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113 Cards in this Set
- Front
- Back
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Naked DNA or RNA virus
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Surrounded by a protein coat called a capsid, capsid is coded for by the NA on the inside of the capsid and is composed of virulent proteins
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Enveloped DNA or RNA Virus
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Has a cell membrane on the outside of the capsid.
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Virion
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complete virus particle with its DNA or RNA core and protein coat as it exits outside the cell
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Virus
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Obligate intracellular parasites that need to get into suceptible cells to reproduce. Can have RNA or DNA not both
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Naked virus replication
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Viral attachment protein is on the surface of capsid it finds the correct receptor and attaches to the cell, this allows the NA to enter the cell.
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Enveloped Virus replication facts
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Need envelope to be effective, if no enveloped the virus is unable to infect cell and replicate.
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Viruses that cause diahrea
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Are all naked!!
Enveloped viruses are have their envelope destroyed by stomach acid |
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How a virus replicates?
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They take over host cell's cellular machinery particularily ribosomes and make more copies of itself. DNA virus must enter nucleas to be transcribed
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Mechanism for replication of NAKED VIRUS
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1.RNA enters the cell, if Negative Sense viral ribosome makes complemenary strand of RNA so host ribosomes can work on it. POSITIVE SENSE the ribosomes work on it right away since strand can be read by ribosomes.
2.Ribosomes assemble viral proteins like capsid which assembles around the NA. 3. Naked viruses then lyse the cell and explode out into the body |
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Mechanism for replication of Enveloped viruses
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1. Replicate NA
2. Assemble structural proteins around NA. 3. Specific Virus receptor protein is inserted into PM to modify it so the capsid and NA can bind there and take the modifed PM and envelope and get out. |
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Naked DNA or RNA virus
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Surrounded by a protein coat called a capsid, capsid is coded for by the NA on the inside of the capsid and is composed of virulent proteins
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Enveloped DNA or RNA Virus
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Has a cell membrane on the outside of the capsid.
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Virion
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complete virus particle with its DNA or RNA core and protein coat as it exits outside the cell
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Virus
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Obligate intracellular parasites that need to get into suceptible cells to reproduce. Can have RNA or DNA not both
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Naked virus replication
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Viral attachment protein is on the surface of capsid it finds the correct receptor and attaches to the cell, this allows the NA to enter the cell.
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Phenotypic Mixing
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When Virus A and B infect a cell at the same time and proteins mix
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MAsking
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When virus A NA gets into virus B capsid
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Complementation
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Virus A can't replicate in cell, Virus B comes along and supplies components Virus A needed
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Assortment
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Virus Segments get intermingled
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Negative Sense
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When the RNA that enters the cell from a virus is unable to be read by the ribosomes. Has an enzyme with it that allows for the synthesis of a complemenary strand that can be read by the ribosomes. Complimentary strand acts as mRNA
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Positive Sense
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Viral RNA that enters the cell can be read by the ribosomes and acts as mRNA
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Ambisense
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Has positive and negative sense characteristics
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Naked virus cell replication
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1. RNA enters cell and it is replicated by the host or by itself so that proteins can be assembled right awy like the capsid and structural viral proteins which assemble around the NA.
ONce the virus replicates it lyses the cell to escape into the blood stream. Body responds to cell lysing and infection by creating antibodies that bind to virus and neutralize it |
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Enveloped virus replication
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Enters the cell and causes replicate NA, assemble structural proteins around NA go to the specific virus receptor protein in PM with capsid so it can get out.
The body lyses these cells in order to stop production of enveloped viruses since they are like giant factories. |
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Specific virus receptor protein
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Protein in PM that are inserted by enveloped viruses so they can take part of the cells membrane when they leave the cell.
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Body response?
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The body responds to the infection after a large amount of virus is already in the body. The killed cells release cytokines and cause inflammation and etc due to cell death.
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Viruses travel in the body?
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Viruses have to get to specific cells that have their receptors for infection to spread. Larger amount of virus in the blood greater chance of infection
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Subclinical concepts
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infection that does not cause disease
Only way to test for this if no symptoms present are to test for antigens |
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Target organ
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Organ that viruses need to get to in order to cause infection.
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Viral Pathogenesis
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Virus enters body and the body responds to stop it from getting to target cells.
Virus can hide in nervous cells since the immune system cannot get there (latent viruses result <herpes>) There are no antivirals that can cure latent infections just reduce time of infection |
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Inclusion bodies-Cytopathogenic effects-
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accumulation of viral proteins that accumulate in the cytoplasme of the cell. IE Herpes simplex 2 have viral protein that causes fusion of neiboring cells. Giant cell that is multinucleated
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Subclinical disease and inapparent disease
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Cause no apparent symptoms but possibly produce antigens
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Acute Infections
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Have short incubation time, get infected virus goes to target cause clinical disease
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Localized infection
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Virus infects the body and disease occurs at site of infection influenza
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Disseminated
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Longer incubation time since the virus must get to its target cell, Viruses travel throughout the body in different pathways.
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Persistent viruses
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Infections that take a long time to go away
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Latent
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may or may not have symptoms after infection but the disease comes and goes
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Chronic
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disease that you see early but then the virus hangs around for a long time and has infectious virus there Hepatits B
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Slow infection
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get infect and takes years in order for the disease to manifest itself. HIV
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Adenoviruses
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Nonenveloped, DS linear DNA
Latent infections of lyphoid tissue tonsils Can cause cancer by suppressing tumor suppression proteins p100Rb and p53. These are affected by E1a to p53 and E2a in p100Rb. Causes pink eye |
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Papillomaviruses
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Nonenveloped, DS circular DNA
Koilocytotic cells (cytoplasmic vacoules and enlarged nuclei) Cancer causer by having E6 suppress p53 and E7 to supress p100Rb |
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Herpesvirus,
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Enveloped Linear DS DNA viruses
CANCER CAUSING E-Barr Burkitt's lymphoma Causes Herpes virus 1 and 2 can cause cell rounding and inclusion bodies Latently infect Neruons Varicella Zoster virus, Cytomegalovirus (latently affects monocytes, macrophages and lymphocytes, makes heterophile negative mononucleosis) also Epstein-Barr Virus (makes heterophile positive infectious mononucleosis) <test by mono spot test> are also in this category |
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Hepadnaviruses
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Enveloped Circular DS DNA VIRUS
CANCER CAUSING inactivates p53 Hep V Virus- Replication-by virion associated multifuctional enzyme complex with reverse transcriptase, DNA poly., ribonuclease activity. (HOW HIV replicate) Dignosis: Produces unique antigens (HBsAG, a surface antigen and HBcAG and HBeAg core associated antigens |
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Envelped SS Positive Sense RNA
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Togavirus, Favivurses, Coronaviruses
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Togavirus
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Enveloped SS positive sense
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Flavivurses
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Enveloped SS positive Sense RNA
Dengue Virus, Hepatitis C (causes 90% of blood transfussion or blood transfussion or blood product administration-associated hepatitis)--> implicated in primary hepatocellular carcinoma. Yellow fever and west nile (arbovirus <transfered by bird> leading cause of arboviral encephalitis in the US) |
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Coronaviruses
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enveloped SS positive sense RNA
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enveloped SS NEgative sense Linear RNA
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Rhabdoviruses
Paramyxovirus |
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Enveloped SS Negative Sense Segmented RNA
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Arenaviruses
Bunyaviruses Orthomyoviruses |
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Rhabdoviruses
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Enveloped SS Negative sense Linear RNA
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Paramyxoviruses
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Enveloped SS Negative Sense Linear RNA
Parainfluenza (croup infant disease) Mumps, Measles, Respiratory syncytial virus (respiratory tract pathogen of infants) |
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Bunyaviruses
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Enveloped SS negative segmentd RNA
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Orthomyxoviruses
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Enveloped SS negative segmented RNA
Need RNA pol, neets to go to nucleus to replicate, Influenza virus M2 protein |
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Enveloped Diploid positive sense retrovirus
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Lentiiruses
Oncoviruses |
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Lentiviruses
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Enveloped Diploid Positive Sense Retrovirus
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Oncovirus
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Enveloped Diploid positive sense retrovirus
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Non-specific Defenses
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Structure of the body; chemical barriers, cell resistance which lack cell receptors cell, inflammation in some places
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Humoral Immunity
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Secreted antibodies produced by B-lymphocytes, B-lymphocytes become plasma cells which secrete antibodies
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Cell mediated immunity
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involves the activation of macrophages and NK cells antigen specific cytoxin
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Interfuron-
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FIRST DEFENSE MECHANISM
Used to treat chronic viral infections: Inhibts virus replication by inhibiting several virus kinases. All cells in the body can synthsize interferon, it is the transferd to neighboring cells to creat Protein Kinases and S'A sythetase which causes the cell to become anti-viral stopping replication. CELLS ARE MADE ANTIVIRAL TO ALL VIRUSES SPECIES Specific |
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THE real first line of defense if the virus has been seen before
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Immunoglobin A that is not in the blood normally
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Induced Immune Suppression
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when virus takes over a cell and stops its normal function. If virus takes over enough cells in the body, particularily lymphocytes, no longer able to make immune responses and the immun system is suppresssed for a time
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active immunization
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an injection of a virus into your body that causes you to make the antibodies. Takes a while for the body to ramp up the antibodies and make sensitized cells
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passive immunization
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when someone else makes the antibodies and then you have their antibodies injected into you (Rabies virus vaccine has this)
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Live vaccines
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Live virus given to an individual in an attenuated version that isn't that viral to the body, body kills it to make antibodies
1. Administered in single dose and follows normal route of infection so the body makes stronger resistance. 2. Very short half life, there is a chance that it can revert back to viralence and cause disease |
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Killed Vacines
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Take inactive virus inject into ppl that allows them to make antibodies (Virus Doesnt go thru replication so the bodies defenses aren't as broad)
1. Allows for combination of a number of diff. virus strains. 2. Needs to be given more than once so the body can buid up its resistance again and again |
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Recombinant Vaccine Third type using just the surface antigens
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HPV (Gardacil) uses rotovirus
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5 Mechanism for antiviral agents
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Inhibit fusion and uncoating
Inhibitors of NA synthsis (Main ONE) Protease Inhibitors Neurominidase Inhibitors Messenger RNA Inhibitors |
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Inhibitors of NA synthesis
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Cause problems in cell that the virus infects and stops NA from occuring by altering cellular Nucleotide pools and inhibiting RNA synthesis.
Stop viral polymerase from working right and keep NA from replicating CREATES ANALOGS TO NUCLEOTIDES THAT STOP IT |
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Protease Inhibitors
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Used to treat HIV inhibit HIV protease
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Neurominidase Inhibitor
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Attacks Neurominidase on Influenza A and B.
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Neurominidase
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Attacks and breaks up neuraminc acid this facilitates the release of virus from cell
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Seven Classes of HIV Inhibitors
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1.Nucleoside Inhibitors of Reverse transcriptase
2.Nonnucleoside Inhibitors of Reverse Transcriptase 3.Nucleotide Inhibitor of Reverse Transcriptase 4. Integrase Inhibitor 5.Protease Inhibitor 6.Attachment Inhibitor 7.Cell Fusion Inhibitor |
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Seriological Tests
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Tells if the person has had a virus before. Tests for antigens to a virus
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Nucleic acid hybridization
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used to monitor the HIV level in the blood, more virus in blood the worse it is for the patient
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Epstein Barr virus
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Creates Heteophile positive infectious mononucleosis
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Cytomegalovirus traits?
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Can latently infect monocytes, macrophages, and lymphocytes
Heterophile negative mononucleosis |
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Picornaviruses
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Eneteroviruses (coxsackie), Echoviruses, Polioviruses, Hepatovirus (hepatitis A) rhinoviruses
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Retroviruses
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Make HIV has 3 components
gag-structural proteins pol-reverst transcriptase env-envelope glycoproteins |
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Reoviruses
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double stranded RNA virus
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Rotaviruses
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11 segments of DS RNA
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Viroid Like Agents (hep. D virus)
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SS RNA molecule with an internal core antigen surrounded by HBV envelope
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Nonpermissive cells
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infected cells that do not support total virus replication
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Transformed cells??
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Have poor or no control over cell growth
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Prions
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NOT VIRUSES but are infectious particles that maybe acquired or inhereted and is closely related to PrP-sen which is on all PM
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PrP-sen
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normal prion that is present on PM.
When it comes in contact with PrP-res it goes through conformational change to become PrP-res |
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PrP-res
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bad form of prion causes disease
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Steps of Prion disease
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1. PrP-res combines with other PrP-res to make amyloid fibers in brain.
2. Amyloid fibers kill brain cells 3. Astrocytes come in to clean up the killed cells 4. Spongoform created by astrocytes cleaning out dead cells |
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AA code of prions
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It is the same in PrP-sen as in PrP-res they are just folded differently
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Creutzfeldt-Jakob disease
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human disease that has a prion that is similar to scapie prion of sheep and goats.
PRIONS CAN CROSS SPECIES |
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Permissive cells
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Allow complete Viral replication, the cell then dies/is lysed to release the virus.
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Nonpermissive cells
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Cells that don't allow virus to replicate, the cell is instead transformed and cannot control its cell growth.
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Creutzfeldt-Jakob disease
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human disease that has a prion that is similar to scapie prion of sheep and goats.
PRIONS CAN CROSS SPECIES |
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Permissive cells
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Allow complete Viral replication, the cell then dies/is lysed to release the virus.
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Nonpermissive cells
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Cells that don't allow virus to replicate, the cell is instead transformed and cannot control its cell growth.
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Proto-oncogen
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normal form of cellular genes
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Oncogene
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causes cancer, the gas pedal for tumor formation
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Nondefective viruses
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have all virogens and can replicate themselves, also have high oncogenic potention if they contain oncogen
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Defective viruses
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Have virogene or part of virogene replace by oncogene, need helper viruses to help provide missing virogen products.
HIGH ONCOGENIC POTENTIAL |
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Retrovirus Replication
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Are the ones that cause oncoviruses. Only diploid virus has reverstanscriptase
TYPE C retrovirus has oncovirus |
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Retrovirus must do what in order to infect a cell
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They must enter the nucleus, In order to produce viral DNA the viral mRNA must be incorporated into host DNA using viral reverse transcriptase
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Acute transforming virus
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A virus that lacks all the necessary viral genes but has picked up an oncogene, this can tranform the cell
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Chronic transforming virus
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Insertal activation or promoter insertion
Put DNA copy of viral RNA onto site of chromosome that was previously shut down, it is then turned on and leads to uncontrolled cell proliferation. Essentially, as a result of making viral proteins the viral mRNA makes a product that activates synthesis. Takes a long time |
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Steps of Retrorvirs introduction into cells
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1. Rna tumor virus enters cell
2.Reverse Transcriptase incorportates it into host cell DNA. 3. Transcription viral proteins and mRNA made in host cell. 4.This is then emmited from the cell, if it picked up a cellular oncogen during transcription it can then tranform the next cell infected into a tumor cell |
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Viruses that affect the Cardiovascular System
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Coxsackie B Virus, Dengue Virus
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Centeral Nervous System viruses
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Herpes simplex, Varcella-zoster, polio, and other enteroviruses, Like Rabies, MM,
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Eye viruses
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Herpes simplex, adenovirus
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GI System
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Caliciivirus, ROTAVIRUS IS HUGE!!!
adenovirus |
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Liver virus
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Hepatitis, yellow fever
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Respiratory Tract virus
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Influenza, syncytal, Epstein Barr, rhino, hanta
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Salivary gland virus
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Epsteen Barr, mumps
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Skin and Mucous Membranes
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Herpes, varicella-zoster, papilloma Measles
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Systemic
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Retroviruse, entero, rubella, measles virus, cytomegalovirus
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