A strange endocytobiont revealed as largest virus

Abstract

A lot of endocytobionts (or endosymbionts) have been discovered within free-living amoebae in recent years. In this article the results of a long lasting effort to derive valuable data about an extraordinary spore-like infectious microorganism (endocytobiont, endosymbiont) within host amoebae (Acanthamoeba sp.) recently isolated from the contact lens case of a patient with keratitis, are presented. It took some time until this endocytobiont could be attributed to the genus Pandoravirus following a publication of two other pandoraviruses isolated from aquatic environments. Consequently the molecular biological investigation led to the taxonomic affiliation of the endocytobiont with the genus Pandoravirus and to the description of a new Pandoravirus species, Pandoravirus inopinatum after whole-genome sequencing in 2015. The fact that it was isolated from a contact lens container of a keratitis patient gives another dimension to these findings showing paradigmatically, how readily these 'new' giant viruses get to humans.