Exam 2.2 Flashcards
(97 cards)
1
Q
What is the iceberg effect of measles
A
Essentially zero
2
Q
How is measles spread
A
from person to person via respiratory droplets. Super contagious
3
Q
What kind of virus causes measles and mumps
A
Paramyxovirus
4
Q
What kind of genome does measles virus have
A
enveloped, (-)ssRNA
5
Q
What kind of capsid does measles virus have
A
helical
6
Q
How many measles virus serotypes are there
A
just 1
7
Q
What kind of vaccine is the measles mumps and rubella vaccine (MMR)
A
attenuated
8
Q
What factors increase death rate from measles infection
A
poverty that causes malnutrition
9
Q
What percent of the population must be vaccinated against measles virus to have herd immunity
A
92-94% because it is so highly infectious
10
Q
What is one unusual effect of a measles virus infection
A
It suppresses the immune system which allows for secondary infections
11
Q
Is it possible to completely rid the world of measles, mumps and rubella viruses
A
Yes, because humans are the only reservoir for all three
12
Q
What kind of genome does mumps virus have
A
(-)ssRNA, enveloped
13
Q
How is mumps spread
A
from person to person via respiratory droplets
14
Q
What tissue does measles virus initially infect
A
Lung epithelium and local lympathics
15
Q
What tissue does mumps virus initially infect
A
Lung epithelium, and also potentially eyes and nose
16
Q
After measles virus goes systemic, what tissue does it infect
A
Epi/endothelium, thus the characteristic measles rash
17
Q
After mumps goes systemic, what tissue does it infect
A
Glands including salivary and testicular ducts, but especially the parotids
18
Q
What is the most common permanent damage caused by mumps virus infection
A
Duct damage resulting in deafness or sterility
19
Q
Who is especially at risk in a rubella infection
A
Baby has a 25% chance of severe birth defects if mom gets a primary rubella infection in the first trimester
20
Q
What is the iceberg effect of mumps virus
A
25% of infected individuals don’t show signs and symptoms
21
Q
What type of virus is Rubella
A
togavirus
22
Q
what kind of genome does rubella virus have
A
(+)ssRNA, enveloped
23
Q
How is rubella virus spread
A
from person to person via respiratory droplets
24
Q
What tissue does rubella initially infect
A
respiratory tract.
25
What kind of virus is Respiratory Syncytial Virus
Paramyxovirus
26
What kind of genome does RSV have
(-)ssRNA, enveloped
27
How is RSV spread
from person to person via respiratory droplets
28
What tissue does RSV initially infect
Lung epithelium
29
What is the course of development of RSV infection
75% individuals develop UIR, 25% develop LRI and of those 3-5% require hospitalization
30
Who is most at risk for complications from RSV infection
kids with cystic fibrosis often die from RSV
31
Is it possible to eradicate RSV
No because there is no vaccine. But were there a vaccine then yes, because humans are the only reservoir
32
How many infected people are necessary to maintain an acute infection in a population
300,000
33
How many infected people are necessary to maintain a chronic infection
way less than 300,000 because it is always infectious
34
What sort of pathology do accidental hosts have
Super severe with high mortality rates
35
What sort of pathology do natural hosts have
little or no disease
36
What 2 things qualify a virus as 'emerging'
1. new infectious agents causing new disease 2. known disease increasing in incidence or geographical range
37
What kind of genome do most currently emerging disease have
ssRNA viruses because they have no spell checker mechanism and no proof reading strand which makes it easier to jump between species
38
What are arboviruses
viruses that have an arthropod vector (bugs and mites)
39
What is an emerging flavivirus
West Nile. We are accidental hosts; it kills crows
40
What is an emerging togavirus
Chikunganya. mosquito vector; just mutated to infect different breeds and now is in the Caribbean (also rubella)
41
What are roboviruses
Viruses that have a rodent vector
42
What is an emerging bunyavirus
Hanta fever, which infects mice in the 4 corners region
43
What is an emerging arenavirus
Lassa fever, which is like a less deadly version of ebola
44
What is an emerging filovirus
Ebola. 70% death rate with a possible bat reservoir
45
Which emerging viruses cause encephalitis
Chikungunya, West nile
46
Which emerging viruses cause hemorrhagic fever
Hanta, Lassa, Ebola
47
What causes a hemorrhagic fever
Complete use of all the clotting factors because the virus attacked the endothelium
48
What is zoonosis
having a mammal or bird reservoir
49
What is a dead end host
Accidental host in which the pathology is so severe you die before you have a chance to transmit the disease
50
What is the mechanism of action in prion disease
Protease resistant proteins cause other proteins to misfiled to become protease resistant, which leads to a buildup of proteins (ameloid plaque)
51
What are prions resistant to (in comparison to DNA)
Heat, formaldehyde, UV, Proteases
52
What makes prion disease particularly insidious
It doesn't even trigger an immune response because technically it is a host protein
53
What was the first prion disease discovered
Scrapie, found in sheep
54
What is Kuru
Human transmissible spongiform encephalitis
55
What is the most common human transmissible spongiform encephalitis disease
Creutzfeldt-Jakob Disease (1:10,000,000/year)
56
What is vCJD
Varient Creutzfeldt-Jakob disease, now thought to be caused by consumption of BSE infected beef, is the same except faster than CJD
57
How does one get CJD
a prion could randomly misfold, or it could be transmitted by receiving brain products, like GH extracted from a cadaver
58
What is Smallpox's real name
Variola major
59
What kind of genome does smallpox virus have
dsDNA, half enveloped, half not. Almost as large as the smallest bacteria
60
How is smallpox virus spread
From person to person via respiratory route or from skin lesion once the rash develops
61
What tissue does smallpox virus initially infect
Respiratory tract and then takes macrophage taxis to the lymph nodes
62
What is the classic presentation of smallpox infection
Pox distributed more on extremedies and face (cmp to chicken pox) along with fever, etc
63
What are the outcomes of smallpox infection
1/3 die 1/3 terribly scarred, 1/3 moderate-mild scarring on face and hands
64
What is variolation
purposely infecting someone with a mild strain of smallpox as a sort of immunization
65
What's convenient about a cowpox infection in a human
It stays localized in the hands and is not deadly, but is similar enough to smallpox to give immunity to it.
66
Who is the last person to die from smallpox
Jen Parker, a medical photographer, caught it from a research lab and died, as did her father(MI) and the researcher who caused her illness(suicide)
67
What kind of virus is HIV
Retrovirus
68
What type of genome do all retroviruses have
two copies of (+)ssRNA
69
What is the significance of having 2 copies of the ssRNA
Even if a strand is mutated so that it can't complete its "life"cycle, it still has a chance of infecting more cells or individuals because it can be carried by a "healthy" virus
70
Why are you never "cured" from HIV
Because the virus integrates into the host genome where it can lay latent indefinitely
71
What must be included in every retrovirus particle
along with the genome, reverse transcriptase, to turn RNA into DNA
72
What are the 3 classes of exogenous retroviruses
Oncoviruses(tumor), lentiviruses (slow), spumaviruses (foamy)
73
What is a human oncovirus
HTLV I causes human leukemias; rare STI
74
What are the human lentiviruses
HIV 1 (immunodeficiency), HIV 2 (brain lesion)
75
What a spumavirus
? cytopathic, no overt pathology
76
What is an HERV
Human endogenous retrovirus is a virus that integrates itself into germ line genome.
77
Are HERVs dangerous
They are degenerate and no longer pathogenic. In fact, they make up 8% of our genome and may even be involved in placenta formation and other aspects of health
78
How is HIV transmitted
Mainly sexual transmission, but also needles and transplacental and even health care products. Needles, sex, and blood
79
How many HIV carriers are there
40 million, with 2 million AIDS cases
80
How does one increase one's risk of getting HIV
1. Have more sexual partners 2. Have sex with someone with a large viral load 3. Have lots of sex with someone who is HIV + 4. Lose genital epithelial barrier from a different STI (particularly Chlamydia)
81
Where is HIV definitely increasing
Eastern Europe and central asia; USSR collapsed and with it went public health plus IV drug use up since Afghanistan war
82
What are the 4 major gene segments in a retrovirus
gag, pro, pol, and env,
83
What is an LTR
long, terminal repeat. Found at both ends of a retrovirus genome and serves as a promotor, for insertion stuff
84
What does the GAG segment code for
proteins involved in viral structure, like the capsid
85
What does the POL segment code for
Enzymes for replications, like integrase and REV
86
What does ENV code for
proteins that stabilize the envelop, spikes, like GP41 and GP120
87
What does PRO code for
Protease
88
What does GP120 do
bind CD4 via CCR5 or CXR4
89
What does GP41 do
helps HIV virus fuse with the cell membrane
90
how is an HIV virion activated
It must bud off while protease cleaves the polyprotein into functional proteins
91
After the one long strand of HIV mRNA is made, what happens
The section that codes for spike proteins is cleaved and the two strands are transcribed separately
92
What is the one step of HIV viral replication that can't be block (yet)
transcription and translation of viral DNA into mRNA and proteins
93
What is R-5 tropic HIV
HIV with a high affinity for CCR5 receptor (found on macrophages)
94
What is T-tropic or X-4 tropic HIV
HIV that has a high affinity for CXCR4 receptor (found on T-helpers)
95
What is the receptor affinity progression in HIV
Normally starts as R-5 tropic and mutates to X-4 tropic
96
What is the benefit and harm of the affinity progression of HIV
X-4 type is less infectious, but more damaging to the infected individual
97
Why is HAART (drug cocktail) the gold standard treatment for HIV
Because using just one drug makes it super easy for the virus to mutate and avoid the drug
