Australasian Science: Australia's authority on science since 1938

Pythons Trick Doctors

By Stephen Luntz

The saliva from pythons, and possibly other non-venomous snakes, can trigger cross-reactions in venom detection kits, leading to the wasteful use of antivenoms.

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A/Prof Bryan Fry of the University of Queensland argues that hospitals should make sure a patient is actually in danger before applying treatments.

Pythons have long since given up using toxins to kill their prey, preferring to squeeze them to death. Their glands secrete large quantities of mucus because, as Fry puts it: “The average child makes a pretty dry meal”. However, Fry has revealed that the saliva still contains relics of the venom used by the distant ancestor of pythons, and this can react with the tests given to a snake-bite victim.

“Part of the problem is that venom detection kits are misnamed,” says Fry. “They should really be called ‘identification kits’ and certainly should not be used to decide whether antivenom needs to be applied.”

Fry argues that hospitals need to base decisions about the need for treatment on the clinical signs. “We had a case where a member of our team was bitten by a curl snake, and Mt Isa Hospital argued he didn’t need antivenom because the detection kit didn’t indicate anything. We told them this was because the patient, who was showing all the signs of a severe reaction, had been bitten by a snake so rare it was not in the standard kit, and they needed to give him the polyvalent antivenom. Eventually they did and it worked well.”

The kits exist because polyvalent antivenoms are much more expensive than...

The full text of this article can be purchased from Informit.