Previous work by Camilli and Seed, published last year in Nature, provided the first evidence that a phage could acquire a wholly functional and adaptive immune system. They observed that the phage could use this acquired immune system to disarm a phage defense system of the cholera bacteria, allowing the phage to ultimately destroy its bacterial host. This study bolstered the concept of using phage to prevent or treat bacterial infections, and extended the idea that phages can be extremely sophisticated bacterial predators. The team is now investigating the details of this particular arms race between phage and bacteria in hopes of better understanding how phage influence cholera outbreaks and how we can further leverage phages to treat or prevent infections.