Wednesday, January 19, 2011

Rattlesnake Bites

            About a year ago a man called late one evening to say his two dogs had been struck by a rattlesnake and he wondered if he should bring them in for treatment.  He was in the desert, 50 miles away and the dogs had been vaccinated against snake venom six months previously.  I told him I thought they would be OK until morning.
            When they arrived the next day the dogs’ heads were swollen.  But being protected against venom by vaccination, the dogs were not too much the worse for wear and tear.  This was quite remarkable for the dogs were bitten by a big snake, fang-marks were 1 ¾ inches apart.  Both dogs were treated with a diuretic that limited swelling, removed venom from their tissues and expelled it through the kidneys.  The owner claimed that a week later there was no evidence they had been bitten by a rattlesnake.
            Just the other day the man with his dogs returned for their annual vaccinations and asked if revaccination against snake venom was necessary.  The vaccine manufacturer recommends it be done yearly.  If you think about it, that’s a good idea.  Normally, after vaccination or a snake bite immunity peeks shortly and after a while, say a year, it declines to a low level, possibly too low for immediate protection.  When a snake bites, a dog needs immunity right now not three days after the bite which happens when immunity declines.  Annual revaccination will assure adequate immunity is present when needed.