Webster's New World Medical Dictionary

epidemic hemorrhagic fever
See 
hemorrhagic
fever, viral.
epidemic myalgia
See 
Bornholm disease.
epidemic typhus
See 
typhus, epidemic.
epidemiologist
A person engaged in epidemiol-
ogy. Epidemiologists can be people with MD, PhD,
DPH (Doctor of Public Health), MPH (Master of
Public Health), RN, or other degrees.
epidemiology, classical
The study of popula-
tions in order to determine the frequency and dis-
tribution of diseases, and then to measure the risks
of those diseases.
epidemiology, clinical
Epidemiology focused
specifically on patients with diseases of clinical
importance.
epidermis
The upper, or outer, layer of the two
main layers of cells in the skin (the other being the
dermis). The epidermis is mostly made up of flat,
scale-like cells called squamous cells. Under the squa-
mous cells are round cells called basal cells. The deep-
est part of the epidermis also contains melanocytes,
cells that produce the substance melanin, which gives
skin its color. See also 
dermis; skin.
epidermoid carcinoma
See 
carcinoma, squa-
mous cell.
epidermolysis bullosa
One in a group of blis-
tering skin conditions. The skin is so fragile in peo-
ple with epidermolysis bullosa that even minor
rubbing may cause blistering.
epididymis
A structure within the scrotum that is
attached to the back side of the testis. The epididymis
is a coiled segment of the spermatic ducts that stores
spermatozoa while they mature and then transports
the spermatozoa between the testis and the tube con-
necting the testes with the urethra (vas deferens).
epididymitis
Inflammation of the epididymis.
Epididymitis can be caused by sexually acquired
bacteria, such as gonorrhea and chlamydia; or by
bacteria that come from somewhere else, such as E.
coli from the bowel. Sometimes no bacteria are
found to be associated. Bacterial epididymitis is
treated with antibiotics. If no bacterial cause is
detected, medications to reduce inflammation are
sometimes helpful.
epidural
Outside of the dura mater, the outer-
most and most fibrous of the three membranes
(dura mater, arachnoid membrane, and pia mater)
covering the brain and the spinal cord. See also
epidural anesthetic.