patho

Causes of Infection

  • Viruses

    • Can infect the body through various vectors.

  • Fungi

    • Another source of infection; often associated with skin and respiratory issues.

  • Helminths

    • Includes worms that can infect the digestive system.

  • Mycobacteria

    • A type of bacteria with both bacterial and fungal characteristics.

  • Prions

    • Abnormal proteins causing neurodegenerative diseases affecting the central nervous system (CNS).

    • Symptoms include confusion, headaches, seizures, light sensitivity, etc.

Symptoms of Infection

  • CNS Symptoms:

    • Confusion

    • Loss of consciousness

    • Seizures

    • Headaches

    • Light sensitivity

  • Digestive Symptoms:

    • Nausea

    • Vomiting

    • Diarrhea

  • Urinary Tract Symptoms:

    • Painful urination

    • Frequent urination

    • Possible symptoms of hematuria (blood in urine)

  • Voice Symptoms:

    • Hoarse voice often linked to smoking, affecting the lung area.

Phases of Infection

  1. Incubation Period

    • Time after infection without symptoms.

    • Duration: typically 48 to 72 hours, during which bacteria multiply.

  2. Prodromal Period

    • Early stage showing mild symptoms indicating potential infection.

Classifications of Infection Sources

  • Endogenous Infections:

    • Originates from within the body (e.g., opportunistic infections).

  • Exogenous Infections:

    • Arises from external sources.

Transmission of Infectious Agents

  • Germs must exit the infected person to infect another.

Routes of Germ Transfer

  • Feces

  • Urine

  • Vomitus

  • Tears

  • Semen

  • Open wounds/blood

  • Saliva

Modes of Infection Transmission

  • Direct Contact:

    • Touching an infected surface (e.g., phone).

  • Airborne:

    • Particles remain airborne for hours (e.g., TB).

  • Droplet Transmission:

    • Larger particles that can travel short distances (e.g., sneezing).

  • Vehicle Transmission:

    • Ingestion of contaminated food or water

  • Inhalation:

    • Breathing in germs.

  • Vector Bites:

    • Transmission via insect or animal bites.

  • Transplacental Transmission:

    • Germs passing from mother to infant during pregnancy.

  • Injections:

    • Through needles or medical equipment.

  • Skin-to-Skin Contact:

    • Direct contact that may spread the infection.

Factors Affecting Infection Susceptibility

  • Virulence:

    • Strength of the germ and exposure needed to cause disease.

  • Reservoir:

    • A person carrying a germ that may or may not show symptoms.

  • Susceptibility:

    • Likelihood of an individual getting sick based on various factors:

    • Lack of sleep

    • Age

    • Concurrent diseases

    • Drug use

    • Hygiene

Body’s Defense Mechanisms Against Infection

  1. First Line of Defense:

    • Mechanical barriers like skin and mucous membranes.

    • Functions include:

      • Oil and sweat on skin

      • Cilia in lungs

      • Vomiting and cough reflexes

  2. Second Line of Defense:

    • Inflammatory response to fight foreign particles.

  3. Third Line of Defense:

    • Immune response including antibodies targeting specific pathogens.

Patterns of Infection

  • Local Damage:

    • Harm to a specific area by an organism.

  • Toxin Production:

    • Release of toxins in the infected area.

  • Rapid Spread:

    • Pathogens may damage cell membranes and quickly spread to nearby cells.

Conclusion: Key Bacterial and Viral Infections

  • Antibiotic Resistance:

    • Bacteria developing resistance to antibiotics over time.

  • Bacterial Shapes:

    • Coccus (spherical)

    • diplococci (pairing)

    • streptococci (chains)

    • staphylococci (clusters)

    • Bacillus (rod-shaped)

    • Spiral-shaped bacteria.

  • Gram Staining:

    • Gram-positive (thick cell wall) vs. gram-negative (thin cell wall).

Common Bacterial Infections

  • Staphylococcus:

    • Causes various skin infections and is a common pathogen in hospital settings.

  • Streptococcus:

    • Group A can lead to throat and skin infections. Group B can affect pregnant women and newborns.

  • Clinical Implications:

    • High vigilance is needed in settings with antibiotic-resistant bacteria.

Viral Infections

  • Herpes Simplex Virus:

    • Types 1 and 2, causing oral and genital herpes.

  • Cytomegalovirus:

    • Mild illness in healthy individuals but severe in immunocompromised.

  • Chickenpox/Shingles:

    • Caused by varicella-zoster virus; leads to long-term immunity.

Fungal Infections

  • Mycosis:

    • Any disease caused by a fungus.

  • Pneumonia due to fungi:

    • Serious infections in immunocompromised patients.