Study Notes for Microbiology Chapter 26: Microbial Diseases

Explore gastrointestinal infections, genitourinary infections, HIV/AIDS, and systemic infections including malaria, plague, and CNS infections.

Gastrointestinal Infections:

  • Caused by pathogens such as bacteria, viruses, and parasites.

  • Common examples include:
      - Norovirus: Highly contagious virus leading to gastroenteritis.
      - Salmonella: Bacterial infection often associated with contaminated food.
      - E. coli: Can cause severe abdominal cramps and diarrhea.

  • Symptoms may include nausea, vomiting, diarrhea, and abdominal pain.

Genitourinary Infections:

  • Often caused by bacteria.

  • Common types include:
      - Urinary Tract Infections (UTIs): Often caused by E. coli, characterized by frequent urination, burning sensation, and lower abdominal pain.
      - Sexually Transmitted Infections (STIs): Such as Chlamydia and Gonorrhea, which can lead to serious reproductive health issues if untreated.

HIV/AIDS:

  • Human Immunodeficiency Virus (HIV) leads to Acquired Immunodeficiency Syndrome (AIDS).

  • Primarily transmitted through blood, sexual contact, and from mother to child.

  • Symptoms vary, including flu-like symptoms initially, progressing to more severe conditions.

  • Key management involves antiretroviral therapy (ART) to manage the infection and maintain immune function.

Systemic Infections:

  • Malaria:
      - Caused by parasites transmitted through Anopheles mosquito bites.
      - Symptoms include fever, chills, and flu-like illness.

  • Plague:
      - Caused by the bacterium Yersinia pestis, transmitted to humans through flea bites or contact with infected animals.
      - Symptoms include swollen lymph nodes, fever, and chills.

  • Central Nervous System (CNS) Infections:
      - Include conditions such as meningitis and encephalitis, which can be viral, bacterial, or fungal in origin.
      - Symptoms often include headache, fever, stiff neck, and altered mental status.

Prions are infectious agents composed primarily of protein, with no nucleic acids. They are misfolded proteins that cause normal proteins in the brain to misfold, leading to neurodegenerative diseases. Prions are resistant to standard sterilization processes and can induce abnormal folding in normal proteins, resulting in brain damage and characteristic symptoms such as cognitive decline, personality changes, and motor dysfunction. Common prion diseases include:

  • Creutzfeldt-Jakob Disease (CJD): A rare, degenerative brain disorder that leads to rapidly progressive dementia.

  • Bovine Spongiform Encephalopathy (BSE): Also known as mad cow disease, affecting cattle and can be transmitted to humans through consumption of infected meat.

  • Scrapie: Affects sheep and goats, causing neurological symptoms.
    Prion diseases are typically fatal and have no known cure.