A Note on Venom

Since I made contact with Astri Leroy (from the Spider Club of South Africa) in connection with the spider web photo I took the other day, she’s sent me some spider-related material. Astri is very concerned about the bad rap that spiders get. In one of her emails (after I asked how many poisonous spiders we have where I live), she says “Really to set your mind at rest, very few spiders in any part of South Africa pose any danger to people at all, and in the last 60 – 100 years no deaths from spider bites have been recorded.” 60 – 100 years? Does that mean that in those 40 years there were some unaccounted for deaths?! 😉

She also sent me the following excerpt from an article she has written.

A Note on Venom by Astri Leroy

Most spiders produce venom which is a mixture of saliva, venom and digestive fluids, used to subdue, kill and digest their prey – usually invertebrates. In general it has little effect on large mammals including people. A bite may hurt at first, can itch for several days but if left to subside without being scratched will disappear with no lasting ill effects. Venom does not persist in the body and the effects of a bite will not recur later. Spiders will only bite if squashed against our skin – they don’t even bite in self-defence as some larger creatures do. They do not eat people. They do not make a living from sucking our blood and are not vectors of any human diseases. In fact they will avoid contact with big, dangerous creatures like us. This means that spider bites are really rare and the effect venom of most spiders on humans is unknown because they simply don’t and often cannot bite us.

Many supposed spider bites turn out to be tick, flea, mosquito or other arthropod bites, but most often they are bacterial infections. Fungal infections or lesions resulting from some underlying medical condition are also sometimes blamed on spiders. People with impaired immune systems are more susceptible to infections and such infections often cannot be diagnosed so medical practitioners take the cautious route of prescribing broad spectrum antibiotics. These work for most bacterial infections with the exception of the difficult to treat deep seated bacterial infections such as MRSA (methicillin-resistant Staphylococcus aureus). Of course antibiotics do not work on fungal or viral infections and need to be treated differently.

However, she does admit that what is known in South Africa as the Brown Button Spider (Latrodectus geometricus), and elsewhere as the Brown Widow Spider, has always been common in our area. Great! Just what I needed to hear. A venomous spider in my area.

Brown Button or Brown Widow Spider (Latrodectus geometricus) Image source: Wikipedia

So, if you see a spider with that very “spider-like” shape (like they use in movies and comic books) and an hourglass marking underneath (Like I’m really going to be turning a spider like this over to check!), or you see a spider egg sac that has spines on it, DO NOT TOUCH. Call the branch of your local Spider Club instead!

Latrodectus Egg Sac (Image source: Wikipedia)