Common krait
The common krait (Bungarus caeruleus)
is often considered to be the most dangerous snake species in India. Its venom
consists mostly of powerful neurotoxins which induce muscle
paralysis. Clinically, its venom contains presynaptic and postsynaptic
neurotoxins, which
generally affect the nerve endings near the synaptic cleft of the brain. Due to the fact that krait venom contains many
presynaptic neurotoxins, patients bitten will often not respond to antivenom
because once paralysis has developed it is not reversible. This species causes an estimated
10,000 fatalities per year in India alone. There is a 70-80% mortality rate in
cases where there is no possible or poor and ineffective treatment (e.g., no
use of mechanical ventilation, low quantities of
antivenom, poor management of possible infection). Average venom yield per bite
is 10 mg (Brown, 1973), 8 to 20 mg (dry weight) (U.S. Dept. Navy,
1968), and 8 to 12 mg (dry weight) (Minton, 1974). The lethal adult human dose is
2.5 mg. In mice, the LD50 values of its venom are
0.365 mg/kg SC, 0.169 mg/kg IV and
0.089 mg/kg IP.
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