Epidemiology

Question 1

What are the advantages of ELISA?

Answer 1

Sensitive
Reproducible
Qualitative and quantitative
Greater scope
Suitable for automation

Question 2

Radioimmunoassay

Answer 2

Purified antigen labelled with radioisotope competes with unlabelled standard for antibody binding. Amount of radioactivity associated with antibody is measured.

Question 3

Immunoblot (western blot)

Answer 3

Detects for a specific protein associated with a specific organism. Highly specific and sensitive. Involves separation of proteins, transfer of proteins from gel to nitrocellulose membrane and identification of protein with a specific antibody.

Question 4

In vivo testing

Answer 4

Antigens introduced directly into body to determine presence or absence of antibodies
Tuberculin skin test and allergy testing

Question 5

What is epidemiology?

Answer 5

The study of transmission, incidence and frequency of disease
The study of when and where diseases occur

Question 6

Who was John Snow?

Answer 6

Created map of people who died from chloera in London and what water pump they drank from.

Question 7

Who was Florence Nightingale?

Answer 7

Statistically linked disease and death with poor food and unsanitary conditions

Question 8

Define symptom

Answer 8

A change in body function that is felt by a patient as a result of disease

Question 9

Define sign

Answer 9

A change in the body that can be measured or observed as a result of disease

Question 10

Define syndrome

Answer 10

A specific group of signs and symptoms that accompany a disease

Question 11

Communicable disease

Answer 11

A disease spread from one host to another e.g. tuberculosis

Question 12

Contagious disease

Answer 12

A disease that is EASILY spread from one host to another e.g. chicken pox

Question 13

Noncommunicable disease

Answer 13

A disease that is not transmitted from one host to another e.g. tetanus

Question 14

What are the stages of infectious disease, and when are they contagious?

Answer 14

Incubation period
Prodomal period
Illness period
Decline period
Convalescence period
Normally contagious in incubation and prodomal periods

Question 15

What is a sub-acute disease?

Answer 15

Sudden onset but lasts a long time.

Question 16

Sporadic disease

Answer 16

Occurs occasionally in a population at irregular intervals

Question 17

Endemic disease

Answer 17

Continually present in a population at low frequency and a steady level

Question 18

Epidemic disease

Answer 18

High frequency over short time period, many hosts in an area, sudden increase of morbidity and mortality above the normal level

Question 19

Pandemic disease

Answer 19

Worldwide

Question 20

Common source epidemic

Answer 20

Disease spread from one source, little transmission e.g. food poisoning

Question 21

Propogated epidemic

Answer 21

Disease continously transmitted from infected, higher numbers and longer lasting e.g. influenza

Question 22

Herd immunity

Answer 22

Many people in a population are immune so cannot get infected and more important cannot spread the disease

Question 23

Describe the microbialdiease cycle

Answer 23

Reservoir - Transmission - Portal of Entry - Disease - Portal of Exit - Reservoir

Question 24

Symptomatic Reservoir

Answer 24

Obvious source of infectious agent

Question 25

Asymptomatic Reservoir

Answer 25

No obvious symptoms of disease e.g. some STIs

Question 26

Define Zoonose

Answer 26

A disease that occurs in domestic and wild animals and can be transmmitted to humans

Question 27

Name 5 transmission routes of zoonoses

Answer 27

``` Direct contact Contamination with infected pet waste Air contaminated from hides, fur etc. Insect vectors Consuming infected animal products ```

Question 28

Define droplet transmission

Answer 28

Pathogens spread in droplet nuclei (mucus droplets) Typically travel short distance Sneezing, coughing etc.

Question 29

Define inanimate reservoir

Answer 29

Water, Food, Air for example

Question 30

Define mechanical vector

Answer 30

Just a vehicle like fleas carrying plague from one host to another

Question 31

Define biological vector

Answer 31

Some of the development of the microbe takes place within the vector e.g. mosquitoes and malaria

Question 32

Define a nosocomial infection

Answer 32

Acquired in hospitals | 5-15% of patients affected

Question 33

Name 4 factors that could contribute to nocosomial infections

Answer 33

Patient population immunocompromised Misuse of antibiotics which increases chance of resistant strains Medical devices as new portals of entry Hospital staff as reservoir

Question 34

Name 4 ways to prevent nocosomial infections

Answer 34

Appropriate use of antibiotics Safe and effective decontamination and sterilisation Hygiene Screening of patients

Question 35

Name 7 factors that are contributing to the emergence of infectious diseases and give examples

Answer 35

Genetic recombination e.g. H5N1 Evolution or new serovars e.g. V. cholerae Inappropriate use of antibiotics and pesticides e.g. M. tuberculosis Global warming or weather changes e.g. Hantavirus pulmonary syndrome Modern transportation e.g. cholera Ecological disaster e.g. coccidiodomycosis after Northridge earthquake Public health failures e.g. missed hepatitis immunisations

Question 36

Define Molecular epidemiology

Answer 36

To identify microparasites responsible for infectious diseases and to determine their physical sources, biological relationships, routes of trnasmission and the genes responsible for their virulence, vaccine relevant antigens and resistance.

Question 37

Define infectious disease outbreak

Answer 37

Geographically and temporally associated cluster of cases of acute illness caused by a pathogen, in excess of what is usually expected for that time or place.

Question 38

Define short term (local) epidemiology

Answer 38

The isolates recovered from a localised outbreak of disease - the same or different strains

Question 39

Define long term (global) epidemiology

Answer 39

How are strains causing disease in one geographical area compared to those isolated worldwide

Question 40

Name 3 reasons why isolates are forwarded to the National Reference Library

Answer 40

To confirm identity To further characterise the isolates To provide reference collection for the future

Question 41

What is subtyping?

Answer 41

The characterisation of bacteria below the species or subspecies level. Strains from the same source are likely to show similar subtypes.

Question 42

Why do we subtype?

Answer 42

It helps to separate outbreak associated cases with sporadic cases.

Question 43

Name 6 things an ideal subtyping method should have.

Answer 43

``` Fast Robust Portable Reproducible Differentiates unrelated strains Cost effective ```

Question 44

What is Biotyping?

Answer 44

The differentiation of strains within a species on the basis of physiological or biochemical characteristics