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Giardiasis

Updated : March 12, 2024





Background

Giardiasis is an intestinal infection that is caused by Giardia duodenalis protozoa. It is prevalent in low-income areas, and it frequently manifests as flatulence and diarrhea with mucus. The disease is particularly prevalent among overseas tourists, wilderness adventurers, and daycare workers in the United States.

Though frequently asymptomatic, some individuals may lose weight or get dehydrated due to this illness. In many cases, treatment with antihelminthic or nitroimidazole drugs can cure the disease.

Epidemiology

Approximately 2% of adults and 8% of children in developed countries suffer from giardiasis, the most common enteric protozoal infection in the world. Additionally, an estimated 33% of indviduals in underdeveloped nations are plagued with this disease. As asymptomatic carriers, most cases remain unidentified in the United States, resulting in an estimated prevalence of 1.2 million cases.

In 2012, the CDC recorded 15,223 cases. Children up to the age of 4 were the most affected demographic, with the northwest US reporting the highest proportion of cases. Because of outdoor water activities, late summer and early fall have the highest prevalence. Protozoa are transmitted via the fecal-oral route, typically by the consumption of contaminated food or water.

It can also be transmitted from person to person or, less frequently, from animal to person. An infected person can shed between 108 and 1010 cysts per day, although even 10 cysts can constitute an infectious dose.

Carriers of a subclinical illness are able to infect others. Populations at risk in the United States include international tourists, wilderness travelers, daycare workers, males who have sex with other men, and individuals who work with human feces.

Anatomy

Pathophysiology

The cause of giardiasis symptoms is not completely understood. Trophozoites use their ventral disc to cling to the gut wall. Researchers hypothesize that protozoa affect epithelial cell connections and brush border enzymes in the small intestine.

Patients affected may exhibit impaired gastrointestinal motility. The protozoa secrete lectins and thiol proteinases which are cytotoxic. This interaction increases permeability and lowers the capacity to digest saccharides.

Etiology

Giardia duodenalis is the protozoa that causes giardiasis. It is also commonly called Giardia intesinalis and Giardia lamblia. Cysts are released by infected animals into freshwater where they can remain infective for weeks or months. Only genotypes A and B are known to infect humans out of seven genetic assemblages (A-F).

Inadequate sanitation and hygiene have a crucial role in disease transmission. Today, daycares have become epicentres of the virus, primarily as a result of insufficient handwashing when changing diapers or handling such waste. In the intestinal tract, the cysts undergo excystation and then release trophozoites. Trophozoites are flagellated, pear-shaped protozoa which contain two nuclei.

Genetics

Prognostic Factors

Most cases of Giardiasis are asymptomatic and require no medical interventions. Antihelminthic drugs are prescribed to patients if they suffer from severe symptoms. Even severe cases generally present a good prognosis and undergo a rapid recovery after receiving medication.

Clinical History

Physical Examination

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Medication

 

tinidazole 

2g orally once



mebendazole 

(off-label)
Take a dose of 200 mg orally every eight hours up to five days



 

tinidazole 

>3 years: 50mg/kg/day orally for three days; maximum 2g
<3 years: Safety and efficacy not established



metronidazole 

15 mg/kg per day intravenously or orally every 8 hours for 5 days



 

Media Gallary

References

https://www.ncbi.nlm.nih.gov/books/NBK513239/

Giardiasis

Updated : March 12, 2024




Giardiasis is an intestinal infection that is caused by Giardia duodenalis protozoa. It is prevalent in low-income areas, and it frequently manifests as flatulence and diarrhea with mucus. The disease is particularly prevalent among overseas tourists, wilderness adventurers, and daycare workers in the United States.

Though frequently asymptomatic, some individuals may lose weight or get dehydrated due to this illness. In many cases, treatment with antihelminthic or nitroimidazole drugs can cure the disease.

Approximately 2% of adults and 8% of children in developed countries suffer from giardiasis, the most common enteric protozoal infection in the world. Additionally, an estimated 33% of indviduals in underdeveloped nations are plagued with this disease. As asymptomatic carriers, most cases remain unidentified in the United States, resulting in an estimated prevalence of 1.2 million cases.

In 2012, the CDC recorded 15,223 cases. Children up to the age of 4 were the most affected demographic, with the northwest US reporting the highest proportion of cases. Because of outdoor water activities, late summer and early fall have the highest prevalence. Protozoa are transmitted via the fecal-oral route, typically by the consumption of contaminated food or water.

It can also be transmitted from person to person or, less frequently, from animal to person. An infected person can shed between 108 and 1010 cysts per day, although even 10 cysts can constitute an infectious dose.

Carriers of a subclinical illness are able to infect others. Populations at risk in the United States include international tourists, wilderness travelers, daycare workers, males who have sex with other men, and individuals who work with human feces.

The cause of giardiasis symptoms is not completely understood. Trophozoites use their ventral disc to cling to the gut wall. Researchers hypothesize that protozoa affect epithelial cell connections and brush border enzymes in the small intestine.

Patients affected may exhibit impaired gastrointestinal motility. The protozoa secrete lectins and thiol proteinases which are cytotoxic. This interaction increases permeability and lowers the capacity to digest saccharides.

Giardia duodenalis is the protozoa that causes giardiasis. It is also commonly called Giardia intesinalis and Giardia lamblia. Cysts are released by infected animals into freshwater where they can remain infective for weeks or months. Only genotypes A and B are known to infect humans out of seven genetic assemblages (A-F).

Inadequate sanitation and hygiene have a crucial role in disease transmission. Today, daycares have become epicentres of the virus, primarily as a result of insufficient handwashing when changing diapers or handling such waste. In the intestinal tract, the cysts undergo excystation and then release trophozoites. Trophozoites are flagellated, pear-shaped protozoa which contain two nuclei.

Most cases of Giardiasis are asymptomatic and require no medical interventions. Antihelminthic drugs are prescribed to patients if they suffer from severe symptoms. Even severe cases generally present a good prognosis and undergo a rapid recovery after receiving medication.

tinidazole 

2g orally once



mebendazole 

(off-label)
Take a dose of 200 mg orally every eight hours up to five days



tinidazole 

>3 years: 50mg/kg/day orally for three days; maximum 2g
<3 years: Safety and efficacy not established



metronidazole 

15 mg/kg per day intravenously or orally every 8 hours for 5 days



https://www.ncbi.nlm.nih.gov/books/NBK513239/

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