TROPICAL DISEASES
GIARDIASIS
Definition:- This is an infestation caused by Giardia intestinalis (also called G. lamblia and duodenalis). Peak infections are sporadic due to fecal contamination of food or drink, person-to-person, or anal-oral sexual contact. Travelers, campers, gay men, and people with low immune status are also affected.
Incubation period 1-3 weeks.
Clinical features: Children are most affected (more than 20% in developing countries), although adults are not immune. It is possible that achlorhydria, malnutrition, low IgA secretion from the intestine, and low blood gamma globulin level may predispose to infection. Children often produce symptoms, while adults often do not. Symptoms include diarrhea with a characteristic foul odor, bulky, greasy, and frothy stools, abdominal pain, bloating, flatulence, and gradual emaciation. Symptoms may suggest amebiasis or sprite syndrome. Anorexia, nausea, vomiting, and fever may sometimes develop. In severe cases, malabsorption syndrome may be observed. This can result in a fat- and protein-losing enteropathy associated with disaccharidase and vitamin B12 deficiency, which can persist long after apparent cure. Allergic manifestations may also develop. Diagnosis This is done by finding the characteristic cysts and vegetatives of G. intestinalis in the feces. The concentration method can also be used. When the stool examination is negative, duodenal or jejunal aspirates of mucus obtained by string-test endoscopy can be examined for the parasite. The z7S coproantigen by ELISA and IFA are also highly specific (90-400%) and sensitive (85-90%). Radiological investigation may also show increased transit time, thickened mucosa, and impaired small bowel motility.
Treatment drugs: 1 metronidazole tablet (250 mg) can be administered three times a day for 7 to 10 days. A higher dose of 350-750 mg three times daily for 10 days or even 2 g per ounce daily for 3 days has also been recommended for some patients.
Gastrointestinal side effects, eg nausea, vomiting, metallic taste in the mouth, are commonly seen. Other reactions include headache, dizziness, Candida overgrowth, and disulfide-like reaction in alcoholics. However, in some parts of the world this drug is not recommended for Giardiasis due to its mutagenicity. Tinidazole can also be used in a dose of 150 mg three times a day for 8 days. A single dose of 0.5 to 2 g may also be helpful. Side effects may be seen as with metronidazole therapy, but are less marked.
Quinacrine hydrochloride (Mepacrine) 0.1 g three times a day is given for 5 to 7 days. It should not be administered in psoriatic subjects.
Furazolidone (Furoxone) 100 mg 4 times a day for 7 days can be used. Of all these drugs, the first two drugs are used most often by doctors because they have virtually few side effects.