Epidemiology Of Diseases

Question 1

What are the 3 stages of AIDS

Answer 1

1. Acute primary infection (glandular fever like illness)
2. Symptomless (latent) period
3. Symptomatic stage

Question 2

Name 5 sources of the HIV virus

Answer 2

Blood
Semen
Vaginal secretions
Breastmilk
Saliva

Question 3

Name 3 ways the HIV virus can be transmitted

Answer 3

Sexually
Needle sharing
In utero from mother to child via great milk

Question 4

Name 2 ways HIV can be diagnosed

Answer 4

Serology (study of blood serum and its constituents)

ELISA- screen for antibodies

Question 5

What is the definition of aids

Answer 5

The presence of one of the 25 conditions indicative of SEVERE IMMUNOSUPPRESSION

Question 6

Name 4 ways AIDS can be prevented

Answer 6

Safe sex
Needle exchange schemes
Voluntary testing for high risk categories
SICPs

Question 7

How is the Hep A virus transmitted

Answer 7

Faecal to oral route

Person to person, food borne, water borne

Question 8

What are clinical features of Hep A

Answer 8

Incubation period : 2-7 weeks
Many sub clinical infections
Patients experiences fatigue, anorexia, nausea, fever, possibly jaundice
No chronic disease

Question 9

How is Hep A diagnosed

Answer 9

Demonstration of Hep A virus (HAV) antigen in faeces

Serology- detection of IgM anti-HAV

Question 10

Name 3 ways Hep C is diagnosed

Answer 10

1. Detection of antibodies to HCV
   - screening test: ELISA
   - supplementary test: RIBA
2. Detection of viral genome
   - PCR for HCV RNA
3. Histological features on liver biopsy

Question 11

How can HCV be treated

Answer 11

Interferon alpha

In Combination with ribavirin

Question 12

What virus does Hep D require and why

Answer 12

Requires Hep B for replication

Because the virus is surrounded by Hep B antigen ‘coat’

Question 13

What 3 ways are drugs used in inflammation and give and example for each

Answer 13

1. Used to reduce (generation of) inflammatory mediators
   - non-steroidal anti-inflammatory drugs (NSAID)
2. Used to reduce inflammation process (reduce inflammation by reducing the triggers)
   - corticosteroids
3. Block nerve transmissions
   - LA

Question 14

How do NSAIDs works

Answer 14

True action unknown

INHIBIT prostaglandin synthesis (hormone, inflammation mediator)

Question 15

How does aspirin work? And what is its dosage?

Answer 15

Inhibits COX 1

• decreases synthesis of prostaglandins
• decreases production of inflammatory mediators
• anti-pyrexic (decreases temp.)

300-600mg, upto 4x a day

Question 16

Name 5 aspirin side effects

Answer 16

1. Gastric irritation (with long term use)
   - erosions, ulceration
   - worse with alcohol
2. Inhibition of platelet function
   - enhanced bleeding
3. Bronchospasm
   - exuberate asthma
4. Allergic reactions (rash)
5. Drug interactions
   - significant protein binding- WARFARIN potentiation (enhancement)

Question 17

What type of drug is ibuprofen? What’s its dosage?

Answer 17

NSAID

200-600mg, 3x a day

Question 18

Describe diclofenac and give its dosage

Answer 18

Prescription only, anti-inflammatory
More potent than ibuprofen

50mg, 3x a day

Question 19

Describe COX 2 inhibition

Answer 19

Better for long term use (e.g. Arthritis)
Decreased gastric side effects compared to COX 1
Much more expansive
Increased incidence of cardiac death

Question 20

What 4 ways does corticosteroids reduce inflammation?

Answer 20

Inhibit:
Capillary permeability
Formation of bradykinin (vasodilator)
Migrations of WBCs
Reduce eicosanoid synthesis

Question 21

What 2 ways can corticosteroids be administered?

Answer 21

Topically (on surface of desired tissue)

Systemically (given to whole organism)

Question 22

Name 3 types of topical corticosteroids and what they are for

Answer 22

Steroid inhalers in asthma
- beclometasone

Hydrocortisone cream for eczema

Steroid pastes for mouth ulcers
- triamcinolone

Question 23

Name 2 types of systemic corticosteroids and what they’re used for

Answer 23

Prednisolone

• prevent transplant rejection
• treat ‘auto-immune’ diseases e.g. Rheumatoid arthritis

Dexamethasone
- decrease swelling after surgery e.g. Wisdom tooth removal

Question 24

Name 7 side effects of prednisolone

Answer 24

High blood pressure
Weight gain (fluid)
Fat distribution change
Gastric ulceration
Adrenal suppression
Osteoporosis
Diabetes

Question 25

Name 5 clinical features of AIDS

Answer 25

1. Lymphadenopathy and Fever
   - may be accompanied by weight loss and malaise
2. Opportunistic infections
   - pneumonia
   - candidosis
   - herpes virus
3. Malignancies
   - NHL
4. Wasting
5. AIDS related dementia

Question 26

What are the 6 stages in chain of infection?

Answer 26

Infectious agent
Reservoir
Portal of exit
Mode of transmission
Portal of entry
Susceptible host

Question 27

What 2 factors make a microbe infectious?

Answer 27

Ability of microbe to cause disease (virulence)

The number of microbes entering the body (dose)

Question 28

Name 4 reservoirs for microbes

Answer 28

Humans
Animals
Environment
Fomites (contaminated objects/surfaces)

Question 29

What is the incubation period?

Answer 29

Time between contamination and development of symptoms

Question 30

Define colonisation

Answer 30

Presence of microorganisms in or on a host, with growth and multiplication,
BUT without any clinical expression (infection) at time microorganism is isolated