|
Neisseria
meningitidis
|
Clinical Features |
Fever,
headache and stiff neck in meningitis
cases, and sepsis and rash in
meningococcemia. |
|
Etiologic Agent |
Multiple
serogroups of Neisseria meningitidis. |
|
Incidence |
0.5-5/100,000 for endemic disease,
worldwide in distribution. During
1996-1997, 213,658 cases with 21,830
deaths were reported in West African
countries. Up to 2% in epidemics in
Africa. |
|
Sequelae |
10%-14% of
cases are fatal. Of patients who recover
11%-19% have permanent hearing loss,
mental retardation, loss of limbs, or
other serious sequelae. |
|
Transmission |
N.
meningitidis colonizes mucosal
surfaces of nasopharynx and is
transmitted through direct contact with
large droplet respiratory secretions
from the patients or asymptomatic
carriers. Humans are the only host. |
| Risk
Groups |
Risk groups
include infants and young children (for
endemic disease), refugees, household
contacts of case patients, military
recruits, college freshmen who live in
dormitories, microbiologists who work
with isolates of N. meningitidis,
patients without spleens or with
terminal complement component
deficiencies, and people exposed to
active and passive tobacco smoke. |
Streptococcus pneumoniae
Disease
|
Clinical
Features |
Pneumonia,
bacteremia,
otitis
media,
meningitis,
sinusitis,
peritonitis
and
arthritis. |
|
Etiologic
Agent |
Streptococcus
pneumoniae.
More
than 90
serotypes
exist;
of
strains
causing
invasive
disease,
88% are
serotypes
included
in the
23-valent
polysaccharide
vaccine.
Before
the new
pneumococcal
conjugate
vaccine
was
introduced
in 2001,
over 80%
of
invasive
isolates
in
children
<5 years
old were
included
in the
7-valent
vaccine. |
|
Incidence |
Until
2000,
S.
pneumoniae
infections
caused
100,000-135,000
hospitalizations
for
pneumonia,
6
million
cases of
otitis
media,
and
60,000
cases of
invasive
disease,
including
3300
cases of
meningitis.
Incidence
of
sterile-site
infections
showed
geographic
variation
from 21
to 33
cases
per
100,000
population.
Disease
figures
are now
changing
due to
conjugate
vaccine
introduction.;
in 2002,
the rate
of
invasive
disease
was 13
cases
per
100,000
in the
United
States. |
|
Sequelae |
Death
occurs
in 14%
of
hospitalized
adults
with
invasive
disease.
Neurologic
sequelae
and/or
learning
disabilities
can
occur in
meningitis
patients.
Hearing
impairment
can
result
from
recurrent
otitis
media.
|
|
Transmission |
Person
to
person.
|
|
Risk
Groups |
Persons
at
higher
risk for
infection
are the
elderly,
children
under 2
years
old,
blacks,
American
Indians
and
Alaska
Natives,
children
who
attend
group
day care
centers,
and
persons
with
underlying
medical
conditions
including
HIV
infection
and
sickle-cell
disease.
|
|
Clinical
Features |
Haemophilus
influenzae
Serotype
b (Hib)
Disease
Invasive
disease
caused
by
Haemophilus
influenzae
type b
can
affect
many
organ
systems.
The most
common
types of
invasive
disease
are
pneumonia,
occult
febrile
bacteremia,
meningitis,
epiglottitis,
septic
arthritis,
cellulitis,
otitis
media,
purulent
pericarditis,
and
other
less
common
infections
such as
endocarditis,
and
osteomyelitis.
|
|
Etiologic
Agent |
Haemophilus
influenzae
serotype
b. |
|
Incidence |
Due to
routine
use of
the Hib
conjugate
vaccine
since
1990,
the
incidence
of Hib
disease
in
infants
and
young
children
has
decreased
by 99%
to fewer
than 1
case per
100,000
children
under 5
years of
age. In
the
United
States,
Hib
disease
occurs
primarily
in
underimmunized
children
and
among
infants
too
young to
have
completed
the
primary
immunization
series.
In
developing
countries,
where
routine
vaccination
with Hib
vaccine
is not
widely
available,
Hib
remains
a major
cause of
lower
respiratory
tract
infections
in
infants
and
children. |
|
Sequelae |
3%-6% of
cases
are
fatal;
up to
20% of
surviving
patients
have
permanent
hearing
loss or
other
long-term
sequelae. |
|
Transmission |
Direct
contact
with
respiratory
droplets
from
nasopharyngeal
carrier
or case
patient. |
|
Risk
Groups |
Infants
and
young
children
,
household
contacts,
and
day-care
classmates.
American
Indian/Alaska
Native
populations
are also
at
increased
risk. |
|