Section I. FLY-BORNE DISEASES
Arthropods are any of the insects, arachnids, or crustaceans consisting of a
jointed body and limbs with the brain dorsal to the alimentary canal and connected with
a ventral chain of ganglia. The source of the arthropod-borne disease is known as the
reservoir. The vector, usually an arthropod, transmits the causative organisms of
disease to a susceptible person. The organism on which the parasite lives and from
which the parasite obtains its nourishment is called the host. Autoinfection describes an
infection by bacteria that is present within one's own body.
a. Transmission. Diseases are transmitted by houseflies on their hairs and in
their feces and vomitus. Flies breed in manure, human waste, and decaying organic
matter. This decaying organic matter is defined as the fly's host since it provides the fly
with nourishment. Flies ingest the solid food by vomiting the contents of their stomach
onto the food and then sponging it up.
b. Diseases. Dysentery, cholera, and typhoid fever are the most important
diseases transmitted by flies.
DISEASE TRANSMITTED BY FLIES
(1) General. Dysentery is the term applied to a number of intestinal
disorders (especially of the colon) that are characterized by inflammation of the mucous
membranes. It is a common disease that is often self-limiting and mild but can be
serious for babies up to 3 years old. A rise in strains of dysentery which are resistant to
multiple antibiotics has been noted recently.
(2) Signs and symptoms. Dysentery usually begins abruptly and the patient
has diarrhea, and suffers lower abdominal cramps and tenesmus. Blood and mucus
are often found in the diarrheal stool. Other symptoms include fever (up to 104F in
young children), chills, headache, and lethargy. Meningismus, coma, and convulsions
occur in the most severe cases. Dehydration, weakness, and a tender abdomen follow
as the illness progresses. In infants, dehydration, acidosis, and electrolyte imbalance