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103 Cards in this Set
- Front
- Back
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Can HPV cause cancer? |
yes |
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virus analogy spaceship without fuel tanks |
virus can't make energy by itself |
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virus analogy drifts in space until in can dock in a mother-ship |
viruses needs to attach to cells to take energy from it |
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virus analogy when it docks, it offloads cargo what is the cargo? |
the cargo is the viral genome, allowing the virus to make clones |
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virus analogy Clones leave mothership and drift, looking for their own niche |
the new virus cells leave the host cell, and infect other cells |
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Virus biology |
they are infectious particles, but not living cells |
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Viruses and doctor visits |
Viruses are responsible fro the majority of visits to family physician |
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viral transmission |
blood transfusion mucus droplets aerosols fomites water food vectors |
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Virus and antibiotics |
antibiotics can't be used on viruses b/c it doesn't have the cellular processes and units that antibiotics will use to find bacteria |
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virus treatment |
viruses must be treated with different therapeutic strategies than other microorganisms |
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Virus Vs. Bacteria size |
10-500nm vs 500- about 2000 nm small vs big |
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Virus Vs. Bacteria reproduction dependence |
can only multiply inside of cells Vs. can multiply in the absence of other cells |
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Virus Vs. Bacteria genetic material(s) |
DNA or RNA, never both Vs. Always both DNA and RNA |
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Virus Vs. Bacteria enzymes |
few enzymes Vs. many enzymes |
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Virus Vs. Bacteria ribosomes and enzymes for metabolizing nutrients |
none vs contains ribosomes and enzymes for metabolism of nutrients |
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Virus and metabolism |
viruses can't metabolize proteins or make use of nutrients |
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Virus can be seen with.. |
electron microscope |
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Virus size |
smaller than bacteria 30-300nm diameter |
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virus shape |
viruses can change its shape depending on environment |
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envelope virus |
has a membrane around it |
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naked virus |
only has covering made out of protein |
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other name for virus |
virion |
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virion |
complete infectious viral particle with nucleic acid surrounded by a protein coat |
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nucleoclaspid |
complete unit of a virion |
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make up of nucleoclaspid |
RNA or DNA + capsid- protein coat |
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capsomeres |
make up the protein coat capsid |
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liquid envelopes |
a fluid membrane outside of the nucleocapsid |
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glycoproteins/ spikes |
inserted in envelopes or capsid |
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influenza virus structure |
influenza A is enveloped it is one of the most dangerous types of Influenza |
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Virus range |
usually can infect every life form- bacteria, fungi, plants, animals, humans |
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virus host range or specificity |
usually viruses are specific to one type |
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example of virus host range or specificity |
ex. bacteriophage infects only bacteria |
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bacteriophages |
viruses that infect bacterial cells |
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bacteriophages function |
transfer new genes from one bacteria to another |
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bacteriophages function: genetic engineering |
can be used as tool for genetic engineering ex. production of human insulin from e.coli |
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bacteriophages function: toxins |
can transfer genes for production of toxin |
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classifying viruses |
viruses are grouped into families based on DNA/RNA composition and structure DNA vs. RNA viruses |
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which type of virus mutates quickly? |
RNA |
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DNA viruses |
1. Papillomaviridae (HPV) 2. Adenoviridae (adenovirus) 3. Hepadnaviridae (hepatitis B) 4. Herpesviridae (HSV-1 & -2, HHV-3) 5. Poxviridae (smallpox, monkey pox, etc.) 6. Parvoviridae (B-19) |
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RNA viruses |
1. retroviridae (HIV) 2. Flaviviridae (Yellow fever virus, West Nile virus) 3. orthomyxoviridae (Influenza A,B,C) |
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Attachment and penetration into host cell: fusion |
usually used by enveloped virus; the virus fuses its envelope with the plasma of the cell and once its in, it releases its nucleic acid and begins replication |
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Attachment and penetration into host cell: pinocytosis |
usually used by naked virus; the virus pulls itself down the membrane |
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explain |
dna to rna to mrna replication of dna |
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DNA Virus |
host cell DNA polymerase may be used directly to make more virus DNA |
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RNA virus |
virus carries its own RNA polymerase enzyme to produce RNA from viral RNA ( No RNA polymerase in host cells) |
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RNA retrovirus |
carries its own reverse transcriptase enzyme in the virus capsid. integrated viral DNA is then transcribed by host cell polymerase and makes more virus RNA ex. HIV |
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Reverse transcriptase |
makes ssDNA from ssRNA, then dsDNA is formed and intergrates with the host DNA in chromosome |
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DNA dependent DNA polymerase |
DNA viruses uses DNA dependant DNA polymerase either host or virally derived for replication of genome viral DNA->viral DNA |
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RNA Dependent RNA polymerase |
RNA viruses use RNA Dependent RNA polymerase for replication of genome. RNA viruses must carry this enzyme into the cell viral RNA-> viral RNA |
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RNA dependent DNA polymerase= reverse transcriptase |
retrovirus uses RNA dependent DNA polymerase/ reverse transcriptase to make DNA |
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Assembly and Release of New Virus |
newly replicated RNA or DNA associate with newly made viral proteins to create new nucleocapsids |
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Assembly and Release of New Virus if enveloped virus |
envelope components are produced and inserted into the host cell plasma membrane, viral particles then attached to the plasma membrane and buds through |
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antiviral drugs: fuzeon |
stops entry (fusion) of HIV into cells |
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antiviral drugs: Acyclovir |
stops replication of herpes viruses by interfering with viral DNA polymerase |
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antiviral drugs: HAART |
Highly Active AntiRetroviral Therapy- combination of antiviral drugs used to stop replication of HIV helps prevent virus from becoming resistant to drugs |
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antiviral drugs: TamiFLu oseltamivir |
stops budding release of influenza virus from cell |
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Host-Virus Interactions acute/productive infection |
virus replicates, produces many virions host cells often killed- lytic infection |
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lytic infection |
means cell will explode |
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Host-Virus Interactions Latent infection |
viral genome persists in host cell but does not replicate. At a later time, with the right environment, will grow. Can lay dormant for years |
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Host-Virus Interactions chronic infection |
virus replicates w/o causing host cell lysis and can persist for long periods of time |
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Chicken pox: acute infection that becomes latent |
1. fever, itchy, rash 2. rash spreads mainly on trunk and head 3. more rash=sever illness 4. most children have 250-500 skin lesions 5. skin lesions can get secondary infections 6.virus inrash escapes via airborne 7. skin vesicles present in different stages of lesion formation |
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Chicken Pox becomes latent |
virus is present in cells, sitting in ganglia. doesn't replicate until triggered by external factors |
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Shingles |
second outset of latent chicken pox |
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cause of shingles |
trigger is mainly age, the decline of immune system stress also affects onset of singles |
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shingles and symptoms |
rash and pain untreated rash can stay for 2-5 weeks infectious |
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untreated shingles |
can lead to chronic nerve pain, must stop replication asap |
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shingles and lesions |
skin bacteria can be exposed to lesions by scratching rashes, flesh eating disorder can occur |
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chicken pox/shingles transmission |
airborne through vesicles can be spread during 14 day incubation period of vesicles |
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Chickenpox complications |
most common complication is inmmunocompromised is secondary bacterial infection 1. CNS Disease: encephalitis, meningitis, etc. 2. Hemorrhagic complications: neutropenia and thrombocytopenia 3.Primary vacirella pneumonia |
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Chickenpox parties |
bad idea, increases chance for flesh eating disease |
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Zoster/shingles complications |
development of PHN Post Herpatic Neuralgia, causes chronic pain and permanent nerve damage, can cause blindness |
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Active immunization |
live attenuated vaccine, higly protective, memory cells produced can be included with MMRV |
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Passive immunization |
Effective when used for exposed patent up to 3 days post-exposure |
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Passive Immunization: VZIG: varicella-zoster immunoglobulin |
used for immunocompromised exposed children and neonates born to mothers with varicella |
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Antivirals: Acyclovir and analogues treatment |
treatment must start within 2-3 days of debut of shingles lesions to prevent PHN chickenpox in normal individuals are not treated with antivirals |
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oncogenic viruses |
transform normal host cells to cancer cells can be RNA or DNA viruses |
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Oncogenic viruses exception |
not all 'transformed' cells become cancerous ex. wart virus often benign tumors |
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Epstein-barr virus |
causes Burkitt's Lymphoma most common cancer in Africa |
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viral diagnosis: PCR |
polymerase chain reaction molecular biology technique used to detect the genes in an organism |
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viral diagnosis: culture |
patient specimens added to cultured cells and after a period of growth, observed for CPE (cytopathic effects) on cultured cells labour intensive, slow- depends on viral growth rates |
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Syncytia- a type of CPE |
one cell got infected by a virus, the clump of cells that was around the infected cell become one big cell with lots of nuclei, almost like a virus factory, making and pouring out cells once cell doesn't have energy, cell will die causing inflammation |
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Influenza A: FA Stain |
DFA- Direct Fluorescent antibody test for viral pathogens. antibody latches on pathogen |
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Smallpox |
last case in somalia 1977 two viral strains exist, one in the US and one in Russia |
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Monkey pox |
thought to be second coming of smallpox but caused by prairie dogs |
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Orthopoxvirus, variola virus= smallpox |
enveloped DNA virus immunity to smallpox= immunity to monkeypox |
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other members of the orthopoxvirus family: |
Vaccinia monkeypox cowpox |
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smallpox portal of entry |
1.mucous membranes in uper respiratory tract 2. droplet transmission (coughs and sneezes) 3. direct and indirect transmission ex. smallpox in blankets given to native americans |
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sequence of events in smallpox infections entry |
entry via mucosal membranes of respiratory systems- then enters lymphoid tissue |
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sequence of events in smallpox infections virus spread |
Viremia and spread of virus in the RE(reticuloendothelial) system the lymphatics |
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sequence of events in smallpox infections multiplication in RE |
multiplication of virus in the RE system, release of virus to blood |
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sequence of events in smallpox infections more spread |
secondary, more intense viremia, spread to tissue |
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sequence of events in smallpox infections disease is full blown |
clinical disease, development of lesions |
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two forms of smallpox |
variola major 30% mortanilty variola minor 1% mortality |
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smallpox infection type |
smallpox is a primary infection- no matter how strong your immune system is, you will get sick |
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1-4 papular 1-4 also vesicular 2-6 pustular 2-4 weeks crusts fall off after first sign of lesion |
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Smallpox immunity: vaccination |
vaccination with vaccinia virus provides immunity for at least 5 yrs |
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smallpox immunity: neonates-newborn babies |
protected via IgG from mother fro 2-3 months, then can be vaccinated |
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smallpox treatment: methisazone |
only effective for prophylaxis no effect for established disease |
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smallpox epidemiology |
no asymptomatic carriers (no symptoms) or subclinical disease. sick but don't show symptoms or only mild ones no non-human reservoir, no animals carried small pox |
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smallpox immunity |
complete immunity after an infection |
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complications of smallpox |
lesions become infected with secondary bacteria such as staphlycoccus aureus can lead to bacteremia and sepsis, even death |
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difference between chickenpox and smallpox |
chickenpox-lesions are in different stages smallpox- all lesions are in the same stage of develeopment |
