Last episode we discussed the current H5N1 flu that is hitting birds pretty hard. But is bird flu different from swine flu? Is there just a 'human flu', or do we only catch influenza from other animals? Let's get into the evolutionary history of the flu and primary hosts! References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7328453/ https://www.ncbi.nlm.nih.gov/books/NBK8611/ https://journals.asm.org/doi/full/10.1128/JVI.01080-14 https://www.cdc.gov/flu/weekly/index.htm https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268205/ https://www.woah.org/en/disease/avian-influenza/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3784916/ https://www.frontiersin.org/articles/10.3389/fevo.2018.00131/full https://www.science.org/doi/10.1126/science.1176225 https://pubmed.ncbi.nlm.nih.gov/32967956/