• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/104

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

104 Cards in this Set

  • Front
  • Back
Influenza virus infects w/c cells?
Mucosal cells but not basal cells
Rotavirus infects w/c cells?
Rotavirus-infect intestinal cells only
Polio wild type infects w/c cells?
Poliovirus-wild type infects intestinal cells/neurons
What happens when APC of MHC II encounters an Ag?
It expresses pieces of this Ag to helper T cells --> induces B cells to proliferate--> plasma & memory B cells.
CMI is involved w/ w/c MHC?
MHC I R w/c express pieces of viral Ag.
How is CMI involved in viral infection?
Cytotoxic T cells recognize & bind to MHC I & illicit apoptosis
what are the enteroviruses?
b. Members of Note:
i. Poliovirus Three serotypes (P1, P2, and P3)
ii. Coxsakie A Virus. Twenty-Three serotypes (CA1…)
iii. Coxsakie B Virus. Six serotypes (CB1…)
iv. ECHO Virus. Thirty-two serotypes (E1, E2…)
what are the picornoviruses?
Enteroviridae, Rhinoviridae, Cardioviridae, and Apthoviridae. Foot and mouth disease, rhinitis, enterovirus, hepatitis A, etc.
enteroviruses can survive at what pH?
Further Characteristics of Enteroviridae: Stable at pH of 3, can survive passage through the stomach.
What is ICAM-1, it’s role in virus attachment to the host
ICAM-1 stands for intracellular adhesion molecule-1. ICAM-1 is the cellular receptor for viruses of the Rhinoviridae family, which is in turn a member of the Picornaviridae super family.
What are the differences between lymphotropic and neurotropic phases of polio virus
a. Subfamily Alphaherpesvirinae, neurotropic
i. Genus Simplexvirus - HSV 1, HSV 2, B virus
ii. Genus Varicellavirus - varicella-zoster virus
iii. WIKI: A neurotropic virus is a virus which is capable of infecting nerve cells, or which does so preferentially.[
b. Subfamily Gammaherpesvirus, lymphotropic
i. Genus Lymphocryptovirus - Epstein-Barr virus
ii. Human T-lymphotropic virus (HTLV) is a human, single-stranded RNA retrovirus that causes T-cell leukemia and T-cell lymphoma in adults and may also be involved in certain demyelinating diseases, including tropical spastic paraparesis. Adult T-lymphotropic virus (ATLV) is a strain of this disease that affects primarily adults. A closely related virus is bovine leukemia virus BLV.
What is the CPE seen w/ HSV 1 & 2, & VZ?
multinucleated giant synchytial cells w/ intranuclear inclusion bodies
what is the MC infectious cause of corneal blindness in the USA?
herpetic keratitis caused by HSV 1 or 2
what are the viruses that belong to the herpesvirus family?
1) HSV 1
2) HSV 2
3) VZ
4) CMV
5) EBV
Compare and contrast IPV and OPV. What are the advantages and disadvantages of each.
a. No exclusive use of live vaccine (OPV)
b. Give IPV first then OPV ; or just IPV alone
c. IPV: Formaldehyde inactivated; need series of 3 immunizations
IPV: does NOT produce nasal and duodenal IgA protection
OPV: DOES produce nasal and duodenal IgA
Poliovirus has the ability to infect w/c 2 types of cells?
peyer's patches of the intestines & motor neurons w/c explains the fecal oral MOT & paralytic poliomyelitis
where does polio virus initially replicate & its course of infection thruout the body?
tonsils & peyer's patches, spreading to the blood & across the blood-CNS barrier to the anterior horn of the SC.
what are all the hepatitis viruses & what is their families?
Hep A: picornovirus
Hep B: hepadnavirus
Hep C: Flavivirus
Hep D: incomplete RNA virus
Hep E: hepevirus
Hep G: flavivirus
what is the transmission of Hep C?
Transmission
--Percutaneous: injecting drug use, clotting factors before viral infection, transfusion (transplant from infected donor), therapeutic (contaminated equipment), Occupational (needlestick)
what immunity is responsible for the symptoms seen in Hep B?
Antibody and Cell mediated immunity are responsible for the symptoms
List the measure US need to take to eliminate HBV
a. Prevent Perinatal HBV infection
b. Routine vaccination of all infants
c. Vaccination of Children in High Risk Groups
d. Vaccination of Adults in High Risk Groups
e. Vaccination of Adolescents
i. All un-vaccinated children of ages 11-12
ii. High risk adolescents of all ages
What are the important features of HCV transmission via injecting drug use
a. Highly Efficient among injection drug users
b. Rapidly acquired after initiation
c. Four times more common than HIV
d. Prevalence 60-90% after 5 years
Where does replication of HSV 1 occur?
In the nucleus
What is an important enzyme involved in HSV 1 replication?
Thymadine kinase
what are the 3 proteins involved in replication of HSV 1?
• Alpha Porteins: 2-4 hours after infection; DNA binding proteins that may regulate latency
Beta Proteins: Early Proteins, DNA polymerase
Gamma Proteins: late proteins, structured proteins
function of early proteins in HSV 1 replication?
Early Proteins: include scavenger enzymes for deoxyribonucleotide substrates (thymadine kinase). These enzymes permit replication in slowly or non-growing cells. Viral particles accumulate in the nucleus and bud through the nuclear membrane.
Describe primary & recurrent infection seen w/ HSV 1?
Primary infections may be asymptomatic or associated with lesions in the oral cavity.
•Recurrent disease of mucosal/cutaneous surfaces (cold sores)
Most common cause of fatal/sporadic/encephalitis in the U.S.
HSV1- associated encephalitis. Antibodies to HSV-1 are present but don’t stop encephalitis.
what are the infections associated w/ HSV 2?
HSV-2 Genital Infections
•Primary infections may be asymptomatic or cause genital lesions
•Recurrent = reactivation of virus in sacral ganglion (Ganglion = Alphaherpes). Recurrent episodes are usually less severe/shorter duration.
Which herpes virus family member causes cancer
a. Human Herpes 8 (HHV8)
i. Causes Kaposi’s Sarcoma
ii. Affects Oncogenes. Oncogenes are needed for regular gene regulation, disruption of said genes leads to cancer.
T/F: CMV dz is associated w/ CPE
False: CMV disease doesn’t cause CPE
what are the viruses that cause upper respiratory infections?
Viruses that cause upper respiratory disease
•Orthomyxovirus: Inflenza
•Paramyxovirus: Parinfluenza
•Adenovirus
•Respiratory Synctial Virus: RSV
•Respiratory Coronavirus
What is the characteristics of current commercial flu shots
Each year, three strains are chosen for selection in that year's flu vaccination by the WHO Global Influenza Surveillance Network. The chosen strains are the H1N1, H3N2, and Type-B strains thought most likely to cause significant human suffering in the coming season. The Global Influenza Surveillance Network's selection of viruses for the vaccine manufacturing process is based on its best estimate of which strains will be predominant the next year, amounting in the end to well-informed but fallible guesswork
w/c enzymes enhance infectivity of rotaviruses?
proteolytic enzymes like trypsin
immunity to rotavirus infection requires what?
the presence of Ab primarily IgA in the lumen of the gut.
Ribavirin is used for w/c viruses?
Severe RSV infection & hep C infection
T/F: ribavirin is a prodrug?
True
How does ribavirin work on viral infections?
It interferes w/ RNA metabolism required for viral replication
What are the SE of ribavirin?
Hemolytic anemia & has also been shown to teratogenic in some animal species
Tamiflu is used for the treatment of what infection?
Influenza A
What is the generic of tamiflu & what is its MOA?
Oseltamivir & it acts as a neuraminidase inhibitor preventing progeny virions from emerging from infected cells.
What is rimantadine use of treatment?
Treat or in rare cases prevent influenza A
What other drug is similar to rimantadine?
Amantadine
When given w/ 1-2 days, what could rimantadine do?
Shorten duration & moderate the severity of influenza
Does rubella cause cytopathology?
Rubella disease is not cytopathic (CPE), meaning infection doesn’t end in cellular lysis.
Relate # of serotypes to long term immunity?
(↑ serotypes, ↓ long term immunity).
What is meant by fulminant hepatitis? Which hepatitis virus causes it
Acute liver failure – usually HepB and C – rarely A.
Which herpes virus is more problematic for AIDS patients
Human Herpes 8 (HHV8) causes Kaposi’s Sarcoma
Who may experience post polio syndrome?
a. Previous polio infection
b. A condition that affects approximately 25–50% of people who have previously contracted poliomyelitis—a viral infection of the nervous system—after recovery from the initial paralytic attack. Typically the symptoms appear 15-30 years after the original infection, at an age of 35 to 60. Symptoms include acute or increased muscular weakness, pain in the muscles, and fatigue.
Highest concentration of HBV is found in body in:__________
Blood, serum, wound exudates
Highest number of HCV positive individuals are found among _____________, and __________
Blacks and Hispanics
What are common features of all herpes viruses?
Structure
Enveloped icosahedral capsid 100 nm
Nine glycoproteins
30 structural proteins (codes for about 120) -- No enzymes determined in virion
Tegument is amorphous
*no common Ag
Genome
ds DNA 124-235 kbp
Naked DNA infectious
Unique and repeated DNA sequences (vary by specific virus…)
Multiplication
Attachment: glycoprotein on viral envelope from B-lymphocytes
Penetration: direct or endocytosis
Multiplication cycle
Envelopes are acquired at inner nuclear membrane
Virions are released by reverse phagocytosis
Cell is not killed, but the functions are taken over by the virus
What are the classes of antibiotics that target protein synthesis mechanism
Aminoglycosides – e.g. gentamicin, amikacin, neomycin, streptomycin
Tetracyclines – e.g. chlortetracycline, oxytetracycline, doxycycline
Chloramphenicols
Why protein synthesis process is an appropriate site for antibacterial agents and not for others?
Ribosomal subunits involved in mRNA translation in bacterial systems are smaller (30S & 50S) than in eukaryotic translation (40S & 60S).
What are the three basic principles of antimicrobial therapy?
a. Selective toxicity – to exploit differences in structure and metabolism of pathogens and host cells
b. Reach the site of infection at inhibitory concentrations
c. Penetrate and bind to target, avoiding inactivation and intrusion
How resistance may disseminate throughout the microbial world?
a. Chromosomally-mediated resistance: mutant selection
b. Plasmid-mediated resistance: spread of resistance plasmid
c. Plasmid-mediated resistance on a transposon: spread of resistance gene
Name the typical targets of antibiotics.
a. Cell wall synthesis (mammalian cells lack a cell wall)
b. Protein synthesis (ribosome)
c. Nucleic acid synthesis
d. Cell membrane function
i. Good for fungal infections
e. Metabolic pathways
i. Unique pathways
f. Structural analogs
What is the mechanism of action of beta lactam antibiotics?
They all act by binding to penicillin-binding proteins (PBPs). PBPs are enzymes in cross-linking bacterial cell wall components. Different bacteria may have different PBPs. Spectrum of activity depends on whether the antibiotic binds to PBPs found in the organism.
Which organisms make antibiotics and what is its purpose in nature?
Mold – it is a decomposer
Name two ways by which bacteria may acquire resistance to antibiotics.
a. Altered target
i. target enzyme or other sites may be altered
ii. Lower affinity for antibacterial but target can still function adequately
b. Altered uptake
i. By increasing permeability of cell wall (loss of bacterial proteins – porins)
ii. By pumping drug out of cell (efflux)
c. Drug inactivation
i. Production of enzymes which modify or destroy the antibacterial agent
What is meant by selective toxicity?
To exploit differences in structure and metabolism of pathogens and host cells
How humans can prevent development of antibiotic-resistance bacteria?
a. Do not dispense antibiotics without a prescription
b. Control use of antibiotic in industry
c. Control misuse of antibiotics – inadequate indications
d. Antibiotic policies
e. Surveillance of antibiotic use coupled with monitoring emerging patterns of resistance
Why is it harder to achieve selective toxicity with drugs targeting viral diseases and eukaryotic disease than of the prokaryotes?
Their cells are more similar to host tissue. Targeting these cells may involve accidental damage to host.
What is the specific site of action of antifungal drugs? What is the mechanism of action of these drugs?
They target the cell membrane of the fungi either in it synthesis or function. They either block CYP450 step in biosynthesis of ergosterol or bind to sterols in the cell membrane, causing leakage of cellular components and cellular death.
Which protozoan infection could also be transmitted via sexual contact?
Sarcoptes scabiei or scabies
What is the significance of drug Metroniazide in treating anaerobic infections?
It forms an “electron sink”
Which protozoans are capable of causing skin infection? Which one causes both skin and systemic inectcion?
Leishmaniasis and scabies. Leshmaniasis can cause skin and systemic infection.
What is the significance of Cryptosporidium parvum?
Causes cryptosporidiosis and has a low ID50.
Which protozoan invades RBC?
Malaria
Relapse could be consequence of which of the protozoan infections?
Malaria
What are the complications of measles
Sub-acute sclerosing panencephalitis, sub-acute measles encephalitis, acute post-infectious measles encephalitis
Describe pathogenicity of Rotavirus. Mode of transmission, clinical features, and treatment.
Fecal-oral route. Attacks intestinal cells and stimulates IgA and IgG. Non-bloody diarrhea, fever, vomiting – treatment is rehydration with water and electrolytes
Describe replication of polio virus. How virus reaches its target.
Replicates in the oropharynx, internalization in vesicles, which exposes hydrophobic groups of virus
Which hepatitis virus is called serum hepatitis?
Hepatitis B virus
What are the top five signs and symptoms of HIV infection
Fever, Lymphadenopathy, Pharyngitis, Rash, Myalgia
Name two protozoan infections associated with HIV infection
Leishmaniasis, Malaria
How protozoans are classified.
Usually by means of locomotion, whether they use flagella/cilia/pseudopodia or are amoebic/amotile
List sites on bacteria that could be used as target for antibiotics.
Cell wall synthesis, Protein synthesis, Nucleic acid synthesis, Cell membrane function, Metabolic activity, Structural analog
Which protozoan infects reticuloendothelial cells.
Viseral Leishmaniasis
Greasy, frothy and foul-smelling stool is indicative of which protozoan infection
Giardia lamblia
Flask-shaped lesion in colon is indicative of which protozoan infection
Entamoeba histolytica
Explain the role of pH in uncoating step during virus replication
Low pH causes fusion of virus to endosome and spurs uncoating (release of nucleic acid…)
How rubella virus may cause congenital defects
If the mother doesn’t have Ab to Rubella (from vacc or prior infection…) the virus can replicate in the placenta and spread to the fetal blood supply – this can alter normal growth, mitosis, and chrom structure resulting in cataracts, mental retardation and deafness
List the three viral syndrome caused by flu virus
Uncomplicated rhinotracheitis (URTI) – graph shows infection is not very severe and there is a quick recovery
Respiratory viral infection followed by bacterial pneumonia – follows the graph of URTI and then spikes sharply upward
Viral pneumonia – immediately spikes upward – severe!
Explain the possible association between multiple sclerosis and herpes virus infection –
MS is associated with demyelination and HHV-6 is active in most MS pats in areas like the CNS, lymph nodes, and areas where blood flow is superficial – HHV-6 is not found in normal control pts
What are the two forms of protozoans
Cyst - inactive, transmission form that exists outside of the body – generally, very resistant to temp, chlorine etc – water treatment plants now use ozone to eradicate
Trophozoite – active form inside the body
List the four clinical stages of HIV infection? Which one has the highest virus load?
Acute (primary infection) – exhaustion occurs here because virus load is highest and immune system burn itself trying to fight it off
Asymptomatic
Early symptomatic
AIDS (CD4 count down to about 300 micron/ml)
What is the relationship between injecting drug use and HCV transmission/infection
a. Highly Efficient among injection drug users
b. Rapidly acquired after initiation
c. Four times more common than HIV
d. Prevalence 60-90% after 5 years
How HCV can be a nosocomial infection?
Contaminated equipment (Hemodialysis and Endoscopy) and Unsafe injection practices (Plasmopheresis, phlebotomy Multiple doe medication vials, Therapeutic injections)
What are the modes of transmission of HCV?
a. Percutaneous
i. Injecting drug use: rapidly acquired after initiation, 4x more common than HIV, prevalence 60-90% after 5 years
ii. Clotting factors before viral infection, transfusion (transplant from infected donor), therapeutic (contaminated equipment), Occupational (needlestick)
b. Premucosal (lower incidence to percutaneous)
i. Perinatal
ii. Sexual
Which body fluids have the highest number, which ones have moderate amount of virus, and which ones have the lowest number of HBV?
a. Concentrations of HBV
i. High: blood, serum, wound exudates
ii. Moderate: semen, vaginal fluid, saliva
iii. Low: urine, feces, sweat, tears, breastmilk
List the name of the viruses capable of causing viral meningitis
a. Mumps virus
b. Measles virus
c. Enteroviruses (Coxsackie B/A7/A9 viruses and Polio)
d. Herpes simplex virus
What are the characteristics of viral meningitis, mode of transmission? Compare this with bacterial meningitis
a. Spread by fecal-oral route, coughing, sneezing, and poor hygiene
b. Found in sewage-polluted water
c. Incubation up to 3 weeks
d. More common that bacterial meningitis and less severe
e. Observe headache, fever, stiff neck with or w/o vomiting
List viral infections for which a vaccine is available
Vaccines are available for Hep A and B, Influenza, Measles, Mumps, Rubella (MMR), Polio, Rabies, Smallpox, tick-borne encephalitis, Varicella-Zoster, and Yellow Fever
List ways viruses may evade the host immune system
Inhibit MHC 1 and 2, down regulate CD4, interfere with apoptosis, inhibit the NK cell lysis and cytokine actions, antigenic variation
List some of the host damages caused by viral infection
Damage from cell lysis (from complement – Ab complex binding to cell), capsid expression, IgE Abs, and sheer numbers with viral replication – toxins produced, DNA altered, start abnormal cell processes and alter the cell structure (synticia – fusing of cells)
What are the minimum components every virus must have
Every virus has genetic material a capsid (protein coat) for protection, recognition of host cell, and binding and genetic material
What is meant by sub-microscopic, obligate intracellular parasite, when we discuss viruses
Organism too small to be seen by a light microscope that must live within a host cell. Cannot live otherwise.
What is meant by extra-intestinal infection? What organs are at risk of extra-intestinal amoebiasis infection?
Trophozoite invasion of the GI lining (by E. histolytica specifically…) may result in extraintestinal lesions giving the organism access to blood vessels of the large intestine from which it can be transported to other organs. Brain, liver, and lungs are at risk.
What are the important features of infection by Histoplamosis
Severe infections resemble ARDS, large pulmonary lesions that become nodules, mediastinal granulometosis and fibrosis, infection of the lymph nodes – causes necrosis and fibroblastic proliferation around the lymph nodes; if chronic, it diseases upper lobes of lung
*African version affects mostly skin
Name drugs targeting: cell membrane, DNA, RNA
a. Cell membrane (for fungus)
i. Azoles (e.g. miconazole, fluconazole): block CYP450 step in biosynthesis of ergosterol so it will leak out material
ii. Polyenes (amphotericin B, nystatin): binds to sterols in cell membrane, causing leakage of cellular components and cell death
b. DNA
i. Metronidazole: when reduced it can react with DNA, oxidizing it and causing strand breakage. Works against anaerobic organisms
c. RNA
i. Rifamycins: specific inhibitors of bacterial DNA dependent RNA polymerase by blocking mRNA
Name possible ways bacteria make antibiotics ineffective.
a. Altered target
i. target enzyme or other sites may be altered
ii. Lower affinity for antibacterial but target can still function adequately
b. Altered uptake
i. By increasing permeability of cell wall (loss of bacterial proteins – porins)
ii. By pumping drug out of cell (efflux)
c. Drug inactivation
i. Production of enzymes which modify or destroy the antibacterial agent
What stage of HIV infection has the highest titer of virus? What stage has persistent immune activation
a. Highest titer = Acute/Primary infect and AIDS
b. Persistent immune activation = Primary infection
What are the important features of retroviral reverse transcriptase?
Allow virus to make DNA from RNA