More than 10,000 dead birds were collected in Finnmark county, according to Norwegian officials.
Hundreds of mammals around the world have been infected by avian influenza amid the ongoing global outbreak.
While traces of the virus were later found on raw meat eaten by one of the cats, it remains unclear if that is how the cat was infected.
A team of scientists from the MRC-University of Glasgow Centre for Virus Research studied hundreds of genes normally expressed by human cells.
The infected cats were found in locations separated by hundreds of kilometers.
While the viruses' risk to humans remains low, the researchers noted only a few amino acid changes are needed for that to change.
"These favorable results provided sufficient guarantees to launch a vaccination campaign as early as autumn 2023," the farm ministry wrote on its website.
Black irises could be used as a likely indicator of prior infection with avian influenza.
The new study, which has not yet been peer-reviewed, studied virus samples taken from infected birds and mammals.
The last bird flu case reported in Israel was reported on January 19.
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