Giardia Lamblia

Giardia Giardia lamblia is a flagellated protozoan that infects the duodenum and small intestine. range from asymptomatic colonization to acute or chronic diarrhea and malabsorption. more prevalent in children

life cycle of G. lamblia is composed of 2 stages: trophozoites cysts

EPIDEMIOLOGY usually occurs sporadically major reservoir for spread :water contaminated with Giardia cysts Giardia cysts are relatively resistant to chlorination and to ultraviolet light irradiation Boiling is effective for inactivating cysts. Person-to-person spread also occurs. Human milk contains glycoconjugates and secretory IgA antibodies that may provide protection to nursing infants.

CLINICAL MANIFESTATIONS incubation period :1–2 wk clinical manifestations :asymptomatic. acute infectious diarrhea, chronic diarrhea with failure to thrive and abdominal pain or cramping. Symptomatic infections occur more frequently in children than in adults. Most symptomatic patients : acute diarrhea. low-grade fever, nausea, and anorexia; intermittent or more protracted course characterized by diarrhea, abdominal distention and cramps, bloating, malaise, flatulence, nausea, anorexia, and weight loss develops

CLINICAL MANIFESTATIONS stools may be profuse and watery and later become greasy and foul smelling Stools do not contain blood, mucus, or fecal leukocytes Varying degrees of malabsorption may occur.

Abnormal stool patterns may alternate with periods of constipation and normal bowel movements. Malabsorption of sugars, fats, and fat- soluble vitamins has been well documented and may be responsible for substantial weight loss. Giardiasis has been associated with growth stunting and repeated Giardia infections with a decrease in cognitive function in children in endemic areas.

Giardiasis should be considered in young children in child care or in any person who has had contact with an index case or a history of recent travel to an endemic area who has persistent diarrhea, intermittent diarrhea and constipation, malabsorption, crampy abdominal pain and bloating, failure to thrive, or weight loss

DIAGNOSIS established by microscopy documentation of trophozoites or cysts in stool specimens, 3 stool specimens are required to achieve a sensitivity of >90%. Stool enzyme immunoassay (EIA) or direct fluorescent antibody tests are more sensitive aspiration or biopsy of the duodenum or upper jejunum

TREATMENT should receive therapy : acute diarrhea failure to thrive exhibit malabsorption

Asymptomatic excreters generally are not treated except: in specific instances such as in outbreak control, for prevention of household transmission by toddlers to pregnant women and patients with hypogammaglobulinemia or cystic fibrosis, and in situations requiring oral antibiotic treatment where Giardia may have produced malabsorption of the antibiotic

Tinidazole: >3 yr: 50 mg/kg/day once daily nitazoxanide Metronidazole: 15 mg/kg/day in 3 divided doses for 5–7 days Second line alternatives: furazolidone 6 mg/kg/day in 4 divided doses for 10 days albendazole: >6 yr: 400 mg once a day for 5 days paromomycin, and quinacrine :6 mg/kg/day in 3 divided doses for 5 days

PREVENTION Handwashing purify public water supplies adequately include chlorination and filtration. Travelers to endemic areas are advised to avoid uncooked foods that might have been grown, washed, or prepared with water that was potentially contaminated. Purification of drinking water can be achieved by a filter or by brisk boiling of water for at least 1 min