Giardia Lamblia



Giardia lamblia, also known as Giardia intestinalis or Lamblia intestinalis is a microscopic parasite that infects the gastrointestinal tract of humans.

Infection causes giardiasis, a diarrhoeal illness. It is a type of gastroenteritis.

It is a major cause of intestinal disease worldwide. It is also one of the most common causes of waterborne disease.

It can be found in both drinking and recreational water such as swimming pools, hot tubs and Jacuzzis.

Giardiasis can occur throughout the population. However, it has a higher prevalence is in children than adults. Chronic giardiasis is more common in adults than in children.

Transmission of Giardiasis

The parasite lives in the intestine of infected humans and animals. It can be found in soil, food, water, or surfaces that have been contaminated with the excrement from infected humans and animals.

You can become infected after ingesting the parasite accidentally or by:

  • Eating or drinking something that has been exposed to human or animal waste infected with Giardia.

  • Drinking water contaminated with Giardia. This includes water in swimming pools, hot tubs, Jacuzzis, fountains, lakes, rivers, springs, ponds, streams etc that can be contaminated with sewage as well as human and animals’ excrement.

  • Eating uncooked food contaminated with Giardia.

  • Ingesting Giardia picked up from surfaces such as bathroom, changing tables, diapers, toys etc contaminated with excrement from an infected person.

    The infection is an issue for people camping in the wilderness or swimming in contaminated streams or lakes.

    Artificial lakes formed by beaver dams are especially susceptible. Giardiasis is therefore often referred to as Beaver Fever.

    Use of a filter or boiling is recommended for purifying drinking water in wilderness camping etc.

    Cool moist conditions favour the survival of the parasite.

    Giardia Symptoms

    Some people infected with giardiasis show no symptoms. Such people can still serve as carriers of the disease.

    Others will show the following symptoms:

  • Severe diarrhoea
  • Upset stomach
  • Abdominal cramps
  • Bloating
  • Flatulence
  • Fatigue
  • Nausea
  • Vomiting
  • Weight loss

    Vomiting and nausea are the major symptoms. The symptoms generally show up 7 to 10 days after the organism is ingested. The symptoms may last 2 to 6 weeks and sometimes slightly longer.

    Chronic infections are rare but when they do happen, they can last for months or years.

    Giardia Treatment

    Young children and pregnant women are very susceptible to dehydration resulting from diarrhoea. They should therefore drink plenty of fluids while ill.

    A number of drugs are available to treat the infection. Metronidazole, whose brand name is Flagyl, can be taken 3 times a day for 5 to 10 days. Its side effects include a metallic taste in the mouth and nausea.

    Flagyl should not be used alongside alcohol. It should also not be taken in the early stages of pregnancy.

    Young children under 5 years can be treated with furazolidone whose brand name is Furoxone. It has fewer side effects and comes in a liquid form. It should not be given to babies under 1 month old.

    Giardiasis is very contagious and the whole family needs to be careful if one of its members is sick.

    Sometimes, a doctor can require medicine be taken for a long duration. A different medicine may also be given after the first dose is completed to ensure a complete cure.

    Preventing Giardia Infection

    The infection is very contagious. To prevent it:

  • Thoroughly wash your hands with soap and hot water after using the bathroom, changing diapers, before eating and preparing food.

  • Do not swim in pools, hot tubs, lakes or rivers, the ocean, etc if you have Giardia. Wait for a further 2 weeks after diarrhoea stops.

  • Avoid swallowing water while swimming or while using public recreational facilities.

  • Avoid drinking untreated water from shallow wells, lakes, rivers, springs, ponds, and streams.

  • Avoid drinking untreated water during outbreaks of disease caused by contaminated drinking water.

  • To ensure your drinking water is safe, always boil, filter or use bottled water.

  • Thoroughly wash and/or peel all raw vegetables and fruits before eating.

  • Use safe, uncontaminated water to wash all food that is to be eaten raw.

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