The first case of the more dangerous variant of mpox, Clade 1, was reported in the Nordic country of Sweden in Northern Europe on Thursday, August 15.

“The affected person has also been infected during a stay in an area of Africa where there is a large outbreak of mpox Clade 1,” Olivia Wigzell, acting head of the Swedish public health agency, informed reporters.

According to the US Centers for Disease Control and Prevention (CDC), Clade 1 causes more severe illness and deaths. Clade 1 is endemic to central Africa. Meanwhile, Clad 2 is primarily found in West Africa and is usually associated with milder symptoms.

The viral mpox disease (formerly known as monkeypox) was declared a public health emergency of international concern by the World Health Organization (WHO) on Wednesday (August 14).

This follows an upsurge of mpox in the Democratic Republic of Congo (DRC) and a growing number of countries in Africa.

Mpox has been reported in the DRC for more than a decade, and the number of cases reported each year has increased steadily over that period.

Last year, reported cases increased significantly, and already the number of cases reported so far this year has exceeded last year’s total, with more than 15,600 cases and 537 deaths.

Mpox is a zoonosis, a disease that is transmitted from animals to humans, with cases often found close to tropical rainforests where there are animals that carry the virus.