giardia intestinalis causing giardiasis. medically

giardia ntestinalis parasite infection protozoa diarrhea gastrointestinal giardiasis contamination waterborne fecaloral cysts trophozoites intestines absorption malnutrition bloating cramping nausea vomiting stool dehydration microscopy diagnosis treatment metronidazole prevention hygiene sanitation traveler 039 disease zoonotic transmission flagellate chronic acute host immune system flagella pathogen public health outbreak endemic contaminant foodborne protozoan intestinalis causing medically microscopic leading symptoms like abdominal pain malabsorption humans