Hi all
I think it's important to make a clear distinction between the effects of venom on the one hand, and an allergic reaction on the other.
> Massive envenomations can cause death in nonallergic individuals. The estimated lethal dose is approximately 20 stings/kg in most mammals.
> Most deaths related to Hymenoptera stings are the result of immediate hypersensitivity reactions, causing anaphylaxis. Anaphylactic reactions to Hymenoptera stings are not dose dependent or related to the number of stings.
> The major component of honeybee venom is mellitin, which acts as a detergent to disrupt cell membranes and liberate biogenic animes, and potassium. Mellitin is a protein that hydrolyzes cell membranes, alters cellular permeability, and causes histamine release. Mellitin is considered the agent most responsible for local pain.
> Phospholipase A2 is the major allergenic component of bee venom and acts in concert with mellitin to cause intravascular hemolysis. Hyaluronidase causes changes in cell permeability by altering cell membranes and disrupts collagen, allowing other venom components to penetrate into the victim’s tissues; it is called the “spreading factor.”
> Apamin in bee venom is a neurotoxin that acts on the spinal cord. Adolapin inhibits prostaglandin synthetase and has anti-inflammatory actions, and it has been postulated that it may be useful in the treatment of arthritis.
> Four primary reactions may be seen after a Hymenoptera envenomation. First and most commonly seen is local pain and swelling. This reaction occurs in all envenomated (stung) individuals to some degree and is caused by vasoactive components of bee venom rather than by an allergic mechanism.
> Second is a larger, regional reaction, mediated by allergic mechanisms, involving parts of the body in continuity with the sting site. The third and more severe type of reaction is a systemic, anaphylactic response ...Anaphylactic signs usually are apparent within 15 minutes of the sting. The fourth possible reaction is uncommon and consists of skin rashes and serum sickness-like symptoms occurring within 3 days to 2 weeks after envenomation.
&c, &c
Fitzgerald, K. T., & Flood, A. A. (2006). Hymenoptera stings. Clinical techniques in small animal practice, 21(4), 194-204.
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