New research has found that a flu virus strain that occurs in horses, dogs, birds and seals, can go undetected in host pigs, raising concern among scientists over a possible increase in the risk of the virus being capable of spreading to humans.
The finding, which relates to the H3N8 strain, comes from research carried out at Pirbright Institute in Surrey by Dr Maria Montoya.
Her work has shown for the first time that two different strains of the H3N8 influenza A virus are able to infect and replicate in pigs; one isolated from seals and an avian strain circulating in poultry in the US.
Dr Montoya’s work also revealed that when exposed to the standard inhibition test, used to detect flu in livestock, H3N8 remained undetected in pigs.
“It has been shown that the H1N1 strain that caused the 2009 (human) flu pandemic had been previously circulating in the pig population,” said Dr Montoya. “With H3N8 acting as a sneaky virus in pigs and able to go undetected through standard testing, it is not difficult to imagine that it could be a candidate for future outbreaks.”
She also warned that “with humans being more closely related to pigs than other livestock carriers of the virus”, concern arises when avian strains come together and reassort with pig strains to create a “highly pathogenic virus that is more readily able to infect humans”.
“If H3N8 is able to cross the species barrier and circulate undetected in pigs, then the chance of it coming together with circulating strains of avian influenza A viruses are increased,” she said.