[size= small; font-family: Calibri]Could parasites/bacteria stimulate physical reactions like pain, fever, tissue death or even anaphylaxis within its host as a means of control?  [/size]Are there any examples of this in nature?

You could argue that some pathogens promote their spread by causing physical reactions, like vomiting. Look at the life-cycle of the typhoid organism, which causes massive diarrhea containing millions of infectious cells. The rabies virus causes increased saliva production and agression which increases transmission.

Some common pathogens produce immune system toxins. Strains of Staphylococcus and Streptococcus are known to produce toxic protiens which induce wild, undirected immune responses, simlar to anaphilactic shock, called toxic shock syndrome. Other strains produce related proteins which have a similar action, but less acute. This family is called superantigens. The theory goes that if the invading bug can distract the immune system from it's proper job, it can do better.

http://en.wikipedia.org/wiki/Superantigen

The pathogens which cause gangrene isolate the infected tissues from general circulation by killing surrounding blood vessels.


Other pathogens completely change the behaviour of their host. Look up some baculovirus literature, and check out the co-opted virus used by parasitic wasps.

http://sciencefictionbiology.blogspot.c … avior.html
http://www.jstor.org/stable/2830998?seq=1
http://www.newscientist.com/article/dn1 … r-dna.html
http://www.narcis.info/research/RecordI … anguage/nl

Last edited by John Steemson (21st Apr 2010 07:31:59)