For years, monkeypox has been known to primarily spread from small mammals to humans, with human-to-human transmission being a rare occurrence. However, recent research by an international team of scientists suggests that the monkeypox virus has been jumping from human to human since 2016, marking a significant change in how experts understand the spread of the virus. Led by epidemiologist Áine O’Toole from the University of Edinburgh, the study highlights the urgent need for new public messaging around outbreak management and control.
Unveiling a Shift in Transmission
Historically, monkeypox, which causes similar symptoms to smallpox, was predominantly contracted from monkeys or rodents. The virus was first identified in the 1950s when a group of research monkeys in Denmark fell ill. Though the first human case was reported in the 1970s, the transmission from human to human remained rare for many decades. Most cases occurred in central, east, and west Africa, with the source of the virus still unknown.
In 2017, however, Nigeria experienced a monkeypox outbreak that eventually spread internationally by 2022. Genome sequencing of the cases revealed a lineage of the virus called clade IIb, which is generally non-fatal. Researchers discovered that this lineage looked distinct from other endemic strains in Africa, indicating a potential human-to-human transmission. Subsequent analysis showed that many of the mutations identified in the clade IIb lineage were consistent with exposure to a human enzyme called APOBEC3, which has antiviral properties. The accumulation of these mutations suggests widespread transmission.
Implications for Public Health
The findings of O’Toole and her colleagues indicate that the human immune system has been combatting this particular lineage of the monkeypox virus for approximately seven years. While some cases still originate from animals, the researchers assert that since 2016, the majority of cases are likely the result of human-to-human transmission, which continues unabated. This revelation raises concerns about undiscovered monkeypox epidemics in certain regions, which could potentially seed outbreaks in other parts of the world through travel.
In light of this research, it is crucial for global public health to prioritize monkeypox cases in countries with historically recognized endemic reservoir species. The authors emphasize that equal attention and concern should be given to such cases, regardless of geographic location. This shift in understanding necessitates the development of new strategies for outbreak management and control.
The discovery of sustained human transmission of the monkeypox virus represents a fundamental shift in the way experts perceive the spread of the disease. The identification of a distinct virus lineage and the accumulation of mutations characteristic of exposure to a human enzyme suggest widespread transmission among humans since 2016. This finding underscores the need for updated public messaging, outbreak management, and control strategies. As global travel facilitates the potential spread of undisclosed monkeypox epidemics, it is vital that global public health agencies address the issue promptly and comprehensively. By recognizing the changing dynamics of monkeypox transmission, we can effectively mitigate the impact of this emerging public health concern.
Leave a Reply