Protozoan or Fungal infection - Essay Example

Giardiasis Organism Giardiasis is infection of the bowels caused by Giardia lamblia. Though it was von Leewenhoek who first identified the protozoanin 1600s, it was Vilem Dusan Lambl and Alfred Giard who recognized the organism first in human stools in the 19th century and it is named after them. Incidentally, it is the first of the protozoan parasites that has been described and this organism has caused several community outbreaks. Epidemiology Infection due to Giardia lamblia is infact the most prevalence of protozoal infections in the intestines of human beings.

It is one of the most common causes of endemic and epidemic (def) diarrhea all over the world. In the United States, it is the most commonly identified intestinal pathogen that is water-borne and this is evident from the fact that the protozoa has been detected in 80 percent of water supplies from raw sources and 15 percent of filtered water samples. Populations that are affected most commonly are children, travelers, homosexual individuals and those with immunodeficiencies (def). Until now, since 1960s, more than 90 outbreaks related to Giardia have occurred and these outbreaks have affected more than 23,000 individuals.

There are some reports that the incidence of this infestation is more common in the Northern states. Internationally, Giardia is a major cause of childhood diarrhea epidemics in United Kingdom and other parts of the world. The prevalence rates are variable, between 4 to 42 percent. Giardiasis is not associated with mortality. Morbidity also is minimal and related to chronic infection. Transmission The life cycle of Giardia is simple and has 2 stages; the trophozoite (def) stage and the cysts (def) stage.

The trophozoite exists in the small intestine of the human beings and the cyst exists in the environment. There are no intermediate hosts for this protozoa. Ingestion of food or water contaminated with cysts causes excystation in the duodenum and the stomach by various enzymes derived from the stomach and the pancreas. The trophozoites released thus enter into the small intestine where they undergo rapid multiplication and double every 9-12 hours. As the trophozoites reach the large intestine, they become encysted because of secondary bile salts and neutral pH.

These cysts enter the environment through stools and the cycle repeats thus. Signs and symptoms In 15 percent of the cases, the infection is asymptomatic and self-limited. These individuals pass only cysts. The most common presentation of acute infection is acute diarrhea that can be associated with bloating, abdominal cramping and flatulence. Large numbers of these protozoa can occlude the mucosa and compete for nutrition leading to epithelial damage and absorption changes like mucus secretion alterations and lactase deficiency.

Chronic infection can lead to malabsorption, malnutrition (def) and growth retardation in children. These children cal present with chronic sporadic diarrhea, lactose deficiency, malaise, growth failure and anorexia. Extraintestinal features are rare and can present as reactive arthritis and urticaria. Physical examination is usually normal. Diagnosis Examination of stools for ova and parasite is the main diagnostic method. Fresh specimens or specimens preserved with 10 percent formalin or polyvinyl alcohol are necessary for stool examination.

Ideally, specimens must be collected on 3 different days. Other than stools, samples from duodenal aspirate can also be used for viewing trophozoites. However, the yield is low and it is an invasive test. Other tests include enzyme-linked immunosorbent assays of stool antigen. But they are expensive. Other than specific tests, tests like complete blood picture and electrolytes may be necessary to evaluate the general condition of the patient. In those with chronic malnutrition, tests to ascertain fecal fat, disacchardise deficiency, etc.

, may be done. Imaging studies have no role in the diagnosis and management of giardiasis. Treatment The main treatment is antibiotic therapy. The drug of choice is metronidazole. Other drugs which are useful include albendazole, furazolidone, nitazoxanide and tinidazole. No special diet is required unless the patient has disaccharidase deficiency. Prevention The main prevention strategy is to drink water that is boiled and filtered. Water from swimming pools and other sources like lakes must not be taken.

Hand washing before eating food and after cleaning feces is very important to prevent transmission of the disease. Care must be taken about disposal of feces and animal wastes. Glossary Epidemic: affecting a large number of people atypically. Cyst: a sac that is closed and has a distinct membrane and that which develops abnormally in a structure. Trophozoite: vegetative form of a protozoan that is different from the resting or reproductive forms. Immunodeficiency: inability of the body to produce normal quantities of antibodies in response to antigens.

Malnutrition: Inadequate intake of nutrients either due to faulty intake or due to faulty digestion and absorption. Bibliography Ballweber, L.R., Xiao, L., Bowman, D.D., Kahn, G., Cama, V.A. (2010). Giardiasis in dogs and cats: update on epidemiology and public health significance. Trends Parasitol., 26(4):180-9 CDC. (2011). Parasites – Giardia. Retrieved on 2nd April, 2011 from http://www.cdc.gov/parasites/giardia/ Dawson, D. (2005). Foodborne protozoan parasites. Int J Food Microbiol, 103(2):207-27.

Mukherjee, S. (2009).Giardiasis. Emedicine from WebMD. Retrieved on 2nd April, 2011 from http://emedicine.medscape.com/article/176718-medication#2 Hookenek, M. (2008). Pediatric Giardiasis. Medscape reference.Retrieved on 2nd April, 2011 from http://emedicine.medscape.com/article/998168-treatment Huang,D.B., White, A.C. (2006). An updated review on Cryptosporidium and Giardia. Gastroenterol Clin North Am., 35(2):291-314.