Exam #4 Study Guide, Part 2 – Select Microbial Diseases

Disease List

• Measles
• Influenza
• Polio
• Diphtheria
• Pertussis
• Tetanus
• Tuberculosis
• Malaria
• HIV-AIDS
• Staphylococcus aureus infections
• Streptococcus pyogenes infections
• Streptococcus pneumoniae infections
• Group B Streptococcus – neonatal meningitis
• Human Herpes Viruses (HHV 1 – 4)

Disease Details

• Measles:
  • Microbe: Measles virus (RNA virus).
  • Transmission: Respiratory droplets.
  • Reservoir: Human.
  • Vaccine: MMR.
  • Treatment: No antiviral; prevention key.
  • R₀ ~12–18, extremely contagious.
  • Severe complications: Encephalitis, pneumonia, immune amnesia.
• Influenza:
  • Microbe: Influenza virus (RNA virus).
  • Transmission: Respiratory droplets.
  • Reservoir: Human, birds, pigs.
  • Vaccine: Yes (annual).
  • Treatment: Yes (antivirals); resistance varies.
  • Antigenic Drift: Small mutations; seasonal changes.
  • Antigenic Shift: Reassortment; new subtypes = pandemics (e.g., H1N1).
• Polio:
  • Microbe: Poliovirus (RNA virus).
  • Transmission: Fecal-oral.
  • Reservoir: Human.
  • Vaccine: Yes (IPV, OPV).
  • Treatment: Supportive care only.
• Diphtheria:
  • Microbe: Corynebacterium diphtheriae (Gram-positive bacteria).
  • Transmission: Respiratory droplets.
  • Reservoir: Human.
  • Vaccine: DTaP, Tdap.
  • Treatment: Antitoxin + antibiotics.
• Pertussis:
  • Microbe: Bordetella pertussis (Gram-negative bacteria).
  • Transmission: Respiratory droplets.
  • Reservoir: Human.
  • Vaccine: DTaP, Tdap.
  • Treatment: Antibiotics; resistance rising.
• Tetanus:
  • Microbe: Clostridium tetani (Gram-positive bacteria).
  • Transmission: Wounds/skin.
  • Reservoir: Soil.
  • Vaccine: Tdap, DTaP, Td.
  • Treatment: Antitoxin + antibiotics.
• Tuberculosis (TB):
  • Microbe: Mycobacterium tuberculosis (Acid-fast bacteria).
  • Transmission: Airborne.
  • Reservoir: Human.
  • Vaccine: BCG (limited use in U.S.).
  • Treatment: Long antibiotic course; resistance ↑.
  • Latent TB: No symptoms, not contagious.
  • Active TB: Cough, weight loss, contagious.
  • Diagnostics: PPD skin test, IGRA blood test, chest X-ray, sputum.
  • High-Risk Groups: Immunocompromised, healthcare workers, homeless, incarcerated.
  • Resistance Factors: Long treatments, patient non-adherence, MDR/XDR strains.
• Malaria:
  • Microbe: Plasmodium spp. (Protozoa).
  • Transmission: Mosquito bite.
  • Reservoir: Human + mosquito.
  • Vaccine: No.
  • Treatment: Antimalarials; resistance ↑.
  • Cycle: Mosquito → injects parasite → liver → red blood cells → mosquito.
  • Fever/chills = RBC rupture releasing toxins.
  • Prevention: Nets, repellents, prophylaxis, mosquito control.
• HIV-AIDS:
  • Microbe: Human Immunodeficiency Virus (RNA retrovirus).
  • Transmission: Body fluids.
  • Reservoir: Human.
  • Vaccine: No.
  • Treatment: ART (HAART); resistance issues.
  • Targets: CD4+ T cells.
  • Latency: Virus dormant in genome.
  • Stages: Acute retroviral syndrome, clinical latency, AIDS (CD4 < 200).
  • Drugs: HAART, PREP, PEPFAR.
• Staphylococcus aureus:
  • Microbe: Staphylococcus aureus (Gram-positive bacteria).
  • Transmission: Skin, contact, food.
  • Reservoir: Human.
  • Vaccine: No.
  • Treatment: Yes; MRSA = resistant strain.
  • Diseases: Skin, sepsis, pneumonia, endocarditis, TSS, food poisoning.
  • Virulence: Coagulase, leukocidins, enterotoxins.
• Streptococcus pyogenes:
  • Microbe: Streptococcus pyogenes (Gram-positive bacteria).
  • Transmission: Respiratory, wounds.
  • Reservoir: Human.
  • Vaccine: No.
  • Treatment: Yes; resistance rare.
  • Classification: Lancefield groups, Hemolysis.
  • Infections: Strep throat, scarlet fever, necrotizing fasciitis.
  • Virulence: M protein, streptolysin, hyaluronidase.
  • Complications: Rheumatic fever, glomerulonephritis.
• Streptococcus pneumoniae:
  • Microbe: Streptococcus pneumoniae (Gram-positive bacteria).
  • Transmission: Respiratory.
  • Reservoir: Human.
  • Vaccine: Yes (PCV, PPSV).
  • Treatment: Yes; some resistant strains.
  • Infections: Otitis, sinusitis, pneumonia, meningitis.
  • Virulence: Capsule.
• Group B Streptococcus (S. agalactiae):
  • Microbe: Streptococcus agalactiae (Gram-positive bacteria).
  • Transmission: Vaginal canal → newborn.
  • Reservoir: Human.
  • Vaccine: No.
  • Treatment: Intrapartum antibiotics.
  • Disease: Neonatal meningitis.
• Human Herpes Viruses (HHV):
  • Microbe: Herpes Simplex Virus 1 & 2, VZV, EBV (DNA virus).
  • Transmission: Mucous membranes / saliva.
  • Reservoir: Human.
  • Vaccine: Yes (VZV).
  • Treatment: Acyclovir, antivirals.
  • HHV-1/2 (HSV-1/2): Latency in neurons.
  • HHV-3 (VZV): Chickenpox → Shingles; Latency in dorsal root ganglia.
  • HHV-4 (EBV): Infectious mononucleosis; Latency in B cells.

General Information

• Types: Bacteria, virus, protozoa.
• Classification: Gram stain, acid-fast, DNA/RNA.
• Transmission: Airborne, contact, blood, vectors.