Nikhil Prasad Fact checked by:Thailand Medical News Team Oct 05, 2025 2 days, 21 hours, 33 minutes ago
Medical News: Rising Concerns Over a New Monkeypox Strain
Scientists have issued a serious warning about a newly emerging strain of monkeypox virus, known as clade Ib, which appears to be evolving to become more dangerous. This latest discovery comes from researchers at the Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC)–Universidad Autónoma de Madrid, and the Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), CSIC, Spain. According to this
Medical News report, clade Ib not only spreads more efficiently than earlier strains but also shows more severe disease outcomes in experimental models.
Spanish Researchers Warn That Monkeypox Virus is Evolving to be More Virulent
What Makes Clade Ib Different
Monkeypox, now officially called mpox, has long been known in parts of Central and West Africa. In 2022, a global outbreak occurred, driven by clade IIb lineage B.1, which spread widely but caused relatively mild disease in most cases. However, the newly identified clade Ib is showing worrying changes. Laboratory tests revealed that clade Ib spreads between cells more effectively than clade IIb, suggesting a stronger ability to multiply and cause damage in the body.
Severe Effects Observed in Animal Studies
In experiments using mouse models, clade Ib caused rapid weight loss, severe illness, and a high death rate compared to clade IIb. When exposed to the virus through both respiratory and systemic infection, almost all animals infected with clade Ib died within a short time. In contrast, clade IIb showed only limited sickness, and most animals survived. Clade Ib also triggered severe lung damage, with inflamed tissue, hemorrhages, and widespread viral antigens detected throughout the lungs. Even more concerning, the virus spread beyond the lungs to vital organs like the spleen, something not seen with clade IIb.
Genetic Clues Behind the Danger
Genomic analysis showed that clade Ib carries a distinct signature of mutations linked to sustained human-to-human transmission. These changes, likely driven by the body’s defense enzyme APOBEC3, do not appear to weaken the virus as much as in clade IIb. Instead, clade Ib retains high virulence, with mutations in key viral genes possibly altering immune evasion and making the virus more efficient at spreading inside the host.
Why This Matters Globally
While the mouse model is not identical to human infection, previous studies have shown that severity in mice often mirrors disease patterns in humans. This means clade Ib could pose greater risks to people, especially in regions with weaker healthcare systems or high rates of immunocompromised populations. With cases of clade Ib already reported outside Africa, including in Europe, Asia, and North America, scientists stress the urgent need for close monitoring. If the virus continues to evolve while transm
itting between humans, new lineages with unpredictable virulence could emerge.
Final Thoughts
The findings from this Spanish research team make it clear that monkeypox is far from a fading threat. The virus is adapting, and its new forms may be harder to control. Public health systems worldwide must be prepared for the possibility of more severe outbreaks, with better surveillance, genomic monitoring, and preventive strategies. Ignoring these warning signs could allow the virus to take a stronger hold in both endemic and non-endemic regions.
The study findings were published on a preprint server and are currently being peer reviewed.
https://www.biorxiv.org/content/10.1101/2025.09.22.677787v1
For the latest on Monkeypox, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/news/drug-resistant-mpox-strains-discovered-in-five-american-states
https://www.thailandmedical.news/news/understanding-the-multi-organ-impact-of-mpox-monkeypox
https://www.thailandmedical.news/news/plantagoside-and-narcissoside-from-plantago-lanceolata-can-inhibit-monkeypox-mpox-virus-s-profilin-like-protein-a42r
https://www.thailandmedical.news/articles/monkeypox
Share
Tweet
Share
