This morning, the Community of Madrid alerted eight patients with symptoms “clinically compatible” with monkeypox and announced that it had taken the necessary measures to exclude this contagious disease. Not for the less: It is a rare disease (and much less serious than the old smallpox), but it can cause serious problems. But beyond that, he is the protagonist of one of the rarest epidemiological epidemics ever in this decade. And that’s a lot to say.

What’s going on?. On 7 May 2022, the British NHS identified a case of monkeypox in a patient who had recently traveled to Nigeria. So far everything is normal. This is something that happened in the UK in 2018, 2019 and 2021. The problem is, seven days later, two more people who had no apparent connection to the original case were found. To date, there are “seven cases with no previous links (although two out of four people have common contacts) or no travel history.

This is weird. Fernando Simón, director of the Center for Health Alerts and Emergencies Coordination, said this morning, “although monkeypox is a serious illness, the information we have [nos dicen] “self-limiting outbreaks”, i.e. there are usually no large population outbreaks. However, data from the UK are so “rare and unusual” that the director of the UK Health Safety Agency agreed that the evidence suggests there was community transmission.

It should be noted that the longest known documented chain of transmission consisted of six individuals, as described in SMC Spain. Therefore, the emergence of cases across Europe (in addition to the Spaniards, Portugal has confirmed three more cases in Lisbon and 15 more cases are under investigation) has taken researchers by surprise.

What exactly is ‘monkey flower’?. It is a virus of the smallpox genus (variola viruses) despite its name, it is usually transmitted by small mammals such as rodents. This is important because it will be key when it comes to finding a possible vector of contamination. This contamination requires direct contact with blood, fluid or open lesions.

As we said in humans, transmission is limited. Also, of the two main strains we know of (one from West Africa and one from Congo), the first ever found in the UK is the least lethal and also the least contagious. We’re talking about “fever, myalgia, inguinal lymphadenopathy (swollen glands), and a chickenpox-like rash on the hands and face.” But most of all, we’re talking about a 1% mortality rate (compared to 10% in Congo).

a growing disease. The virus was first found in macaques in 1958 and has been closely controlled for decades. The problem is that this “control” was largely due to the cross immunity provided by the smallpox vaccine. As this immunity has disappeared (as new vaccines are no longer being made to the extent that smallpox is eradicated), the immunity of monkeys outside and inside the African continent is increasing.

What can we expect from this epidemic? The first cases outside of Africa were found in 2003, with 47 cases originating from a group of prairie dogs from Ghana who lived with animals and were sold as pets. This was characteristic of all epidemics known so far: they were very localized. Now that’s not happening, and there aren’t many clues yet, other than a theory linking the epidemic to sexual transmission.

Image | HCM