Giardia lamblia, also known as Giardia duodenalis or Giardia intestinalis, is a flagellated enteric protozoan and a common cause of diarrhea (endemic and epidemic) throughout the world. In the United States, Glamblia has been demonstrated in 4%-7% of stool specimens, making it the most commonly identified intestinal parasite. There is a bimodal distribution, with the illness being reported most frequently in children aged 1-9 years and adults aged 35-45. Disease prevalence is highest during late summer and fall.
The parasite is spread via the feces of an infected person or animal. Acquisition occurs when cysts are ingested via contaminated water or food, or via person-to-person contact. After excystation, trophozoites colonize and multiply in the small bowel and may disrupt epithelial brush border, mucosally invade, or elaborate an enterotoxin. The incubation is usually 7-14 days, with symptoms often lasting more than 2-4 weeks; however, patients may continue to shed cysts for 6 months or longer.
Most foodborne illness, also known as food poisoning, comes from bacteria in food that has multiplied, either from poor handling, improper cooking, or poor storage of food. Other things, such as toxins, parasites, chemicals, and viruses, can contaminate food.
Giardiasis comes from an intestinal parasite. It is obtained by eating or drinking contaminated food or water.
Who’s At Risk
Foodborne illness can occur in any person shortly after ingestion of contaminated food. Illness may occur when a person complains that food he/she has eaten "didn't taste right" or ate food that was old, improperly prepared, or was left at room temperature for more than 4 hours. There may be no indication that food or water has been contaminated until the symptoms of illness occur.
Certain people are more prone to foodborne illness than others, such as:
Elderly adults – Older age plays a factor in sensitivity to foodborne illness because the immune system becomes slower to respond and weaker with increasing age.
Infants / young children – Younger age plays a factor in sensitivity to foodborne illness as well, as young children and infants' immune systems are not fully developed.
Others with lowered immune systems – People with diabetes, those with AIDS, those going through therapy for cancer (ie, radiation or chemotherapy), and those who are pregnant.
Giardiasis is more common in Brazil, Cuba, India, Russia, and Serbia, but it is found all over the world, including in the United States.
Signs & Symptoms
Within hours or days of eating contaminated food, symptoms generally include diarrhea, nausea, abdominal pain, fever, and, sometimes, vomiting. Foodborne illness is often mistaken for the flu, as the symptoms are similar.
If you become sick from foodborne illness, resting and drinking plenty of liquids is key. Drink Gatorade or water to prevent dehydration.
Foodborne illness can be prevented by following these general guidelines:
Wash your hands before handling food.
Wash your hands after using the toilet, changing diapers, smoking, blowing your nose, coughing, or sneezing.
Wash your hands after touching raw meat or eggs.
Use plastic (rather than wooden) cutting boards for cutting raw meats.
Thoroughly clean all surfaces and utensils that came into contact with uncooked meat or eggs.
Cook meats and eggs thoroughly before eating.
Do not eat or drink foods made from raw or undercooked eggs, meats, or unpasteurized dairy products.
Wash all produce thoroughly before eating.
Avoid cross-contamination of foods by keeping produce, cooked foods, and ready-to-eat foods separate from uncooked meats and raw eggs.
When to Seek Medical Care
Seek professional medical care if you suspect you have giardiasis and one or more of the following is true:
Your symptoms last for more than 2 weeks.
Prolonged diarrhea leads to weight loss.
You have recently traveled to South America, India, or the former Soviet Union.