Monkeypox - the next exciting zoonosis

There has been an unusual increase in monkeypox infections in Europe and the USA in recent weeks. The cause is not yet clear.

What is monkeypox?

Monkeypox is caused by the Orthopoxvirus simiae, a relative of the human pox viruses (variola, smallpox) and cowpox viruses. Monkeypox is a regular occurrence in Africa, probably transmitted from rodents to monkeys, sometimes to humans. They are pretty rare outside Africa.

Smallpox (variola) was a dreaded infectious disease until the last century, which is hopefully a thing of the past thanks to consistent worldwide control and large-scale vaccination campaigns - in 1980, the WHO declared smallpox eradicated.

Compulsory vaccination was abolished in the FRG in 1976 and in the GDR in 1982. This vaccination was carried out at an infant age; older people usually bear extensive scars on their upper arms.

Smallpox also raged horribly in Europe before vaccination, which is why the reports of monkeypox are spreading so much fear right now. According to the WHO, it is the West African strain of the virus, which usually causes a relatively mild course. The disease begins with fever, headache, aching limbs and fatigue, followed by pustules. The symptoms typically disappear on their own after two to four weeks. However, there are considerable complications in severe cases such as pneumonia or blindness, and children, pregnant women, older people, and people with immune deficiencies are at greater risk.

Since the monkey and human smallpox viruses are very similar, the old variola vaccinations also offer some protection against monkeypox, according to the RKI. In addition, a modern smallpox vaccine has been approved in the EU since 2013 (Imvanex), which is better tolerated than older smallpox vaccines.

The Federal Ministry of Health stocks the smallpox vaccine. A unique vaccine against monkeypox has been ordered and is to be vaccinated from June. Karl Lauterbach stated in an interview that a monkeypox pandemic is unlikely but that this outbreak should be contained.

A lot of other experts see it the same way. A plan for vaccination services and target groups is currently being developed.

Transmission of monkeypox

Until now, the rare cases of monkeypox in Europe and the USA have been traced back to people or animals travelling from Africa. Typically, the virus is transmitted through close interactions with infected animals, bites, secretions or excretions, or the consumption of undercooked meat. Since transmission to humans repeatedly occurs in Africa, the virus is a potentially dangerous zoonosis and is monitored by institutions such as the WHO, the RKI and others.

The virus reservoir is primarily rodents such as mice and rats, which are found everywhere in many species and individuals, including in human settlements. According to the Friedrich-Löffler-Institut (FLI), monkeys and humans are so-called false hosts, in which the infection is usually mild. At the FLI, that is, with up-to-date facts and lots of background details, as is the European Centre for Disease Prevention and Control at the European level.

In 2020, I also interviewed zoonoses researcher Fabian Leendertz for my article on the origin of Covid19. He headed the working group "Epidemiology of Highly Pathogenic Microorganisms" and worked on monkeypox, among other things. I was pleased that he became the founding director of the One Health Institute in Greifswald in 2021. "One Health" means that health care in tropical and subtropical regions, where high biodiversity, many people, settlements in forests and poverty often meet unchecked, begins on site. Leendertz had explained an early warning system to me in the interview about surveillance sites: small clinics in high-risk areas with a doctor, a few nurses and a small laboratory for diagnostics can provide on-site health care while watching for signs of emerging new diseases or abnormalities. This includes increased mortality of apes and an early warning system for diseases potentially transmissible to humans. Monkeypox, for example, can be transmitted through the consumption of bushmeat, i.e. eating wild animals. Both animals killed by humans and animals found dead are bushmeat. Since the countries where new zoonoses usually arise are rarely able to install a health system, let alone in remote areas, such centres would have to be operated and financed by the WHO or other institutions. Health policy and care, even for industrialised nations, begins in the jungles of Africa, South America and Asia. For example, scientists like Leendertz have described new regional monkeypox outbreaks for a long time.