Mpox, formerly known as monkeypox, has garnered significant attention recently due to its evolving nature and rapid spread. Discovered in the late 1950s, the virus initially emerged in laboratory monkeys in Denmark. Despite its name, mpox has little to do with monkeys, which are not the primary carriers. Instead, the virus is believed to originate from rodents, with a suspected role of these animals in transmitting the virus to humans.

The virus was first identified in humans in 1970 when a nine-month-old boy in the Democratic Republic of Congo was diagnosed. The boy lived in a tropical rainforest area where monkeys were present, but it remains unclear whether he contracted the virus from a monkey or another source. Although there were likely human cases before this, the disease was not officially recognized in humans until then.

Mpox cases remained relatively contained until 2003, when an outbreak in the US linked to infected prairie dogs marked a significant spread outside Africa. Further outbreaks occurred in various countries, including the UK, Israel, and Singapore. The most concerning recent development began in May 2022, with a surge in cases globally, including the US, UK, Australia, Europe, and Canada. However, Africa remains the epicenter, with over 19,000 cases and 900 deaths reported in the Democratic Republic of Congo since January 2023.

The World Health Organization (WHO) renamed the virus to mpox at the end of 2022 and briefly declared it a public health emergency of international concern in July 2022, though this was lifted in May 2023. The Africa Centres for Disease Control and Prevention (Africa CDC) declared a new public health emergency in August 2024 due to a more transmissible variant causing significant outbreaks in several African countries.

Origins and Evolution

Mpox was first identified in Copenhagen in 1958 in monkeys imported from Singapore. The initial human case was reported in 1970 in the Democratic Republic of Congo. The disease was found to spread to the US through infected prairie dogs in 2003 and has since re-emerged in various regions, with the latest outbreaks linked to new variants of the virus. Genetic analysis suggests that the West African strain (clade II) may have acquired the ability to spread between humans as early as 2017, with several mutations enhancing its transmission.

The emergence of a new variant, clade Ib, in the DRC, particularly among children, further complicates the situation. This variant appears to spread more easily through close contact and may have been circulating undetected since September 2023.

Transmission and Risk

Unlike Covid-19, which spreads through respiratory droplets, mpox relies on close physical contact for transmission. This can occur through direct contact with an infected person's rash, lesions, or bodily fluids, and possibly through contaminated objects. Although mpox DNA has been detected in semen, there is no clear evidence of sexual transmission.

Mpox primarily affects those with close contact with infected individuals. A study from 2022 found that most cases in 16 countries were among men who have sex with men, though this might reflect community spread rather than specific transmission routes. The virus is not more infectious in men compared to women.

Disease Severity and Vaccination

Mpox, while generally less deadly than smallpox, can be quite severe. The Central African strain (clade I) has a mortality rate of around 10%, whereas the West African strain (clade II) has a survival rate of 99.9%. Symptoms include flu-like signs initially, followed by a distinctive rash and lesions that can lead to significant discomfort and scarring.

Smallpox vaccines, which remain effective against mpox with up to 80% efficacy, are being replenished in some countries, particularly in the West. However, the disparity in vaccine distribution highlights a broader issue: African nations, where mpox is endemic, have historically received inadequate support in handling outbreaks compared to wealthier nations.

Global Response and Future Outlook

Mpox has shown that the world needs to be vigilant against zoonotic diseases—those that jump from animals to humans. Despite the availability of vaccines and the relatively slow spread of mpox compared to Covid-19, the recent outbreaks underscore the importance of global cooperation and preparedness.

Investment in understanding zoonotic diseases, improving monitoring, and enhancing response capabilities in affected regions are crucial. As the world moves forward, it must remain alert for new diseases, recognizing that global health threats can arise anywhere and require a coordinated international effort to address them effectively.