This 2003 electron microscope image shows mature, oval-shaped monkeypox virions, left, and spherical immature virions, right, obtained from a sample of human skin associated with the 2003 prairie dog outbreak. Credit: Cynthia S. Goldsmith and Russell Regner / CDC via AP

Public health officials hoping to cut off transmission of monkeypox in the United States say the virus is likely spreading within communities across the country and could become difficult to contain.

Only nine cases have been identified so far in seven states: Massachusetts, Florida, Utah, Washington, California, Virginia and New York. But some of those cases are among individuals with no known contacts to travelers from West or Central Africa, where monkeypox has circulated for decades.

“Given that not all of these had active travel histories to endemic areas, I think we need to presume that there is some community spread,” Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, told reporters in a briefing on Thursday. “There is active contact tracing that is happening right now to understand whether and how these cases may have been in contact with each other, or with others in other countries.”

Dr. Jennifer McQuiston, deputy director of the CDC’s Division of High Consequence Pathogens and Pathology, said “it’s a little too early to tell” whether the virus has the potential to become endemic in the United States.

“I think we’re in the very early days of our investigations,” said McQuiston. “We don’t yet know how many (cases) there might be.”

“We’re working hard to contain the cases that are happening so they don’t spread onward. So I think it’s a little too early to tell,” she said.

But an outbreak of the virus in 2003 that resulted in the infection of hundreds of animals and several people was successfully contained, McQuiston noted, giving the agency hope that the current outbreak can be managed as well.

“After that outbreak, we didn’t see it become endemic, and we see any animal reservoirs that ended up becoming established,” she said. “So I think we’re hopeful that we’ll be able to similarly contain it.”

Monkeypox is within the same family of viruses as smallpox and is spread through skin-to-skin contact and infectious bodily fluids. Vaccines and treatments exist for the disease, which can cause fever, fatigue, headache, swollen lymph nodes and a distinct rash typically concentrated in the face or groin area. Cases often resolve on their own over several days or weeks.

Seventy-four labs across 46 states are currently using an FDA-cleared test to spot viruses in the orthopox family. The CDC is then able to process positive test results to determine whether monkeypox, specifically, has been identified.

The current outbreak appears to be concentrated among gay and bisexual men. Past monkeypox outbreaks have circulated primarily within other communities, Walensky and other officials said, noting that anyone is susceptible to infection.

Sylvie Briand, director for global infectious hazard preparedness at the World Health Organization, said on Tuesday that the global monkeypox outbreak is “not normal” but remains containable.

Over 130 cases of the virus have been identified in 19 countries where it is not known to circulate.

Michael Wilner, McClatchy Washington Bureau