Giardiasis
Giardiasis is a parasitic disease caused by Giardia duodenalis (also known as G. lamblia and G. intestinalis). Infected individuals who experience symptoms (about 10% have no symptoms) may have diarrhoea, abdominal pain, and weight loss. Less common symptoms include vomiting and blood in the stool. Symptoms usually begin one to three weeks after exposure and, without treatment, may last two to six weeks or longer.
| Giardiasis | |
|---|---|
| Other names | Beaver fever, giardia |
| Giardia cell viewed with scanning electron microscope | |
| Specialty | Infectious disease, gastroenterology |
| Symptoms | Diarrhea, abdominal pain, weight loss, nausea |
| Usual onset | 1 to 3 weeks after exposure |
| Causes | Giardia duodenalis spread mainly through contaminated food or water |
| Risk factors | Hypogammaglobulinemia |
| Diagnostic method | Stool testing |
| Differential diagnosis | Irritable bowel syndrome |
| Prevention | Improved sanitation |
| Treatment | Antiprotozoal medications |
| Medication | Tinidazole, metronidazole |
| Frequency | Up to 7% (developed world), up to 30% (developing world) |
Giardiasis usually spreads when Giardia duodenalis cysts within faeces contaminate food or water that is later consumed orally. The disease can also spread between people and through other animals. Cysts may survive for nearly three months in cold water. Giardiasis is diagnosed via stool tests.
Prevention may be improved through proper hygiene practices. Asymptomatic cases often do not need treatment. When symptoms are present, treatment is typically provided with either tinidazole or metronidazole. Infection may cause a person to become lactose intolerant, so it is recommended to temporarily avoid lactose following an infection. Resistance to treatment may occur in some patients.
Giardiasis occurs worldwide. It is one of the most common parasitic human diseases. Infection rates are as high as 7% in the developed world and 30% in the developing world. In 2013, there were approximately 280 million people worldwide with symptomatic cases of giardiasis. The World Health Organization classifies giardiasis as a neglected disease. It is popularly known as beaver fever in North America.