The stages of infectious disease include incubation, prodrome, illness, and convalescence. During incubation, pathogens grow and multiply without symptoms appearing. Prodrome involves nonspecific symptoms before specific symptoms of illness. Illness is when signs and symptoms specific to the infection are present. Convalescence occurs as acute symptoms disappear. An infection develops when an infectious agent enters a host through a portal of entry, multiplies within the host, and exits through a portal of exit, facilitated by the mode of transmission between reservoirs. Nurses follow infection control practices to break this chain and prevent infection.

1. STAGES OF INFECTIOUS DISEASE:
INCUBATION;
Time from entrance of pathogen into the body to appearance of first symptoms;
during this time  pathogens grow and multiply
PRODROME:
Time from onset of nonspecific symptoms such as fever, malaise, and fatigue to
move specific symptoms
ILLNESS:
Time during which child demonstrates signs and symptoms specific to an infection
type
CONVALESCENCE:
Time when acute symptoms of illness disappear
The Nature of Infection
The straightforward definition of an infection is the entry and
multiplication of an infectious agent in the tissue of a host. In other
words, an infection is an overgrowth of bad bacteria. The infectious
agent is called a pathogen.

2. The presence of a pathogen does not mean that an infection will
necessarily begin. The development of an infection happens in a cycle
that depends on all elements of the cycle being present. There are six
elements in the chain of infection:
• Infectious agent – A microbial organism with the ability to cause
disease. The greater the organism's virulence (ability to grow
and multiply), invasiveness (ability to enter tissue) and
pathogenicity (ability to cause disease), the greater the
possibility that the organism will cause an infection. Infectious
agents are bacteria, virus, fungi, and parasites.
• Reservoir – A place within which microorganisms can thrive and
reproduce. For example, microorganisms thrive in human beings,
animals, and inanimate objects such as water, table tops, and
doorknobs.
• Portal of exit – A place of exit providing a way for a microorganism
to leave the reservoir. For example, the microorganism may
leave the reservoir through the nose or mouth when someone
sneezes or coughs. Microorganisms, carried away from the body
by feces, may also leave the reservoir of an infected bowel.
• Mode of transmission – Method of transfer by which the organism
moves or is carried from one place to another. The hands of the
health care worker may carry bacteria from one person to
another.
• Portal of entry – An opening allowing the microorganism to enter
the host. Portals include body orifices, mucus membranes, or
breaks in the skin. Portals also result from tubes placed in body
cavities, such as urinary catheters, or from punctures produced
by invasive procedures such as intravenous fluid replacement.
• Host – A person who cannot resist a microorganism invading the
body, multiplying, and resulting in infection. The host is
susceptible to the disease, lacking immunity or physical
resistance to overcome the invasion by the pathogenic
microorganism.
An infection will only develop if this chain stays intact. As nurses we
follow infection prevention and control practices to break the chain so
that infection will not develop.
Contusion Discoloration and edema of eyelids
Corneal abrasion  May require ointment to smooth injury or
antibiotic ointment
Eyelid injury Vision is usually unaffected

3. Foreign body Requires careful removal only by a health care
professional
Scleral hemorrhage Erythema that resolves gradually without
intervention
VISION AND HEARING MILESTONES:
FUNCTIONAL HEARING Eye color  Binocular vision  Visual acuity of 20/20
SIGNS AND SYMPTOMS OF CHILDREN WITH HEARING LOSS AT (A) INFANT, (B)
YOUNG CHILD, (C) OLDER CHILD STAGES:
INFANT:
-Wakes only to touch, not environmental noises
-Does not startle to loud noises
-Does not turn to sound by 4 months of age
-Does not babble at 6 months of age
-Does not progress with speech development
YOUNG CHILD:
-Does not speak by 2 years of age
-Communicates needs through gestures
-Does not speak distinctly, as appropriate for his/her age
-Displays developmental (cognitive) delays
-Prefers solitary play
-Displays immature emotional behavior
-Does not respond to ringing of the telephone or doorbell
-Focuses on facial expressions when communicating
OLDER CHILD:
-Often asks for statements to be repeated
-Is inattentive or daydreams
-Performs poorly at school
-Displays monotone or other abnormal speech
-Gives inappropriate answers to questions excepts when able to view face of
speaker