Encyclopedia of Health and Medicine

F–G
fever An elevation of body temperature above
the normal range. Body temperature varies over
the course of a circadian cycle, roughly equivalent
to 24 hours, to accommodate the body’s metabolic
needs. Body temperature is lowest just before
waking in the morning and highest in the late
afternoon or early evening, times that typically
correlate with the body’s lowest and highest
expenditures of energy. The normal range of body
temperature is 97.6ºF to 99.6ºF, with the mean
of 98.6ºF generally perceived as the standard normal
temperature. Health-care providers generally
view a body temperature of 100ºF or higher as a
fever.
The body’s IMMUNE RESPONSE raises body temperature
as a mechanism for fighting INFECTION. Elevated
body temperature increases the body’s
METABOLISM, which enhances the IMMUNE SYSTEM’s
ability to contain and eradicate the pathogens
responsible for infection. Each degree of elevation
in body temperature accelerates metabolism by 10
to 15 percent. The various types of white BLOOD
cells (leukocytes) release INTERLEUKINS, PROS-
TAGLANDINS, TUMOR NECROSIS FACTORS (TNFS), and
other biochemicals (CHEMOKINES) that temporarily
reset the body’s thermoregulatory mechanisms.
Though common practice is to attempt to lower
a fever through measures such as cool baths and
acetaminophen or other medications, doctors now
believe fever does not ordinarily require treatment.
To the contrary, recent research shows that
the immune response and most ANTIBIOTIC MEDICA-
TIONS work more effectively when body temperature
is elevated. Doctors recommend treating fever
only when there is risk for febrile seizures, when
the person cannot eat or drink enough to meet
the body’s metabolic needs, or when the fever creates
discomfort. Medications to treat other symptoms
due to the infection, such as HEADACHE, also
reduce fever.
See also ANALGESIC MEDICATIONS; HEAT EXHAUSTION;
HEAT STROKE; LEUKOCYTE; NONSTEROIDAL ANTI-INFLAM-
MATORY DRUGS (NSAIDS); PATHOGEN.
foodborne illnesses Diseases resulting from consumption
of foods contaminated with pathogenic
BACTERIA, fungi, parasites, or viruses. Foodborne
illnesses, also called food poisoning, are common,
affecting 76 million Americans each year. There
are several hundred known foodborne illnesses,
most of which cause mild to moderate gastrointestinal
symptoms including abdominal cramping,
NAUSEA, VOMITING, and DIARRHEA. Illness results
from consuming a food contaminated with
pathogens. Common sources include undercooked
meats and cooked foods that remain at room temperature
for longer than two hours. Most often, it
is not possible to tell from taste, smell, or appearance
that a food contains pathogens.
Prevention is the primary focus when it comes
to foodborne illnesses. The simple measure of
washing the hands before and after preparing
foods, eating meals, changing diapers, and using
the bathroom could eliminate many foodborne illnesses
by preventing bacteria and other pathogens
from contact with foods. Other FOOD SAFETY measures
to reduce the risk for infection from foodborne
pathogens include
• using separate utensils and surfaces for meats
and for other foods
• washing fruits and vegetables, including “rind”
fruits such as oranges and watermelon, in running
water before eating or preparing them
326