Question

2. What is the relationship between a microbe's ease of transmission and the severity of the symptoms of the disease it causes?

3. How did FIV in big cats lead to the discovery of HIV resistant people?

4. Protection from what disease in the past may protect humans from HIV today?

5. What are the preliminary findings in the study of Bavarian children and allergies?

Answer 1

Infection is the process by which a pathogen establish itself in host tissues, multiplies and caryy out its own metabolism.

• The pathogen multiplication and metabolic implications results in substances causing symptoms in host body that characterizes any disease.
• Thus, to cause a disease, the infectious agent must first be established in the host. This relates to the mode of transmission (MOT) or the rate of transmission of the infectious agent.
• The pathogen may be transmitted as: vertical transmission- as congenital, genetic, but more commonly the infectious agents follow Horizontal mode of transmission-like direct contact, through aerosol, sexual transmission etc.
• The relative rate of transmission is proportional to the ease in infection establishment in a host or is referred to as the infectiousness.
• Thus, the transmission rate is related to faster establishment of infection that may lead to a disease.
• The branch of epidemiology relates the transmission to disease.
• Epidemic curves are important for describing epidemic diseases.
• Point source epidemic- group of individuals are exposed for a short period with the infectious agent and the disease occurs in everyone at the same time or within similar incubation period. Steep slope is indicated.
• Continuous common source epidemic- source of infection is same, but may be exposed for a longer time period or prolonged incubation period. Slope is like a plateau.
• Log-normal epidemic- similar to point source has smaller incubation with same incubation or the group. Curve has sharp incline with slow decline.
• Propagated epidemic- Infection occurs from person to person, through contact. The curve shows several peaks with interval periods.