Tiger snake

Tiger snake

Tiger snakes (Notechis spp) are highly venomous. Their venoms possess potent neurotoxins, coagulants, haemolysins and myotoxins and the venom is quick-acting with rapid onset of breathing difficulties and paralysis. The untreated mortality rate from tiger snake bites is reported to be between 40 and 60%. They are a major cause of snakebites and occasional snakebite deaths in Australia.

Common death adder

Common death adder

The Common death adder (Acanthophis antarcticus) is a highly venomous snake species with a 50-60% untreated mortality rate. It is also the fastest striking venomous snake in the world. A death adder can go from a strike position, to strike and envenoming their prey, and back to strike position again, in less than 0.15 seconds. The SC LD₅₀ value is 0.4 mg/kg and the venom yield per bite can range anywhere from 70–236 mg. Unlike other snakes that flee from approaching humans crashing through the undergrowth, common death adders are more likely to sit tight and risk being stepped on, making them more dangerous to the unwary bushwalker. They are said to be reluctant to bite unless actually touched.

Eastern brown snake

Eastern brown snake

The Eastern brown snake (Pseudonaja textilis) has a venom LD₅₀ value of 0.053 mg SC according to (Brown, 1973) and a value of 0.0365 mg SC according to (Ernst and Zug et al. 1996). According to both studies, it is the second most venomous snake in the world. Average venom yield is 2–6 mg according to (Meier and White, 1995). According to (Minton, 1974) average venom yield (dry weight) is between 5–10 mg. Maximum venom yield for this species is 155 mg. This species is legendary for its bad temper, aggression, and for its speed. This species is responsible for more deaths every year in Australia than any other group of snakes.

Inland taipan

Inland taipan

The Inland taipan (Oxyuranus microlepidotus) is considered the most venomous snake in the world with a murine LD₅₀ value of 0.025 mg/kg SC. Ernst and Zug et al. 1996 list a value of 0.01 mg/kg SC, which makes it the most venomous snake in the world in their study too. They have an average venom yield of 44 mg. Bites from this species have a mortality rate of 80% if left untreated, although it is very rare for this species to bite. This species is known to be a very shy, reclusive and a laid-back snake that will nearly always slither away from disturbance. It is not an aggressive species and rarely strikes.

Malayan krait

Malayan krait

The Malayan krait (Bungarus candidus) is another dangerously venomous species of krait. In mice, the IV LD₅₀ for this species is 0.1 mg/kg. Envenomation rate among this species is very high and the untreated mortality is 70%, although even with antivenom and mechanical ventilation the mortality rate is at 50%.

Many-banded krait

Many-banded krait

The Many-banded krait (Bungarus multicinctus) is the most venomous krait species known based on toxinological studies conducted on mice. The venom of the many-banded krait consists of both pre- and postsynaptic neurotoxins (known as α-bungarotoxins and β-bungarotoxins, among others). Due to poor response to antivenom therapy, mortality rates are very high in cases of envenomation - up to 50% of cases that receive antivenom are fatal. Case fatality rates of the many-banded krait envenoming reach up to 77%–100% without treatment. The average venom yield from specimens kept on snake farms was between 4.6—18.4 mg per bite. In another study, the average venom yield was 11 mg (Sawai, 1976). The venom is possibly the most toxic of any Bungarus (krait) species and possibly the most toxic of any snake species in Asia, with LD₅₀ values of 0.09 mg/kg—0.108 mg/kg SC, 0.113 mg/kg IV and 0.08 mg/kg IP on mice. Based on several LD₅₀ studies, the many-banded krait is among the most venomous land snake in the world. The Taiwan National Poison Control Center reports that the chief cause of deaths from snakebites during the decade (2002-2012) was respiratory failure, 80% of which was caused by bites from the many-banded krait.

Terciopelo

Terciopelo

The Terciopelo (Bothrops asper) has been described as excitable and unpredictable when disturbed. They can, and often will, move very quickly, usually opting to flee from danger, but are capable of suddenly reversing direction to vigorously defend themselves. Adult specimens, when cornered and fully alert, should be considered dangerous. In a review of bites from this species suffered by field biologists, Hardy (1994) referred to it as the "ultimate pit viper". Venom yield (dry weight) averages 458 mg, with a maximum of 1530 mg (Bolaños, 1984) and an LD₅₀ in mice of 2.844 mg/kg IP. This species is an important cause of snakebite within its range. It is considered the most dangerous snake in Costa Rica, responsible for 46% of all bites and 30% of all hospitalized cases; before 1947, the fatality rate was 7%, but this has since declined to almost 0% (Bolaños, 1984), mostly due to the Clodomiro Picado Research Institute, responsible for the production of antivenom. In the Colombian states of Antioquia andChocó, it causes 50-70% of all snakebites, with a sequelae rate of 6% and a fatality rate of 5% (Otero et al., 1992). In the state of Lara, Venezuela, it is responsible for 78% of all envenomations and all snakebite fatalities (Dao-L., 1971). One of the reasons so many people are bitten is because of its association with human habitation and many bites actually occur indoors (Sasa & Vázquez, 2003).