The moment a viper’s venom enters the body, its enzymatic components set about their nefarious work. Metalloproteases begin the assault by mowing down structurally essential components of blood vessels and tissues, weakening walls and making holes that leech fluid. Capillaries hemmorrhage and the area swells while the proteases keep at their attack, taking out skeletal muscle through mechanisms poorly understood. Phospholipases join in, with their sights set on cell membranes. Some cut apart membrane lipids making lethal holes, while others seem to be just as destructive without enzymatic activity. The end result: muscle tissue dies. Hyaluronidases and serine proteases aid in the efforts, and the helpless tissue succumbs to the venom’s siege.
And that’s not even the worst part. The metalloproteases and phospholipases have other tricks up their sleeves. They don’t just fight their own war on our flesh: they enlist our own immune system to help them do it. The liberation of tumor necrosis factor and immune-stimulating cytokines by metalloproteases and the release of bioactive lipids by phospholipases cause immune cells to rush to the wound. Our body’s forces are trained to kill, usually setting their sights on bacteria and viruses. But without those clear targets, the body’s army gets confused. They can’t tell friend from foe, yet the immune cells fire anyway, blindly attacking an unseen danger. Valiant volleys act as friendly fire, adding to the death toll of innocent tissues.
