INSECT BITES AND STINGS. Insects may be the cause of disease or of morbid conditions in man in several different ways: (I) by living on his skin or hair, as in the case of three varieties of pediculi or lice (the head-louse, the body-louse, the crab louse) ; or in his skin, as with the itch-insect (though this is strict ly not an insect at all but a spider-like parasite), or with the tropical chigger, jigger or sand flea; (2) by depositing their eggs on the skin or mucous membrane, or on wounds, whence the larvae find their way below the surface, usually by boring or bur rowing, as is the case with several tropical flies; (3) by being the instrument of transferring a bacterial infection to man from some other animal, as is the case with the rat flea in plague, or by taking part as host in the life-cycle of a spirochaete or a protozoon and passing the parasite on to man, as is done by certain mos quitoes in yellow fever or in malaria; (4) by the direct and immediate effects of their bite or sting. It is with this last method only that the present article is concerned.
In Great Britain and the United States, as in most other coun tries, such bites and stings are exceedingly common, the most frequent biting insects being the common flea, the bed-bug, gnats and mosquitoes, and the most frequent stinging insects being the wasp, the bee, the hornet and the ant. It should be realized, too, that the effects of the louse are due not merely to its presence, as mentioned above, but to its actual bite.
The consequences of these bites and stings are well known, very few persons escaping some personal experience thereof, though susceptibility varies widely in different persons. Local irritation may be extreme, and the skin lesion produced may vary from a small reddened or erythematous patch or a tiny papule, to large urticarial or nettle-rash wheals, or even to a spreading cellulitis or inflammation of the tissues under the skin. These effects, usually pass off completely in a few hours or at most a day or two. Occasionally, however, dangerous developments occur.
The conditions most likely to lead to such developments are: (I) a very large number of stings, as when a swarm of angry bees settles on the body ; (2) the lesion being on a mucous surface such as the tongue, the palate or the pharynx; (3) the supervention of some local complication such as erysipelatous or other strepto coccal infection, or the direct transmission of some form of septic poisoning as by the bite of a fly which has been feeding on putrid material. In all such cases skilled surgical aid should at once be sought, as in extreme instances death has occasionally resulted and urgent measures may be necessary to deal with the situation.
The most convenient substance to use to relieve the irritation of mosquito bites is moist toilet soap. Late experience shows that the so-called "chigger bites" or the irritation caused by the entrance of any larval mites into the skin are best treated with a phenol-camphor mixture known in medicine as camphora carbolisata.
As preventive measures when insects are prevalent, camphor, menthol, lavender and oil of eucalyptus appear to have some virtue ; and skilful and assiduous campaigns against flies, mos quitoes and wasps have of late added greatly to the amenities of a number of localities. A good preventive lotion against mos quitoes is composed of one part oil of citronella, one part spirits of camphor and one-half part oil of cedar. (See BACTERIOLOGY; KALA-AZAR ; PARASITOLOGY.) (H. B. B.)