And now, the human metapneumovirus, or HMPV for short, is infecting thousands of Americans around the country. The highly contagious virus, which belongs to the same group as respiratory syncytial virus (RSV),

The CDC’s actions come in response to China's government-run media confirming that positivity rates of HMPV hare rising in children under the age of 14, despite respiratory illnesses being down overall since last year.

As China continues to monitor an increase in cases of human metapneumovirus (HMPV), here's what you need to know about the illness.