Not Medical Advice: It is very seldom that people die from a black widow's bite, because they are non-aggressive and they only bite for self-defense. Life-threatening reactions are commonly seen only in small children and the elderly. However, in worst case scenarios seek medical assistance whenever you suspect a black widow bite, as there is anti-venom available specifically to counter a Black Widow Spider bite.
Black widow spider bite venom is a potent neurotoxic protein that affects the nervous system, it is about 15 times stronger than a rattlesnake's. But fortunately, the relatively small size of the black widow spider means that only a small amount of venom is produced and injected. A human body will therefore typically be able to dilute and break down the venom, and the signs will begin to diminish after a day or so.
Just recently, delayed flights are a fairly common occurrence, however the holdup last Saturday at Missouri's Kansas City International Airport (KCI) is because of a spider infestation and at least three employees at the air traffic control center were bit by spiders, likely in relation to a hatched spider nest, exterminators discovered after the fact. Find out more at The Huffington Post.