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Giardia: Introduction

Giardia is the name of a type of parasite, Giardia lamblia. Giardia lamblia is a microscopic organism that can cause food borne illness or food poisoning. An infection of Giardia is also called giardiasis. Giardia infection is the most common food borne illness caused by a parasite.

Giardia infection is spread through contaminated water. Giardia can also be spread through foods that contain or are prepared with water contaminated with Giardia lamblia. Giardia can also be spread directly from person to person and by not washing their hands after touching feces or other things contaminated with Giardia lamblia.

Giardia infection results in irritation and inflammation of the gastrointestinal tract. This leads to symptoms that include abdominal pain, nausea, vomiting, fever, headache, and diarrhea that lasts ten days or longer. Giardia infection can result in a serious complications that include dehydration. For more details about complications and symptoms, see symptoms of Giardia infection.

Giardia infection can occur in any age group or population. It occurs most often in traveller to developing countries and in hikers and campers who drink untreated water from streams, lakes or ponds. It is also most common in people who swim in public pools, children in day care, homosexual males, and people who have close contact with people who have a giardia infection.

People most at risk for serious complications due to Giardia infection include older adults, pregnant women, infants, and people who have compromised immune systems. This group includes people with diseases that affect the normal functioning of the immune system, such as HIV/AIDS, diabetes, cancer, and kidney disease. People at risk also include those who take medications that affect the immune system, such as chemotherapy.

Diagnosing Giardia infection and its root cause begins with taking a thorough personal and family medical history, including symptoms, and completing a physical examination.

A stool sample is generally taken and tested in the laboratory to determine if signs of the parasite Giardia lamblia are present.

A chemistry panel is a blood test that can evaluate if Giardia infection has lead to the complication of dehydration. An urinanalysis can also help to determine dehydration.

A diagnosis of Giardia infection can be delayed or missed for a variety of reasons. For information on misdiagnosis, refer to misdiagnosis of Giardia infection.

Giardia infection can often be prevented by taking simple hygiene and drinking water precautions. Treatment of Giardia infection involves ensuring good hydration and medication. For more information on prevention and treatment, refer to treatment of Giardia infection. ...more »

Giardia: Giardia lamblia Giardia lamblia (intestinalis) is a single celled animal, i.e., a protozoa, that moves with the aid of five flagella. In Europe, it is sometimes referred to as ... more about Giardia.

Giardia: Contagious parasitic digestive infection. More detailed information about the symptoms, causes, and treatments of Giardia is available below.

Giardia: Symptoms

The symptoms of Giardia infection can vary in intensity form person to person. Many people may have no symptoms at all.

Giardia infection can result in the symptom of diarrhea that lasts ten days or more. Diarrhea may be explosive and very foul smelling. There may also be abdominal pain, nausea, vomiting, fever, chills, bloating, gas, and weight loss.

...more symptoms »

Giardia: Treatments

The first step in treating Giardia infection is prevention. This includes not drinking untreated water from ponds, streams or lakes. Swimmer should also avoid swallowing water from swimming pools. It is also important not to drink water that is labelled as "not potable" or any water that might be unsafe. It is a good idea to only drink bottled water in developing countries. ...more treatments »

Giardia: Misdiagnosis

Making a diagnosis of Giardia infection can be delayed or missed many people may not have any symptoms. In addition, in some cases Giardia infection may not be severe enough for a generally healthy person to seek medical care.

In addition, symptoms of Giardia infection are similar to symptoms of a wide variety of diseases and disorders. These include irritable ...more misdiagnosis »

Symptoms of Giardia

Treatments for Giardia

Home Diagnostic Testing

Home medical testing related to Giardia:

Wrongly Diagnosed with Giardia?

Giardia: Related Patient Stories

Giardia: Complications

Read more about complications of Giardia.

Causes of Giardia

Read more about causes of Giardia.

More information about causes of Giardia:

Disease Topics Related To Giardia

Research the causes of these diseases that are similar to, or related to, Giardia:

Giardia: Undiagnosed Conditions

Commonly undiagnosed diseases in related medical categories:

Misdiagnosis and Giardia

Chronic digestive conditions often misdiagnosed: When diagnosing chronic symptoms of the digestive tract, there are a variety of conditions more »

Intestinal bacteria disorder may be hidden cause: One of the lesser known causes of diarrhea is an imbalance of bacterial in the gut, sometimes called intestinal more »

Antibiotics often causes diarrhea: The use of antibiotics are very likely to cause some level of diarrhea in patients. The reason is that antibiotics kill off not only "bad" bacteria, but can also kill the "good" bacteria in the gut. more »

Food poisoning may actually be an infectious disease: Many people who come down with "stomach symptoms" like diarrhea assume that it's "something I ate" (i.e. food poisoning). In fact, it's more »

Mesenteric adenitis misdiagnosed as appendicitis in children: Because appendicitis is one of the more feared conditions for a child with abdominal pain, it can be over-diagnosed (it can, more »

Celiac disease often fails to be diagnosed cause of chronic digestive symptoms: One of the most common chronic digestive conditions is celiac disease, a malabsorption disorder with more »

Chronic digestive diseases hard to diagnose: There is an inherent difficulty in diagnosing the various types of chronic digestive diseases. Some of the better known more »

Giardia: Research Doctors & Specialists

Research related physicians and medical specialists:

Other doctor, physician and specialist research services:

Hospitals & Clinics: Giardia

Research quality ratings and patient safety measures for medical facilities in specialties related to Giardia:

Choosing the Best Hospital: More general information, not necessarily in relation to Giardia, on hospital performance and surgical care quality:

Giardia: Rare Types

Rare types of diseases and disorders in related medical categories:

Latest Treatments for Giardia

Giardia: Animations

Prognosis for Giardia

Prognosis for Giardia: Normally illness lasts for 1 to 2 weeks, but there are cases of chronic infections lasting months to years. Chronic cases, both those with defined immune deficiencies and those without, are difficult to treat. (Source: FDA Bad Bug Book)

Research about Giardia

Visit our research pages for current research about Giardia treatments.

Clinical Trials for Giardia

The US based website lists information on both federally and privately supported clinical trials using human volunteers.

Some of the clinical trials listed on for Giardia include:

Prevention of Giardia

Prevention information for Giardia has been compiled from various data sources and may be inaccurate or incomplete. None of these methods guarantee prevention of Giardia.

Statistics for Giardia

Giardia: Broader Related Topics

Giardia Message Boards

Related forums and medical stories:

User Interactive Forums

Read about other experiences, ask a question about Giardia, or answer someone else's question, on our message boards:

Article Excerpts about Giardia

FDA Bad Bug Book (Excerpt)

Giardia lamblia Giardia lamblia (intestinalis) is a single celled animal, i.e., a protozoa, that moves with the aid of five flagella. In Europe, it is sometimes referred to as Lamblia intestinalis. (Source: FDA Bad Bug Book)

FDA Bad Bug Book (Excerpt)

Giardia duodenalis, cause of giardiasis (GEE-are-DYE-uh-sis), is a one-celled, microscopic parasite that can live in the intestines of animals and people. It is found in every region throughout the world and has become recognized as one of the most common causes of waterborne (and occasionally foodborne) illness. (Source: FDA Bad Bug Book)

Giardiasis: DPD (Excerpt)

Giardiasis (GEE-are-DYE-uh-sis) is a diarrheal illness caused by Giardia intestinalis (also known as Giardia lamblia), a one-celled, microscopic parasite that lives in the intestine of people and animals. The parasite is passed in the stool of an infected person or animal. The parasite is protected by an outer shell that allows it to survive outside the body and in the environment for long periods of time. During the past 2 decades, Giardia has become recognized as one of the most common causes of waterborne disease (drinking and recreational) in humans in the United States. The parasite is found in every region of the United States and throughout the world. (Source: excerpt from Giardiasis: DPD)

Definitions of Giardia:

A species of parasitic protozoa that attaches itself to the intestinal mucosa and feeds on mucous secretions. The organism is roughly pear-shaped and motility is somewhat erratic, with a slow oscillation about the long axis. Considered for many years to be non-pathogenic and often found in completely asymptomatic individuals, there is presently strong evidence for its pathogenic potential. - (Source - Diseases Database)

A suspected cause of diarrhea in humans - (Source - WordNet 2.1)

Giardia is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Giardia, or a subtype of Giardia, affects less than 200,000 people in the US population.
Source - National Institutes of Health (NIH)


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