Herpes is a big success as an organism, that is if you define a virus as an organism but we wont enter that debate. It has successfully established itself in the human population and does what the most successful parasites do. It may inconvenience its host but it does not kill it. If you think about it, a parasite that kills its host is depriving itself of a home.

It appears that there is a version of herpes that is not quite so benign. Koi herpes virus, or KHV, is killing four out of every five carp that it infects, and has spread rapidly around the world. The disease threatens two important fish populations: the ornamental koi carp industry, which is worth tens of millions of dollars in Japan, and the common carp, the world's fourth most-farmed fish.

It was first identified in Israel in 1998 which prompts The Green Man to wonder what bizarre practices are engaged in in that country via-a-vis fish and herpes infected humans. Perhaps it is better not to think to much about that. Anyway it has spread to Europe, Asia and the United States, which prompts the question "How come we haven't got it in Australia?" It seems that everywhere that likes carp have got it and Australia, that hates carp (they are an environmental nightmare here) has missed out. Ah the irony.

You can read more about this carp social disease in Nature here.