CHAPTER-5-CONTROL-AND-PREVENTION-OF-COMMUNICABLE-1

Chapter V - Control and Prevention of Communicable Diseases

Introduction to Communicable Diseases

• Public Health Focus: Major focus on preventing the spread of communicable diseases within populations.

• Categories of Diseases:

  • Communicable Diseases: Can be transmitted directly to humans or through mediums.

  • Non-communicable Diseases: Not transmissible between individuals.

• Micro-organisms:

  • Includes bacteria, parasites, fungi, prions, and viruses.

• Germ Theory: Explains that the growth and reproduction of micro-organisms (germs) can cause specific diseases.

Pathogens and Disease Susceptibility

• Pathogen: Micro-organisms that cause disease; not all exposures lead to illness.

• Susceptibility: A person's vulnerability combined with the pathogenicity of the microorganism increases the risk of disease.

The Immune System

• Defense Against Pathogens: The human body has an immune system to fight off infections.

• Types of Immune Systems:

  • Innate Immune System: Non-specific, first line of defense; does not provide long-term immunity.

  • Adaptive Immune System: Specific, provides long-term immunity and memory against pathogens.

Components of the Innate Immune System

• Physical Barriers:

  • Skin, mucous membranes, saliva, urinary and tear flushing actions, stomach acid.

• Cells Involved:

  • Neutrophils: First responders, abundant phagocytes.

  • Phagocytes: Cells that engulf and digest pathogens.

  • Cytokines: Chemical mediators that help recruit immune cells to infection sites.

  • Inflammation: Characterized by rubor (redness), calor (heat), dolor (pain), and tumor (swelling).

Functions of Innate Immune System

1. Recruitment of immune cells to infection sites.

2. Activation of the complement cascade to identify pathogens.

3. Identification and removal of foreign substances by white blood cells.

4. Antigen presentation to activate the adaptive immune system.

5. Physical and chemical barriers to infectious agents.

Adaptive Immune System

• Characteristics:

  • Highly specific, generates memory cells for future protection against pathogens.

• Key Functions:

  1. Recognition of specific antigens.

  2. Tailored responses to eliminate specific pathogens.

  3. Development of immunological memory via memory B and T cells.

• Types of Lymphocytes:

  • B-lymphocytes: Produce antibodies.

  • T-lymphocytes: Include helper T cells, cytotoxic T cells, memory T cells, and suppressor T cells.

Immunological Memory

• Types:

  • Passive Immunity: Temporary, such as maternal antibodies passed to infants.

  • Active Immunity: Long-term memory developed through exposure or vaccination.

• Vaccines: Introduce antigens to stimulate an immune response without causing disease.

Vaccines Types

1. Live Attenuated Vaccines: Weakened pathogens that cannot cause disease (e.g., measles, mumps).

2. Inactivated Vaccines: Killed pathogens; require multiple doses to build immunity.

Transmission of Communicable Diseases

• Transmission Modes:

  • Direct Contact: Skin to skin transfer.

  • Indirect Contact: Contact with contaminated objects.

  • Airborne: Pathogens survive in the air for long periods.

  • Vector-borne: Transmission through vectors like mosquitoes.

Public Health Implications

• Understanding disease transmission is essential for preventing and controlling communicable diseases.

• Interventions include:

  • Protection (immunization, preventive measures).

  • Education and awareness regarding transmission methods.

  • Environmental sanitation to reduce breeding grounds for vectors.

Case Definitions and Monitoring

• Definitions:

  • Case: An individual with or suspected of having an infection.

  • Case Monitoring: Tracking reported cases, especially notifiable diseases.

Public Health Strategies for Control

• Interventions may target:

  1. Agent: Characteristics of the pathogen.

  2. Host: Susceptibility and immune responses.

  3. Environment: Conditions promoting or inhibiting disease spread.

Specific Disease Control Examples

• Tuberculosis: Caused by Mycobacterium tuberculosis, primarily transmitted through the air.

  • Diagnosis methods include sputum smear microscopy, skin tests, and chest X-rays.

• Malaria: Caused by Plasmodium species, transmitted by mosquitoes. Diagnosed through blood tests.

• Rabies: Affects the nervous system, contracted from bites of infected animals.

Legislative Framework for HIV Control

• Philippine AIDS Prevention and Control Act: Mandates policies for prevention, testing, care, and handling of PLHIVs.

• Rights Protection: Protects against discrimination and promotes access to healthcare.

• Monitoring: Essential for tracking the epidemic's progression.

Conclusion

• Effective control and prevention strategies require an integrated approach considering all aspects of communicable diseases, public awareness, and legislative support.