Controversy was stirred among the public and at the Diet Wednesday, after an infectious disease expert posted a now-deleted video online in which he claimed to have seen inadequate anti-virus contamination measures on the Diamond Princess cruise ship.

In the YouTube clip posted late Tuesday, Kentaro Iwata, a professor at the infectious disease division of Kobe University Hospital, claimed he saw there was no clear separation of noncontaminated "green zones" and potentially dangerous "red zones" within the ship. "The cruise ship was completely inadequate in terms of the infection control," he can be heard saying in English in the video clip.

"I never had fear of getting infection myself, for Ebola, SARS, cholera because I know how to protect myself and how to protect others and how the infection control should be ... (but) I was so scared of getting COVID-19" inside the Diamond Princess, he said.