A highly contagious respiratory virus is rapidly spreading among children right at the start of back-to-school season. The virus, known as parvovirus B19 , typically causes a pink facial rash ― which is nicknamed “slapped cheek” ― in kids and joint pain in adults. It’s endemic, meaning the virus consistently circulates in the United States, but a spike in recent activity prompted the Centers for Disease Control and Prevention to issue a health alert on Aug.

13. As Dr. Amesh Adalja , a senior scholar at the Johns Hopkins University Center for Health Security and an infectious disease expert, explained, the health alert is meant to inform clinicians so they can keep an eye out for the disease and treat patients accordingly.

The illness, in most cases, is mild and resolves within a week. But the flu-like symptoms could still put a dent in your end-of-summer plans. Here’s what you should know about parvovirus B19.

As with most infectious diseases, people respond differently to parvovirus B19. About 25% of people who contract the infection remain asymptomatic and never develop any noticeable symptoms, while half experience flu-like symptoms, said Jennifer Walsh , a pediatric nurse practitioner and an assistant professor in the George Washington School of Nursing. The disease tends to strike in two phases.

During the first phase, which hits a week after contracting the infection and lasts about five days, people experience a fever and malaise. The second phase, which oc.