Los Angeles County health officials announced Monday that a resident has died from monkeypox, believed to be the first recorded U.S. fatality linked to the virus. 

The Los Angeles County Department of Public Health announced the cause of death, and a spokesperson said it was confirmed by an autopsy. The patient was severely immunocompromised and had been hospitalized. The county didn’t disclose any other information for privacy purposes.

18 people outside the country have died of the disease in 2022, the CDC reports, but the world’s largest monkeypox outbreak belongs to the United States; it’s recorded almost 22,000 monkeypox cases so far this year.

Rarely seen outside Africa before the spring, the virus, a less deadly cousin of smallpox, has now triggered a 58,000-person global emergency, reaching 103 countries, 96 of which had not historically seen the disease.

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Health officials are also investigating whether monkeypox contributed to the death of an immunocompromised Texas adult in August. That patient was also severely immunocompromised, the Texas Department of State Health Services said.

The World Health Organization declared monkeypox a “public health emergency of international concern,” in July, joining COVID-19 and polio in that designation.

Monkeypox generally starts with flu-like symptoms — fever, swollen glands, muscle aches, and headaches. A rash usually develops a few days later, though in this outbreak it sometimes comes first, said Dr. Marshall Glesby, an infectious disease specialist at Weill Cornell Medicine and New York-Presbyterian.