Monkeypox, a rare tropical disease transmitted by wild animals in West Africa, has unexpectedly spread abroad over the past two months, raising questions about exactly what it is and how dangerous it could be.
According to the World Health Organization (WHO), there are 2,208 confirmed cases in the UK as of July 21, with infections reported in many countries outside Africa, including the US, Mexico, Argentina, Australia, the United Arab Emirates, Spain, Portugal, and France , Germany, Italy, Sweden and India.
The relatively mild viral infection has an incubation period of six to 16 days and initially leads to fever, headaches, swelling, back pain, sore muscles and general listlessness.
Once that passes and the fever breaks, the sufferer experiences a rash, with a rash spreading across the face, followed by the rest of the body, most commonly the palms of hands and soles of the feet.
The blemishes progress from lesions to crusted blisters, which can then take three weeks to heal and go away.
According to the US Centers for Disease Control and Prevention: “The main difference between the symptoms of smallpox and monkeypox is that monkeypox causes lymph nodes to swell (lymphadenopathy), while smallpox does not.”
The virus can be difficult to diagnose without the help of laboratory analysis due to its superficial resemblance to other conditions that cause a rash, such as chickenpox, measles, scabies, and syphilis.
The WHO has traced the disease to the tropical rainforests of central and western Africa and defines it as a viral zoonosis – meaning it can be transmitted from animals to humans – with the first case being recorded in 1970 in what is now the Democratic Republic of the Congo.
While it would initially have been transmitted to humans through contact with the blood or body fluids of contaminated primates, or via intermediate rodents such as tree squirrels and Gambian rats, it is much more likely to be caught by fellow humans.
There is currently no vaccine or specific treatment, but the smallpox vaccine that already exists has been shown to be 85 percent effective in controlling the disease.
The UK Health Security Agency (UKHSA) is currently investigating possible links between infected patients and found that as of Monday May 16 four people diagnosed together were gay or bisexual men and warned that this could indicate that the Virus is sexually transmitted in this community.
Mateo Prochazka, an infectious disease epidemiologist at the UKHSA who is leading the agency’s investigation, said the shared circumstances “strongly suggest sexual network spread”.
dr Susan Hopkins, UKHSA’s senior medical adviser, said: “We urge gay and bisexual men in particular to be alert for any unusual skin rashes or lesions and to contact a sexual health service immediately.”
The Spanish Newspaper The country meanwhile, Elena Andradas, head of public health for the Madrid region, quoted earlier this month that “22 of the 23 suspected cases reported having had sex with other men in the past few weeks”.
However, some scientists have questioned the theory that monkeypox might have evolved the ability for sexual transmission.
“It may not be transmitted through sexual intercourse, but through the close contact that involves intercourse,” said Professor Keith Neal, an epidemiologist at the University of Nottingham.
“Further work examining whether the virus is found in semen is needed to say that it is truly sexually transmitted.”
Professor Francois Balloux, Director of the UCL Genetics Institute, said: “I would like to caution at this point before concluding that monkeypox has evolved into a sexually transmitted infection.
“Monkeypox is not particularly transmissible and the number of cases in which the route of transmission is known is relatively small.”
According to the UKHSA, very few of the newly infected people in the UK had traveled to a country where monkeypox is endemic, Nigeria.
A man who fell ill during the current outbreak in Massachusetts had also recently spent time in the same country, as had the two people diagnosed in Texas and Maryland last year and the travelers who brought the first cases to the UK in 2018 brought.
However, the worst outbreak to date in the US, which resulted in 47 cases in six states in 2003, was caused by a shipment of infected animals from Ghana.
dr Michael Head, senior research fellow in global health at the University of Southampton, admitted how concerned the public should be that there are “current gaps in our knowledge”.
However, he added that it would be “very unusual to see more than a handful of cases in an outbreak” and stressed that “we will not see Covid-style transmission rates”.
The WHO puts the mortality rate for the disease at just one in ten.