Monkeypox: 5 keys to transmission provided by scientific studies carried out on patients


The monkeypox outbreak in 2022 has a different pattern and symptoms than the cases recorded in Africa since 1970/Archive

More than 34,000 people have already been diagnosed with monkeypox or monkeypox. in more than 90 countries in the world since last May. There are now four published scientists on the outbreak showing that the symptoms and pattern of spread of the virus causing the disease do not resemble what had been observed from 1970 onwards in West and Central Africa. In that region of the world, the monkeypox virus has caused isolated and persistent outbreaks for decades.

Early predictions that the monkeypox virus is transmitted primarily through repeated skin-to-skin contact between people have been largely confirmed, according to a series of new studies. “When you put all these studies together, we see that the clinical presentation is similar everywhere, but also surprising,” told the magazine Nature Dr. Oriol Mitjà, an infectious disease researcher at the Germans Trias i Pujol University Hospital in Barcelona, ​​Spain, co-author of one of the recent studies in the journal The Lancet. Studies on cases in Spain were also published in the journal Eurosurveillance (see here) and another led by scientists from Italy in The Lancet Infectious Diseases.

The rapid spread of the virus prompted the World Health Organization to issue its highest public health alert on July 23, declaring the monkeypox outbreak “a public health emergency of international concern.” On August 4, the President of the United States, Joe Biden, also declared smallpox a public health emergency. Here are some clues from the studies to understand the current situation:

More than 34,000 people have already been diagnosed with monkeypox or monkeypox.  in more than 90 countries in the world since last May/ REUTERS/Dado Ruvic/File
More than 34,000 people have already been diagnosed with monkeypox or monkeypox. in more than 90 countries in the world since last May/ REUTERS/Dado Ruvic/File

1- Smallpox is being transmitted by skin contact during sexual intercourse

Although some women and children have been infected since May, the majority of cases so far have been in men who have sex with men (MSM), especially those with multiple sexual partners or who engage in anonymous sex. It is likely that the virus has taken advantage the sexual networks of the MSM community to spread effectively, according to Dr. Mitjà. The more the virus spreads, the more opportunities it has to infect other populations, including wild animals, which scientists have warned could establish viral reservoirs that could repeatedly infect humans.

“Our study – he pointed out to the newspaper ABC Cristina Galván, dermatologist at the University Hospital of Móstoles, in Madrid and co-author of the study in The Lancet– has found that skin samples are more frequently positive and reflect a greater abundance of viral genome than samples from other areas such as the throat. In the context of a sexual relationship, he adds, “this intimate contact with the skin or external mucous membranes of an affected person undoubtedly occurs. Positive PCR for monkeypox virus has been found in vaginal secretions and semen, but its infective capacity and, therefore, whether it can be transmitted through these fluids has yet to be determined. Right now, rather than saying it’s a sexually transmitted infection, “we should say it’s an infection that is transmitted during sexual intercourse,” he said.

Rather than stating that it is a sexually transmitted infection,
Rather than stating that it is a sexually transmitted infection, “we must say that it is an infection that is transmitted during sexual intercourse,” said an expert from Spain. (Getty Images)

2. Symptoms are often different from outbreaks in Africa in previous years

When a person contracts monkeypox, they may develop flu-like symptoms, enlarged lymph nodes, and distinctive fluid-filled lesions on the skin. Although some researchers have suggested that the monkeypox virus could be spread through respiratory droplets or airborne particles, as SARS-CoV-2 does, Mitjà and colleagues report that samples, taken when a person is diagnosed, from skin lesions contain much more viral DNA than those from the throat. Lesions appear to be comparatively “virus-ridden”said Boghuma Titanji, an infectious disease physician at Emory University in Atlanta, Georgia, who was not involved in the study in The Lancet.

In the first case of monkeypox diagnosed in Argentina without a history of travel abroad, the patient also had symptoms that were not the classic ones that had been described for the disease. In dialogue with Infobae one of the doctors and co-author of the work published in the journal Medicina (Buenos Aires), Maria Celia Cuestawho is a member of the Argentine Society of Infectious Diseases, said that today it can be difficult to diagnose smallpox because it is a new infection in the country and not all patients have the classic symptoms. “In the case we report, the patient had a type of pharyngitis with exudate, which has not been frequently reported in other countries”Dr. Cuesta commented.

In another study, researchers from the United Kingdom, Israel, Germany, Canada, Mexico, Spain, Switzerland, Italy, Belgium, France, the Netherlands, and Denmark, among other nations, published data on symptoms and transmission for more than 500 patients from 16 countries. The document, which was published in the magazine The New England Journal of Medicine (NEJM), warned that Solitary genital skin lesions and those affecting the palms of the hands and soles of the feet can easily lead to a misdiagnosis of syphilis. and other sexually transmitted infections, which in turn can delay detection.” Experts noted that identifying these new clinical symptoms of monkeypox infection will help future diagnosis and curb the spread of the infection. Since many of the infected individuals tested in the study presented symptoms uncharacteristic with the current medical definitions of monkeypox.

Pustules on the skin, fever and sore throat can be symptoms of monkeypox/ARfile
Pustules on the skin, fever and sore throat can be symptoms of monkeypox/ARfile

3- Airborne transmission of the monkeypox virus is still under study

Several studies, including Mitjà’s, show that few people contract the disease from an infected family member with whom they have not had sexual contact. This finding, along with data on viral load, suggests that respiratory droplets and airborne particles are probably not the main route of transmission, Titanji said.

Detailed data on how a person’s viral load changes over time is still lacking, said Dr. Jessica Justman, an infectious disease physician at Columbia University in New York. Although Mitjà and her colleagues did not detect much viral DNA in the samples they collected from people’s throats early in the infection, it is possible that if they had collected them later – or even earlier – the viral levels would have been higher. , she acknowledged.

It is also suspected that there are cases that have not yet been diagnosed. “We cannot know the percentage of patients who have remained undiagnosed, either because this possibility has not been taken into account or because they have had few symptoms.. But we do have ongoing studies aimed at answering this question, which is so important for controlling the spread of the disease”, according to Galván.

Detailed data on how a person's viral load changes over time is still lacking/Cdc
Detailed data on how a person’s viral load changes over time is still lacking/Cdc

4- Health authorities need to improve communication on smallpox prevention

Dr. Mitjà and his colleagues found that, in the people they examined, having more lesions in the mouth and throat was related to oral sex, and having more lesions in and around the anus was related to receptive-anal sex. Considering all these results, Titanji stated that it is essential that public health officials do not shy away from talking about sex in their guidance and be explicit about the types of protection available.

Uncertainty regarding knowledge gaps should also be shared with the community. It is not yet clear if monkeypox is sexually transmitted in absolute terms, that is, if it passes from one person to another through blood, semen or other bodily fluids during sexual intercourse. However, several studies have found that monkeypox virus DNA is present in a person’s semen for weeks after infection. One study also isolated infectious virus from the semen of a single individual six days after their symptoms appeared.

Taking into account the epidemiological data of the cases of the current outbreak, “it seems that the respiratory tract has not participated in an important way in the transmission. The number of people affected is already abundant and cases of transmission in circumstances other than sexual contact are almost non-existent,” said Dr. Galván. But he prefers to be cautious. “In cases of classic monkeypox -which has affected endemic countries or in outbreaks limited to non-endemic countries after a trip or another episode of sporadic contagion- the presence of the virus in the respiratory mucous membranes can be demonstrated. As is the case with its detection in genital fluids and saliva, research, already underway, is very important to determine its ability to transmit the infection.”

Public health officials should discuss sex in their guidance and be explicit about the types of protection available/REUTERS/Eric Cox
Public health officials should discuss sex in their guidance and be explicit about the types of protection available/REUTERS/Eric Cox

5- Access to smallpox vaccination may be limited

Some researchers are already concerned that the outbreak is beyond the point of containment, given reports of inadequate vaccine stockpiles and unaffordable antiviral treatments, as well as insufficient testing. Funding and motivation to study monkeypox is limited compared to COVID-19, Dr. Justman warned.

If future studies find infectious virus in semen, it will be important to understand how long it can persist in that body fluid. Viruses like Ebola can persist in semen for months, if not years, after infection, which has complicated efforts to prevent outbreaks. Until researchers know more, the UK Health Security Agency recommends that people continue to use condoms for eight weeks after infection.

KEEP READING:

COVID-19 and monkeypox: what are the 5 differences between the two health emergencies facing the world
Monkeypox: with more than 10,000 cases in the Americas, PAHO promotes equitable access to vaccines
Monkeypox: how to avoid stigma on patients so as not to repeat what happened with HIV




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