Study Uncovers that a Mutated Swine Flu Virus Could Pose a Threat Once More to Our Health
The possibility exists that swine flu could undergo evolution and resurface in humans. However, by implementing measures to control its transmission among individuals in close contact with pigs, we can effectively avert such a scenario.
The first instance of swine flu (H1N1pdm09) in humans was documented in 2009, marking 14 years since its initial appearance. The virus has proven to be a significant global health concern, as per CDC estimates, resulting in the death of approximately 151,700 to 575,400 individuals worldwide. Even today, it persists as a seasonal flu virus in human populations.
A Frequent Occurrence with Evolutionary Implications
A recent study indicates that since its emergence, pdm09 has transferred from humans to pigs on 370 occasions. This repeated transmission of the virus from humans to swine may have provided opportunities for further evolution. Consequently, there exists a potential risk of an evolved pdm09 strain infecting humans and triggering another outbreak.
The researchers involved in the study emphasize that their analysis supports the notion that pdm09 frequently overcomes the species barrier between humans and swine.
Is there a potential threat of a new swine flu pandemic?
Swine flu, also known as H1N1pdm09, belongs to the type A influenza virus family (influenza A virus or IAV) and can infect various animals such as pigs, humans, birds, dogs, cats, and even whales. Researchers have raised concerns about the virus’s ability to undergo genetic changes due to its transmission in different animal hosts.
Evolution of pdm09 from Humans to Pigs
Their study focused on assessing the risk of an evolved pdm09 strain infecting humans via pigs. The researchers examined data regarding swine flu transmission from 2009 to 2021 and observed that around 370 instances involved the transmission of pdm09 from humans to pigs.
Even during the period of COVID-19, when the circulation of pdm09 among humans was low, the virus remained stable in swine. However, it is worth noting that approximately 40 percent (150 cases) of human-to-pig transmission events occurred in the years preceding the COVID-19 pandemic, specifically between 2018 and 2020.
While most instances of transmission between humans and pigs did not lead to significant genetic changes in the virus, a few events have drawn the attention of researchers. These select transmission events have resulted in the continuous circulation of genetically advanced pdm09 variants within pig populations.
Five Worrisome pdm09 Variants
The researchers identified at least five such variants, which surprisingly demonstrated the ability to evade protection provided by the seasonal swine flu vaccine.
“Our data indicates that pdm09 viruses established in US swine have diverged from human seasonal vaccine strains, potentially reducing immunity in the human population,” the researchers noted.
Despite the risk posed by an evolved swine flu virus, the study also presents an optimistic strategy to prevent the spread of potent pdm09 strains from pigs to humans. By effectively controlling virus transmission among individuals who frequently interact with pigs, such as farmers, it becomes possible to minimize pdm09 circulation in pig populations and prevent further evolution.
The study authors emphasized, “Controlling influenza A virus infection in humans can limit virus spillover into pigs and reduce virus diversity within swine populations. This, in turn, can mitigate the emergence of novel viruses and the potential for swine-to-human transmission of influenza A virus.”
With these findings, there is hope that proactive measures can be implemented to avert any future swine flu outbreaks.
Read the original article on Interesting Engineering.
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