Giardiasis-introduction

Giardia is an infection of the small intestine caused by a protozoa. It is usually asymptomatic in humans but may produce abdominal cramps, diarrhea, and nausea. The species that infects humans and causes diarrhea is Giardia lamblia. The genus Giardia that may be parasitic in the intestines of vertebrates including most domestic animals.

What are the main causes of  Giardiasis?

Giardia is caused by infection with the single-celled parasite Giardia lamblia, also known as Giardia intestinalis or Giardia duodenalis.
It is caused by the infection of Giardia intestinalis, which is an intestinal flagellate causing endemic and epidemic in man.

Giardiasis mat also be spread by direct person-to-person contact, which has caused outbreaks in institutions such as day-care centers. Giardiasis may be spread, most commonly by eating food contaminated by the unwashed hands of an infected person or by drinking groundwater polluted by the feces of infected animals such as dogs and beavers (hence the nickname "beaver fever"). The cells have a large disc or sucker on their anterior ventral surfaces , by which they attach to the intestinal mucosa
the infection can be spread from person to person by contamination of food with feces, or by direct fecal-oral contamination. Cysts also survive in water, for example in fresh water lakes and streams. As a result, giardiasis is the most common cause of water-borne, parasitic illness in the United States. Domestic mammals (for example, dogs, cats, calves) and wild mammals (for example, beavers) can become infected with Giardia; however, it is not clear how often domestic or wild mammals transmit giardiasis to humans.

Some other reasons of causing giardiasis:

Putting anything into the mouth that has touched the stool of a person or animal with giardiasis
Swallowing water (such as from a swimming pool, lake, river, pond, or stream) contaminated with sewage or stool from Giardia-infected people or animals.
Eating uncooked or undercooked food contaminated with Giardia cysts
Touching and bringing to the mouth cysts picked up from surfaces (such as toys, bathroom fixtures, changing tables, diaper pails) contaminated with stool from an infected person.

Infection is the most common cause :

Viral (e.g., influenza, HIV, hepatitis, herpes simplex encephalitis, mononucleosis, adenovirus)
Bacterial (e.g., pneumonia, endocarditis, tuberculosis, meningitis, pyelonephritis, appendicitis, cholecystitis, cellulitis)
Lyme disease
Malaria
Drug fever :

Often temporally associated with the initiation of a new medicine Often associated with a rash (biopsy reveals leukocytoclastic vasculitis)
Eosinophilia is common
Water is the main source of giardia infection. The parasites are found in lakes, ponds, rivers and streams worldwide, as well as in municipal water supplies, wells, cisterns, swimming pools, water parks and spas. Giardia parasites have even turned up in touch tanks in aquariums and museums.
Giardia parasites can be transmitted through food — either because food handlers with giardiasis don’t wash their hands or because raw produce is irrigated or washed with contaminated water.

 Family members, daycare workers, and others in contact with infected stool may then themselves become infected.