The Hobo Spider (Tegenaria agrestis) is a member of the Genus of spiders known colloquially as Funnel Web Spiders. It is one of a small number of spiders in North America whose bites are generally considered to be medically significant.
The spider’s venom is strong enough to cause considerable local pain and also to cause tissue death (necrosis) at and near the bite.
Agrestis is indigenous to western and central Europe, but is now also found in the north-western USA and south-western Canada. It has recently spread to southern Alaska, becoming the first spider dangerous to humans in the state. Recently it has been found in great numbers in Denmark on a small island (Peberholm), which is on the route of the Oresund highway, and according to media it has spread from there to the province of Skane in southern Sweden.
While the reported effects of Hobo Spider bites can go so far as to include local tissue death (necrosis), they are not known to be fatal to healthy humans. The necrosis is similar to, but less serious than, the necrosis caused by the Brown Recluse Spider. If such a lesion is severe it may take months to heal. Other symptoms include intense headaches that may last from a couple of days to a week, and in some cases there are vision abnormalities and/or a general feeling of malaise.
Humans may have unfortunate interactions with these spiders on account of careless contact with them in their lairs, or unintentional contact while in bed sleeping when the males wander by searching for mates.