When is the earliest that a giardia infection would be seen in a tourist who went on houseboat in kerala?

Giardia Lamblia: Incubation period is 1 to 14 days ( with an average of 7 days). Giardiasis is a waterborne illness caused by Giardia parasite. Sx's – there may be no sx's or diarrhea, oily floating stool, gas, nausea, vomiting & abdominal cramps. If untreated it can cause bloody diarrhea, dehydration & weight loss. Diagnosis- via blood test for antibodies, stool antigen & checking stool for ova & parasites.