ABC Medical Center > Giardia infection (giardiasis)

What is Giardia infection (giardiasis)?

21:54 - 4 May , 2021


It is a parasitic intestinal infection caused by a microscopic parasite called Giardia lamblia, very common in unhygienic places. It usually contaminates the water, whether in rural or urban areas, causing abdominal pain, inflammation, flatulence, liquid diarrhea, and nausea.

In addition to spreading by drinking contaminated water, it is possible to become infected by having contact with someone who is sick or by eating food with the parasite.

Giardiasis typically lasts two to six weeks, but it often leaves long-lasting scars in the gut that take a long time to completely disappear.

Although there are specific drugs against giardiasis, sometimes they do not efficiently eradicate the parasite, so it is more appropriate to take the necessary measures to avoid infection, such as:

  • Avoid drinking water of dubious origin or from wild aquifers. 
  • Disinfect fruits and vegetables. 
  • Don’t eat raw food.
  • Perform hand hygiene continuously, especially after going to the bathroom, changing diapers, or preparing food.
  • Drink only purified water.
  • Avoid consuming ice.
  • Use a condom if you practice anal and oral sex.

Signs and symptoms Giardia infection (giardiasis)

In certain cases, giardiasis does not have symptoms, although those infected can spread it through their fecal matter. When symptoms do appear, the most common are:

  • Tiredness.
  • Weakness.
  • Abdominal pain.
  • Inflammation.
  • Nausea.
  • Intense watery diarrhea.
  • Fetid feces.
  • Flatulence.
  • Decreased body weight.

Possible complications of giardiasis are:

  • Dehydration.
  • Malnutrition. 
  • Slow growth in children. 
  • Lactose intolerance. 

Diagnosis and treatment Giardia infection (giardiasis)

Once your doctor analyzes your symptoms and medical history, they will perform a physical examination and request a stool sample for laboratory analysis to identify Giardia parasite infestation or rule out other intestinal conditions.

The indicated treatment is antiparasitic such as:

  • Metronidazole: it is usually the most used, although it causes nausea and a rusty taste in the mouth.
  • Tinidazole: it is similar to the previous one in effectiveness and side effects, but it has the advantage of requiring smaller doses, normally a single dose is required.
  • Nitazoxanide: it is the most used medication in children since its liquid, although its side effects include flatulence, nausea, and yellowish pigmentation in the eyes and urine.

At ABC Medical Center’s Internal Medicine Department, we offer health care services with the highest quality and safety, from the prevention, diagnosis, timely treatment, and monitoring of infectious, respiratory, endocrinological, dermatological, rheumatic, nephrological, gastrointestinal, and hematological pathologies of both chronic-degenerative diseases and acute conditions, through a comprehensive and multidisciplinary model.


  • Estrada GY, Víctores JL, Camacho AJA, et al. La propolina por intubación duodenal como tratamiento de la giardiasis. Mediciego. 2017;23(3):19-23.
  • Fonte GL, Almannoni SA, Fernández FMÁ, et al. Knowledge, perceptions and practices in relation with giardiasis. Results of a survey applied to pediatricians of Playa, La Lisa and Marianao municipalities. Invest Medicoquir. 2017;9(2):.
  • Lopes AF, Ribeiro NFR, Barbosa PA, et al. Evaluación de la sensibilidad de los métodos Faust y sedimentación espontánea para el diagnóstico de giardiasis. Rev Cubana Med Trop. 2016;68(2):157-164.
  • Herrero AH, Fernández DJ, Vega SS, et al. Pacientes con Giardia lamblia diagnosticada por frotis duodenal. MediSan. 2014;18(12):.

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