On their own, the symptoms don't sound deadly: despondence, weight loss, fatigue. But after a few months, or in some cases a few years, all birds with proventricular dilatation disease (PDD) wind up dead. PDD began appearing in veterinary clinics in the 1970s. It eventually spread to parrots worldwide, and can easily wipe out an entire colony.
From the beginning, veterinarians suspected PDD had viral causes. Then, a few years ago, a parrot owner suggested that his veterinarian contact Joseph DeRisi's lab at University of California, San Francisco (UCSF). DeRisi had made a name for himself by coinventing the ViroChip, a microarray chip that contains conserved genetic sequences from all known viruses. The array identifies new viruses when they are related closely enough to a known virus family to cross-hybridize with the probes on the chip. In 2003, DeRisi and his former colleague David Wang used the chip to identify ...
