Venomous bites and stings are those in which the biting or stinging organism actually injects a toxic cocktail of proteins into the victim, designed in most cases to immobilize, kill and assist in the digestion of prey items. Some venomous organisms, such as the honey bee, sting rays and most venomous fish use their venom primarily as a defensive mechanism. DTH reactions are the persistent, itchy lesions that result following bites by mosquitoes, etc.
Venoms are complex mixtures of enzymes, toxins, and small molecular weight molecules.
While the effects of specific toxins such as neurotoxins, hemotoxins, cardiotoxins, etc. often dominate the clinical picture for a bite or sting from a particular species, victims of significant envenomation usually exhibit multiple signs and symptoms from the same bite or sting. Further sources of information about snakebite can be found in other interesting sites . Powerful neurotoxins dominate the clinical picture in bites by the black widow, while the hobo spider, recluse spiders, and to a lesser extent the yellow sac spiders, can induce necrotic arachnidism. Necrotic arachnidism is characterized by the local destruction of tissues at or near the bite site. More information on necrotic arachnidism can be found in hobo spider poisoning .