Mpox: Symptoms, Spread and Global Outbreaks

Mpox, previously called monkeypox, belongs to the Orthopoxvirus family of pathogens, alongside its close relative, the smallpox virus.

The infection passes on through contaminated bodily fluids or close contact with infected people or animals. It may lead to illness ranging from mild to severe and, in certain instances, can be fatal.

What are the symptoms of mpox?

Around one to two weeks after infection, mpox can cause fever, headaches, muscle pain, swollen lymph nodes and fatigue. A few days afterwards, a rash may develop, most commonly on or near the face. This can develop into fluid-filled pustules, which form scabs before healing over the weeks that follow.

While its symptoms resemble those of smallpox in several respects, mpox is fortunately considered self-limiting and is therefore much less severe.

Even so, mpox remains a serious disease and can result in lasting complications. These range from sepsis and encephalitis to blindness caused by eye infections. In the absence of treatment or vaccination, almost one in ten infected people may face fatal complications, particularly young children.

Next to the devastation caused by smallpox, which at its height killed almost one in every three people infected, mpox may appear less alarming. Yet, if the COVID-19 pandemic taught us anything, it is that caution is preferable when dealing with potentially deadly viruses.

How does mpox spread?

Human-to-human mpox transmission occurs through close contact with a person who has the mpox rash. Contact may be face-to-face, skin-to-skin, mouth-to-mouth or mouth-to-skin. According to the World Health Organization (WHO), droplets or aerosols over short distances can transmit the virus when someone has mouth ulcers or sores.

A person is regarded as infectious until every lesion has crusted over, although scientists still have much to discover about the most recent outbreaks.

Can you catch mpox from a surface?

A contagious individual may leave the mpox virus on surfaces and items, including clothes, mobile phones, toilet seats and bedding. Another person may then become infected after handling them.

The WHO also states that the virus may be passed to a fetus during pregnancy.

It is not yet known whether asymptomatic carriers can transmit the virus between people.

Should we be worried about a mpox pandemic?

On 23 July 2022, the WHO formally declared the mpox outbreak a global health emergency of international concern. More than 16,000 cases had been recorded across 74 countries when the declaration was made.

The organisation's experts could not reach agreement on whether the highest level of alert was justified, leaving WHO chief Tedros Adhanom to make the final decision.

Previously, outbreaks involved only a small number of infected people, with minimal or no person-to-person transmission, so spread was limited. Furthermore, unlike SARS-CoV-2, mpox cannot spread through the air. Because the smallpox vaccine works against the virus, authorities are already well equipped if concerns continue to grow.

The apparent spread of the virus does, however, illustrate how readily viruses travel when journeys increase and hygiene practices relax. As with the AIDS epidemic of the 1980s, a strong link to risk-taking behaviour and minority demographics can encourage stigma, making communication about infections more difficult.

Although society is well placed to limit the spread of viruses, COVID-19 demonstrated how rapidly communities can become complacent, distrustful and weary of both collective and personal healthcare measures.

Why was it called monkeypox?

The previous name, monkeypox, originated in 1958 after the virus caused an outbreak among laboratory monkeys at a research facility in Copenhagen. The name is misleading, however: although monkeys can become infected and spread the virus, it is more commonly acquired from widely eaten forms of so-called bushmeat, such as dormice and African squirrels.

The first human case was not identified until 1970, while the WHO was working to eradicate smallpox in the Democratic Republic of the Congo. Most infections still occur in this central African country today, although outbreaks have also been documented in several neighbouring nations.

Why is mpox spreading around the world now?

Although the mpox outbreaks of 2022 attracted headlines, this was not the first occasion on which the virus had appeared beyond African populations.

In the middle of 2003, the CDC received reports of 71 cases across six US states, 35 of which laboratory tests confirmed were caused by the mpox virus. Every confirmed case was linked to infected prairie dogs bought from an animal distributor in Illinois. Those animals had themselves been infected by Gambian giant rats and dormice imported from Ghana.

The UK also reported three cases in 2018. Notably, one case had no direct connection to the other two. Each person had recently travelled to Nigeria, where mpox is known to circulate.

At first glance, the many simultaneous outbreaks in mid-2022 could suggest a possible pandemic, especially after the recent emergence of the devastating SARS-CoV-2. Suspected and confirmed cases in numerous countries, including the US, UK, Spain, Portugal, Italy and Australia, point to unobserved and extensive transmission.

Most infections seem to have resulted from close intimate contact, mainly between men, with diagnoses made after people attended health clinics. At the time this article was written, no deaths had been reported.

As there is no evidence of a mutation that might explain greater virulence in the microbe, the outbreaks were likely being aided by a sharp rise in travel following the easing of COVID restrictions.

All Explainers are judged by fact-checkers to be accurate and relevant when published. To ensure information remains current, text and images may be changed, removed or added as an editorial decision.