If people were armed with extremely impregnated mosquitos, pro-NRA Americans would surely reconsider.
Besides created a health problem, this can be defeated with bug repellent.
There are laws restricting what can be carried in public such as the size of the blade and how fast a knife can be opened. If you need to create a mace take the ends off a can and punch tack through it. Then attach them with the points sticking out to a stick and you have an effective weapon.