VIROPHAGE. Illustration of virophages infecting a mamavirus. Mamavirus is a virus of very large size, discovered in 2008. It is related to mimivirus, giant virus discovered in 2003 in the ameba Acanthamoeba polyphaga, and considered until then as the largest existing virus capsid of 400 nm of diameter, that is bigger than certain bacteria and visible in optical microscopy, which explains its name of mimivirus mimicking microbe virus. Mamavirus is a variant of the mimivirus but slightly larger. I