Lonomia Obliqua, Deadly Caterpillar

A typical envenomation incident involves a person unknowingly leaning against, placing their hand on, or rubbing their arm against a group of these caterpillars that are gathered on the trunk of a tree. The effects of a dose from multiple caterpillars can be dramatic and severe, including massive internal hemorrhaging, renal failure, and hemolysis. The resulting medical syndrome is sometimes called Lonomiasis.
To date, no one has calculated the LD50 values of Lonomia venom; the rate of human fatality has been documented as 1.7%, compared to a rate for rattlesnakes at about 1.8%, despite the amount of venom being only a minute fraction (less than 0.001) of that in a snake bite. Accordingly, it seems likely that when measured, the LD50 for Lonomia venom will be among the lowest for any natural toxin known. As the plants the larvae feed upon are not unusually toxic, they presumably synthesize the toxin directly, but the biochemical pathways used have apparently not yet been documented.