Control of Acute R espiratory
Tract Infections( ARI)
Dr. Nadia Aziz
C.A.B.C.M.
Department of Community Medicine
Baghdad Medical College
Objectives
1- Determine the causative agents that cause
the ARI.
2- Identify the burden of ARI on the
community.
3- Identify the causative agent of viral
influenza, its occurrence.
4- The ways to prevent and control the
occurrence of an epidemic.
Introduction
ARI responsible for 20% of childhood (< 5
years) deaths
ARI
mortality highest
–
HIV
- infected
–in children
under 2 year
of age
–
Malnourished
–
Weaned
early
–
Poorly educated
parents
–
Difficult access
to healthcare
Introduction
- Most young children worldwide have
4 to 8
episodes of respiratory infections per year.
- Incidence of acute lower respiratory
infections (pneumonia) is very high in
developing countries
- Four millions
child
die
each year due to ARI.
Anatomical classification
Upper respiratory tract infection
1- Pharangitis
2- Tonsillitis
3- Sinusitis
4- Otitis media
5- L aryngotracheobronchitis
6- Epiglositis
Anatomical classification
Acute lower respiratory tract infection
1- Bronchiolitis
2- pneumonia
Risk factors
•Malnutrition
•L ow birth weight
•Absence of breast feeding
•Vitamine A defficency
•Indoor air pollution
•L ow socioeconomic status
•Poor hygiene
•Missing EPI vaccination
Etiological agents
Viruses
Para influanzae virus
R espiratory syncytial virus
Influenza virus
Bacteria
Streptococcus pneumonia
Haemophilus influanzae
INFL UENZA
Differential Diagnosis
Influenza may be clinically
indistinguishable
from disease caused by other respiratory
viruses and undifferentiated acute respiratory
disease.
INFL UENZA
ICD-10 J10, J11
Identification
An acute viral disease of the respiratory tract
characterized by:
fever
, headache, myalgia, prostration, coryza, sore
throat and cough.
Cough
is often severe and protracted.
other manifestations are self-limited in most patients,
with recovery in 2–7 days.
INFL UENZA
Influenza derives its importance from:
- The rapidity with which
epidemics evolve
- The
widespread morbidity
- The seriousness of
complications
( viral and
bacterial pneumonias).
- Emergence among humans of influenza viruses with
new surface proteins can cause pandemics
INFL UENZA
High risk group
Severe illness and death occur among:
- The elderly
- Debilitated by chronic cardiac, pulmonary,
renal or metabolic disease.
- Anemia or immunosuppression.
Complication
Reye syndrome
- Involving the
CNS
and
liver
, is a rare but serious
complication following virus infections in children
who have ingested salicylates.
- Children and teenagers recovering from
chickenpox or flu- like symptoms
should never
take aspirin.
Diagnosis
• Isolation of influenza viruses
from pharyngeal or
nasal secretions or washings on cell culture or in
embryonated eggs.
• Direct identification of viral antigens in
nasopharyngeal cells and fluids (
FA test or EL ISA
).
• Rapid diagnostic
tests
• Viral RNA amplification
(used to identify small
amounts of
RNA
in test samples)
Infectious agents
Three types of influenza virus are recognized:
A, B and C.
Type A
includes 15 subtypes of which only 2 (
H1
and
H3
)
are associated with widespread epidemics.
Type B
is infrequently associated with regional or
widespread epidemics.
Type C
with sporadic cases and minor localized
outbreaks.
Infectious agents
The antigenic properties of the 2 relatively
stable internal structural proteins, the
nucleoprotein
and the
matrix
protein, determine virus type.
Infectious agents
Influenza A subtypes are classified by the
antigenic properties of surface
glycoproteins
:
Hemagglutinin
( H)
Neuraminidase
(N).
Frequent
mutation
of the
glycoproteins of influenza A and influenza B
viruses results in emergence of new variants.
Infectious agents
Pandemics
results from:
1- Emergence of completely new subtypes at
irregular intervals (
only for type A
) results from
antigenic shift
in HA gene
Minor antigenic changes (
antigenic drift
) of
A and B
viruses
responsible for
frequent epidemics and
regional outbreaks
and require annual reformulation
of influenza vaccine.
Infectious agents
Pandemics
2- Unpredictable
recombination
of human and
mammalian or
avian antigens.
INFL UENZA
Occurrence
As
pandemics
(rare),
epidemics
(almost annual),
localized outbreaks
and sporadic cases.
Ranking as global health emergencies
(pandemic e.g. 1918, 1957, 1968) with millions of
deaths (
40 million in 1918
).
INFL UENZA
Influenza viral infections with different
antigenic subtypes also occur
naturally
in
swine
,
horses
,
mink
and
seals
, and in many other
domestic
species in many parts of the world.
Aquatic birds
are a natural reservoir and
carrier for all influenza virus subtypes.
INFL UENZA
Reservoir
Humans
are the primary reservoir
for human infections.
Birds
and
mammalian
reservoirs such as swine
INFL UENZA
Mode of transmission
Airborne spread
INFL UENZA
Incubation period
Short, usually 1–3 days.
INFL UENZA
Susceptibility
impact of epidemics and pandemics depend upon:
level of
protective immunity
in the population,
strain
virulence
, extent of
antigenic variation of new
viruses
and number of previous infections.
Pandemics
( emergence of a new subtype):
Total
population immunologically naive
Methods of control
A. Preventive measures:
1)
Educate
the public and health care personnel
in basic personal hygiene, especially
transmission via unprotected coughs and
sneezes, and from hand to mucous membrane.
Vaccine
2)
Immunization
with
Inactivated
and
live
virus vaccines may provide
70% –80% protection against infection in healthy
young adults.
Live vaccines
, used in the Russian Federation for
many years, registered for
intranasal application
in healthy individuals aged
5–
49
.
Vaccine
In the elderly
Inactivated vaccines
may reduce severity of
disease and incidence of complications and
deaths.
Vaccine
Two doses
more than 1month apart are essential for
children under 9.
Routine immunization
programs directed towards:
- Those at risk of
serious complications
or death
- Those who might
spread infection
( health care
personnel and household contacts of high-risk persons).
- Immunization of
children on aspirin
treatment to
prevent development of Reye syndrome.
Vaccine
Contraindications:
Allergic hypersensitivity
to egg protein
or other vaccine components is a
contraindication.
Chemoprophylaxis
3)
Effective chemoprophylaxis
of influenza A:
Amantadine hydrochloride (CNS side- effects)
Rimantadine hydrochloride
Chemoprophylaxis
Oseltamivir
have been shown to be safe and
effective for both
prophylaxis
and
treatment
of
influenza A and B.
B. Control of patient, contacts and the
immediate environment
1) Report to local health authority:
Reporting outbreaks or laboratory-confirmed
cases Class 1.
Control of patient, contacts and the
immediate environment
In epidemics
isolate patients
(especially infants and young
children)
Control of patient, contacts and the
immediate environment
Protection of contacts:
A specific role has been shown for antiviral
chemoprophylaxis with
amantadine
or
rimantadine
against type A strains
Control of patient, contacts and the
immediate environment
Specific treatment: Amantadine or
Rimantadine started
within 48 hours
of onset
of influenza A illness and given for
approximately 3–5 days in 2 divided doses
Control of patient, contacts and the
immediate environment
During treatment with either drugs,
drug-
resistant
viruses may emerge late in the
course of treatment and be transmitted to
others.
Epidemic Measures
-
health care
personnel should be
immunized
annually.
- Maintaining adequate supplies of
antiviral
drugs
would be desirable to treat
high-risk
patients and
essential personnel
in the event of
the emergence of a
new pandemic strain
for
which no suitable vaccine is available in time for
the initial wave.