Infections and Diseases

1. List ten factors that might influence the virulence of an infection.

Factors from both the parasite and the host can influence the severity of an infection.

Parasite/ Micro-organism Variables

1. Variability of gene expression of multiple pathogenic mechanisms (Ref 3)

2. Potential for damage or stress of the micro-organism (Ref 3)

3. Interactions with other organisms (Ref 3)

Variables of the Host

4. Age (Ref 3)

5. General health (Ref 3)

6. Pregnancy (Ref 3)

7. Metabolic disorders

8. Medications--OTC or prescription (Ref 3)

9. Immune competence (Ref 3)

10. Amount of food consumed (Ref 3)

2. Infectious diseases can be acquired through a number of different modes of transmission. List seven such modes and describe each in a sentence or two.

1. Food and waterborne diseases: They are transmitted by intake of contaminated food and drink. For example some diseases transmitted by food and water are hepatitis A, typhoid fever and cholera. (Ref 1)

2. Vector-borne diseases: A number of particularly serious infections are transmitted by insects and other vectors such as ticks. Examples of vector-borne diseases are malaria and yellow fever. (Ref 1)

3. Zoonoses (diseases transmitted by animals): Many infections can be transmitted to humans through animal bites or contact with contaminated body fluids or faeces from animals, or by consumption of foods of animal origin, particularly meat and milk products. Examples are rabies and brucellosis. (Ref 1)

4. Sexually transmitted diseases: Are passed from person to person through unsafe sexual practices. Examples of sexually transmitted diseases are hepatitis B, HIV/AIDS and syphilis. (Ref 1)

5. Blood borne diseases: are transmitted by direct contact with infected blood or other body fluids. Examples of blood borne diseases are hepatitis B and C, HIV/AIDS and malaria. (Ref 1)

6. Airborne diseases: are transmitted from person to person by aerosols from coughs