Giant oversights in the human gut virome

We read with interest the paper by Zuo  et al ,1 which used deep sequencing to identify gut mucosal virome alterations in individuals with UC. One of many interesting findings reported by the authors was the detection of giant viruses infecting algae and amoeba ( Mimivirus and Chrysochromulina ericina virus). The authors suggested an association with the geographical distribution of individuals and concluded that they were more abundant in patients with UC than controls. We reanalysed the data and propose that issues related to the virome analysis pipeline led to the incorrect identification of these viruses. First, the DNA extraction method states that 0.22 µm filters were used to remove bacterial and eukaryotic cells, followed by chemical and enzymatic degradation of DNA unprotected by viral capsids. Mimivirus has a capsid with a diameter of 0.5 µm, surrounded by a 0.125 µm thick layer of closely packed fibres,2 …