Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FunMed Microbiology > Describe infectious disease epidemiology > Flashcards

Describe infectious disease epidemiology Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is an epidemic

A

An outbreak; an increase in the number of cases of an infection over and above expected levels
Or a single case or small number of cases of an unusual organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is an pandemic

A
  • Epidemic involing more than one country
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

name example of pandemic

A
  • Swine H1N1 flu pandemic 2009
  • European measles pandemic 2009
  • Ebola outbreak 2014-15
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is incidence

A
  • Incidence is a measure of the probability of infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is prevalence

A
  • Prevalence is the proportion of infection found to be affecting a particular population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the incidence rate

A
  • The incidence rate is the number new cases per population at risk in a given time period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the difference between incidence and prelevance

A

Incidence conveys information about the risk of contracting the disease whereas prevalence indicates how widespread the disease is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the source of infection

A

Environment – food, water, soil, airborne
Animals – zoonosis, animal carrier, vector-born
Humans – human carrier – symptomless and convalescent – some people are just carriers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How are pathogens transmitted

A

General transmission
- Abiotic environment factors; wind, water, inhalation of spores, entry into skin
- Animal vectors – mosquitos, malaria, dengue, fleas(bubonic plague)
Human to human transmission
- Direct contact – pathogen survives best inside the body such as herpesviruses Ebola
- Indirect contact – pathogen survives harsh environment, pick up pathogen from surface or air such as influenza, norovirus
- Droplets- pathogens are in droplets but do not survive long this way, for example Ebola, Bordetella pertussis
- Airborne – pathogens aerosolized and stay infected such as influenza tuberculosis
- Faecal and oral – through contaminated water or food such as cholera, norovirus, shigella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the transmission terminology

A
  • Index – the first case identified
  • Primary – the case that brings the infection into a population
  • Secondary – infected by a primary case
  • Tertiary – infected by a secondary case
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the three factors influencing disease transmission

A
  • Agent
  • Host
  • Environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the agent influencing disease transmission characteristics

A
  • Infectivity – how infectious is the virus
  • Pathogenicity – if you kill the host too quickly then it doesn’t spread very far
  • Virulence -
  • Immunogenicity – how immunogenic it is, how easily it can escape the immune system
  • Antigenic stability
  • Survival
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the characteristic of the host influencing disease transmission

A
  • Age
  • Sex
  • Genotype
  • Behaviour
  • Nutritional status
  • Health status
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the characteristics of the environment influencing disease transmission

A
  • Weather – some viruses are seasonal like flu
  • Housing
  • Geography
  • Occupational setting
  • Air quality
  • Food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the animal full of disease

A
  • Bat – biggest reservoir for Ebola, other mammal species are infected and these infect humans in different ways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe breakouts in Ebola

A
  • Simultaneous outbreaks in 1976 in DRC (318 cases, mortality rate 88%) and Sudan (284 cases, mortality rate 53%)
  • Sudan index case – cotton factor workers or spread by use of contaminated needles among member
  • Named after a small river in northwester DRC

Chronologoy of elbola viruse disease outbreak
2013-15
- Countries Guinea, Sierra Leone, Liberia, cases 28,646, case fatality 39.5%

17
Q

what was the index case in ebola

A
  • More close population easier that it will spread
  • Idex case – boy aged 2, got ebola after the symptoms he died within 2 days, but before he died he transmitted it to his sister, his mother and family friend
  • Then it was transmitted to the grandmother – she was a nurse and midwife who travelled between towns so it spread between towns, millions of people caught it
18
Q

how is ebola transmitted

A
  • Transmission is blood secretions
  • Skin abrasion
  • Needle stick
  • Mucosal surfaces
    Spread after primary infections to the lungs and reticuloendothelial cells
19
Q

what are the symptoms of ebola

A
  • Day 7-9 = headache, fatigue, fever, muscle soreness
  • Day 10 – sudden high fever, vomiting blood, passive behaviour
  • Day 11 – bruising, brain damage, bleeding from nose, mouth, eyes, anus
  • Day 12 = loss of consciousness, seizures, massive internal bleeding, death
20
Q

what was the ebola outbreak not controlled

A
  • Poor countries
  • Fragile healthcare systems
  • High rate of infected healthcare workers
  • Movement across porous borders
  • Lack of leadership
21
Q

how does survicielnce and ring vaccinations work

A

Contact tracing
- Sick individual are ased to identify contract, authorities attempt to find and isolate contact\
- Hard in urban environments because of unknown contacts
- Sick individuals have a long time to infect others before being hospitalised
Community monitoring
- Communities with infected individuals monitored daily, effective due to early identifications of infections
- Sick individuals are isolated before they have a chance to infect others
Now have a recombinant vaccine, it was used in 2017 but we still don’t know the extent to which it is working, around 50% of people given the vaccine had only mild disease
- Need to be tested in big numbers of people
Identify the index case, primary infection and secondary infection

22
Q

describe the history of influenza

A
  • 412BC – first mentioned by Hippocrates
  • 1580 – first pandemic described
  • 1580-1900 – 28 pandemics
  • First isolated in the UK in 1933
  • Influenza recovered from throat washes of an infected ferret
23
Q

describe influx epidemiology

A
  • Yearly infections infect 15-20% of the world’s population
  • 3-5 million severe cases
  • 250-500,000 deaths/year
24
Q

what is the mode of transmission of influenza in humans

A
  • droplet infection
25
Q

what are the symptoms of influenza

A
  • sudden onset of symptoms
  • persists for 7 days
  • incubation period 1-4 days, average 2 days
  • infectious period of wild type – adults shed virus typically from 1 day before through 5 days after onset of symptoms, children shed higher titers for a longer duration than adults
26
Q

what are the types of influenza

A
  • A - humans and animals and birds
  • B - humans only
  • C - humans only
27
Q

describe the influx virus

A 
orthomyxovrisu 
-	envelope 
surface spikes 
-	haemglglutin protein – bidsn to the cell
-	neuramidnisase protien 
-	SS – RNA
-	8 segmented genes
28
Q

name some examples of influenza pandemics

A
  • H1N1 – Spanish flu – 20-40 million deaths
  • H2NH2 – Asian flu – 1 million deaths
  • H3N2 – Hong Kong flu – 1 million deaths
  • H1N1 – swine flu – 200,000 deaths
29
Q

describe antigenic drift in the evolution of the virus

A

Antigenic drift and the evolution of the virus

  • Minor changes in the antigen character
  • Mutation rate highest for type A, lowest for type C
  • Most meaningful mutations occur in HA1 protiens

Antigenic shift
• Phylogenic evolution that accounts for emergence of new strains of virus
• Immunologically distinct, novel H/N combinations
• Genetic reassortment between circulating human and animal strains is responsible for shifts
• Segmented genome facilitates reassortment – only observed in type A
• Only been observed in type A, since it infects many species

30
Q

what can be done to slow the spread of a pandemic

A

• Vaccine:
– not expected to be available until later in a pandemic
• Antivirals:
– likely to be insufficient quantities, effectiveness unclear
• Disease containment measures:
– may be the only measures available in the early stages of a pandemic
– may be helpful in slowing the spread of a pandemic, allowing more time for vaccine production

31
Q

describe infection control

A

and hygeien – wash hands regulatory soap and water, if no water available 60-95% alcohol based sanitizer

  • Cover cough strategy
  • Environmental cleaning – 1;10 bleach solution, EPA registered disinfectant
  • Gloves, gowns and masks
32
Q

describe public health in practise

A 
• Surveillance 
– Notifiable Diseases, Flu surveillance 
• Diagnostics 
– Population-Screening, improving diagnostics 
• Immunisation / prevention 
– Polio eradication, Vaccination programmes 
• Outbreak management 
– Containment, Treatment Centres, etc.
33
Q

what are the Zika virus outbreaks

A

2007 outbreak on Yap Island (5,005/6,892 residents) first outside Africa, Asia 2013 outbreak French Polynesia (30,000, 11% of population)
2014 New Caledonia (1,400, 0.8%), Cook Islands (905), Easter Island (50) 2015 Vanuatu, Solomon Islands, Samoa, Fiji

34
Q

what are the symptoms of the zika virus

A
  • Most infections believed to be asymptomatic (approx. 80%)
  • Onset of symptoms is 3 to 12 days after infection
  • Short viraemic period
  • Fever, rash, headache, conjunctivits
35
Q

how is Zika virus spread

A
  • Semen
  • Urine
  • Saliva
  • Blood
  • Breast mild

FunMed Microbiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions