Farmed mink and influenza - Canadian preprint findings
Multiplexed SARS-CoV-2 surveillance finds unexpected asymptomatic H3N2 infection in remote mink herd in Canada
Once again, I owe awareness of this bioRxiv preprint to Michael Coston:
Here is the direct link to the pre-print:
First note that this is a widely disseminated non-zoonotic swine influenza strain! We are not discussing an imminent public health threat here! However, it does illustrate geographical reach and interspecies potential for influenza A infections.
As Michael documents, influenza in mink is not a new phenomenon. Mink are carnivores; their diet may include poultry processing by-products. Turkeys may occasionally be contaminated with low internal levels of H1/H3 low pathogenic avian influenza (LPAI), especially in flocks raised in swine dense areas with endemic H1 and H3 influenza in pig populations. Swine are widely shipped in both directions between the U.S. and Canada, spreading clades widely among the combined North American swine herd. Thus, it is not inconceivable to find a widely disseminated swine influenza clade transmitted via contaminated via turkey slaughter by-products to a mink herd found in Canada.
This is a highly speculative scenario, in that we have no proof of the herd’s feed supply, nor of any known sub-clinically H3N2-affected turkey flocks sent to slaughter in Canada. But it does illustrate that standard industry practices may have unintended consequences in disease transmission, leading to further required biosecurity steps for mitigation.
While wild animal incursions are always possible sources for unexplained infections, we should always first consider the daily inputs - air (area infections), feed, water, and people. With influenza, any of those could be sources for the outbreak!