Chinese Cobra - Venom

Venom

The Chinese cobra is a highly venomous member of the true cobras (genus Naja). Its venom consists mainly of postsynaptic neurotoxins and cardiotoxins. Four cardiotoxin-analogues I, II, III, and IV, account for about 54% of the dry weight of the crude venom and have cytotoxic properties.

The LD₅₀ values of its venom in mice are 0.29 mg/kg IV, and a range of 0.29 mg/kg - 0.67 mg/kg SC. The average venom yield from a snake of this species kept at a snake farm was about 250.8 mg (80 mg dry weight). According to Minton (1974), this cobra has a venom yield range of 150 to 200 mg (dry weight). Brown listed a venom yield of 184 mg (dry weight).

The distribution of the venom of the Chinese cobra has been studied in mice using a whole-animal radiographic technique. Results indicate that venom accumulates primarily in the kidney (marked localization in the cortex) with little or no activity in the brain of mice sacrificed one to two minutes after intravenous injection of massive dose levels of venom. Using I-labelled cobra venom (Naja atra), 1 μg/g mice, its isolated I-neurotoxin (0.2 μg/g) or cardiotoxin (4 μg/g), it has been found that, after subcutaneous injection into the thigh, the neurotoxin was more rapidly absorbed than either crude venom or cardiotoxin.

Although this is not a spitting cobra, some individuals (mostly specimens from Guizhou Province) are capable of ejecting venom towards a threat within a distance of 2 metres (6.6 ft). In Taiwan there were 593 recorded cases of envenomation by the Chinese cobra from 1904–1938, of those 87 cases were fatal which is a 15% mortality rate. This is higher than mortality rates for Naja naja (the Indian cobra).

Local symptoms in victims caused by a Chinese cobra bite are wound darkening, localized redness and swelling, pain, insensibility, and invariably blisters and necrosis. Necrosis is a serious problem in cases of cobra bite as it may persist for many years after the general recovery of the victim. The following systemic symptoms may also occur: chest discomfort, fever, sore throat, difficulty in swallowing, loss of voice, weak feeling in limbs, walking haltingly, general ache, lockjaw, and difficulty in breathing. Fatality occasionally occurs. The antivenom is widely available and deaths are much rarer than they used to be.