The Salivary Gland Poison of the Aëdes Aegypti.

Abstract

The nature of the poison contained in the salivary glands of mosquitoes is little understood. That this substance is very irritating to the human skin (and to that of other animals) has long been an established fact. Those who dwell in the tropical belt are well aware of this though the nuisance of mosquitoes is by no means limited to warm climates. Not all species of mosquitoes bite man, indeed some seem to prefer animal blood to that of man, but a human blood meal is usually acceptable if no other is available. On the other hand, there are many different kinds of mosquitoes which prefer the blood of man and in some instances refuse to partake of the blood of certain animals. When the mosquito bites, some of the salivary secretion is injected into the wound and this, in most instances, is followed by the appearance of a wheal, surrounded by an area of erythema and accompanied by intense itching. This is the characteristic reaction following the bite of the Aëdes aegypti and we have been interested in the substance contained in the salivary glands of this particular insect which causes this reaction.

People vary in susceptibility to this poison. Some state that mosquitoes never bother them. Others develop the most intense reactions following these bites. Still others state that they believe that they have become immune to certain mosquitoes. Several individuals have reported to us that 2 or 3 years ago, when they first came to Porto Rico, they were bothered by mosquito bites and developed intense lesions following them and that after 2 or 3 years in residence here they have gradually become “immune” to mosquitoes and seriously doubt if they are ever now bitten.