(2) Regurgitation. Some arthropods regurgitate, or vomit, a portion of their
stomach contents into the wound made for feeding. These stomach contents often
contain large masses of disease organisms.
(3) Defecation. Many arthropods defecate while feeding. The fecal material,
containing disease organisms, is then introduced into the wound made by the
arthropod--usually by scratching the irritated area.
(4) Contamination with crushed tissue. The biting of an insect causes an
itching sensation, which normally compels the bitten person to scratch. Scratching
often crushes the insect, causing the introduction of crushed tissues---containing
disease organisms--into the wound.
Arthropods transmit disease
CATEGORIES OF ARTHROPOD-BORNE DISEASES
Arthropod-borne diseases may be classified by a number of ways: by the type of
infective organism, that is., bacteria, viruses, rickettsia, and so forth; by the type of
vector, that is mosquito, fly, tick, flea, and so forth.; or by the symptoms of the disease
or the part of the body affected, that is., the central nervous system, the lymphatics, the
circulatory system, etc. For convenience, the diseases discussed in this text will be
considered according to the following classification:
Section II. MOSQUITO-BORNE DISEASES
The mosquitoes make up the most important group of disease vectors. Mosquitoes
transmit numerous diseases that have military importance. Some of these are malaria,
yellow fever, dengue fever, encephalitides viruses, and filariasis.