Black Widow, Brown Recluse and Hobo Spiders

 A venomeous spider species found in the western regions of the United States.  The female's body is black, often with an hourglass-shaped red mark on the lower abdomen.  The male of the species is generally a tan color with lighter striping on the abdomen  The species, as with others of the genus, build irregular webs, the strands of which are very strong 

 Black widow spider venom contains components known as latrotoxins, which cause the release of the neurotransmitter acetylcholine, stimulating muscle contractions.  This can affect the body in several ways, including causing painful abdominal cramps, as well as interfering with respiration, and causing other systemic effects.

 If the above symtoms are present, get the victim to a medical facility.  In severe cases, narcotic pain relievers are used to treat the pain.  There is an anti-venom for black widow toxin, but some are allergic, so a skin test is needed.  Very rarely does a life-threatening complication occur in healthy adults.

 Spiders known to have necrotic venom are found in the family Sicariidae, a family which includes the Brown Recluse Spider.  Bites by spiders in this family can produce symptoms ranging from minor localized effect to severe dermonecrotic lesions and systemic reactions including renal failure, and in some cases, kidney failure, coma and death.  The bite may for a necrotising ulcer that destroys soft tissue and may take months to heal.

 There is no known anti-venom for the Brown Recluse Spider bite.  Initial treatment of ice packs to reduce pain and swelling and then elevating the affected limb above the heart may reduce the spreading of the toxin throughout the body.