Task: Translation
Input (English): At least some of the three pandemics during the last (20th) century are thought to have come from an animal or bird influenza virus that itself mutated or swapped genes with a human influenza strain (so called recombination) and acquired the ability to both infect humans and, more importantly, spread between them.
Output (Swedish): Minst några av de tre pandemierna under det senaste århundradet (1900-talet) tros ha härstammat från ett djur- eller fågelinfluensavirus som muterades eller utbytte gener med en mänsklig influensastam (så kallad rekombination) och därmed både kunde smitta människor och ännu viktigare spridas mellan dem.