The Virus Kept Multiplying for 14 Days, Yet the Intestine Was Barely Damaged

Explanation

Hand, foot, and mouth disease is an illness that causes blisters on children's hands, feet, and inside the mouth. One of its causes is enterovirus A71 (EV-A71), which can rarely cause severe symptoms in the brain and nerves. However, what happens in the 'intestine,' the site where this virus first multiplies in the body, had not been well understood until now, because there had been no way to observe the human intestine directly over a long period.

Professor Kazuo Takayama of Institute of Science Tokyo and colleagues created an 'intestine chip (intestine MPS)' from human pluripotent stem cells. It is a small device within a culture dish that reproduces conditions close to a patient's actual intestine. They infected it with EV-A71 and tracked the changes over 14 days.

The results differed from expectations. Even though the virus kept multiplying continuously for all 14 days, the intestinal cells were barely damaged. Furthermore, in the infected intestine chip, the immune response mediated by interferon (a substance cells release to fight viruses) was not sufficiently activated.

In other words, EV-A71 may not destroy the intestine and run rampant, but instead may continue multiplying quietly while slipping past immune surveillance. This could offer a clue as to why the virus spreads while no symptoms are showing.

This finding was published in the academic journal Journal of Virology on July 28, 2026 (DOI: 10.1128/jvi.00250-26).