Treacherous And Ugly- The Most Dangerous Spiders

Spider venom work on one of two fundamental principles; they are either neurotoxic (attacking the nervous system) or necrotic (attacking tissues surrounding the bite, and in some cases, attacking vital organs and systems). Both sound nasty, but that’s enough of the science stuff; we’re checking our shoes before we put them on!

Brazilian Wandering Spider

In 2010, the Brazilian wandering spider was named in the Guinness World Records as the most venomous spider in the world. It is also aggressive, obviously making the chance of a bite from it more likely. It has a highly potent neurotoxin that can lead to breathing problems then asphyxiation and death in those bitten. Another effect of its venom is priapism, meaning erections that last a long time – hours to days – and can result in permanent impotence. However, the venom is being studied as a possible fix for erectile dysfunction. The spider only needs to inject 6 ug of its venom to kill a 20-gram mouse, and a full venom load is 1.069 mg. Death in humans has been known to occur even after antivenom has been administered.

Six-Eyed Sand Spider

The Six-eyed Sand Spiders‘ Genus is Sicarius, which is latin for “murderer”; a strong hint that this is a toxic beastie. One bite can kill a rabbit in just a few hours. While there are no recorded cases of human fatalities, this is one spider you should avoid. The six-eyed sand spider lives in desert areas in southern Africa, like the Kalahari and Namib deserts. It’s sometimes called the crab spider because it moves like a crab. It buries itself in the sand and waits for its victims to wander by before it strikes. The venom of the six-eyed sand spider is hemolytic/necrotoxic, which causes blood vessel leakage, tissue destruction and multi-organ breakdown. Luckily, this is one shy spider.

Sydney Funnel-Web

Sydney funnel-web spiders are among the most venomous on earth. They have large fangs and unlike some of the other very venomous spiders invariably deliver a full dose of venom instead of dry bites. They are also are more likely to bite than run away and will strike multiple times.  A compound in the Sydney funnel-web’s venom called atracotoxin is very dangerous to all primates – including us! One child died within 15 minutes, but that was before the discovery of an antivenom. The funnel-web’s LD-50 is just 0.16mg/kg.

Black Widow Spider

Black widows are notorious spiders identified by the colored, hourglass-shaped mark on their abdomens. Several species answer to the name, and they are found in temperate regions around the world. This spider’s bite is much feared because its venom is reported to be 15 times stronger than a rattlesnake’s. In humans, bites produce muscle aches, nausea, and a paralysis of the diaphragm that can make breathing difficult; however, contrary to popular belief, most people who are bitten suffer no serious damage—let alone death. But bites can be fatal—usually to small children, the elderly, or the infirm. Fortunately, fatalities are fairly rare; the spiders are nonaggressive and bite only in self-defense, such as when someone accidentally sits on them.

Red-back Spider

The Red-back spider is a dangerous spider endemic to Australia. It is a member of widow family of spiders, which are found throughout the world. The female is easily recognizable by her black body with a prominent red stripe on the upper side of her abdomen. Females have a body length of about a centimeter while the male is smaller, being only 3 to 4 millimeters long. The Red-back spider is one of few arachnids which display sexual cannibalism while mating. Red-backs are considered one of the most dangerous spiders in Australia. The Red-back spider has a neurotoxic venom which is toxic to humans with bites causing severe pain. There is an anti-venom for Red-back bites which is commercially available.         source

vadicjagat.com