Monkeypox: understanding transmission, symptoms and the vaccine

The World Health Organization (WHO) declared monkeypox a public health emergency of international concern six days ago. Known internationally as monkey poxthe disease, which is endemic in parts of Africa, has already affected 20,637 people in 77 countries this year.

In Brazil, there are 978 cases, including 744 in São Paulo alone. Considering the importance of information to fight against the advance of the epidemic, the Federal University of Rio de Janeiro (UFRJ) organized, this Thursday (28), a meeting where experts presented what the we already know about the disease and also answered questions about the face- face to the participants and on line.

A monkey pox is caused by a smallpox virus of the subgroup orthopoxvirusas for other diseases such as smallpox and smallpox, eradicated in 1980 through vaccination. The endemic picture on the African continent is due to two distinct strains.

Transmission and symptoms

– Follow-up after announcement –

Monkeypox was first described in humans in 1958. At the time, monkeys were also affected and they died. Hence the name of the disease. However, in the transmission cycle, they are victimized like humans. In nature, wild rodents represent the animal reservoir of the virus.

Without an animal reservoir, worldwide transmission has occurred from person to person. The infection comes from wounds, bodily fluids and droplets of the patient. This can occur through close and prolonged contact without respiratory protection, contact with contaminated objects, or skin contact, including sexual contact.

The incubation time for the virus varies from five to 21 days. The most characteristic symptom is the formation of painful rashes and nodules on the skin. Fever, chills, headache, muscle aches and weakness may also occur.

According to the WHO protocol, cases where the patient has at least one skin lesion on any part of the body and meets any of these requirements within the last 21 days should be considered suspicious: history of travel to a country with confirmed cases, contact with travelers who have been to that country, or intimate contact with strangers.

diagnosis and treatment

The UFRJ’s Molecular Virology Laboratory has established itself as one of the national centers for diagnosing the disease. The first case in the state of Rio de Janeiro was detected on June 14, five days after the country’s first case was confirmed in São Paulo. Since then, there have been 117 positive results in Rio State. Other states have also sent samples for analysis to UFRJ.

These analyzes are carried out on fluids taken directly from the skin lesions, using a swab [cotonete estéril] dry. It is expected that the population will soon have access to rapid antigen detection tests, similar to those carried out for covid-19.

Even in the most characteristic cases, the examination is important to confirm the clinical analysis. A challenge in detecting the disease is the similarity of its lesions to those caused by chickenpox, a disease known as chickenpox and caused by a virus from another group. The changing profile of symptoms has also raised the alarm of experts. In monkeypox, the rashes tend to appear more or less together and move at the same rate.

Once the disease is detected, treatment is based on clinical support and medication to relieve pain and fever. An antiviral called tecovirimat, which blocks the spread of the virus, is already in use in some countries, but is not yet available in Brazil.

According to the doctor, 10% of patients have been hospitalized to control pain, usually when there are lesions in the anus, genitals or oral mucosa, making swallowing difficult.

Prevention and vaccines

Surveillance for the rapid identification of new cases and the isolation of infected people are essential to prevent the spread of the disease. It may take up to 40 days to resume social activities. Even if the patient feels better, he should remain isolated while he still has a rash. “In chickenpox, the crusted lesion no longer transmits the virus. In monkeypox, this lesion is transmitted,” Rafael pointed out.

The infectious disease specialist warned of the importance of avoiding contact with people who are part of risk groups. According to him, although there are few case studies involving pregnant women, the results are not good. “There is a high pediatric lethality. There is what we call vertical transmission, ie the involvement of the fetus in serious lesions: loss of placental structures and spontaneous abortions. With what little is known, it is considered a serious obstetric disease. Suspects of being infected should be instructed to avoid contact with anyone who may be pregnant,” he warned.

With the eradication of smallpox, vaccination was suspended worldwide around 1980. In Brazil more vigorous campaigns took place until 1975, but until 1979 the immunizing agent was applied in the posts health. Evidence indicates that those born before this date who have been vaccinated are protected against monkey pox. The average age of those infected is less than 38 years old.

Although vaccines already exist to help combat the monkeypox epidemic, there are no plans for a mass vaccination campaign.

The WHO guides the protection of health professionals and laboratory researchers. For other population groups, vaccination should take place after exposure. According to virologist Clarissa, this involves using the ring vaccination strategy: people who live and have been in contact with a positive patient are vaccinated in an attempt to block the spread of the virus. “This vaccine works very well up to four days after infection,” he noted.

Clarissa adds that currently there is not a vaccine for everyone and global production will take time. “Manufacturers had no production forecast for a disease that would affect the whole world. Production was exclusively for strategic stock in countries with biodefense programs. Brazil, like many other nations, doesn’t have that,” he explained. According to Rafael, studies have already shown the effectiveness of the ring vaccination strategy in certain outbreak scenarios.

Profile of infected persons

Men under the age of 40 represent the vast majority of those infected. Studies in the UK have found that many victims identify as gay or bisexual. Experts, however, warn that monkeypox can affect anyone, not just sexually active men. Women and adolescents have already been diagnosed with the disease by the Molecular Virology Laboratory of UFRJ.

WHO Director Tedros Adhanom Ghebreyesus this week advised men who have sex with men to reduce their number of sexual partners at this time. At the same time, he warned that “stigma and discrimination can be as dangerous as any virus and could fuel the epidemic”.

Misinformation can leave society unprepared to deal with the epidemic, says Dr Amilcar Tanuri. “It goes back to the history of AIDS and HIV. At first, there was a stigma that only hindered the prevention of the disease. Indeed, when the virus enters an initial group, it takes some time to spread to other groups. With HIV, it started like that. Then we realized that hemophiliacs had HIV, that children were born with HIV. There is no biological evidence that monkeypox virus is sex-specific. In fact, I don’t know which virus has this specificity,” he said.

(With information from Agência Brasil)

Photo: CDC/Cynthia S. Goldsmith

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