Monkeypox (monkeypox). What do we know?

Health authorities and infectious disease experts have directed their attention and concern to the new cases reported in the past three weeks of monkeypox or monkeypox from countries considered non-endemic for this disease in Europe and North America. This infectious disease caused by DNA (deoxyribonucleic acid) virus of the family Poxviridae, the genus Orthomyxinoid to which smallpox also belongs, is a highly lethal disease of great historical importance and the world’s eradication has been considered since 1980, thanks to vaccination.

Picture of skin lesions caused by monkeypox


In 1970, the first case of monkeypox in humans was described in what is now the Democratic Republic of the Congo and has since been considered endemic to countries in central and western Africa. As of May 2022, localized outbreaks usually considered zoonotic (animal-to-human) transmission have been reported in the United States and some European countries. Human-to-human transmission has also been reported, although less commonly, through close contact or inhalation of droplets.

The monkeypox virus was first identified in non-human primates, hence its name, which is in fact inappropriate because the main natural reservoirs include various types of rodents such as squirrels and other small mammals. Human and non-human primates are occasional hosts of the virus. In the current outbreak, the first cases were reported in the UK, Spain and Portugal, and as of May 28, there are 403 confirmed cases in 28 countries on all continents. In particular, the predominant transmission in this outbreak appears to be human-to-human and has occurred in people with no history of travel to endemic areas of the African continent. No deaths were reported among the affected individuals. On May 28, Mexican health authorities confirmed the country’s first case, apparently in a person residing in the United States.

Monkeypox virus disease has a similar presentation to conventional smallpox, although its outcome is milder. It has an incubation period of 6 to 13 days, which can be up to 21 days, during which people experience fever, headache, body aches and, in particular, in contrast to other rash diseases, swollen glands in the neck and other areas. After a few days, skin lesions appear that can range from papules, vesicles, and scabs, affecting any part of the body, and are similar to other infections. The disease is usually self-limiting within 2 to 4 weeks. In contrast to classic smallpox, which has a mortality rate of 30%, monkeypox has a fatal outcome at a lower rate. In the West African variant, which appears to correspond to the current outbreak in Western Europe, a case fatality rate between 1% and 4% was reported compared to the Central African variant of 11%.

To make the diagnosis, it is necessary to have a high susceptibility index, since it can be confused with other types of diseases, infectious or non-infectious, accompanied by a rash. The diagnosis is confirmed by molecular studies that reveal viral nucleic acids in scrapings from skin lesions. These tests are not readily available in routine laboratories at this time, so the services of reference laboratories should be used.

The question is, what are the conditions for the current outbreak and why is it happening at this time? The classic smallpox vaccine provides cross-protection against monkeypox with up to 85% efficacy. In the 1980s, due to the widespread use of smallpox vaccination, the proportion of people who were immune was greater than 80%. Currently, after more than 40 years of no smallpox vaccine, the proportion has fallen to 30%. Population growth, migration, travel and increased trade may create more opportunities for vulnerable populations to be affected by potential animal reservoirs. Although human-to-human transmission is not common, it becomes more likely if the right conditions are provided to facilitate close person-to-person contact.

In the current outbreak, most of the confirmed cases have been in men, many of whom have been identified as MSM. Some have submitted to sexual health clinics. Despite this, it is inaccurate at this time to say that monkeypox is a sexually transmitted infection. It is also inaccurate and it may be dangerous to assume that it is an infection specific to the LGBT community. We all know the damage and public health consequences that population stigmatization has caused in other epidemics.

Currently available information indicates that application of smallpox vaccine can prevent disease or its severity if given after exposure, therefore, direct vaccination of people with monkeypox may be an appropriate strategy that some countries have mainly begun to adopt. with health workers. It will be the responsibility of each country’s health authorities and international agencies to favor the implementation and distribution of vaccines in the different affected countries in the coming weeks in the event of the current outbreak.

It is important that complete and responsible information for health workers and the general population is disseminated. Health workers should have a high indicator of suspicion and inform the relevant health authorities of suspected cases to establish policies for timely diagnosis, isolation and contact tracing. We should certainly strive to expand access to screening tests if the number of cases increases. Health workers who suspect a case of monkeypox should wear protective equipment to avoid exposure through direct contact, as well as inhalation of aerosols.

At this time there are probably more questions than certainty. We don’t know if monkeypox will become a global public health problem and how serious it is now. Attempting to make predictions at this early point in time can lead to miscalculations that ultimately undermine public confidence in public health. Neither public health nor medicine is guesswork. The important thing is to generate the right information and communicate it as it is generated, not to fall into panic situations, on the one hand, or underestimate on the other. Only by confronting health problems based on scientific evidence will we have better options to offer the population. We must have learned a lot from the COVID-19 pandemic. Let’s use these lessons and not repeat mistakes.

Dr. Juan Sierra Madero *

National Institute of Medical Sciences and Nutrition Salvador Zuberan

*by invitation

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