Transcript communicable disease

Communicable
Disease Control

Communicable disease pose a major threat to
public health and are of significant concern to
community health nurses. A communicable
disease is one that can be transmitted from one
person to another. It is caused by an agent that
is infections (capable of producing infection)
and is transmitted from a source, or reservoir,
to a susceptible host.
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Knowledge of communicable diseases is fundamental to
the practice of community health nursing because these
diseases typically spread through communities of people.
Understanding of the basic concepts of communicable
disease control, as well as the numerous issues arising in
this area, helps a community health nurse work effectively
to prevent and control communicable disease in population
and groups.
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It also helps nurses teach important and effective
preventive measures to community members, advocate for
those affected, and protect the well-being of uninfected
persons (including the nurses themselves).
Basic concepts regarding communicable diseases:
Evolution of Communicable Disease Control:
Communicable diseases have challenged health care
providers for centuries. They have led to the
development of countless nursing and medical
preventive measures, form simple procedures such as
hand-washing, sanitation, and proper ventilation to the
research and development of vaccines and antibiotics.
Because these preventive measures have greatly reduced
the spread of communicable disease, many people
consider communicable diseases to be a threat of the
past.
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Yet the is not so. Communicable diseases,
particularly those of epidemic and pandemic
proportions, such as TB and acquired
immunodeficiency syndrome (AIDS), continue
to cost millions of lives and billions of dollars to
the global human society every year.
Global Trends:
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During ht last several decades, substantial
progress has been made in controlling some
major infectious diseases around the world,
although other diseases have not been managed
as well. The following are some of the major
accomplishments:
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The WHO's Expanded Program on Immunization
(EPI) was launched in 1974. as a result, by 1995, more
than 80% of the world's children had been immunized
against diphtheria, tetanus, whooping cough, poliomyelitis,
measles, and TB, compared with fewer than 5% in 1974
(WHO, 1998)
Global eradication of smallpox was achieved in 1980.
In 1988, a campaign for global eradication of
poliomyelitis by the year 2000 was launched. Reported
cases worldwide have declined by 99% since the
campaign began.
The global threat of plague has declined in the last 40
years, largely as a result of the use for antibiotics and
insecticides.
Some major problem communicable diseases and
areas remain, including the following:
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Malaria remains a major threat, even though the mortality
rate has improved in the last 25 years.
Cholera was mainly confined to Asia in the early 20th
century through improvements in sanitation elsewhere.
However, a series of pandemics have affected much of the
world since 1960 and have become more widespread and
more frequent in Africa since 1970s.
TB has made a powerful resurgence in the last 3 decades as
many countries let their control programs become
complacent. WHO declared TB a global emergency in
1993.
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Emerging diseases are rarely or never before
seen.
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Resurging diseases are those communicable
diseases that have been endemic in some parts
of the world but are now endemic in more
countries and are increasing to epidemic
proportions in others.
Modes of Transmission:
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As discussed in Chapter 8, the reservoir of
infection can be a person, animal, insect, or
inanimate material in which the infectious agent
lives and multiplies and which serves as source
of infection to others. Transmission of a
communicable disease can occur by direct or
indirect methods
Direct Transmission:
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Direct transmission occurs by immediate transfer of
infectious agents from a reservoir to a new host. It
requires direct contact with the source, through
touching, biting, kissing, or sexual intercourse, or by the
direct projection of droplet spray onto the conjunctiva
or onto the mucous membranes of the eye, nose or
mouth during sneezing, coughing, spitting, laughing,
singing, or talking. Direct transmission is limited to a
distance of 1 meter or less.
Indirect Transmission:
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Indirect transmission occurs when the infectious
agent is transported within contaminated inanimate
materials such as air, water or food. It is also commonly
referred to as vehicle borne transmission.
Airborne Transmission:
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Airborne transmission occurs through droplet
nuclei – the small residues that result form
evaporation of fluid form droplets emitted by
an infected host. They may also be created
purposely by atomizing devices or accidentally in
microbiology laboratories. Because of their
small size and weight, they can remain
suspended in the air for long periods before they
are inhaled into the respiratory system of a host
Primary Prevention:
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in the context of communicable disease
control, two approaches are useful in achieving
primary prevention:
1.
education using mass media and targeting health
messages to aggregates.
Immunization.
2.
Education:
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Health education in primary prevention is
directed both at helping at – risk individuals
understand their risk status and at promoting
behaviors
that
decrease
exposure
or
susceptibility.
Use of Mass Media for Health:
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Education:
All people need to be informed about the risks
of communicable disease. Often, use of the
mass media is the most effective way to reach
the largest number or people.
Immunization:
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Control of acute communicable diseases through
immunization has been a common practice since the
19th century in the United States. Immunization is the
process of introducing some form of disease-causing
organism into a person's system to cause the
development of antibodies that will resist that disease.
In theory, this process makes the person immune to
that particular infectious disease (ie, able to resist a
specific infectious disease-causing agent).
Vaccine-Preventable Diseases
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Vaccine-preventable disease (VPD), such as
hepatitis B, H. influenza type b, measles, polio,
diphtheria, pertussis, and chickenpox, are
diseases that can be prevented through
immunization.
Schedule of Recommended Immunizations:
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Current recommendations call for a child to
receive ten different vaccines or toxoids (many
in combination form and all requiring more that
one dose) in six or seven visits to a provider
between birth and school entry, with boosters in
the preteen to early teen years (CDC, 2003).
Children vaccination Programme in Palestine
Time
Vaccine
Birth -3 months BCG
Sight
Lt upper arm
2nd month
OPV
DPT
Hep.B
Hib.
Oral drops
Lt. outer mid. Thigh IM
Rt. outer mid .thigh IM
Outer mid.thigh IM
4th month
OPV
DPT
Hep.B
Oral drops
Lt. outer mid. Thigh IM
Rt. outer mid .thigh IM
6TH month
OPV
DPT
Hep.B
Oral drops
Lt. outer mid. Thigh IM
Rt. outer mid .thigh IM
Measles
Hib.
Rt upper arm subcut.
Outer mid.thigh IM
9th month
12-24 month
OPV (Booster dose) Oral drops
DPT
(Booster Lt. outer mid. Thigh IM
dose)
Herd Immunity:
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Herd immunity is central to understanding immunization as a
means of protecting community health. As described in chapter
8, it is the immunity level present in a particular population of
people (Chin, 1999). If there are few immune persons within a
community, there is low herd immunity and the spread of disease
is more likely. Vaccination of more individuals in the community,
so that a high proportion have acquired resistance to the
infectious agent, contributes to high herd immunity.
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High herd immunity reduces the probability that the
few unimmunized parsons will come in contact with
one another, making spread of the disease less likely.
Outbreaks may occur if the immunization rate falls to
less than 85% (scutchfield & Keck, 2001) or if
unimmunized susceptible persons are grouped together
rather than dispersed throughout the immunized
community. An example of lack of herd immunity is
presented in the Global Community.
Barriers to Immunizations Coverage:
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Improving immunization coverage requires
examination of reasons that children are not
immunized. Many barriers exist. They include
religious, financial, social, and cultural factors;
philosophical
objections;
and
provider
limitations that from barriers adequate
immunization.
Adult Immunization:
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Many people erroneously assume that
vaccinations are for children only. Welladvertised influenza vaccination campaigns in
recent years have helped somewhat to correct
this notion.
International Travelers, immigrants, and Refugees
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As Americans interact more and more with their
neighbors in other parts of the world, the
incidence of Americans with tropical or
imported diseases also rises. Within 36 hours of
beginning a trip, any destination in the world can
be reached.
That amount of time is within the incubation
period of most infectious diseases, and
microbial agents are rapidly spread around the
globe.
SECONDARY PREVENTION:
There are two approaches to secondary prevention
of communicable disease:
 Screening
 Contact investigation, partner notification, and
case-finding.
Screening
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The term screening is used in community
health and disease prevention to describe
programs that deliver a testing mechanism to
detect disease in groups of asymptomatic,
apparently healthy individuals.
1.
Venereal Disease Research Laboratory (VDRL)
A syphilis diagnosis.
2.
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Screening is a secondary prevention method
because it discovers those who may have already
become infected in order to initiate prompt early
treatment.
It is important to remember that the screening
itself is not diagnostic but rather seeks to
identify those persons with positive or
suspicious findings who require further medical
evaluation or treatment.
Criteria for Screening Tests:
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Validity and Reliability. The screening test
must be valid and reliable. Validity refers to the
test's ability to accurately identify those with the
disease. Reliability refers to the test's ability to
give consistent results when administered on
different occasions by different technicians.
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Predictive Value and Yield. The predictive
value of a screening test is important for
determining whether the screening intervention
is justified. Yield refers to the number of
positive results found per number tested.
Contact Investigation, Partner Notification,
and Case-Finding
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Another secondary prevention approach is
known as contact investigation, partner
notification, and case-finding. In this approach,
the community health nurse seeks to discover
and notify those who have had contact with a
person diagnosed with a communicable disease
such as with TB and to notify partners in the
case of STDs.
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The objective of contact investigation and
partner notification is specifically to reach
contacts of the index case (diagnosed person)
before the contacts, in turn, become infectious
(CDC, 2002c).
Tertiary Prevention:
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The approaches to tertiary prevention of
communicable disease include isolation and
quarantine (‫ َك َر ْن ِتينا‬, ٌ‫ص ِحي‬
ِ ٌ‫ ) َم ْح َجر‬of the infected
person and safe handling and control of
infectious wastes.