Two people have died after contracting mpox, or monkeypox, South African health authorities said Thursday.

Six recent mpox cases have been confirmed in South Africa, all among men in their 30s. Officials say the two deaths are among the six cases.

One of the men, a 38-year-old, died on Wednesday in eastern KawZulu-Natal province on the same day tests confirmed that he had mpox, according to the health ministry. The ministry also said that another man with mpox died Monday in a hospital near Johannesburg.

Mpox, in the same family as smallpox, is a rare viral infection. Until the World Health Organization noted expanding global cases in 2022, it was not known to spread easily.

Those outbreaks were the first time mpox was seen to spread via sex. The infection can also be contracted through bites from small animals such as rodents.

Genetic tests from the first three cases in South Africa produced results indicating the men had a less-severe version of mpox.

None of the men had a travel history to countries with a current outbreak, suggesting local transmission, said Health Minister Joe Phaahla. He said all six had underlying health conditions.

Last year, the World Health Organization said that mpox is not an international health crisis. A WHO report released last month noted 186 mpox deaths worldwide since 2022, giving a fatality rate of under 1%.

According to Phaala, South Africa’s last mpox case before the recent instances was in 2022. Although South Africa does not currently have mpox vaccines, it is considering an immunization campaign.

The Associated Press and Reuters contributed to this report.