Giardiasis refers to an infection of the small bowel leading to diarrhea and it is caused by a unicellular parasitic organism that is known as Giardia lamblia. This organism is also referred to as Giardia duodenalis or Giardia intestinalis. This microbe belongs to the Giardia genus and it is a flagellated protozoan (Diplomonadida).
There are several ways in which the disease is spread but the principle is the same-accidental swallowing. This accidental swallowing can result following drinking of contaminated water, eating of contaminated food, failure to wash hands before eating, unprotected oral-anal sex with an infected person, and swallowing contaminated swimming pool water (Centers for Disease Control [CDC], 2009).
The swallowed cysts develop into many trophozites and these cause disease by causing inflammation of small intestines as well as physically blocking nutrient uptake (Pommerville & Alcamo, 2004). The lifecycle of Giardia lamblia involves alternation between environment and human intestines where after swallowing of cysts they multiply to form trophozoites in intestines which are then passed out into the environment.
In the environment, they develop into cysts which are swallowed. Though giardiasis can affect any one, certain populations are more prone to infection and these include those in close contact with infected individuals such as care givers, those who take untreated contaminated water, international travelers, campers and hikers whose hygiene level is low, the children who are in child care centers, and people who come into contact with feces during sex (CDC, 2009).
The disease is diagnosed by microscopy observation of fresh stool samples and it should be done on people who have diarrhea and especially those who are likely to have been exposed to poor hygienic conditions such as campers and hikers (Everhart, 1994). Giardiasis is a worldwide infection but the prevalence rates differ depending on the population and the geographic location of those sampled. It is most prevalent in developing countries where it is estimated to be about 20% and least prevalent in developed countries with prevalence being estimated to be 5% (Simjee, 2007).
In United States, it is the most common parasite that causes human waterborne disease with 100, 000-2. 5 million cases being reported annually (Simjee, 2007). The diagnosis begins with a physical examination and evaluation of medical history. Infected people present with signs and symptoms such as fatigue, flatulence, nausea, diarrhea, stomach aches, and greasy foul smelling stools which float on water (Everhart, 1994). Due to diarrhea, some patients get dehydrated. However, it is important to note that some infected individuals do not present with any symptoms.
The disease symptoms appear approximately seven days following infection and naturally they last between 2 weeks to six weeks but medications can reduce this duration (CDC, 2009). Mostly, individuals recover completely but in rare severe cases stunted growth in children and weight loss is observed. Medications and preventive strategies for giardiasis are available. The treatment of choice for giardiasis is metronidazole but other medications are also used and these include furazolidone, tinidazole and Nitazoxanide albendazole (Pommerville & Alcamo, 2004).
A vaccine was recently discovered but it is only used on animals such as cats and dogs and it has shown great success (Olson, Ceri, & Morck, 2000). The best approach to giardiasis is maintenance of proper hygiene and helpful practices include wash of hands after visiting toilet, after changing diapers and before eating, bathing thoroughly before entering swimming pool, drinking of boiled or treated water, and abstinence from swimming if one is diarrheic to avoid spreading (CDC, 2009). Other measures include proper wiping of anus after defecating to avoid spread to one’s sexual partner as well as using a barrier when undertaking oral-anal-sex.
References Centers for Disease Control. (2009). Giardiasis. Retrieved 15 May, 2010 from http://www. cdc. gov/ncidod/dpd/parasites/giardiasis/factsht_giardia. htm#prevention Everhart, J. E. (1994). Digestive diseases in the United States: Epidemiology and impact. Darby, PA: Diane Publishers. Olson, M. E. , Ceri, H. , & Morck, D. W. (2000). Giardia vaccination. Parasitology Today, 16(5), 213-217. Pommerville, J. C. & Alcamo, I. E. (2004). Alcamo’s fundamentals of microbiology (7th ed. ). Sudbury, MA: Jones & Bartlett Learning. Simjee, S. (2007). Foodborne diseases. New Jersey: Humana Press.