Smallpox, a rare tropical disease spread by wild animals in Africa, has spread unexpectedly abroad this month, raising questions about what exactly it is and how dangerous it could be.
So far, three suspicious cases have been reported in the US, 20 in the UK, 23 in Portugal and 30 in Spain.
A relatively mild viral infection, the disease has an incubation period of six to 16 days and sees patients suffering from fever, headaches, swelling, back pain, muscle aches and general apathy in their early stages. .
Once this happens and the fever breaks out, the patient will experience a rash, in which a rash spreads across the face, followed by the rest of the body, most commonly the palms of the hands and the soles of the feet.
The spots evolve from lesions to blistering with bark, which can then take three weeks to heal and disappear.
According to the U.S. Centers for Disease Control and Prevention: “The main difference between smallpox and monkeypox symptoms is that monkeypox causes swollen lymph nodes (lymphadenopathy) while smallpox doesn’t. “
The virus can be difficult to diagnose without the help of laboratory tests because of its superficial resemblance to other conditions that lead to a rash, such as chickenpox, measles, scabies, and syphilis.
The World Health Organization (WHO) has located the disease in the rainforests of central and western Africa and defines it as a viral zoonotic disease, that is, it can be transmitted from animals to humans, with the first recorded case in what is now the Democratic Party. Republic of the Congo in 1970.
Although it was initially transmitted to humans by contact with the blood or body fluids of contaminated primates, or by intermediate rodents such as tree squirrels and Gambian rats, it is much more likely to be caught by other humans. .
No specific vaccine or treatment is currently available, but the pre-existing smallpox vaccine has been shown to be 85% effective in fighting the disease.
The UK Health Security Agency (UKHSA) is currently investigating possible connections between infected patients and noted that four diagnosed together on Monday 16 May were all gay or bisexual men, warning that this could indicate that the virus is spreading. sexually transmitting between this community.
Mateo Prochazka, a UKHSA infectious disease epidemiologist who leads the agency’s research, said the shared circumstance was “highly suggestive of sexual spread”.
Smallpox was first detected in the Democratic Republic of the Congo in 1970
(Reuters)
Dr Susan Hopkins, UKHSA’s chief medical adviser, said in a statement this week: “We are especially urging gay and bisexual men to be aware of any unusual rash or injury and to contact a sexual health service without delay. “.
Meanwhile, the Spanish newspaper El País quoted Elena Andradas, head of public health in the Madrid region, as saying that “22 of the 23 suspected cases have reported having had sex with other men in recent weeks.”
However, some scientists have questioned the theory that monkeypox may have developed the ability to transmit sexually.
“It may not be transmitted through sexual intercourse other than through close contact associated with sexual intercourse,” said Professor Keith Neal, an epidemiologist at the University of Nottingham.
“Additional work is needed on whether the virus is in the semen to say that it is actually sexually transmitted.”
Professor Francois Balloux, director of the UCL Institute of Genetics, said: “I would call for some caution at this stage before concluding that the smallpox of the monkey has turned into a sexually transmitted infection.
“The smallpox of the monkey is not particularly transmissible and the number of cases so far where the route of transmission is known is still relatively small.”
An electron microscopic image shows mature particles of the monkeypox virus in an oval shape
(Reuters)
Only one of the newly infected individuals in the UK had traveled to a country where monkeypox is endemic, Nigeria, according to the UKHSA.
The man who fell ill in Massachusetts this week had also spent some time recently in the same country, as did the two people diagnosed in Texas and Maryland last year and the travelers who brought the first cases to the UK in 2018. .
However, the worst outbreak in the United States to date, with 47 cases in six states in 2003, was caused by a shipment of infected animals arriving from Ghana.
As for the public’s concern, Dr Michael Head, a senior researcher in global health at the University of Southampton, acknowledged that “there are currently gaps in our knowledge”.
But he added that “it would be very unusual to see more than a handful of cases in any outbreak” and stressed that “we will not see levels of transmission in the style of Covid.”
The WHO estimates the death rate from the disease at just one in ten.