Identificación de las características de las enfermedades infecciosas

Module Overview

• Module: General Pathophysiology
• Unit: Identification of the Characteristics of Infectious Diseases
• Program: Higher Technician in Dental Hygiene

Introduction

• An infection occurs when pathogens invade an organism, establish themselves, and multiply.
• The outcome of infection can lead to:
  • Infectious Disease
  • Subclinical Illness
  • Innocuous Coexistence
• Infectious diseases manifest clinically through:
  • Cell damage
  • Toxin secretion
  • Antigen-antibody reactions.
• Transmissible Infectious Diseases: Spread directly (from infected individual through skin/mucosa) or indirectly (via environment/vectors).

Objectives

• Understand the concept and importance of infectious diseases in human health.
• Identify causative agents: bacteria, viruses, fungi, and parasites.
• Recognize modes of transmission: direct contact, respiratory droplets, fecal-oral route, etc.
• Describe clinical characteristics: fever, pain, malaise, skin rashes, etc.
• Understand diagnostic processes: laboratory tests, imaging methods, and clinical signs.
• Identify prevention and control measures: personal hygiene, vaccination, appropriate antimicrobial use, and vector control.

Infectious Agents

Definition of Microorganisms

• Microorganisms: Microscopic living organisms, can be unicellular or colonial.
• Can be beneficial (decomposition, food production, medicine) or pathogenic.
• Microbiology: Study of microorganisms, including bacteriology, virology, mycology, and parasitology.

Types of Infectious Agents

1. Bacteria: Unicellular organisms causing diverse diseases (e.g., respiratory infections, urinary infections).
   • Examples: $ext{Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Salmonella}$
2. Viruses: Require host cells to reproduce, causing illnesses like common cold, HIV, and COVID-19.
   • Examples: $ext{Influenza virus, HIV, Herpes simplex virus}$
3. Fungi: Eukaryotic organisms causing skin, nail, and lung infections.
   • Examples: $ext{Candida, Aspergillus, Trichophyton}$
4. Protozoa: Unicellular eukaryotes causing diseases in poor hygiene regions.
   • Examples: $ext{Plasmodium (malaria), Trypanosoma (Chagas)}$
5. Helminths and Arthropods (Parasites): Multicellular organisms causing intestinal and tissue infections.
   • Examples: $ext{Ascaris lumbricoides, Schistosoma mansoni, Taenia solium}$
6. Prions: Abnormal proteins causing neurodegenerative diseases without nucleic acids.

Types of Infections

• Bacterial, Viral, Fungal, Protozoan, and Parasitic Infections.
• Endogenous Infections: Caused by microorganisms normally present in the body (e.g., $ext{Candida}$).
• Exogenous Infections: Caused by pathogens from external sources (e.g., malaria).
• Opportunistic Infections: Occur when the immune system is weakened (e.g., HIV/SIDA).

Transmission and Dissemination of Infectious Agents

• Infectious Chain includes:
  • Agent: Microorganism causing disease
  • Host: Person receiving the pathogen
  • Reservoir: Environment allowing pathogen persistence
  • Transmission Route: Pathway for the pathogen to enter the host.
• Types of Transmission:
  • Direct: From infected host to another (e.g., kissing, coughing).
  • Indirect: Through contaminated objects, surfaces, food, water, or vectors.
  • Fomites: Inanimate objects harboring pathogens.
  • Common Vehicles: Water, food, air, or blood.
  • Vectors: Living organisms transmitting disease (e.g., mosquitoes).
  • Droplet Transmission: Via droplets expelled during coughing/sneezing.

Phases of Infectious Diseases

1. Exposure Phase: Contact with the infectious agent.
2. Incubation Phase: No symptoms, but the pathogen multiplies.
3. Prodromal Phase: Initial, nonspecific symptoms appear.
4. Acute Phase: Pronounced symptoms, active pathogen spread, immune response.
5. Convalescence Phase: Recovery, symptoms fade.

Inflammatory Response

• A protective mechanism against harmful agents involving biochemical and cellular changes.
• Characterized by:
  • Redness: Increased blood flow
  • Heat: Increased temperature in the inflamed area
  • Swelling: Increased fluid in tissues (edema)
  • Pain: Stimulation of nerves by chemical mediators
  • Loss of Function: Temporary reduction in tissue function.

Acute vs. Chronic Inflammation

• Acute Inflammation: Short-term response to isolate and remove an aggressor.
• Chronic Inflammation: Long-term response linked to persistent stimuli.

Granulomatous Inflammation

• Specific chronic response featuring granuloma formation, typically to foreign substances.

Major Human Infectious Diseases

Gastrointestinal Infections

• Caused by bacteria, parasites, and viruses leading to diarrhea and dehydration.
  • Examples: $ext{Salmonellosis, Brucellosis, Hepatitis}$

Respiratory Infections

• Affecting upper/lower respiratory system; can be viral or bacterial.
  • Examples: $ext{Influenza, Tuberculosis}$

Sexually Transmitted Diseases (STDs)

• Infections spread through sexual contact, caused by various pathogens.
  • Examples: $ext{Chlamydia, Herpes, Gonorrhea, HIV, HPV}$

Fungal Infections (Mycosis)

• Overgrowth of fungi leading to various symptomatic conditions.
  • Examples: $ext{Candidiasis, Tinea, Athlete's foot}$

Infectious Therapeutics

• Therapeutic Goal: Combat infections using antimicrobial therapy.
  • Antibiotics: Target bacterial infections.
  • Antivirals: Address viral infections.
  • Antifungals: Treat fungal infections.
  • Antiparasitics: Treat infections from parasites.
• Additional measures: Symptom control, hydration, nutritional support, and possibly surgery.

Summary

• Infectious diseases arise from various agents: viruses, bacteria, fungi, protozoa, parasites, and prions.
• Transmission methods include direct contact, respiratory droplets, and vector transmission.
• Disease phases, from exposure through recovery, show how infections progress.
• Inflammation plays a vital role in response to infection and can lead to chronic conditions if unresolved.
• Prevention is key: vaccination, hygiene, and proper use of antimicrobials help control diseases.