Monkeypox has now been detected in countries from the US to Australia and is moving closer to these shores with cases detected in Britain. Should we be worried?
Monkeypox is a viral infection typically found in central and western Africa. Cases, usually small clusters or isolated infections, are sometimes diagnosed in other countries, including Britain where the first case was recorded in 2018 in an individual thought to have contracted the virus in Nigeria.
There are two forms of monkeypox, a milder west African strain and a more severe central African, or Congo strain. In Australia and Britain at least, it is thought the recently diagnosed individuals have the west African strain, although not all countries have released such information.
According to the UK Health Security Agency, early symptoms of monkeypox include fever, headache, muscle aches, swollen lymph nodes and chills, as well as other features such as exhaustion.
“A rash can develop, often beginning on the face, then spreading to other parts of the body, including the genitals,” the UKHSA says. “The rash changes and goes through different stages, and can look like chickenpox or syphilis, before finally forming a scab, which later falls off.” Most patients recover from monkeypox in a few weeks.
Monkeypox does not spread easily between humans and requires close contact. According to the US Centers for Disease Control and Prevention, it is thought that human-to-human transmission primarily occurs through large respiratory droplets.
Monkeypox cases have been confirmed in recent weeks in a number of countries where it is not endemic, including the US, Canada, Italy, Portugal and Sweden, with the first cases reported in Germany and Australia on Friday. Suspected cases have been identified in Spain and France.
While some cases have been found in people who have recently travelled to Africa, others have not: of the two Australian cases to date, one was in a man who had recently returned from Europe, while the other was in a man who had recently been to the UK. A case in the US meanwhile appears to be in a man who recently travelled to Canada.
The UK is also experiencing cases of monkeypox, with signs that it is spreading in the community. So far 20 cases have been confirmed, with the first reported on May 7 in a patient who had recently travelled to Nigeria.
Not all of the cases appear to be linked and some have been diagnosed in men who self-identify as gay, bisexual, or men who have sex with men.
The World Health Organization said on Tuesday that it was now coordinating with European health officials.
Dr Michael Head, a senior research fellow in global health at the University of Southampton, says the latest cases may be the first time transmission of monkeypox though sexual contact has been documented, but this has not been confirmed, and in any case it is probably close contact that matters.
“There is no evidence that it is a sexually transmitted virus, such as HIV,” Head says. “It’s more that here the close contact during sexual or intimate activity, including prolonged skin-to-skin contact, may be the key factor during transmission.”
Gay and bisexual men are being advised to look out for unusual rashes or lesions on any part of their body, in particular their genitalia.
The west African strain of monkeypox is generally a mild infection for most people, but it is important those infected and their contacts are identified. The virus is more of a concern among vulnerable people such as those with weakened immune systems or who are pregnant. Experts say the rise in numbers and evidence of community spread are worrying, and that more cases are to be expected as contact tracing by public health teams continues. It is unlikely, however, that there will be very large outbreaks. Head noted that vaccination of close contacts could be used as part of a “ring vaccination” approach.
According to the World Health Organization , “vaccination against smallpox was demonstrated through several observational studies to be about 85% effective in preventing monkeypox”. The jab may also help to reduce the severity of illness.