Protecting families from contaminated food and water
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Protecting families from contaminated food and water
Posted in Our Blog on July 15, 2025
Long term complications of giardiasis, the illness caused by Giardia infection, can last well after initial infection is resolved.
While post-infectious irritable bowel syndrome and growth/cognitive deficiencies have historically been observed, other long term complications of giardiasis have recently been discovered. Complications that have nothing to do with the digestive system.
Follow along as we explore the long term complications of giardiasis and how to protect yourself from infection.
But first, what is Giardia, and how do you get it?
Giardia is microscopic parasite that lives in the intestines of humans and animals. It can infect the environment, drinking water, and food through feces contamination. Even small amounts can spread illness.
Giardia symptoms typically begin with diarrhea 2 to 5 times per day and feeling more tired than usual.
Short-term symptoms may include:
Giardia symptoms often start 1 to 2 weeks after becoming infected with Giardia parasites and last for 2 to 6 weeks. Around 1 in 3 people with Giardia infection experience long-term symptoms that can last for years.
You can become infected with Giardia by swallowing contaminated water, eating contaminated food, person-to-person contact, and contact with Giardia in the environment.
Swallowing contaminated water is one of the most common ways to become infected with Giardia parasites.
All types of water sources can become contaminated with Giardia parasites through agricultural runoff, animal feces, or contamination with wastewater or surface water. Even pools and spas are vulnerable to Giardia contamination.
You can become infected with Giardia by eating contaminated food.
Food can become contaminated by food handlers infected with the parasite. This happens when infected food handlers do not wash their hands thoroughly after using the restroom.
Contamination may also happen if raw produce is irrigated or washed with contaminated water.
Fortunately, cooking kills Giardia parasites. However, drinking water does not undergo that kind of heat treatment unless a boil water ordinance is in place. As such, water is often a Giardia source of “foodborne infection” more so than food.
Giardia infections spread through what is called “fecal-oral-route.” Contaminated feces enter the mouth in some way. Even trace (microscopic) amounts of contaminated feces can cause infection.
Sometimes it is obvious. You change a diaper, help someone in the bathroom, or come into contact with another person’s poop in some other way.
Others are not so obvious.
Such as touching something that a contaminated person has touched or shaking hands. When you touch your mouth or eat without washing your own hands, the Giardia parasite can enter your own body.
The Centers for Disease Control and Prevention (CDC) reports that over one million cases of giardiasis occur in the United States each year. Roughly one-third of those infections result in long term complications.
Some of the more obvious complications involve intestinal effects like functional gastrointestinal disorder and post-infectious irritable bowel syndrome.
Other long term complications of giardiasis are caused by malabsorption resulting from compromised intestinal walls. For example, failure to thrive, growth stunting, impaired cognitive function, and chronic fatigue syndrome.
Some are not so obvious. Such as eye damage, arthritis, and certain allergies. Even cancer.
FGID is a blanket disorder involving gastrointestinal symptoms like abdominal pain, bloating, and altered bowel habits that occur without specific identifiable abnormalities. Experts classify this as a brain-gut interaction disorder. However, this complication may result in post-infectious irritable bowel syndrome.
IBS is the most commonly diagnosed gastrointestinal disorder. Common symptoms include abdominal discomfort and altered bowel habits with no observed abnormalities on routine diagnostic tests. This long term complication of giardiasis can persist long after initial symptoms appear.
Failure to thrive is an overall term used to describe stunted growth and the consequences that complication. This can happen at any time in life, but more common in children under the age of two. This is often caused by reduced absorption of nutrients, excessive loss of nutrients, and malnutrition.
Stunted growth is a long-term consequence of persistent giardiasis in children. This happens when children do not receive the appropriate nutrition to grow. This can be caused by malnutrition, sanitation, loss of intestinal surface area, maldigestion, and malabsorption.
The first two years of life are periods of rapid growth and development. The brain grows rapidly during this time, setting the stage for future cognitive function. Micronutrient deficiencies such as iodine as well as iron has been linked to both diarrheal illness and cognitive developmental problems. This malabsorption has also been connected to impaired visual-motor coordination, auditory short-term memory, information processing, and cortical cognitive function.
Post-infectious fatigue has been observed in certain studies. As much as 41% of people infected with Giardia experienced this complication, compared to 22% of those in the general population. It is unclear why this happens. However, immune response has been considered a possible source.
Ocular lesions caused by iris or blood vessel inflammation or retinal hemorrhages can cause serious eye damage. This type of infection may be caused by toxins produced by these parasites.
A type of arthritis, known as reactive arthritis, can be caused by Giardia infections. Other gems, like Salmonella, Campylobacter, and Shigella can also cause this long term complication. Reactive arthritis happens when antigens in synovial fluids found in the joints (even the eye and urinary tract) respond to the infection. This complication can persist for over a year after giardiasis has been resolved.
Long term complications of giardiasis may also include allergies. A recent study found an increase in serum immunoglobulin E (IgE) levels the body uses in response to common allergens. As a result, the host becomes more sensitive to certain common allergens. Often cow’s milk.
Muscular complications can also occur following Giardia infections. This is often caused by loss of potassium in the body from diarrhea. Resulting in poor nutrient and electrolyte absorption.
Loss of potassium related to diarrhea, impaired nutrient and electrolyte absorption
Pancreatic and gall bladder cancers have been observed in patients following giardiasis. However, existing research has not established the connection, and more research must be performed to better understand this phenomenon.
If you have become seriously ill from a Giardia outbreak or Giardia infection, it is a good idea to get advice from an experienced Food Poisoning Lawyer.
Medical bills, lost work, caring for a sick loved one, and other burdens associated with Giardia infection add up. A Food Poisoning Lawyer can answer questions that you have, and even some that you have not thought of.
If you wish to make a legal claim, The Lange Law Firm, PLLC has a Food Poisoning Lawyer that can help.
The Lange Law Firm, PLLC has successfully represented cases just like yours and won millions of dollars in food poisoning and products liabilities lawsuits.
Reach out by calling (833) 330-3663 or send us an email for a free, no obligation consultation.
Don’t wait. Call today to get the justice you deserve!
By: Heather Van Tassell (contributing writer, non-lawyer)