Lecture 10 - Infectious diseases

Question 1

what is the disease triangle?

Answer 1

the interactions between the disease, the host and the environment

Question 2

in terms of epidemiology, what is most important things about the microbe

Answer 2

type of microbe and virulence factors, route of transmission

Question 3

in terms of epidemiology, what is most important things about the host

Answer 3

risk factors

Question 4

what is a prion?

Answer 4

infectious proteins

Question 5

what is a virus?

Answer 5

infectious particle that requires host cells to replicate and make new nucleic acid and proteins for new virus particles

Question 6

what are parasites?

Answer 6

eukaryotes, may be multicellular.

Question 7

what is an outbreak?

Answer 7

sudden increase in occurence

Question 8

what is a pandemic?

Answer 8

outbreak that has spread across a wide region

Question 9

what is an endemic?

Answer 9

case are at a baseline level in a geographic area

Question 10

what is a pathogen?

Answer 10

a microbe capable of causing damage to a host

Question 11

what is pathogenesis

Answer 11

the mechanism by which a disease develops

Question 12

what is a faculative intracellular organism?

Answer 12

can live inside and outside cells

Question 13

what is an obligative intracellular

Answer 13

not really alive until they invade a host cell

Question 14

what is a reservior

Answer 14

aka source, where was the infectious agent caught from

Question 15

what is the transmission

Answer 15

how the infectious agent gets from reservoir to point of infection

Question 16

describe host carriage and restriction

Answer 16

host carriage is the ability of a host to carry a disease
host restriction is diseases that don’t work on one host but will on another animal

Question 17

what are the most common transmission routes?

Answer 17

• airborne
• direct contact
• indirect contact (fomites)
• blood (bites and wounds)
• fecal-oral route

Question 18

who is most at risk for disease?

Answer 18

people with:
- naiive or failing immunity
- compromised immune system
- unfortunate lifestyle/occupation/location

Question 19

what can cause compromised immunity?

Answer 19

• drug users (and chemo)
• surgery or wound
• existing condidtion eg HIV

Question 20

why are the very young and the very old at risk for diseases

Answer 20

due to naiive or failing immunity respectively

Question 21

what is the general measure of infectiousness?

Answer 21

R0, the higher the number, the more people that can get infected from one person being infected
(R0 of 2-3 means 2-3 people get infected per other infected person on average)

Question 22

what does R0 depend on?

Answer 22

microbe
dose
route of transmission
host susceptibility

Question 23

on top of what R0 depends on, what does a superspreading event depend on?

Answer 23

environment
host infectiousness (people may make the disease easier to pass on)

Question 24

what is the Reff?

Answer 24

the effective R
takes into account public health measures
- what actually happens even after public health measures

Question 25

R0 is the __________ of a disease and Reff is?

Answer 25

capacity, what is actually does after public health measures e.g masks and vaccination

Question 26

what is the incubation period?

Answer 26

time between exposure to infectious microbe and onset of symptoms

Question 27

when are we typically most infectious?

Answer 27

when we are experiencing symptoms, but this does vary with different microbes and different hosts

Question 28

why are diseases with no diseases during the first half of their infectious period hard to control?

Answer 28

because they are unknowingly infecting others while seeming perfectly fine - infectious while in incibation period

Question 29

what are the most important things to consider with symptoms?

Answer 29

- when (onset) - what - severity - organism vs host, what is causing symptoms

Question 30

what is the clinical disease rate?

Answer 30

the proportions of infected people who develop disease

Question 31

what is the infection fatality rate?

Answer 31

the number of estimated deaths as a proportion of all infected

Question 32

what is the case fatality rate?

Answer 32

the number of deaths as a proportion of confirmed cases

Question 33

what is the immunity rate?

Answer 33

the proportion of people immune to reinfection

Question 34

lifespan of an outbreak on a graph looks like?

Answer 34

a camel hump - daily cases vs time since first case (may be a second hump if people begin to get reinfected)

Question 35

what is ebola also known as?

Answer 35

EVD (ebola virus disease) zaire virus

Question 36

how does ebola happen?

Answer 36

Zaire virus attaches to TIM-1 receptors on epithelial cells in body orifices viral RNA is released into the cell and replicated new viruses bud from infected cell

Question 37

what is the reservoir of ebola?

Answer 37

not humans, but usually fruit bats or other infected animal that touched a fruit bat.

Question 38

how can ebola be spread?

Answer 38

through contact with an infected person or animal contact with bodily fluids of the sick or even dead contact with contaminated objects such as needles or bedding

Question 39

describe the incubation period of ebola

Answer 39

2-21 days, no transmission during incubation period

Question 40

what are the early symptoms of ebola?

Answer 40

fever, headache, sore throat

Question 41

what are the severe symptoms of ebola?

Answer 41

severe diarrhoea, vomiting and bleeding

Question 42

how does the risk of spread change with severity of the symptoms of ebola?

Answer 42

the more severe the symptoms, the higher the risk of spread

Question 43

what part of traditions in africa made it difficult to contain the outbreak?

Answer 43

the families like to clean the bodies and prepare them before burial

Question 44

what is the mortality rate of ebola

Answer 44

anywhere between 25-70%

Question 45

what were the three main countries that were impacted in the 2014 western ebola outbreak?

Answer 45

guinea, liberia and sierra leone

Question 46

which ebola virus is the main one nowadays

Answer 46

zaire

Question 47

true or false: ebola coincides with the wet season

Answer 47

false, ebola often occurs more often during prolonged dry seasons and deforestation

Question 48

true or false, ebola happens during civil war and political instability

Answer 48

true

Question 49

what are the main treatments for ebola?

Answer 49

- monoclonal antibody treatments - monitoring - fluid resucitation - treatment of coinfections and seizures but not all countries have access

Question 50

how many vaccines are there for prevention of ebola?

Answer 50

two

Question 51

what ebola do the vaccines not work against?

Answer 51

sudan

Question 52

what is the ERVEBO vaccine

Answer 52

1 intramuscular dose for 18+ - WHO recommends revaccinating if a contact >6 months after vaccination

Question 53

what is the Zabdeno + Mvabea vaccine?

Answer 53

intramuscular and suitable for 1+ can get a zabdeno booster after 4 months if a contact

Question 54

true or false, vaccines make a massive difference to the shortening of and outbreak

Answer 54

true