
• It is estimated that the infected individuals may expel between 1-10 billion cysts a day in their feces