Mpox is a growing global health threat, scientists warn

For decades, the human niche for viruses related to smallpox has remained mostly empty. Since eradicating smallpox, only rare outbreaks of related viruses appeared. But today, mpox, once confined mainly to rural parts of Africa, is spreading globally, and the reasons behind this shift have researchers deeply concerned.

Mpox is a viral disease related closely to smallpox, causing fever, swollen glands, and painful skin rashes. It spreads from animals to humans and traditionally stayed within limited rural settings, usually infecting adolescent boys and their younger siblings.

Unlike other similar viruses, mpox quickly moves beyond the initial infection site, creating widespread secondary rashes on the body. These severe symptoms, resembling smallpox, set mpox apart from other related viruses, raising alarms among scientists and public health officials.

Scientists initially believed mpox rarely spread from person to person, limiting outbreaks to small groups. That changed dramatically in 2022, when a strain called clade IIb suddenly began infecting adults worldwide. Surprisingly, this strain showed no obvious biological changes compared to older samples.

Instead, its rapid global spread linked directly to human behavior, especially among sexually active groups, notably gay men. This change in transmission patterns startled researchers and highlighted how quickly the virus could adapt to new human behaviors.

Carlos Maluquer de Motes, a molecular virology expert at the University of Surrey, explains this new reality clearly: “The most recent outbreaks show that intimate contact is now a significant way the virus spreads. That shift in how it’s transmitted is leading to longer transmission chains and lasting outbreaks.”

This strain created primary rashes directly at infection sites, such as the genital area, allowing the virus to pass more rapidly between people without waiting for secondary rashes to develop.

By shortening the time between infections, mpox established longer chains of transmission, raising the risk of larger, more sustained outbreaks. However, current outbreaks remain mostly limited to specific social groups, particularly those involving frequent intimate contact.

One key factor pushing mpox’s spread is genetic mutations occurring during human infection. Traditionally considered stable, mpox viruses now display unexpected mutations caused by enzymes naturally present in humans, called APOBEC3. These enzymes usually restrict viruses by introducing damaging errors in their genetic material. Strangely, mpox withstands this assault, using mutations as a source of evolutionary variation without weakening significantly.

Scientists tracking these mutations believe the current strain emerged around 2016, earlier than previously thought. As these mutations continue accumulating, researchers fear the virus may become increasingly well-adapted to humans, just as smallpox once evolved from similar viruses.

Dr. Maluquer de Motes emphasizes the potential risk: “These viruses appear to be accumulating specific genetic mutations—driven by enzymes in the human body—that may be changing viral properties. The longer these viruses circulate amongst us, the higher the chances these mutations help mpox adapt to humans.”

Further worrying scientists, outbreaks now include all four known mpox clades. While the globally dominant clade IIb spreads mainly through sexual networks, recent outbreaks of clades Ia, Ib, and IIa also show sustained person-to-person transmission. This shift indicates broader changes in human-virus interactions, especially in regions where immunity from past smallpox vaccinations fades.

Alarmingly, the more aggressive clade I viruses, historically associated with higher death rates, now compete directly with milder clades. This competition creates opportunities for the virus to adapt further, enhancing its spread or severity. For instance, clade Ia infections are increasing dramatically in the Democratic Republic of Congo, often infecting children—raising fears the virus could begin spreading easily among younger populations.

Such a development would drastically widen mpox’s reach, potentially turning small, controllable outbreaks into major epidemics. Although childhood outbreaks remain limited, scientists worry that urbanization and declining vaccine immunity could open new transmission routes. Urban areas offer closer physical contact and denser populations, increasing opportunities for rapid viral spread.

Today’s mpox threat arises partly because of reduced human immunity since smallpox vaccinations stopped decades ago. This declining immunity makes humans increasingly vulnerable to related viruses. While most recent cases remain concentrated in adult sexual networks, especially among men who have sex with men, scientists stress the situation could quickly change.

There’s a growing worry that mutations and wider transmission could eventually cause outbreaks beyond current groups, such as spreading through families or childcare settings. Because mpox remains capable of infecting animals, it cannot be eradicated like smallpox was. This animal reservoir means outbreaks could recur indefinitely unless effectively controlled.

Another concern is the limited number of medical tools available to combat mpox. Current rapid tests, vaccines, and antivirals remain scarce globally, with limited local production capabilities in most regions. Adding to this problem, recent cases revealed the emergence of antiviral-resistant strains, complicating treatment further.

Dr. Maluquer de Motes points out this critical gap: “Mpox control has to climb up the global health agenda. We have limited diagnostic tools and even fewer antiviral treatments. We urgently need better surveillance and local or regional capacity to produce what we need—otherwise, we are at risk of future epidemics.”

Scientists insist global cooperation and urgent investments are essential to keep mpox in check. Rapid, accessible diagnostics, affordable vaccines, and effective antiviral treatments must be produced locally or regionally. Without these measures, future outbreaks could escalate quickly, threatening broader populations and causing severe illness worldwide.

Mpox’s persistent animal reservoirs mean controlling human transmission alone isn’t enough. Efforts must also target preventing animal-to-human infections through better monitoring and preparedness. If these steps aren’t taken seriously, mpox might adapt further, becoming harder to control or treat, and evolving into a recurring global health emergency.

Despite past assumptions that mpox posed minimal risk, recent developments clearly demonstrate its potential global threat. The growing frequency and expanding geography of outbreaks demand swift international action. Investing in stronger healthcare infrastructure, better global disease surveillance, and affordable local vaccine production is critical to preventing future crises.

In the meantime, understanding how human behavior, genetic mutations, and changing demographics drive mpox’s spread can guide public health responses. Scientists remain hopeful that timely action can control current outbreaks and prevent broader epidemics.

But without urgent global commitment, mpox could soon become an even greater health concern, testing our ability to respond effectively and protect public health worldwide.

Research findings are available in the journal Nature Medicine.

Note: The article above provided above by The Brighter Side of News.

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