Infectious Diseases and Microbiology

Latent Infections

• Definition: A dormant infection that is inactive and does not show symptoms.

• Key Characteristics:

  • While inactive, the pathogen (e.g., bacteria, virus) may still replicate and can be transmitted to new hosts.

  • Example: Herpes virus has periods of activity and inactivity.

Sepsis and Septicemia

• Definitions:

  • Sepsis: General term for a severe response to infection.

  • Septicemia: A bloodstream infection, where infection spreads throughout the body.

• Characteristics:

  • Can affect multiple organs leading to systemic inflammatory response.

  • Symptoms include fever, difficulty breathing, low blood pressure, rapid heart rate, and confusion.

• Treatment:

  • Requires antibiotics appropriate for the identified bacteria.

  • Intravenous administration is preferred for rapid effect.

• Bacteremia: A type of sepsis specifically due to bacterial infection.

Preeclampsia and Eclampsia

• Preeclampsia:

  • A pregnancy complication characterized by high blood pressure and protein in urine.

  • Can lead to organ damage, specifically in the kidneys and liver.

  • Frequency: Found only in pregnant women.

• Eclampsia:

  • Severe progression of preeclampsia that includes seizures.

  • Associated with multi-organ dysfunction and high risks during pregnancy.

Infection Types: Acute vs. Chronic

• Acute Infection: Characterized by sudden onset and quick resolution.

• Chronic Infection: Persists over a long period (months to years).

Pathogen Types

• Primary Pathogen: The main cause of an infection.

• Opportunistic Pathogen: Causes infection only when the host's immune system is weakened.

Colonization

• Definition: Presence of bacteria on the body without causing disease.

• Key Point: Many bacteria are present but harmless, often due to immunity or prior infection.

Microbiology Overview

Eukaryotes vs. Prokaryotes

• Eukaryotes:

  • Have a true nucleus and membrane-bound organelles.

  • Can be unicellular (e.g., yeast) or multicellular (e.g., fungi and plants).

• Prokaryotes:

  • Lack a nucleus and are generally simpler.

  • Example: Bacteria categorized by gram-positive or gram-negative based on cell wall composition.

Fungi

• Function: Fungi decompose organic material, recycle nutrients, and can form symbiotic relationships (mycorrhizae with plants).

• Uses: Can be medicinal (e.g., penicillin) or harmful (e.g., infections).

• Infections: Common types include dermatophytes (skin infections) and systemic mycosis.

Protozoa and Algae

• Protozoa:

  • Unicellular and often found in stagnant water.

  • Example: Giardia lamblia causes intestinal disorders.

• Algae:

  • Autotrophic organisms capable of photosynthesis.

  • Used in food sources, do not directly cause human diseases.

Symbiotic Relationships in Ecosystems

• Mycorrhizae: Fungi that form beneficial associations with plant roots, enhancing nutrient absorption.

• Decomposition Role: Break down dead organisms, enriching soil for plant growth.

Health Implications of Fungal Infections

• Common fungal infections can lead to allergic reactions or severe conditions like meningitis.

• Mycosis: General term for fungal infections.

• Allergies: Often triggered by fungal spores or toxins rather than direct contact with the fungus itself.