Deadly Songbird Parasite Evolving Rapidly

The bacteria responsible for the red, swollen, crusty eyes of a sick house finch, which can leave it unable to survive, evolve at an exceptionally fast rate — which is both bad and good news for the future of the songbird, researchers say.

The fast evolution means the bacteria can keep up with their hosts' immune systems. However, in the process of evolving, the bacteria have lost genes that may protect them from viruses. That's a weakness scientists could take advantage of to get rid of the bacteria, which have led to the death of thousands of house finches in the wild since the bacteria jumped species and started an epidemic in the 1990s.

Bird bacteria

The tiny bacteria, Mycoplasma gallisepticum, infected poultry before it adapted to the house finch population. The researchers analyzed several samples of the bacteria from different years of the epidemic (the mid-1990s, 2001 and 2007) and compared them with strains isolated from chickens and turkeys.

Phage attack

The researchers said they aren't sure whether the loss of key immune-system genes was an artifact from the bacteria's move to the new host (perhaps the small population of bacteria that started the epidemic had already lost their immunity genes) or whether they lost them along the way because it somehow gave them an advantage in the house finches

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