Giardiasis: what it is, symptoms, treatment, prevention and more


What is Giardiasis?

Giardiasis, lambliosis or giardiosis, as it is also called, is a disease with symptoms similar to those of amebiasis , despite being caused by different parasites. Giardiasis is caused by Giardia lamblia and is lodged in the small intestine or biliary tract of the human body, while amebiasis is caused by Entamoeba histolytica and can be installed inside or outside the intestine.

The parasite is found in lakes and streams in the hinterland, as well as in swimming pools, hot tubs, wells and even in municipal water supplies. In addition, giardiasis can be transmitted by food or in person-to-person contact.


What causes the infection is a parasite known as Giárdia, which can affect both people and animals. These parasites survive in cocoons in the cysts (eggs) outside the body, which means that they can remain transmissible even for a few months.

The parasite tends to affect tropical countries more frequently due to the pleasant temperature, but it can proliferate anywhere in the world, reaching up to 50% of the same population.


Like amebiasis, giardiasis affects people who do not have good hygiene conditions, especially children. With regard to adults, it usually affects those who are not prevented in sexual relations, especially when it comes to anal sex.

The form of contamination occurs through the cysts. They stay in the feces and, when the hand is not well washed, it goes up to the mouth, and that is enough for the transmission of the disease. Or it can occur through the dirty hand that touches poorly washed food and causes contamination to occur. Animals that have the disease can also transmit it to humans.

Parasite life cycle

  • Ingestion is made by contaminated water or food;
  • The trophozoite leaves the cyst to replicate and feed;
  • It reproduces by binary fission;
  • Few infected people have symptoms (about 1/3);
  • Both forms can be found in the feces (cysts and trophozoites);
  • When they are outside the body, only the cysts survive;
  • The cyst can be found in food, water and feces, and may even survive for weeks or months.

Risk factors

Anyone is willing to contract the disease, but there are groups that are at greater risk of suffering from the disease. They are:

People who do not have access to drinking water

Where there is no basic sanitation, giardiasis is more likely to happen, because water is not reliable to drink. This is also true for the food in this place, as it is washed with the same non-potable water. There is a study that says that in underdeveloped and developing countries, the disease affects 20% to 30% of people, while in developed countries the number varies from 2% to 5%.

Children and those who live with the little ones

As the child is more likely to have contact with feces, they are more likely to contract the disease, especially those who use diapers or are unfurling and learning to use the bathroom. Besides them, daycare teachers and even parents are more likely to have giardiasis than other people, precisely because they are always in contact with the child’s feces.

People who have unprotected anal sex

Having anal intercourse without using condoms increases the risk of “catching” Giardia lamblia, as well as any other sexually transmitted disease.

Symptoms of Giardiasis

From ingesting the parasite until the onset of the disease can take 1 to 4 weeks. Often, the disease is asymptomatic (has no symptoms), and the parasite is normally eliminated in the faeces. When Giardia lamblia is not eliminated, symptoms begin to appear. The main ones are:

  • Tiredness;
  • Weight loss;
  • Watery diarrhea, which can be alternated with fatty stools;
  • Abdominal swelling and cramps;
  • Eructation with bad taste;
  • Nausea.


The doctors who are indicated to treat giardiasis are infectologists, nurses, pediatricians and also general practitioners.

The patient can write down in a notebook what he is feeling, what he ingests during food and also the medications he takes to tell the doctor and make the diagnosis as soon as possible.

The diagnosis can be made in several ways. The exams tend to vary and can be done through stool microscopy, in the search for antigens of the parasite in the stool or in the aspiration of the content that is in the patient’s duodenum.

If necessary, a biopsy of the duodenum can be done. Generally, feces are collected 3 times on alternate days, making the diagnosis accurate to 90%. If done only once, the accuracy is about 70%.

Patients suffering from immunity problems may have a more severe condition.

Treatment for Giardiasis

The disease has treatment and cure, but for this to work it is essential to follow exactly what the doctor says. Most likely, he will prescribe one of these medications:

  • Annita;
  • Flagyl;
  • Helmizol;
  • Secnidazole;
  • Benzoylmetronidazole;
  • Albentel;
  • Metronidazole;

Read more: Secnidazole: how long does it take to take effect?

Patients who have symptoms of diarrhea should always stay hydrated, especially children, as they are more likely to become dehydrated. Eating foods that are not so fat is a good option to give your intestines a break.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Living with the problem

People who have giardiasis must stay hydrated and follow the treatment correctly so as not to cause future problems. If this happens, there is no reason why the treatment will not work.


Children and newborns are the most affected by the problem, as they are most vulnerable. However, in most cases, the disease does not pose as many health risks.


Dehydration in this disease appears as a consequence of diarrhea, causing the body to lack water so that it can perform its natural functions.

Lactose intolerance

People who suffer from giardiasis may become lactose intolerant, due to the sensitivity of the intestine. The problem may persist after the problem is cured.

Growth failure

Chronic diarrhea, in addition to causing dehydration, can cause impairment in the physical and mental development of children.

How to prevent Giardiasis

The best way to ensure good health is to prevent illness. Some preventive measures are:

  • Keeping your hands always hygienic means that most infections are prevented.
  • It is also essential to wash them with soap and water always after changing a child or after going to the bathroom and before washing food.
  • When traveling to places without basic sanitation, it is preferable to use bottled water to perform basic activities such as brushing your teeth and drinking water.
  • It is also important to avoid eating foods that are not processed, as they may have been washed with contaminated water. The same goes for ice.
  • No matter how much water comes from the river, stream, lake, wells or springs, it is important to filter or boil it to eliminate any chance of contamination. For boiling, it is necessary to leave at least 10 minutes in the fire of about 70 ° C. When swimming or entering pools, lakes or streams, avoid swallowing water.
  • When performing anal sex, it is necessary to be fully protected to ensure the prevention of the disease, that although there are almost no health risks, the symptoms can be bothersome.

It is always important to be aware of the symptoms, so that, at the first sign, you can already tell your doctor and treat your problem right away, whatever. Keeping your health up to date is the best way to live longer! Share this text with your family and friends!