Sunday, September 29, 2013

Humans and hornets don't mix

I missed this news item last week that a very aggressive type of hornet, the Asian giant hornet or Vespa mandarin, has increased in numbers in its native southern China to the point that this year they have become a public health hazard.  The venom of these hornets is very toxic to mammals, with laboratory a single sting can kill a mouse. And they will swarm humans-- here is a case report of a man with 100 stings who suffered multiple organ failure and died.The increase of human-hornet contact in China this fall seems to be a consequence of a series of very mild winters increasing hornet populations combined with increasing human incursions into hornet habitat.
The Asian giant hornet. Source:Wikipedia
The venom of these hornets has a few components of interest to pharmacists and scientists. Mandaratoxin, also known as Antigen 5, poisons presynaptic sodium channels, thus in the context of a sting interferes with neuromuscular junctions. Hornet venom also contains Vespakinin-M, an analog of bradykinin, which causes blood vessels to dilate.

The chief reason these hornets are such a health concern is the quantity of venom they inject-- nearly a milligram of venom with each sting, nearly double that of the nearest hornet competitor. Definitely a bug to be avoided.

Update: a summary of this year's hornet attacks in China. 

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