"Immunity" to mosquitoes.

[Daniel & Monica Glaeske]

Perhaps I could introduce a little of the medical perspective.

Reaction to mosquito bites takes two forms -- an immediate (IgE-mediated)
response which is the one that usually produces the welts, and a slower,
cell-mediated response called delayed type hypersensitivity.  Both these
types of immunity evolved in response to potential infections by usually
non-bacterial/nonviral pathogens (e.g., intestinal parasites).
Immunologists speculate that the chemicals released from the IgE-mediated
(immediate reaction) are toxic to the mosquitos, and on a population basis,
may serve to reduce the total human-biting mosquito population in our
original, dry savannah habitats millions of years ago.  This is of course,
little comfort to the unfortunate person who suffers from them.

The DTH (delayed-type hypersensitivity) response produces mild swelling and
redness at the bite site several hours or even a couple of days afterward.
It may help protect us against mosquito-borne pathogens by recruiting
immune cells to the bite site.

Daniel
St. Victor, SK

Kenelm Philip wrote:

>         Michael Gochfeld mentioned an Alaskan who was sensitive to mos-
> quito bites, and thought he might have been sensitized by exposure. As
> a reasonably long-time Alaskan (34 years) who has spent a _lot_ of time
> being punctured by mosquitoes, I would suggest another possibility--
> individual variation in sensitivity regardless of exposure. I don't
> get welts, and never have, and regard the bites as a minor nuisance.
> Gochfeld's friend might still have gotten sensitized, of course--but he
> may also have always been that way. My wife, for example, has always
> gotten welts, whether the mosquitoes were Alaskan or east coastal US.
>
>                                                         Ken Philip
> fnkwp at uaf.edu