The initial identification of Borrelia burgdorferi DNA sequences in Ötzi’s genome was reported in 2011, based on the sequencing data from the 2012 paper. The finding attracted significant attention because it was, at the time, the earliest documented case of Borrelia infection in a human. The Alpine environment where Ötzi lived and died is now known to be endemic for Lyme disease-transmitting ticks, so the presence of Borrelia in a Copper Age Alpine individual was ecologically plausible.
However, subsequent analysis complicated the picture. Later, more detailed examination of the Borrelia sequences found in Ötzi’s genome suggested they might not belong to Borrelia burgdorferi specifically but to a different Borrelia species. The genus Borrelia includes multiple species, some of which cause Lyme disease and some of which cause other tick-borne relapsing fevers. The sequences found in Ötzi matched some B. burgdorferi markers but not all, raising the possibility that he was infected with a different or ancestral Borrelia species.
This distinction matters for interpreting what the finding tells us about ancient Lyme disease specifically versus the broader history of tick-borne Borrelia infections in human populations. If Ötzi carried a Borrelia species ancestral to modern B. burgdorferi rather than B. burgdorferi itself, the finding documents a different point in the evolutionary history of that bacterial lineage.
Regardless of the specific species-level identification, the finding confirms that Borrelia bacteria were infecting humans in the Alpine region at least five thousand years ago. For a person already dealing with degenerative joint disease, the arthralgia associated with Borrelia infection would have added to his overall burden of pain and reduced mobility.