A patient in England has been diagnosed with a rare case of monkeypox, according to a statement released by the UK Health Security Agency on Saturday.

Monkeypox is an uncommon viral virus that is difficult to transfer between individuals, according to the CDC, which rates the overall risk to the general population as “extremely low.” “The virus can spread when someone comes into close touch with an infected individual,” the statement said, “but there is a very minimal risk of transmission to the general community.”

According to the UKHSA, the patient caught the virus in Nigeria before arriving in the UK lately. He or she is being treated in London at the Guy’s and St Thomas’ NHS FoundationTrust’s specialized infectious illness and isolation unit. Fever, headache, muscular pains, backache, enlarged lymph nodes, chills, and tiredness are among the first symptoms, according to the UKHSA.

As a precaution, the UKHSA stated it will contact “everyone who may have had direct contact with the individual to offer information and health advice.” Monkeypox is a close relative of smallpox, which was declared eliminated in 1979, although it is less contagious and lethal. “The fundamental difference between smallpox and monkeypox symptoms is that monkeypox causes lymph nodes to enlarge whereas smallpox does not,” according to the US Centers for Disease Control and Prevention.

Monkeypox may be carried by rodents, including pets, and transmitted to humans by monkeys. Last year, the CDC looked at one instance involving a visitor to Dallas.