1. What is Epidemiology?

The study and analysis of the incidence, distribution and control of diseases

2. What is disease epidemiology?

• Deals with one population e.g humans

• Risk is a case

• Identifies causes

• E.g cancer (radiation source)

3. What is infectious disease epidemiology?

• Two or more populations e.g human and pathogen

• A case is a risk factor

• The cause is often known

4. Give examples of two or more populations in infectious disease epidemiology

• Humans

• Infectious agents: Helminths, bacteria, fungi, protozoa, viruses, prions

• Vectors: Mosquito (protozoa-malaria), Snails (helminths-schistosomiasis), Blackfly (microfilaria-onchocerciasis)

• Animals: Dogs and sheep/goats : Echinococcus, Mice and Ticks: Borrelia

5. What is infectious disease epidemiology used for?

• Identification of causes of new, emerging infections, e,g HIV, vCJD, Zika, SARS-CoV2

• Surveillance of infectious disease

• Identification of source of outbreaks

• Studies of routes of transmission and natural history of infections

• Identification of new interventions

6. What is an infectious disease caused by?

infectious agent

7. What is communicable diseases caused by?

Transmission directly or indirectly from an infected person

8. What is a Transmissible disease caused by?

Transmission through unnatural routes from an infected person

9. Give examples of routes of direct transmission

• Skin-skin: Herpes type 1

• Mucous-mucous: STIs

• Across placenta: toxoplasmosis

• Through breast milk: HIV

• Sneeze-cough: Influenza

10. Give examples of routes of indirect transmission

Food-borne: salmonella

Water-borne: Hepatitis A

Vector-borne: Malaria

Air-borne: Chickenpox

11. What are 3 types of modes of disease transmission?

Contact transmission

Vehicle transmission

Vector Transmission

12. What are some pathogens that cross the placenta?

13. What is the time line for an infection?

14. What are the outcomes of infection?

15. In terms of transmission what is index case?

The first case identified

16. What is primary case?

The case that brings the infection into a population

17. What is secondary case?

Infected by a primary case

18. What is tertiary case?

Infected by a secondary case

19. What is epidemiologic triad?

Disease is the result of forces within a dynamic system consisting of:

20. How do you calculate Infectivity (ability to infect)?

(number infected / number susceptible) x 100

21. How do you calculate pathogenicity (ability to cause disease)?

(number with clinical disease / number infected) x 100

22. Virulence (ability to cause death)

(number of deaths / number with disease) x 100

23. What are Koch's postulates to identify the microbial cause of specific diseases?

24. Microbe must be present in every case of the disease but not in healthy organisms

25. Microbe must be isolated from a disease host and grown in pure culture

26. Disease must be reproduced when a pure culture Is introduced into a non-disease susceptible host

27. Microbe must be recoverable from an experimentally infected host

24. What is endemic?

Transmission occur, but the number of cases remains constant within a certain area

25. What is Epidemic?

A rapid increase in the number of cases in a certain area

26. Whats a pandemic?

When epidemics spread and occur at several continents - a global epidemic

27. Would a world without microbes be safe?

No - we need microbes