The Alarming Resurgence of Monkeypox: From Regional Outbreak to Global Pandemic

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The Alarming Resurgence of Monkeypox: From Regional Outbreak to Global Pandemic

The Alarming Resurgence of Monkeypox: From Regional Outbreak to Global Pandemic

For decades, monkeypox has been endemic in Central and West Africa, with occasional human cases after contact with infected animals.

However, in the past 3 years, monkeypox has seen outbreaks and global spread; to date, this disease has infected nearly 100,000 people in 116 countries.

The Alarming Resurgence of Monkeypox: From Regional Outbreak to Global Pandemic

(sources from references 2)

In May 2017, in Port Harcourt, southern Nigeria, a 35-year-old man sought medical care for multiple lesions across his body, especially deep ulcers on his penis. Although common sexually transmitted infections were ruled out, the cause remained unclear. Over the following months, similar cases emerged, mostly in individuals with advanced HIV infection, some of whom died.

In September of that year, patients with similar symptoms were identified at a university hospital in Yenagoa, Bayelsa State, Nigeria, and confirmed to have monkeypox virus infection. Monkeypox, a viral disease primarily transmitted to humans through contact with forest rodents in Africa, had only been recorded three times previously in Nigeria, the last time 39 years earlier.

The re-emergence and spread of monkeypox raised international concern. Five years after the Nigeria cases were confirmed, by 2022, the monkeypox virus had evolved into a global pandemic, primarily affecting men who have sex with men (MSM). The World Health Organization (WHO) declared it a Public Health Emergency of International Concern (PHEIC) and renamed the disease “mpox” to avoid stigmatization and racist reactions.

Although the PHEIC status was lifted in May 2023 due to a significant drop in cases, on August 14, 2024, the WHO again declared the monkeypox outbreak a PHEIC, underscoring the urgency of the situation. Currently, there are nearly 100,000 cases globally.

Despite genomic research indicating the monkeypox virus originated in Nigeria and had been circulating in the population for at least two years before detection, many questions remain. Why did the Nigeria outbreak not trigger an international alert earlier? Why did the previously unrecorded sexual transmission route not receive more attention? Could this outbreak have been stopped before globalization?

To explore these issues, on August 16, 2024, Jon Cohen and Abdullahi Tsanni published a report in the Science news column titled “Mpox circulated in Nigeria for 8 years before it sparked a global outbreak. What happened? And could it have been stopped?”

The authors found that:

The monkeypox outbreak in Nigeria began in 2017, with initial cases in Bayelsa State.
The virus may have spilled over from wildlife to humans as early as July 2014 and possibly had undetected cases in Lagos as early as 2016.
The virus spread relatively slowly in Nigeria but gradually expanded to other regions, including major cities with busy international airports.
Factors like environmental conditions, human behavior, and socioeconomic activities may have contributed to the virus’s spread.
The disappointing international response was a crucial factor in the monkeypox outbreak spiraling out of control again.

Key Findings:

Origin and Spread: Genomic analysis traced the Nigeria monkeypox virus to its origins and how it spread in the population. The virus may have spilled over from wildlife as early as July 2014 and potentially had undetected cases in Lagos by 2016.
Transmission Speed: Modeling based on genomic evidence suggests the case count roughly doubled every two years, with most transmission chains outside the south interrupted, but exponential growth, albeit slower, within the south.
Evidence of Sexual Transmission: In the 2017 Nigeria outbreak, most cases were not children but young men with genital lesions, and over 60% of patients reported multiple recent sexual partners. Some also had undiagnosed HIV, providing clues that monkeypox may have been spreading sexually.
Viral Adaptation and Mutation: Through the action of APOBEC3 enzymes, researchers found “scars” in the monkeypox virus genome, indicating mutations as the virus adapted to the human host.

Geographical Distribution of Cases:

Initial cases were confirmed in Bayelsa State, Nigeria, but later spread to other regions, including Lagos and the capital Abuja.
By 2024, the monkeypox epidemic is now global.
Africa: Mainly in Central and West Africa, including the Democratic Republic of the Congo, Nigeria, Cameroon, and the Central African Republic.
Europe: Multiple countries, including the UK, Spain, Portugal, Germany, France, and Italy.
North America: Cases reported in the US and Canada.
Other Regions: Sporadic cases in some countries in Asia, South America, and Oceania.

Monkeypox Epidemic:

Social Impact: In Nigeria, the monkeypox outbreak may have been underestimated due to fear of sexually transmitted infections and stigma against same-sex sexual behavior. Legal and social taboos made it harder to determine the nature of sexual transmission.
Global Outbreak Development: By 2022, monkeypox began appearing globally, especially among men who have sex with men, many of whom attended gay gatherings, drawing the attention of virologists.
In 2024, monkeypox showed new changes, with a large number of child cases, indicating that direct skin-to-skin contact has also become an important transmission route.
Response Challenges: Monkeypox virus spread beyond Nigeria to other African countries and globally, posing serious challenges to the global pandemic response, including insufficient vaccine coverage, weakened surveillance, and inadequate understanding of the outbreak.
Ongoing Mutation: In 2024, new, more deadly virus strains emerged, spreading beyond the original LGBTQ+ population. Clade I is a more severe mpox variant currently causing over 17,400 cases and 500 deaths in Africa. This Clade I has now spread to non-endemic African countries, with a recent travel-related case detected in Sweden. Most cases are the Clade Ia subvariant, accounting for over 80% of cases and 85% of deaths, primarily in children. The Clade Ib subvariant is spreading among adults.

The authors’ in-depth exploration of the 2017 Nigeria monkeypox outbreak and its global spread reveals the early sexual transmission routes of monkeypox and emphasizes the importance of early identification, diagnosis, and isolation of cases and high-risk populations.

Clinicians also need to be aware of new monkeypox transmission risks, particularly the 2024 emergence of more child cases linked to close skin contact. The research also strongly highlights the deficiencies in the global public health system in disease surveillance and response, calling for improved international cooperation, enhanced epidemic monitoring capabilities, and strengthened public health education.

Wealthy countries, in particular, should increase aid to African nations to help control the spread of the outbreak. Additionally, the new mutant monkeypox strains underscore the necessity of long-term virus monitoring and research.