As more people are traced by health authorities, scientists expect monkeypox cases to rise this week.
More than 80 cases have been reported in Europe, the US and Australia. The global figure for a disease that is usually confined to central and west Africa is unprecedented.
Doctors have been puzzled by the Monkeypox outbreak and the appearance of cases on different continents at the same time. The virus can only be transmitted from person to person through close physical contact.
Symptoms are usually mild, but monkeypox can cause skin infections which can lead to secondary infections.
Charlotte Hammer is a Cambridge University expert on emerging diseases.
The first cases of the monkeypox outbreak will likely see new infections because of the one to three week incubation period.
The number and range of cases in the present outbreak is unusual, but Monkeypox has been found outside Africa in the past.
Hammer said we face two options, either the virus is inherently different now or our susceptibility to it has changed. It could be that we have encountered a perfect storm of conditions that have allowed the virus to spread. I think the latter is more likely.
There is a chance that the effects of past mass vaccinations are fading, leaving fewer people with protection against monkeypox.
Is the virus the same as it was before? asked Prof Neal, ofNottingham University. It doesn't appear to be any more lethal, but something may have affected its transmissibility. This is a DNA virus and is unlikely to evolve at the same rate as other viruses, including those that cause Covid or HIV. Overall, I'm not too worried.