major pathogenic properties of bacteria, fungi, protozoans, and helminths

Question 1

Bacteria

Answer 1

Virulence factors:
Adherence proteins
fimbriae/pili
Capsules
Other cell components
Enzymes
Antigenic variation

Siderophores and toxins

Question 2

Fungi

Answer 2

No well-defined virulence factors
Some metabolic products are toxic to human hosts

Examples:
Candida, Trichophyton: produce proteases that allow attachment to host cells
Cryptococcus: capsule prevents phagocytosis
Fusarium: trichothecene toxins inhibit protein synthesis

Question 3

Protozoans

Answer 3

• The presence of protozoa and waste produces disease
• Evasion of host cell
  - Plasmodium (causes malaria) evades the host and replicates within the host cell
  - Toxoplasma attaches to macrophages but prevents digestion
• Giardia (causes giardiasis) attaches itself with host discs and digests cells and tissue fluids, causing diarrhea
• Trypanosoma causes African sleeping sickness
  - Evades host by antigenic variation

Question 4

Helminths

Answer 4

• The presence of organisms causes disease and symptoms
• Some use hot tissue to grow and produce parasitic masses
• Wuchereria bancrofti (roundworm) causes elephantiasis
  - Blocks lymph circulation and grotesque swelling of body parts