(NEXSTAR) – Since Sunday, six more states have reported their first cases of monkeypox, bringing the national total to 36 states that have seen at least one case of the virus this year.

Massachusetts reported the U.S.’s first case of the monkeypox virus in May in a man who had recently traveled to Canada. Over 600 cases have been confirmed in the U.S. and Puerto Rico since, the latest data from the Centers for Disease Control and Prevention shows.

California and New York have the greatest number of cases at 117 and 122, respectively. Those case counts are up from 95 and 90, respectively, reported by the CDC one week ago. Florida and Illinois have each reported just over 60 cases, up from the 51 and 53 reported last week.

Ten states have reported just one case, including Arkansas, Connecticut, Louisiana, Iowa, Michigan, and Wisconsin, all of which reported their first cases in the past week. Ten states have recorded over a dozen monkeypox cases since May.

The U.S. makes up less than 1% of the more than 7,000 monkeypox cases confirmed worldwide, according to the World Health Organization.

Monkeypox, clinically known as orthopox, has sickened people for decades in Africa, but until May, the disease had not been known to cause significant outbreaks in multiple countries at the same time and involving people with no travel links to the continent.

It was first discovered in 1958 in monkeys being kept for research. It was found in humans 12 years later in the Democratic Republic of the Congo in a child in a rural rainforest region where smallpox had since been eradicated, according to the World Health Organization.

People with monkeypox often experience symptoms like fever, body aches and a rash; most recover within weeks without needing medical care.

Scientists warn anyone who is in close physical contact with someone who has monkeypox or their clothing or bedsheets is at risk of infection. Vulnerable populations like children and pregnant women are thought more likely to suffer severe disease.

Some experts and advocates are warning the Biden administration is responding too slowly to the monkeypox outbreak, leaving the U.S. at risk of losing control of the disease. David Harvey, executive director of the National Coalition of STD Directors, said three areas, in particular, have been slow: "streamlining testing, making vaccines available, streamlining access to the best therapeutics."

In New York City, which is responsible for nearly 120 of the state's total cases, health officials say they've received thousands of monkeypox vaccine doses and appointments have been filling up quickly.

Earlier this week, commercial labs began testing for monkeypox, a move CDC Director Rochelle Walensky called a "key pillar in our comprehensive strategy to combat this disease."