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Pathology 2 - Second Year BHMS

INFECTION AND DISEASE

INFECTION AND DISEASE

  1. Infection - Infection is a condition where a pathogen invades a host organism, resulting in disease.
  2. Pathogen - A pathogen is any agent that causes disease in a host.
  3. Pathogenesis - Pathogenesis is the study of the development and spread of disease in the body.
  4. Pathogenicity - Pathogenicity is the ability of a pathogen to cause disease.
  5. Virulence - Virulence is the severity of a disease caused by a pathogen.
  6. Infectious disease - An infectious disease is caused by the invasion of a host by a pathogen.

TYPES OF INFECTIONS

  1. Bacterial infection - Caused by bacteria, such as tuberculosis.
  2. Viral infection - Caused by viruses, such as influenza.
  3. Fungal infection - Caused by fungi, such as ringworm.
  4. Parasitic infection - Caused by parasites, such as malaria.

SOURCES OF INFECTION

  1. Airborne transmission - Infection spread through the air.
  2. Contact transmission - Infection spread through direct contact with an infected person or surface.
  3. Droplet transmission - Infection spread through the air when an infected person coughs or sneezes.
  4. Vector transmission - Infection spread through a vector, such as a mosquito.

METHODS OF TRANSMISSION

  1. Inhalation - Infection spread through the air when an infected person coughs or sneezes.
  2. Ingestion - Infection spread through contaminated food or water.
  3. Skin contact - Infection spread through direct contact with an infected person or surface.
  4. Blood-borne - Infection spread through blood transfusions or needle sharing.

FACTORS INFLUENCING VIRULENCE

  1. Genetic factors - The genetic makeup of the pathogen.
  2. Environmental factors - Temperature, humidity, and other environmental conditions.
  3. Host factors - The immune system of the host and other factors.

EXOTOXINS

  1. Definition - Exotoxins are toxic substances produced by bacteria.
  2. Characteristics - Exotoxins are high-molecular-weight proteins that are released by bacteria.
  3. Examples - Botulinum toxin and tetanus toxin.

ENDOTOXINS

  1. Definition - Endotoxins are toxic substances released by bacteria as part of their cell wall.
  2. Characteristics - Endotoxins are low-molecular-weight lipopolysaccharides that are released by bacteria.
  3. Examples - Lipopolysaccharides from Gram-negative bacteria.

DIFFERENTIATION BETWEEN EXOTOXINS AND ENDOTOXINS

  1. Molecular weight - Exotoxins are high-molecular-weight proteins, while endotoxins are low-molecular-weight lipopolysaccharides.
  2. Structure - Exotoxins are complex proteins, while endotoxins are simple lipopolysaccharides.
  3. Release mechanism - Exotoxins are released by bacteria through a complex process, while endotoxins are released as part of the bacterial cell wall.

CLASSIFICATION OF INFECTIOUS DISEASES

  1. Bacterial infections - Caused by bacteria, such as tuberculosis.
  2. Viral infections - Caused by viruses, such as influenza.
  3. Fungal infections - Caused by fungi, such as ringworm.
  4. Parasitic infections - Caused by parasites, such as malaria.

NOSOCOMIAL INFECTIONS

  1. Definition - Nosocomial infections are infections acquired in a hospital or healthcare setting.
  2. Examples - Urinary tract infections, pneumonia, and surgical site infections.

COMMON NOSOCOMIAL INFECTIONS

  1. Urinary tract infections - Caused by bacteria, such as E. coli.
  2. Pneumonia - Caused by bacteria, such as Streptococcus pneumoniae.
  3. Surgical site infections - Caused by bacteria, such as Staphylococcus aureus.