Giardia infection (giardiasis)

Description

Giardia infection is an intestinal infection marked by stomach cramps, bloating, nausea and bouts of watery diarrhea. Giardia infection is caused by a microscopic parasite that is found worldwide, especially in areas with poor sanitation and contaminated water.

Giardia infection (giardiasis) is one of the most common causes of waterborne disease in the united States. The parasites are found in the crossing of rivers and lakes, but also in public water supplies, swimming pools, whirlpool spas and wells. Giardia infection can be spread through food and person-to-person contact.

Giardia infections usually go away within a couple of weeks. But you may have intestinal problems long after the parasites are gone. Several drugs are generally effective against the parasites giardia, but not everyone responds to them. Prevention is the best defense.

Symptoms

Some people with giardia infection never develop signs or symptoms, but still have the parasite and can spread it to others through their feces. For those who do get sick, signs and symptoms usually appear one to three weeks after exposure and can include:

  • Watery, sometimes foul-smelling diarrhea that may alternate with soft, stools greasy
  • Fatigue
  • Stomach cramps and swelling
  • Gas
  • Nausea
  • Weight loss

The signs and symptoms of giardia infection can last from two to six weeks, but in some people they last longer or recur.

When to see a doctor

Call your doctor if you have loose stools, stomach cramps and bloating, and nausea that lasts for more than a week, or if you become dehydrated. Be sure to tell your doctor if you are at risk of contracting the infection, that is to say, you have a child in child care, you have recently traveled to an area where the infection is common, or you've swallowed the water of a lake or stream.

Causes

Giardia parasites live in the intestines of people and animals. Before the microscopic parasites are passed in the feces, become enclosed within the hard shells called cysts, which allows them to survive outside of the intestines for months. Once inside a host, the cysts dissolve and the parasites are released.

The infection occurs when you ingest the cysts of parasites. This can occur by ingestion of contaminated water, consumption of contaminated food, or through person-to-person contact.

Swallowing contaminated water

The most common way of getting infected with giardia is after the safe swallowing (contaminated) water. The parasites Giardia is found in lakes, ponds, rivers and streams all over the world, as well as in public water supplies, wells, tanks, pools, water parks and spas. Ground and surface water can become infected with giardia from agricultural run-off, discharge of sewage or animal feces. Children in diapers, and people with diarrhea may contaminating pools and spas.

Eating contaminated food

Giardia parasites can be transmitted by food, either because of the food handlers infected with giardia do not wash their hands thoroughly or because of the raw products of irrigation or washing unsafe (contaminated) water. Due to the cooking of food kills giardia, the food is a less common form of the source of infection is water, especially in industrialized countries.

Person-to-person contact

You can get infected with giardia if your hands become soiled with feces — parents to change the diaper of a child are especially at risk. So are child care workers and children in child care centers, where the outbreaks are becoming more common. The giardia parasite can also be spread through anal sex.

Risk factors

The giardia parasite is a very common intestinal parasite. Although any person can pick up the parasite giardia, some people are especially at risk:

  • Children. Giardia infection is much more common in children than in adults. Children are more likely to come in contact with feces, especially if you use diapers, they are potty training or spending time in a child care center. The people who live or work with young children are also at higher risk of developing the infection by giardia.
  • People without access to safe drinking water. Giardia infection is rampant and where sanitation is inadequate, or if the water is not safe to drink. You are at risk if you travel to places where infection with giardia is common, especially if you are not careful about what you eat and drink. The risk is higher in rural or wilderness areas.
  • People who have anal sex. People who have anal sex or oral-anal sex without using a condom or other protection are at higher risk of getting the infection, as well as sexually transmitted infections.

Complications

Giardia infection is almost never fatal in industrialized countries. But it can cause lingering symptoms and serious complications, especially in infants and children. The most common complications include:

  • The dehydration. Often a result of severe diarrhea, dehydration happens when the body does not have enough water to carry out its normal functions.
  • Failure to thrive. Chronic diarrhea from giardia infection can lead to malnutrition and damage to children's physical and mental development.
  • Lactose intolerance. Many people with giardia infection develop lactose intolerance — the inability to digest the sugar in milk. The problem may persist long after the infection has cleared.

Prevention

No drug or vaccine can prevent infection by giardia. But the common-sense precautions can go a long way toward reducing the chances that you will become infected or spreading the infection to others.

  • Wash your hands. This is the simplest and the best way to prevent most types of infection. Wash your hands with soap and water for at least 20 seconds after using the bathroom or changing diapers and before eating or preparing food. When soap and water are not available, you can use alcohol-based disinfectants. However, alcohol-based disinfectants are not effective in the destruction of the cyst form of giardia that survives in the environment.
  • Purify the desert of water. Avoid the consumption of untreated water from shallow wells, lakes, rivers, springs, ponds, and streams, unless you filter or boil for at least 10 minutes to 158 F (70 ° C) in the first place.
  • Wash the products. Wash all raw fruits and vegetables with safe, non-contaminated water. Peel the fruit before eating it. Avoid eating raw fruits or vegetables if traveling in countries where they may have contact with the contaminated water.
  • Keep your mouth shut. Try not to swallow water when swimming in pools, lakes, or streams.
  • The use of bottled water . When traveling to areas of the world where water is likely to be unsafe, drink and brush your teeth with bottled water that is open. Do not use ice.
  • Practice safe sex. If you engage in anal sex, use a condom every time. Avoid oral-anal sex, unless you're fully protected.

Giardia infection (giardiasis)

Diagnosis

To help diagnose giardia infection (giardiasis), your doctor is likely to test a sample of your stool. For accuracy, you may be asked to submit several stool samples collected over a period of days. The samples are examined in a laboratory to detect the presence of parasites. The analysis of stool can also be used to monitor the effectiveness of any treatment you receive.

Treatment

Children and adults who are infected with giardia have no symptoms generally do not need treatment unless it is likely that for the propagation of the parasites. Many people who have problems are most likely to spontaneously improve in a few weeks.

When signs and symptoms are severe or the infection persists, doctors usually treat the infection by giardia with medications such as:

  • Metronidazole (Flagyl). Metronidazole is the most commonly used antibiotic for giardia infection. Side effects may include nausea and a metallic taste in the mouth. Do not drink alcohol while you are taking this medication.
  • Tinidazole (Tindamax). Tinidazole works just as well as the metronidazole, and has many of the same side effects, but may be administered in a single dose.
  • Nitazoxanide (Alinia). Because it comes in liquid form, nitazoxanide can be easier for children to swallow. Side effects may include nausea, gas, yellow eyes, and bright yellow color of urine.

There is no consistently recommended medication for giardia infection in pregnancy due to the possible harmful effects of the drug to the fetus. If your symptoms are mild, your doctor may recommend delaying treatment until after the first quarter, or more. If treatment is necessary, discuss the best available treatment option with your doctor.

Preparing for your appointment

While initially you may bring your symptoms to the attention of your family doctor, he or she may refer you to a gastroenterologist — a doctor who specializes in disorders of the digestive system.

What you can do

Before your appointment, you can write a list of answers to the following questions:

  • When did your signs and symptoms begin?
  • Is there something that is better or worse?
  • Do you work or live with young children?
  • What types of medications and dietary supplements you take?

What to expect from your doctor

During the physical exam, your doctor may ask you to lie down so that he or she can gently press on various parts of your abdomen to detect sensitive areas. He or she may also check your mouth and the skin for signs of dehydration. Also can you give instructions on how to bring in a stool sample.

Symptoms and treatment of Giardia infection (giardiasis)