Over the last few days there have been a number of reports in the mainstream media about a new strain of the swine flu virus that could lead to the next pandemic. Without a doubt, we would all like to have the current pandemic behind us before we have to deal with the next. Unfortunately, nature doesn’t care what we prefer.
Here is what we know.
A paper published June 29, 2020 in the Proceedings of the National Academy of Sciences (PNAS) reported on the increasing prevalence of a new swine influenza virus detected through nasal swabs and tissue samples collected from Chinese pigs. The strain that I will refer to as G4, is technically a genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 virus.
We are all familiar with H1N1 viruses. The last pandemic—the 2009 H1N1 pandemic—was the result of the (H1N1)pdm09 virus which is quite similar to the G4 virus. It was first identified in the United States in the spring of 2009 and within a year, had resulted in as many as 500,000 deaths worldwide.
G4 is a Zoonotic Disease
G4 is zoonotic like (H1N1)pdm09 and the SARS-CoV-2 virus causing COVID-19. Zoonotic diseases are those that can be transmitted from animals to humans. There are many zoonotic diseases. Common examples include avian influenza, rabies, Ebola, and anthrax. Of the 1,415 pathogens known to infect humans, 61% of those disease organisms are considered zoonotic.
G4 can spread from pigs to humans. Blood samples collected from swine workers to test for G4 antibodies show that 10.4 percent of those workers had been exposed to the G4 virus. Younger workers—between 18 and 35 years old—had nearly double the exposure rate. Although this trait is unusual for influenza viruses, the virus causing the 2009 pandemic also had the tendency to impact younger individuals.
Should the Swine Industry Be Concerned?
All of this sounds bad. However I don’t think it is time to panic yet. Zoonotic diseases are constantly emerging. Sometimes the conditions are right for there to be significant public health impacts (like COVID-19) or economic consequences (like African Swine Fever). More often, that doesn’t happen.
In the past, we conducted very little animal disease surveillance and were unaware of trends like those identified by the study authors. It certainly doesn’t mean that they didn’t occur.
Currently, there is no indication of human-to-human transmission. To become infected by G4 you would need to have direct exposure to infected pigs. That could change. Influenza virus are infamously unstable and prone to reassortment and recombination. A genetic mutation that leads to human-to-human transmission is possible. To date, that hasn’t happened.
Finally, unlike the virus causing COVID-19, influenza vaccines are relatively easy to create. This will enable public and animal health officials to use vaccination in their efforts to control the disease.
Instead of panicking, I suggest we stay informed about these emerging threats, increase our disease surveillance efforts, and use the lessons we have learned responding to COVID-19 supply chain disruption issues to better prepare for future disease outbreaks.