In a few days, monkey pox or monkeypox spread: since May 6, nine cases of this virus have been detected in the United Kingdom. With the exception of the first infected person, who had recently traveled to Nigeria, these patients were infected across the Channel, according to the British health security agency. Spain and Portugal announced on Monday that they had identified around thirty suspected or confirmed cases of this monkey pox. The same day, the health authorities of the Canadian metropolis of Montreal found more than a dozen potential cases, while the United States confirmed a patient from Canada. A first confirmed case was detected Thursday in Sweden.
The World Health Organization (WHO) said on Monday it is taking a close interest that some of the cases in the UK appear to have been passed on within the gay community. If the various authorities want to be reassuring for the time being, monkeypox being a disease that is not very contagious and very little fatal, the multiplication of these apparent outbreaks in Europe and America is a rare phenomenon.
What is monkey pox?
Endemic to West and Central Africa, monkeypox is a zoonosis caused by a virus belonging to the same family as that of human smallpox. But the name remains misleading: its origin does not come from monkeys, but from many other mammals. “In a Danish pet shop in 1958, monkeys developed a disease, then unknown at the time, which resembled human smallpox. The Danes therefore named this virus monkeypox because it was in these animals that it was first observed. clarify with Release Antoine Gessain, head of the epidemiology and physiopathology of oncogenic viruses unit at the Institut Pasteur, one of the few in France to be interested in the disease.
The transmission reservoirs would actually be squirrels and rodents. It was in 1970 that the first human case was detected in the center of the former Zaire, now the Democratic Republic of Congo, in a 9-year-old child. Many of the cases that Antoine Gessain studied in Africa, in collaboration with Pasteur institutes in the region, were children or young adults who had been in close contact with these small animals.
What are the symptoms ?
Symptoms of monkeypox appear in two stages. They first cover fever, headache, muscle aches, back pain, swollen lymph nodes, chills and fatigue. Rashes can then occur, often on the face, and spread to other parts of the body including the genitals, palms of the hands and soles of the feet.
How is the virus transmitted?
Between humans, the modes of transmission known so far are respiratory droplets and skin lesions which, when scratched, cause scabs to fall off and can be touched by the other. “This virus can also be transmitted in the environment, for example if you touch a door handle”, adds Antoine Gessain.
New fact since the appearance of cases in Western countries, it is noted that the contamination could also take place during a sexual intercourse. “We are seeing transmissions among men who have sex with men,” which is “new information that we need to study properly to better understand the dynamics” transmission,” said Ibrahima Socé Fall, WHO’s deputy director-general for emergency response in Geneva.
The virologist is not surprised by this discovery: “Sexual transmission has been understudied and poorly documented. But lesions can arise on the genitals just like anywhere else on the skin, so it makes sense that you can catch monkeypox during sex.” The Centers for Disease Control and Prevention (CDC), the main federal health agency in the United States, also specifies that “Anyone, regardless of sexual orientation, can spread monkeypox.”
Is this spread unusual?
Since the first case fifty years ago, monkeypox has never really disappeared from Africa. The countries affected by the occasional resurgence of cases are the Democratic Republic of Congo, Cameroon and Nigeria. In the latter region, an epidemic took place in 2017 with several hundred cases. “Only a few have spread to the US, UK, Singapore and Israel,” remembers Antoine Gessain.
But other larger epidemics have spread across the Atlantic. “The typical example is that of the United States in 2003 [47 cas confirmés et probables selon les CDC, ndlr], which primarily concerned children. They had been contaminated by small prairie dogs, which themselves had been contaminated by Gambian rats in a pet store. This is the largest overseas monkeypox outbreak to date compared to Africa.” observes the researcher from the Pasteur Institute.
To Reuters, Jimmy Whitworth, professor of international public health at the London School of Hygiene and Tropical Medicine, assures that this new spread in Europe and America was “very atypical”. “Historically, there have been very few exported cases. This has only happened eight times in the past before this year,” he completed.
Are there any treatments?
No specific vaccine can protect against monkeypox. But the vaccine for human smallpox, which continued to be prescribed until the 1980s, despite its total eradication in 1977, makes it possible to reduce the risks. “In Africa, we notice that people over 50, who have been vaccinated against smallpox, hardly ever catch monkeypox”, emphasizes Antoine Gessain.
Can we imagine reusing this vaccine if the cases multiply? For now, the number of cases is not alarming. Especially since the laboratories have kept very few smallpox strains. They are currently stored in so-called “P4” structures, which house the deadliest viruses on the planet. However, when a person catches monkeypox, it can be treated with antiviral drugs, as specified in the Merck Manual of Diagnosis and Therapeutics, a reference work. “It’s a disease that heals spontaneously after a few weeks,” also highlights Antoine Gessain.
Is the monkeypox virus contagious and dangerous?
While mortality from human smallpox was over 30%, monkeypox is considered much less dangerous. Its lethality is 1 to 10% in African countries, knowing that these populations live “in poor hygienic conditions”, reminds the virologist. According to his observations and those of his colleagues, he asserts that the few people who die from it have generally been exposed to “superinfections”, like that of HIV combined with monkeypox. “It is not a serious disease, especially in our societies where medicine is of good quality”, he wants to reassure.
The monkeypox virus is characterized by a rather long incubation time, between one and two weeks. Reassuringly, an infected person can only infect others when clinical signs (such as pimples on the skin) appear. The virus is therefore rather difficult to transmit compared to other diseases, such as the flu or Covid-19.
Especially since monkeypox is a DNA virus, not an RNA virus, which implies very low mutation rates. “A priori, we are not in a context of evolutionary dynamics and mutation, judges the researcher from the Pasteur Institute. The risk of an epidemic is therefore minimal.