Health, Disease, and Prevention: A Comprehensive Look

Posted on Jan 15, 2025 in Biology

Health

According to the World Health Organization (WHO), health is a state of complete physical, mental, and social well-being.

Determinants of Health

These are the factors that influence the achievement of positive health:

  • Habits and Lifestyle: Healthy eating, regular exercise, etc.
  • Environment: Social, physical, and psychological factors (friends, city, work, allergies).
  • Genetic or Biological Characteristics: Maturity, aging, genetic inheritance, or genetic diseases.
  • Health System: Access to healthcare services, hospitals, etc.

Risk Factors

Risk factors are the probability of developing a disease. They depend on the determinants of health. Risk factors are:

  • Modifiable: These depend on people’s behavior (eating habits, alcohol consumption, smoking, etc.).
  • Non-modifiable: These include age, sex, or heredity.

Public Health and Preventive Medicine

  • Public health is the application of the scientific method to health and disease problems, considering the community as the subject.
  • Preventive medicine is a branch of medicine that deals with preventing the emergence, development, and maintenance of disease in individuals, families, or groups of people.

Levels of Prevention

  • Primary Prevention: Aims to minimize risk factors and disease occurrence.
  • Secondary Prevention: Aims to prevent clinical manifestations of a disease through early detection.
  • Tertiary Prevention: Aims to improve the clinical course of the disease and prevent its complications.

Disease and Its Types

A disease is a significant decrease in any of the three aspects of well-being (physical, social, and psychological). Diseases can be classified in several ways:

Classification by Pathology

  • Somatic: Affects the functioning of organs.
  • Psychic: Affects thinking, reasoning, etc.
  • Psychosomatic: Have a psychic origin but end up affecting a body part (anorexia, bulimia, etc.).

Classification by Prevalence

  • Sporadic: Affects isolated individuals.
  • Epidemic: Affects a large percentage of the population.
  • Pandemic: Affects a very large number of people across multiple regions (e.g., AIDS).
  • Endemic: Only appears in one specific place.

Classification by Cause

  • Non-infectious Diseases:

    Those that are not contagious or transmissible.
Types of Non-infectious Diseases
  • Genetic and Inherited: Caused by malfunctioning genes.
  • Mental: (e.g., Schizophrenia).
  • Organic or Systematic: Some organs do not function as they should (e.g., Alzheimer’s, arrhythmia, diabetes).
  • Autoimmune: When the immune system malfunctions (e.g., Lupus).
  • Injuries: Degenerative (e.g., Osteoporosis).

  • Infectious Diseases:

    Those that are contagious or transmissible.
Types of Infectious Diseases
  • Viral: (e.g., Flu).
  • Bacterial: (e.g., Wound infection).
  • Fungal: (e.g., Papillomavirus).
  • Protozoan: (e.g., Amebiasis).
  • Other: Prions (proteins that alter other proteins upon contact).
  • Parasitic: (e.g., Anisakiasis, tapeworm).

Phases of Infectious Diseases

Infectious diseases typically have three phases:

  • Incubation Period: The time from the entry of the pathogen to the appearance of the first symptoms.
  • Prodromal Period: The emergence of general, non-specific symptoms.
  • Clinical Period: The period in which the specific signs and symptoms that define the disease appear.

Prevention of Infectious Diseases

Prevention strategies focus on:

  1. Acting on the reservoir and source of infection.
  2. Acting on the transmitting agent (e.g., using a mask).
  3. Acting on the susceptible host (e.g., through vaccination).

Defenses Against Infection

The body has an immune system responsible for conferring immunity.

Immunity: Resistance that an organism exhibits against a particular infection.

Types of Immunity

  • Innate Immunity:

    Immune mechanisms present from birth. It works the same way regardless of the infectious agent.
Components of Innate Immunity
  • External Barriers: Skin and mucous membranes.
  • Microbicidal Substances: Activated when external barriers fail.
    • Inflammation: Infection leads to the release of histamine by basophils, increasing blood flow and immune cell activity in the affected tissue.
    • Phagocytes: White blood cells (macrophages) that engulf microbes.

  • Adaptive Immunity:

    Acquired through contact with pathogens. It is specific to each microbe and involves lymphocytes.
Types of Lymphocytes in Adaptive Immunity
  • T Lymphocytes (Thymus): Killer cells involved in the cellular adaptive response.
  • B Lymphocytes (Spleen): Involved in the humoral adaptive response.