The mouse spiders of the genus Missulena are a type of primitive burrowing spider found primarily in Australia and Chile in South America. Several species of this genus are known to possess a venom which contains compounds similar to δ-atracotoxin, the substance in funnel-web venom which can be fatal. However, most bite victims suffer only local pain and bleeding, a few more have limited neurotoxic symptoms (tingling, racing heart, more widespread pain), and there have been several recorded bites by this spider producing severe symptoms requiring medical treatment. There are no recorded human fatalities due to mouse spider bites. When severe envenomation does occur, funnel-web antivenom has been shown to be effective.
