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.

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. 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.

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: 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:

The WHO's Expanded Program on Immunization (EPI) was launched in 1974 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: 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.

Emerging diseases are rarely or never before seen. 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: 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: 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: 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: 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: in the context of communicable disease control, two approaches are useful in achieving primary prevention: education using mass media and targeting health messages to aggregates. Immunization.

Education: 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: 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: 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 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: 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 Sight Birth -3 months BCG 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 6TH month 9th month Measles Rt upper arm subcut. 12-24 month OPV (Booster dose) DPT (Booster dose)

Herd Immunity: 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.

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: 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: Many people erroneously assume that vaccinations are for children only. Well-advertised influenza vaccination campaigns in recent years have helped somewhat to correct this notion.

International Travelers, immigrants, and Refugees 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 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. Venereal Disease Research Laboratory (VDRL) A syphilis diagnosis.

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: 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.

Predictive Value and Yield 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 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.

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: The approaches to tertiary prevention of communicable disease include isolation and quarantine (كَرَنْتِينا , مَحْجَرٌ صِحِّيّ) of the infected person and safe handling and control of infectious wastes.