Monkeypox: How disease symptoms have changed and intrigue doctors

Before this virus spread to other parts of the world, the most common manifestations of the infection were fever, malaise, swollen lymph nodes, headache, sweating and the appearance of various skin lesions, mainly on the face, palms hands and soles of feet.

Now, doctors see another pattern: patients still have fever and malaise, but most of them have few sores, which are mainly located on the genitals and anus. They also appear with different characteristics, and often resemble pimples or a herpes simplex crisis.

A significant portion of those affected, experts report, have very mild symptoms, which makes it even more difficult to suspect and diagnose monkeypox.

It is not yet known for sure what may be behind these changes.

“What we have seen in the current outbreak are atypical conditions, very different from the classic pattern that we knew”, observes virologist Clarissa Damaso, from the Federal University of Rio de Janeiro (UFRJ).

Understand in detail what the most common symptoms of monkeypox are and why they are different from what was described above.

Expectation and reality

This change in the pattern of the disease has already become the subject of a series of scientific articles. One of the most recent, published in the British Medical Journal, followed 197 patients who tested positive for the virus in the city of London, UK.

The survey found that:

• All participants had skin or mucosal lesions (on the inner wall of the mouth or anus, for example)
• In 56%, these sores appeared on the genitals.
• In 41%, they were observed in the anus
• 61% had a fever
• 57% had swollen lymph nodes
• 31% complained of muscle pain
• 13% had only the lesions, without fever or other symptoms

Other common symptoms were pain in the rectum (affected by 36% of participants), sore throat (16%) and swelling or redness of the penis (15%).

The article is in line with what Brazilian doctors have observed in practice. They draw attention to the number of monkeypox patients with very mild, barely noticeable symptoms.

“We have seen the most varied manifestations of the disease. Some arrive with a single lesion, while others have many wounds”, describes infectious disease specialist Mirian Dal Ben, from Hospital Sírio-Libanês, in São Paulo.

“There are also cases where the only symptom is proctitis, a type of inflammation in the rectum”, he adds.

“In other words: they are clinical pictures very different from those described in the literature that we had until then.”

Doctor Alexandre Naime Barbosa, vice president of the Brazilian Society of Infectious Diseases, mentions the case of a patient he followed, whose only symptom was the appearance of a pimple between his mouth and chin.

“It’s a case that, in the vast majority of cases, one would never think of monkeypox”, he says.

Classically, infection by this virus and the onset of symptoms were described in two phases.

The first, which lasted up to five days, was characterized by fever, headache, swollen glands, muscle pain and lack of energy. “These are common signs of any virus”, observes Damaso.

The second, which starts one to three days after the onset of fever, had the eruption of wounds as the main manifestation.

“As a pattern, the lesions appeared on the extremities of the body, such as the hands, feet and face”, details the virologist.

These phases are also more confusing and mixed up now: in the study published in the British Medical Journal, 38% of participants only developed systemic symptoms, such as fever and body pain, after the sores had already sprouted.

Damaso, who is a member of the World Health Organization (WHO) committees on smallpox, understands that the change in the pattern of symptoms makes the diagnosis even more difficult.

“We have at least four subgroups of manifestations, ranging from people who have an absurd amount of sores in the genital region to those who don’t even feel a fever and only have a single lesion.”

“These atypical pictures make it difficult for the health professional to suspect cases”, he considers.

What is behind the phenomenon?

According to experts interviewed by BBC News Brasil, this change in pattern would be related to the lack of knowledge about monkeypox until now.

“Perhaps, in the regions of Africa where it was endemic, the disease already had a milder manifestation. But as they are less developed countries and we are talking about a neglected disease, it is possible that only the most serious cases drew attention”, assumes Barbosa, who He is also a professor at the São Paulo State University (Unesp).

“Now that the virus has reached the richest countries, with greater notification and testing systems, we are getting to know the other possible manifestations”, he adds.

Damaso explains that the monkeypox subtype present in several countries has a lower lethality and, despite not having undergone major mutations in the genetic code, it may have acquired a kind of “pattern of passage”.

“To date, most cases are happening in men who have sex with other men, and they commonly have lesions in the genital region,” he describes.

“Contact with these wounds is usually more intense during sexual intercourse. From there, the virus is transmitted to another individual, who also tends to manifest symptoms in the genital region”, he adds.

In other words, the pattern of passage happens due to close contact with the lesions, which in the current outbreak appear more frequently in the genital region. Thus, the infected person also develops lesions in that part of the body – and can perpetuate the cycle by having more intimate contact with other individuals.

But this, of course, does not rule out the relevance of other forms of transmission of this infectious agent that go beyond sexual intercourse, such as the sharing of objects and droplets of saliva.

To protect yourself, the first step is to avoid the most risky situations, stay tuned for symptoms and seek medical evaluation if they appear.

“Any injury that begins with swelling [inchaço e vermelhidão] and evolves into a plaque, has liquid, forms wounds and crusts, it can be monkeypox”, describes Barbosa.

As mentioned earlier, these manifestations appear most often on the anus, genitals, face and hands – and may or may not be accompanied by other general signs such as fever, body pain and swollen lymph nodes.

“The lesion can also be acne, herpes, herpes zoster or a number of other things. But, when in doubt, it is important to seek medical attention and do a test”, concludes the infectologist.

– This text was published in https://www.bbc.com/portuguese/internacional-62413342