Stomach cramps, nausea and watery diarrhea could indicate a giardia infection. Find out how to treat and prevent this waterborne parasite.
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 unsafe water.
Giardia infection (giardiasis) is one of the most common causes of waterborne disease in the United States. The parasites are found in backcountry streams 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 clear up within a few weeks. But you may have intestinal problems long after the parasites are gone. Several drugs are generally effective against giardia parasites, but not everyone responds to them. Prevention is your best defense.
Some people with giardia infection never develop signs or symptoms, but they still carry the parasite and can spread it to others through their stool. For those who do get sick, signs and symptoms usually appear one to three weeks after exposure and may include:
Signs and symptoms of giardia infection may last two to six weeks, but in some people they last longer or recur.
Call your doctor if you have loose stools, stomach cramping and bloating, and nausea lasting more than a week, or if you become dehydrated. Be sure to tell your doctor if you're at risk of giardia infection — that is, you have a child in child care, you've recently traveled to an area where the infection is common, or you've swallowed water from a lake or stream.
Giardia parasites live in the intestines of people and animals. Before the microscopic parasites are passed in stool, they become encased within hard shells called cysts, which allows them to survive outside the intestines for months. Once inside a host, the cysts dissolve and the parasites are released.
Infection occurs when you accidentally swallow the parasite cysts. This can occur by swallowing unsafe water, by eating infected food or through person-to-person contact.
The most common way to become infected with giardia is after swallowing unsafe (contaminated) water. Giardia parasites are found in lakes, ponds, rivers and streams worldwide, as well as in public water supplies, wells, cisterns, swimming pools, water parks and spas. Ground and surface water can become infected with giardia from agricultural runoff, wastewater discharge or animal feces. Children in diapers and people with diarrhea may accidentally contaminate pools and spas.
Giardia parasites can be spread through food — either because food handlers with giardia infection don't wash their hands thoroughly or because raw produce is irrigated or washed with unsafe (contaminated) water. Because cooking food kills giardia, food is a less common source of infection than water is, especially in industrialized countries.
You can get infected with giardia if your hands become dirty with feces — parents changing a child's diapers are especially at risk. So are child care workers and children in child care centers, where outbreaks are increasingly common. The giardia parasite can also spread through anal sex.
The giardia parasite is a very common intestinal parasite. Although anyone can pick up giardia parasites, some people are especially at risk:
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:
No drug or vaccine can prevent giardia infection. But commonsense precautions can go a long way toward reducing the chances that you'll become infected or spread the infection to others.
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 then examined in a lab for the presence of parasites. Stool tests may also be used to monitor the effectiveness of any treatment you receive.
Children and adults who have giardia infection without symptoms usually don't need treatment unless they're likely to spread the parasites. Many people who do have problems often get better on their own in a few weeks.
When signs and symptoms are severe or the infection persists, doctors usually treat giardia infection with medications such as:
There are no consistently recommended medications for giardia infection in pregnancy because of the potential for harmful drug effects to the fetus. If your symptoms are mild, your doctor may recommend delaying treatment until after the first trimester or longer. If treatment is necessary, discuss the best available treatment option with your doctor.
While you may initially bring your symptoms to the attention of your family doctor, he or she may refer you to a gastroenterologist — a doctor who specializes in digestive system disorders.
Before your appointment, you may want to write a list of answers to the following questions:
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 check for tender areas. He or she may also check your mouth and skin for signs of dehydration. You also may be given instructions about how to bring in a sample of your stool.