Microbiology > Unit III > Flashcards

Unit III Flashcards

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1
Q

who was Dr. Walter Reed

A

Chairman of Yellow Fever commision

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2
Q

who was Dr. Carlos Juan Finlay

A

believed yellow fever agent was transmitted by specific mosquitoes

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3
Q

what is DNA directly surrounded by

A

capsid protein shell that gives shape

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4
Q

what is a virus

A

infectious particle consisting of packaged nucleic acid

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5
Q

what are flu vaccines directed against

A

glycoproteins on the outside of the viral membrane that may have enzymatic activity

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6
Q

describe how viral DNA can exist

A

can be DS or SS RNA or DNA

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7
Q

what is the general makeup of viruses

A

nucleic acid and protein shell

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8
Q

describe the viral membrane

A

came from past host cell membrane with glycoproteins that allow the virus to cause disease

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9
Q

what are the steps of viral multiplication and integration into the host cell

A
  1. adsorption: recognition by virus and host
  2. penetration: phagocytosis
  3. uncoating: fusion of membranes to release viral capsid and RNA into the cytoplasm and possibly integrate viral DNA into host genome in nucleus
  4. Synthesis: RNA decapsulation, new spike, new capsomers, new RNA
  5. Assembly: release of new virus (may kill host)
  6. Release: virus with envelope with spikes
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10
Q

what is Acyclovir

A

acts as an analog to deoxyguanosine triphosphate (dGTP) which results in chain termination & viral polymerase inactivation

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11
Q

how does herpes viruses of the mouth act as recurrent

A

anchors down in trigeminal nerve branches in the face

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12
Q

what is the effect of wet routes

A

keeps the viral particle in liquid protected from the environment
but makes it susceptible to drying out

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13
Q

how are herpes simplex 1/2 and varicella-zoster viruses similar

A

both cause latent infection in nervous system

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14
Q

what is the most concerning infection from cytomegalovirus (CMV)

A

in pregnant women traveling through placenta through wet route causing most common congenital disease in unborn babies (hearing)

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15
Q

how does Burkitt’s lymphoma occur

A

progressed EBV (mono) carcinogen
DNA viral genome causes B cell gene translocation

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16
Q

how would EBV be clinically determined

A

blood sample shows lots of monocytes, WBC

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17
Q

what is multiple sclerosis

A

chronic autoimmune disease
viral protein mimics myelin sheath protein
from EBV

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18
Q

what is the most common liver infection agent

A

Hepatitis B (HBV)

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19
Q

what is the most common STI

A

human papilomaviruses (HPV)

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20
Q

what does the Gardasil vaccine do

A

both prevents a wide range of HPV infections and suppresses cancer

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21
Q

what are the two types of antigens on the surface of Orthomyxoviruses Influenza (sim and diff)

A

HA (hemagglutinin) ENTRY:
NA (Neuraminidase) EXIT:
both primary targets for antibodies

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22
Q

what animals play important ecological roles of influenza

A

domesticated birds (ducks pigeons, turkeys)
and pigs (causing antigenic shift)

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23
Q

what is tamiflu

A

antiviral medication that blocks the activity of the neuraminidase enzyme on the surface of influenza A and B viruses.

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24
Q

what is an Antigenic shift

A

outcome of the segmented RNA genome reassorting during co-infection of one cell by multiple strains of virus

= large changes in viral phenotype

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25
how does an antigenic shift occur (case from bird, human, pig)
the H5N1 of a bird and the H3N2 of a human coinfect a pig creating a H3N1 new virus
26
Compare and contrast antigenic shift and antigenic drift
Antigenic drift is a minor, gradual change in viral surface antigens caused by point mutations in genes encoding hemagglutinin (HA) and neuraminidase (NA). It occurs in both Influenza A virus and Influenza B virus and is responsible for seasonal influenza epidemics. Antigenic shift is a sudden, major change in viral surface antigens due to reassortment of RNA segments when two different strains infect the same cell. It occurs only in Influenza A virus and can lead to pandemics.
27
what is antigenic drift
due to error-prone RNA polymerase copying resulting in mutations leading to viral diversity = small changes in viral phenotype (hemoggluttinin gene)
28
why does antigenic drift occur
RNA polymerase does not have a proofreading effect, so it is error-prone, which can accumulate shifted antigen genes
29
what causes maculopapular rash
endothelial damage from cytotoxic T cells attacking virally-infected skin blood vessels leaking into neighboring tissue causing red spots on skin common symptom of Measels
30
What is the MMR child vaccine
live vaccine that was weakened to prevent Measles, Mumps and rubella virus important because there is no antiviral medication once measles is contracted
31
what is R0
a measure of how transmissible a pathogen is from one person basic reproduction number
32
describe the R0 with respect to 1
<1 each infected person causes less than one new infection =1 each infection causes 1 new inf. >1each infection causes >1 new infection
33
what is the R0 value influenced by
infectious period contact rate mode of transmission
34
what is the most infectious R0
Measles R0=18
35
what are the most common R0 values
Hepatitis C =2 Ebola =2 HIV =4 SARS=4 Mumps=10 Measles =18
36
what is the incubation period for measles
10-14 days where the virus enters body: typically respiratory route noninfectious
37
describe the prodromal period for measles
3 days Symptoms start: high fever, cough, conjuctivitis, coryza (stuffy nose) start to be infectious
38
what is Exanthem for measles
4 days of developing Koplik's spots then red, maculopapular rash from head to extremities
39
describe the recovery phase of measles
10-14 days with persistent cough may die or achieve lifelong immunity
40
what is the msot cause of death from measles
the pneumonia that results from measles weakening the immune system
41
where is Mumps found in body
saliva from enlarged partoid salivary gland are all filled with virus
42
how does RSV cause hospitalization
Bronchiolitis infects the lining of the alveoli (specifically bronchioles) causes dead cell buildup immune system attacks foreign material, inflames the air passageways needing ventilator
43
what does syncytial mean
virus that brings together and fuses cells
44
how does rabies infect humans from animals
animal saliva, muscle, nerve that innervates the muscle, through the nerve to the brain (takes weeks) = negri bodies in brain tissue with viral RNA&protein/typically in brain stem (from autopsy)
45
describe the crown appearance of coronaviruses
viral appearance with spike glycoproteins Mediates host cell binding Subject to variation due to mutation
46
what is spill over
the processes that allow cross-species transmission of viruses causing disease viruses adapted to one animal can spill over as species interact
47
what are the varieties in spilloever
infects but antibodies of the end host clears the infection infects but virulence of pathogen kills the host infects and the new host lives where the pathogen is conserved to go on to transmit again (most problematic) infects same species and shifts the virus with a new host range, worse severity of disease, to transmit a worse disease
48
how do you tell rubella from measles
rubella does not cause high fever like measles rubella is less infectious (R0~6)
49
what are Arboviruses
arthropod borne viruses
50
What are the humans role in West nile virus
Dead End host cannot be spread from person-to-person through casual contact unless through blood transfusions
51
What is the first step of the replicative cycle for HIV (out of 7)
HIV binds to receptors on the surface of a CD4 cell (helpful Tcells)
52
What is ART
Antiretroviral-therapy
53
What is the second step of HIV Replicative Cycle
Fusion: the HIV envelope and the VD4 cell emmebrane fuse, allowing the virus to enter the cell
54
What is the third step of HIV Replicative Cycle
Synthesize DNA using RNA template (backwards) by reverse transcriptase Reverse transcription: Within the CD4 cell, HIV uses enzyme reverse transcriptase to convert RNA to DNA. HIV DNA enters host cell nucleus
55
What is the fifth step of HIV replication cycle
Replication: once integrated into the CD4 cell DNA. HIV begins to use the translational machinery of the cell to make long chains of HIV proteins
56
Describe the clinical course of AIDS
2 weeks after primary infection, HIV RNA copies exponentially increase into Acute HIV syndrome. Cuases wide dissemination of virus and seeding of lymphoid organs till about 10 weeks
57
What happens after 12 weeks of HIV +
CD4 T- lymphocyte count starts dropping HIV RNA copies start slowly growing
58
When does AIDs clinically come in and you are not HIV + anymore
after 8-15 years when the CD4 T-lymphocyte count drops below 200 cells/ml or severe opportunistic infections arise.
59
What happens at about 10^4 HIV RNA copies
weight loss disease opportunistic diseases death
60
What is targeted by Poliomyelitis
spinal cord gray matter
61
How is poliomyelitis contracted and
drinking water contaminated by feces then replicates in intestine. Virus integrates into blood stream and extends to spinal cord where it can cause nerve cell damage
62
How is polio prevented
only by vaccination
63
what is the term relating viruses integrating itself into the bloodstream
viremia
64
What are two culprits of Hepatitis A (HAV)
foreign strawberries contaminated by fecal matter contaminated needles from drug use
65
Why is it unlikely that we will ever have a strong vaccine for Rhinovirus
extreme variability in surface antigens
66
What are the problems with small intestine cell death by Rotavirus
not absorbing properly and diarrhea
67
Describe viral genomes
can be DS/SS RNA or DNA
68
Describe the viral capsid
protein shell
69
what does it likely mean if a virus has a envelope around it
it would cause trouble for humans because that membrane came from some other host cell that it infected also means they have a hard time traveling in the environment without a wet route
70
Which hepatitis viruses are RNA and DNA
HBV: DNA Hepatitis a,c-e: RNA
71
What diseases are known to cause cancers
Helicobacter pylori: Gastric cancer EBV: Burkitts Lymphoma Hepatits B/C: Liver Cancer Human Papilomavirus: Cervical cancer
72
describe the role of HA on a host cell
the antigen that allows virus to recognize and bind to specific cells target of vaccines
73
Describe the role of NA on host cells
allows virus to leave the cell after it has reproduced drugs like tamiflu prevents the release of the virus inhibiting propogation
74
what virus has a characteristically filamentous shape
Ebola virus causing hemorragic fever
75
What virus has a characteristically bullet shape
Rhabdovirus causing rabies causing fatal meningoencephalitis
76
What age group are the most common targets of Respiratory Syncitial Virus
Newborns
77
What part of the body is targeted by Mumps
Parotid gland may move to gentials (Orchitis)
78
how is Mumps tested for
ELISA
79
how is Measles usually ocntracted in the US
import associated must vaccinate children if not use antibodies, vitamins
80
what are characteristics of paramyxoviruses
glycoprotein spikes fusion spikes
81
what are characteristics of Orthomyxoviruses
Viral RNA genome enters nucleus
82
What is the fourth step of the HIV replicative cycle
Integration: inside the CD4 cell nucleus, HIV releases integrase to insert its viral DNA into the CD4 DNA
83
What is the sixth step of the HIV replicative cycle
New HIV proteins and HIV RNA move to the surface of the cell and assemble into immature (noninfectious) HIV
84
What is the seventh step in the HIV replicative cycle
Budding: Newly formed immature (noninfectious) HIV pushes itself out the host CD4 cell. The new HIV releases protease to break up the long protein chains that form the immature virus. The smaller HIV protein combine to fomr mature infectious HIV
85
What does viral ingestion of pliovirus lead to
compromised motor neuron function and muscle atrophy & contracture
86
What are the enveloped DS DNA
Herpesviruses (HSV, VSV, CMV, EBV, HBV) Poxviruses (monkeypox)
87
what are the nonenveloped DS DNA
Adenoviruses Papilomaviruses
88
What are the ss nonenveloped RNA viruses
Picornaviruses (Poliomyelitis, Hepatitis A, Rhinovirus)
89
What are the nonsegmented enveloped SS RNA
Paramyxoviruses (measles, mumps) RSV Rabies Ebola Coronavirus Rubella West Nile Virus HIV
90
What are the segmented enveloped ss RNA
Orthomyxoviruses (influenza)
91
What is the nonenveloped DS RNA
Reoviruses (rotavirus)
Microbiology
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