Re: How does the venom from a brown snake affect a humans body?

G'day Kate!


I'm assuming the australian brown snake you're talking about is the one 
you normally try to avoid when you're bushwalking, it's called Pseudonaja 
textilis, the Common Brown Snake.  It's a pretty nasty bugger and often 
when they bite they hit you so hard it leaves a really nasty bruise and it 
usually bites a few times.  But I'll get to the point.. Although it's 
fangs and venom yield are small, the venom is highly neurotoxic and 
coagulant.  This means that it interferes with the electrical activities 
of your nerves, preventing them from working, and it makes your blood 
clot.  The venom also has some blood-destroying properties making the 
Common Brown snake one of our most deadly species!!
You can find out more this snake and a lot of other Australian Snakes in 
"Snakes of Australia" by Graeme F. Gow, 1983 (Angus and Robertson 
Publishers). 
I hope I answered your question Kate, but remember, snakes are more scared 
of us than we are of them, so the coming across one in the wild doesn't 
happen often.  But watch where you step anyway!!
Happy Trails
Rochelle.
ADMIN NOTE: Bryan Fry adds

Brown snakes contain three main types of molecules in their venoms:
neurotoxic peptides (6-8 kDa), neurotoxic phospholipase A2s (14 kDa), and
prothrombin activators (50 + kDa).  The neurotoxic peptides act
postsynaptically in a manner similar to curare.  The PLA2s act
presynaptically and destroy the nerves.   The prothrombin activators are
procoagulant but have a net anticoagulant results.  They convert
fibrinogen to fibrin, but then destroy the fibrin rather than letting it
form clots.  Thus, the blood becomes essentially incoagulable.  There are
other minor bleeding factors and also hypotensive agents in the blood.  

The statement regarding the bruising is incorrect.  Bruising would be
caused by venom effects rather than physical trauma.

Further information regarding Australian venomous animals can be found on
the Australian Venom & Toxin Database
http://www.uq.edu.au/~ddbfry/index.html

Cheers,
Bryan Grieg Fry
Centre for Drug Design & Development
University of Queensland