Stay away from the seals: Seals pose influenza threat. For the first time, an animal reservoir of the influenza B virus has been discovered. After an ailing seal found on the Dutch coast was diagnosed with the flu in 1999, up to 2% of seals in the area were found to be infected. Animal reservoirs of viruses that infect humans pose a potentially devastating threat because they (a) allow viruses to resurface after hiatuses when human resistance has faded, and (b) also allow viruses to mutate into more virulent strains unimpeded. (Mutation into a more deadly strain in a human population would usually, in contrast, be self-limiting, because the infection would kill its hosts so rapidly that it could not spread far; notice how many of the terrifying recently-emergent diseases appear to have jumped from animal reservoirs.) The ‘A’ type of the influenza virus is harbored in birds and mammals (“swine flu”) and the cyclical emergence of new virulent A strains has been responsible for serious flu epidemics worldwide. In contrast, the influenza B virus was thought to be exclusively human. Stored seal blood samples showed no signs of infection prior to 1995 but, since that date, 2% of the samples showed evidence of the virus. The viral “footprint” for all infected seals indicates a 1995 strain. Scientists speculate that someone coughed or sneezed in the face of a stranded seal encountered on a beach somewhere in 1995 and the virus made the jump to the new species. [BBC]