Influenza A can cause influenza in humans, birds, pigs and other mammals. Between 2009 and 2010, a pandemic caused by the pdm09 strain (commonly known as “swine flu” because it contains genetic sequences from bird flu, swine flu, and human flu) killed thousands of people worldwide.
A new study of this strain shows that The virus has passed from humans to pigs about 370 times since 2009and subsequent circulation in pigs led to the evolution of the pdm09 variant, which then jumped from pigs to humans.
To gain a deeper understanding of this risk, a team of US scientists analyzed data on the spread of pdm09 between 2009 and 2021.They also investigated how these cross-species events might affect Affects genetic diversity of viruses in pigs and subsequent risk of human infection.
Their analysis revealed that since 2009, pdm09 has been transmitted from humans to pigs approximately 370 times. Most events occurred when pdm09 burden was highest in humans. During the COVID-19 pandemic in 2020 and 2021, pdm09 transmission in humans decreased, but transmission in pigs persisted due to approximately 150 human-to-pig events between 2018 and 2020 .
They found that most incidents of human-to-pig transmission were isolated, but some resulted in Ongoing circulation of different pdm09 genetic lineages in pigs Vaccines offer little protection.The analysis also showed that sustained circulation of pdm09 in pigs was associated with At least five cases of pig-to-human transmission.
These findings provide further evidence that controlling influenza A infection in humans who work with pigs can help prevent transmission of the virus to pigs, thereby reducing the risk of transmission to humans.
“Controlling influenza A virus infection in humans can minimize virus transmission to pigs and reduce the diversity of viruses circulating in pig herds. Limiting viral diversity in pigs minimizes emergence of new viruses “And the potential for transmission of influenza A virus from pigs to humans,” comment the study’s authors.