Map shows how quickly monkeypox spread through the US in the biggest-ever outbreak beyond Africa

• Every state in the US with data is now reporting at least one monkeypox case, per the CDC.
• The disease has historically been confined to Africa and has never spread elsewhere at scale.

Monkeypox has been spreading quickly across the US, touching every state that is reporting data.

As of Friday, the CDC recorded 2,891 cases of monkeypox in the US. Two of those were among children, the CDC said on Friday.

These are the five states with the most reported cases as of July 22:

• New York: 900.
• California: 356.
• Florida: 247.
• Illinois: 238.
• Georgia: 211.

There has never been a global outbreak on this scale before

This is the biggest such outbreak reported outside of African countries. The second-largest outbreak was reported in the US in 2003, where it was limited to 300 cases.

The World Health Organization on Saturday declared the outbreak a public health emergency of international concern, which means this is an "extraordinary event" that needs a rapid global response.

Over 16,000 cases have been reported in 74 countries in just over two months. Of these, 68 "have not historically reported monkeypox," according to the CDC.

The true number is cases is much larger than the data shows, WHO director-general Tedros Ghebreyesus said on July 6, citing limited volumes of testing.

Men who have sex with men (MSM) have been disproportionately affected by the disease. A large study of more than 500 monkeypox cases diagnosed across the globe found about 98% of cases were among MSM.

Public health agencies, however, have emphasized that sexual orientation has no influence on the spread of the disease.

Not very lethal, but very painful

Infections in this outbreak have not proven particularly lethal — five deaths have been reported so far, none of which were in the US.

The symptoms are thought to resolve on their own within a few days of contracting the virus.

But people have reported the symptoms can be extremely painful. Several have had to be hospitalized to manage the pain.

Symptoms of monkeypox include a rash, fever and backache. Early symptoms include swollen lymph nodes, chills and exhaustion.

Historically, the rash has tended to break out on the hands and feet, but this outbreak sets itself apart with lesions around the anal and genital areas, which can easily be mistaken for a sexually transmitted disease, the large study into this outbreak has found.

The disease is very infectious and can be passed on through direct contact with the lesions, bed sheets, and surfaces. Face-to-face contact can also spread the disease, as the virus particles can travel in large droplets such as those let off during a sneeze.

There is no treatment for monkeypox. A smallpox vaccine, however, can provide some protection against infection.