Monkeypox: What we know (and don’t know) about monkeypox

The emergence of monkey pox in several countries where it does not occur, sparked a concern among specialists and among the population, which began to worry about the streamingyou symptoms and the severity of the frame. As of May 25, 219 cases have been confirmed in around 20 countries outside Africa.

The first records of the disease, caused by the virus monkeypoxbegan to be carried out in the second week of May, and the genetic sequencing of the current virus was carried out on the 19th. In other words, it is too early to make precise statements about the spread, lethality and possible path of the pathogen.

In any case, as pointed out by the scientific journal nature, the number of cases detected outside the African continent in recent days has already surpassed the accumulated of the last 50 years. Hence the need to monitor the situation and think about containment policies.

“With the global alert that was given, and because it is a disease that is easy to identify and block, the tendency is for us to have an increase in notifications followed by stabilization”, comments infectious disease specialist Alexandre Naime, vice president of the Brazilian Society of Infectious Diseases ( SBI).

Despite the new scenario, monkeypox has been known and monitored for decades. Let’s go, then, to what we know with more certainty and what is still doubtful.

Monkey pox is less dangerous than “human” pox

It is a milder relative of smallpox. “Most of those infected have an initial condition with malaise, headache, body ache and fever. A few days later, the skin lesions”, points out infectious disease specialist Gerson Salvador, from the University of São Paulo (USP).

At this stage, there may be a swollen nodes – the lymph nodes located in the neck, armpits and groin. “The wounds usually start out red and flat, then turn into pustules. [bolhas com pus] and, finally, they heal”, highlights Naime. It is in the purulent phase that transmission is greatest.

As with viral illnesses, most cases resolve within a few weeks (two to four on average). “However, it can be fatal”, points out Salvador. are at greater risk individuals with compromised immune systemsuch as the elderly and those with chronic diseases.

There are two main subtypes of monkeypox:

1. The one that affects Central Africa, especially the Congo, has a lethality of 10% – a high rate
2. The most common in West Africa, causing the current outbreak, which has a lethality of 2 to 3%, similar to Covid-19

To get an idea, the most severe version of human smallpox killed up to 30% of those infected. It is estimated that the disease, eradicated from the planet in 1977 thanks to mass vaccination, has killed around 300 million people throughout history.

The virus is more stable and less transmissible than Sars-CoV-2

In fact, these things are difficult to compare. THE monkeypox It is a virus made of DNA, a more stable and complex molecule than RNA, the main genetic component of the coronavirus.

RNA viruses have fewer mechanisms to contain errors when duplicating their genetic material. Therefore, they undergo more mutations that give rise to unpredictable variants – as we have seen with the coronavirus.

+ Also read: How does a variant of the coronavirus arise?

Of course, DNA pathogens also mutate, but they are more discrete and less frequent. “The first analyzes show small differences between the original lineage, but we don’t know what this changes in the behavior of the virus”, points out virologist Fernando Spilki, a member of CâmaraPox, the monkeypox monitoring committee established by the Ministry of Science, Technology and Innovations (MCTI).

In addition, because it is heavier and larger, the monkeypox it doesn’t seem to be able to stay suspended in the air for so long or travel in smaller particles, like the droplets on which Sars-Cov-2 hitches a ride. In other words, its ability to spread would be lower in this way.

Monkeypox is not a new disease

It was discovered in 1958 in a colony of monkeys living in a laboratory in Denmark. The first infection in humans was diagnosed in 1970 in Congo, a country that still concentrates the largest number of cases of the disease.

Africa has lived with monkeypox for a long time – it is considered endemic in 11 countries. This, incidentally, draws attention to the issue of neglected diseaseswhich reach poor countries and receive less investment in research for treatment and prevention.

This is not the first outbreak outside the continent. In 2003, 70 cases occurred in the same region of the United States, after rodents imported from Ghana infected pet squirrels.

Monkeys might not even have anything to do with it

The disease is a zoonosis – that is, it passes from animals to humans. But, of course, it is also transmitted directly between us, as we are seeing now.

Despite the name, the most widely accepted theory is that Rodents are the main vectors of the disease. “Contagion occurs more easily in contact with a sick animal, through bites, secretions or ingestion of contaminated meat”, explains Salvador.

As several species are hosts, including domestic ones, reducing contact with these animals is important to contain the outbreak. “If a human contaminates a species from the city, household or zoos, they can become reservoirs for the virus,” says Spilki.

Vaccine and medicines against other diseases can help

The human smallpox vaccine offers cross-protection. According to previous data from Africa, the effectiveness in preventing infection reaches 85%. But this immunizer has not been used for over 40 years.

New batches could even be produced. But by containing the live virus of a disease that disappeared from the planet, this vaccine would probably be used very sparingly, in people in the risk group or highly exposed to the pathogen.

+ Also read: The numbers don’t lie: understand the math of vaccines

The issue of treatment is controversial. There are no approved drugs for monkeypox, but antivirals used against other pathogens have been tested on animals.

For example: the combination of cidofovir and brincidofovir, which treat cytomegalovirus and smallpox, respectively, have already shown action against the monkey version in preliminary studies. The drug tecovirimatealso for classic smallpox, would be another option.

It is worth mentioning that the three drugs are not registered in Brazil – all were approved in the United States. And that research in humans would be necessary to ensure the effectiveness and safety of these alternatives in the face of monkeypox.

“Finally, there is still the option of giving smallpox immunoglobulin, which would be ready-made antibodies, to infected individuals at high risk of worsening the condition”, says Naime.

Human smallpox transmission appears to occur through skin-to-skin contact.

According to the WHO, the main route of transmission is close contact with an infected person, through respiratory droplets and body fluids. THE sexual route is still being studied, but it seems to be more a matter of physical proximity than sex itself.

“It is known that it is a virus that resists for a long time in the environment. Hence the concern with sharing contaminated objects and materials, such as bedding”, comments Spilki.

THE incubation period of the disease can vary between 5 and 21 days, which would help to explain its spread around the world. Someone who traveled infected, for example, would only be diagnosed in another country. But transmission, as we said, is more common in the symptomatic phase.

Infection is not restricted to men who have sex with men

Although most cases have been diagnosed in young men who claim to have sex with other men, they are not the only ones affected. And it is not a sexually transmitted disease “among homosexuals”, an unfounded concept, reminiscent of the time of the heyday of HIV.

“In no way should we stigmatize this issue, because anyone who comes into contact with someone who is infected can become infected”, points out Naime.

It is possible, for example, that the first person infected by an animal attended an event attended by a large number of men who have sex with other men. Hence the disease spread among them.

You can contain the outbreak

As transmission occurs more in the symptomatic phase, it is simple to train health professionals and guide the population so that early diagnosis takes place. “We need to properly isolate and receive the first patients, as well as trace their contacts,” says Spilki.

It is also important to maintain continuous epidemiological surveillance and continue studying confirmed cases, even to answer open questions. We highlight two main ones:

Why is monkeypox spreading now?

Some theories are under study. One postulates that the population is more susceptible now, as virtually all those under 50 years of age have not been vaccinated for the smallpoxwhich guaranteed cross protection in the past.

Another is the possibility of a super spreader event, like a party. “There are events of this type under investigation in Canada and Spain. In this scenario, an infected person would have come into contact with many others, who had traveled to other countries,” says Naime.

This would be easier at the current moment, with intense resumption of international travel, return of agglomerations and relaxation of preventive measures such as the use of masks.

+ Also read: Masks: you can relax, but they are still essential indoors

It should also be noted that it is normal for emerging diseases arise. In recent decades, the movement of people between countries has grown considerably, which facilitates the spread of infectious agents.

In addition, with the pandemic, authorities began to monitor new infections more closely. Any new outbreak, then, gains more visibility, including in the press.

“We have two of these now, monkeypox and hepatitis of unknown origin. In addition to the issue of greater circulation, we also diagnose and identify the fastest pathogen today”, comments Salvador.

Finally, the climate changes and the loss of natural vegetation facilitate contact between wild animals and species that interact with humans. An increase in infectious diseases is expected in the coming years because of this.

How big should the problem be?

Considering all this, the arrival of the disease in Brazil seems to be a matter of time, although it is not possible to predict when and with what intensity. But that shouldn’t be a reason to panic. “At first, monkeypox doesn’t spread as fast as Covid,” says Salvador.

The National Health Surveillance Agency (Anvisa) suggests the use of masks and reinforcement of distancing to postpone the arrival of the pathogen and its possible spread. for the rest, you don’t need to take any extra protective measures so far. “It’s another problem for scholars and health professionals, who must act precisely to avoid a public health problem”, completes the USP infectologist.

Finally, it doesn’t hurt to reinforce: doctors and authorities are learning to deal with the issue, which appeared on the international scene less than a month ago. Be suspicious, therefore, of the certainties you find out there.