No. of Recommendations: 5
Hi, not hummingbird, but "Current public health risk: Low" doesn't have a strong future looking component.
Virus reproduce, mutate, and share evolved advantages extremely rapidly. Some depends on the complexity of the viral genomes and if they are dna or rna viruses, but the risk is from evolved ability to exploit shared structural proteins within a host population.
Simply, a bird may have different cellular proteins embedded in its cellular membranes than a person. The "H" and "N" in fact refer to hemagglutinin and neuraminidase which are surface proteins on the viral envelope. Protein folding modeling and prediction of binding site interactions is frontier science.
As the virus evolves rapidly, it gains functionality in terms of reproducing in hosts and those binding site competencies change. That may be in a way that makes it better adapted to spread in, cattle, bats, or felines, for example. Now these are mammalian hosts instead of avian ones.
As it evolves over generations in the time frame of single host infections, it adapts to mammalian environments. That makes crossovers to human hosts more possible, and it becomes a matter of probability and time in terms of when the unlucky mutation that allows human to human transmission possible.
Then the relentless evolutionary process the adapts the virus to the host quickly and it becomes endemic. You could expect a sars-covid-19 progression. I haven't kept an eye on the efficacy of flu vaccines or know if they'd have to be reformulated, or what the rate of drift would be early on.
