Giardiasis - Beaver Fever Giardiasis — popularly known as beaver fever — is a disease caused by the flagellate protozoan Giardia lamblia (also sometimes called Giardia intestinalis and Giardia duodenalis).
Giardia lamblia lives in the intestine as a trophozoite, where it undergoes asexual reproduction. In this image, the trophozoites' microtubule skeletons are immunostained (red), while their paired nuclei are DAPI stained (fluorescent blue).
It looks cute but this little protozoan will give you terrible diarrhea. Scanning electron micrograph (SEM) depicting a Giardia lamblia protozoan undergoing binary fission, creating what appears to be a microscopic “heart.