Giardia infection (Giardiasis)


Giardia infection, also known as giardiasis, is a waterborne intestinal infection brought on by the parasite Giardia. Once an individual encounters the parasite, it can establish residence within their intestines. The infection is characterized by symptoms such as stomach cramps, bloating, nausea, and episodes of watery diarrhea.

The parasite associated with Giardia infection is globally widespread, particularly prevalent in areas with inadequate sanitation and unsafe water sources. Giardia parasites can spread by contact with infected individuals as well as through contaminated surfaces, food, and water.

Giardiasis is treatable with antibiotics. However, prevention measures, including access to clean water and proper sanitation, are crucial in defending against Giardia infection. While Giardia infections typically resolve within a few weeks, some individuals may experience lingering intestinal problems even after the parasites are eliminated.


Giardiasis typically manifests symptoms one to three weeks after exposure, although it is possible to be asymptomatic. Individuals who do not exhibit signs and symptoms are still carriers of the parasite, capable of transmitting it to others through their feces.

The signs and symptoms can last anywhere from two to six weeks, although in certain individuals, they can recur or persist longer.

Symptoms of giardiasis include:

  • Watery or greasy diarrhea
  • Bloating or gas
  • Stomach cramps
  • Fatigue, or prolonged excessive tiredness
  • Nausea, or unsettled stomach
  • Dehydration, which could result in weight loss

If any of the signs and symptoms persist or becomes worrisome, consult a healthcare provider for proper diagnosis and treatment. Dehydration resulting from diarrhea poses a significant threat, particularly for infants and pregnant women. In the case of infants, a decrease in the number of wet diapers may indicate dehydration.

It is important for individuals to inform their healthcare providers if they are at risk of giardia infection, which includes having a child in childcare, recent travel to regions where the infection is prevalent, or ingestion of water from lakes or streams.


Giardiasis is brought about by the presence of the parasite Giardia intestinalis, which can be transmitted through contaminated food or water. The infection spreads via surfaces that have been infected with Giardia cysts, resilient shells housing the parasite.

Despite the usual dependence of parasites on a host for survival, Giardia’s protective shell allows it to endure independently for extended durations. The parasites go out when the cysts dissolve inside the host.

Giardiasis is often contracted by swallowing the parasite in unsafe water or even in tiny amounts of contaminated stool. It can be spread to others by individuals with giardiasis, even if they do not show any symptoms.

  • Person-to-person contact: Parents who change a child’s diaper, staff members and the kids at child care centers are particularly vulnerable to the infection. Hands contaminated with feces can get infected with giardia. Anal intercourse can transmit the giardia parasite.
  • Swallowing contaminated water: Contamination of ground and surface water can occur due to various factors, including agricultural runoff, discharge of wastewater, or the presence of animal feces. Giardia parasites are present in various water sources globally, including lakes, ponds, rivers, streams, public water supplies, wells, cisterns, swimming pools, water parks, and spas. Pools and spas may be accidentally contaminated by children in diapers or individuals experiencing diarrhea. Ingesting unsafe or contaminated water is the primary method of contracting giardia.
  • Consuming contaminated food: Food is a less common source of infection than water since heating destroys giardia. The transmission of Giardia parasites through food can occur due to the use of unsafe water for irrigating or washing raw produce, or inadequate handwashing by food handlers with giardia infection.

Risk factors

Anyone can be infected with giardia parasite. However, specific individuals have a higher risk of contracting it. This include:

  • Children: Children, particularly those wear diapers, undergoing toilet training, or attending childcare centers, are more likely to encounter fecal matter. Individuals residing or working closely with young children also face an elevated risk of contracting giardia infection. Generally, compared to adults, children are considerably more likely to get giardia infection.
  • No access to clean drinking water: Areas that are remote or wilderness have the highest risk of infection. Traveling to areas where giardia infections are widespread puts a person in danger, particularly if they disregard what they eat and drink. Giardia infections are common in areas with poor sanitation or unsafe water.
  • Engaging in anal sex: People who do not use forms of protection during anal or oral-anal intercourse are more vulnerable to contracting giardia infections and other STDs.