(NEXSTAR) — As COVID-19 continues to spread globally, a new virus outbreak has begun. In the United States, at least two cases of monkeypox have been confirmed and another 50 possible cases are under investigation.

What are the signs and symptoms of the rare virus? According to the Centers for Disease Control and Prevention, monkeypox is like a milder case of smallpox.

“The main difference between symptoms of smallpox and monkeypox is that monkeypox causes lymph nodes to swell (lymphadenopathy) while smallpox does not,” the CDC writes.

In the early stages of infection, symptoms include:

  • Fever
  • Headache
  • Muscle aches
  • Backache
  • Swollen lymph nodes
  • Chills
  • Exhaustion

A few days in, a rash typically starts to develop, according to the CDC. The rash will often start on people’s face and then spread to the rest of the body. The bumps from the rash will eventually scab over and fall off.

This 1997 image provided by CDC, shows the right arm and torso of a patient, whose skin displayed a number of lesions due to what had been an active case of monkeypox. (CDC via AP)

The full cycle of illness usually lasts between two and four weeks, the CDC says.

The disease is endemic in animals in Africa, but isn’t usually seen outside the continent. To date, the World Health Organization has recorded more than 90 cases of monkeypox in a dozen countries including Britain, Spain, Israel, France, Switzerland, the U.S. and Australia. 

There is no proven treatment for monkeypox, the CDC says. In Africa, the virus kills as many as 1 in 10 people who contract it. However, most people recover on their own without requiring hospitalization.

All the cases in the latest global outbreak have been mild so far.

The virus was first discovered in a colony of monkeys in 1958 – hence its name. The first human case was recorded in 1970, says the CDC.

The Associated Press contributed to this report.