Scientists from the Africa Centres for Disease Control and Prevention (Africa CDC) say they are alarmed by the speed at which a new strand of mpox has been spreading.

Since the beginning of the year, more than 13,700 cases and 450 deaths have been recorded in the Democratic Republic of Congo. The virus, which can cause lesions across the whole body, has spread to other African countries, including Burundi, the Central African Republic (CAR) Kenya and Rwanda.

• What is mpox and how is it spread?

The declaration of a public health emergency will help governments co-ordinate their response and potentially increase the flow of medical supplies and aid into affected areas.

Health chiefs outside Africa will also be monitoring the situation to assess the risk of the outbreak spreading further. Mpox spreads from animals to humans and between people through close contact with someone who is infected – including through sex, skin-to-skin contact and talking or breathing close to another person.

It can cause symptoms such as fever, muscle aches and lesions across the body. If left untreated, mpox can be deadly.

There are two main strains of the virus known to exist. The milder one caused the global outbreak in 2022 that affected Europe, Australia, the US and many other countries – and was mainly spread through sexual contact.

The second more deadly strain, endemic in central Africa, is behind the new recently discovered variant in DR Congo.

There are three vaccines that exist but only people at risk or who have been in close contact with an infected person are usually able to have it.