Diagnosis, Trmnt, Control, Prevention (Ex2) Flashcards
1
Q
Explain the steps of PCR
A
- Denaturation: DNA sample is heated so it separates
- Annealing: twp primers attach to ends of the two DNA strands
- Elongation: Taq polymerase synthesizes new strands using the originals as templates, adding free nucleotides to the attached primers
2
Q
What is Real-Time PCR?
A
- also Quantitiative PCR
- allows monitoring and quantification of PCR products/nucleic acid load as the reaction progresses
- Uses fluorescent dye-labeled target probes, or other dyes
3
Q
What is genome sequencing?
What is the most commonly used method?
A
- the process by which the sequence of bases in a DNA molecule can be obtained and read
- Modification of the Sanger dideoxy method, involves using chain-terminating dideoxynucleotides
4
Q
Define Metagenomics
How is it done?
A
- the study of the collective set of microbial populations in a sample by analyzing the sample’s entire nucleotide sequence content
- amplification and sequencing of whole genome content of a given sample, followed by filtering and analysis of the data by comparing with genome databases
5
Q
What is Phylogenic Analysis?
A
- the use of virus genome sequence data to study evolution of viruses and genetic relationship among viruses
6
Q
Describe Microarrays
A
- thousands of known DNAs, amplified by PCR, are put onto a glass or chip
- target DNA are fluorescently labeled and added to the glass/chip
- positive reaction generate fluorescent signal
7
Q
Define Antimicrobial Chemotherapy
A
the treatment of infectious diseases by drugs that are inhibitory or lethal to the pathogenic microbe
8
Q
What is Acyclovir?
A
- antiviral against Herpesvirus
- administered as prodrug, requires virus enzymes in infected host cell to become active
- non-toxic to uninfected cells
- a synthetic nucleoside analong of deoxyguanosine
9
Q
Mechanism of Acyclovir
A
- enters virus infected cell, converted to monophosphate by virus enzyme
- host cell enzymes at 2 phosphates, making it triphosphate, and transport to the nucleus
- herpes simplex enzyme cleaves the 2 phosphates, making monophosphate
- herpes DNA polymerase incorporates the monophosphate into the growing DNA strands
- prevents growth: acyclovir monophosphate lacks attachment points for nucleotides
10
Q
What is Amantadine?
What does it do?
A
- synthetic tricyclic amine
- acts as antiviral and anti-Parkinsons drug
- inhibits replication of most strains of influenza A viruses by blocking un-coating of the virus
11
Q
Mechanism of Amantadine
A
- clogs the M2 ion channel in the endosomal membrane, and prevents it from pumping protons into the virion
- so the pH in the virion interior will not decrease
- viral RNAs remain bound to M1 protein, and cannot enter the nucleus when released from endosome
12
Q
What is Oseltamivir/Tamiflu?
A
a prodrug that, after its metabolism in the liver, releases and active metabolite that inhibits neuraminidase
- this slowing virus spread
13
Q
Neuraminidase and Hemagglutinin action
A
- HA binds to receptors containing sialic acid on host cell membranes
- after budding, HA of progeny influenza virions are still bound
- NA on virus will cleave the sialic acid and release HA
- the virus is freed from the infected cell
14
Q
What are the targets for anti-retroviral therapy?
A
- inhibit fusion
- inhibit reverse transcriptase
- inhibit integrase
- inhibit protease
15
Q
What is ZDV/AZT?
A
- nucleoside analog reverse transcriptase inhibitor
16
Q
Mechanism of ZDV/AZT
A
- phosphorylated by kinase in host cell into AZT-triphosphate
- reverse transcriptase cleaves 2 phosphates, and inserts AZT monophosphate into the cDNA
- blocks growth of cDNA because it has a N3 end instead of OH, so no other nucleotides can attach
17
Q
Effects of protease inhibitors on HIV
A
- inhibits proteases so HIV polyproteins cannot be cleaved into functional proteins
- HIV needs to cleave large Gag-Pol polyprotein, Gag polyprotein, and Env polyprotein
- HIV cannot mature, and noninfectious viruses are produced
18
Q
What is the purpose of immunization/vaccination?
A
- to protect susceptible individuals from infection or disease
- prevent transmission of infectious agents by creating an immune population
19
Q
What are the four Ws of immunization?
A
- Where: populations in endemic areas
- When: season or outbreak of non-endemic disease
- Who: population at risk
- Why: loss caused by disease must be greater than cost of immunization
20
Q
Live-attenuated Virus Vaccines
4 types
A
- vaccines produced from naturally occurring attenuated viruses
- vaccines produced by attenuation of viruses by serial passage in cultured cells
- vaccines produced by attenuation of viruses by serial passage in heterologous hosts
- vaccines produced by attenuation of viruses by selection of cold-adapted mutants and reassortments
21
Q
Non-replicating Virus Vaccines
2 types
A
- vaccines produced from inactivated whole virions
- vaccines produced from purified native viral proteins
22
Q
Vaccines produced by Recombinant DNA and related technologies
(4 types)
A
- vaccines produced by attenuation of viruses by gene deletion or site-directed mutagenesis
- subunit vaccines produced by expression of viral proteins in eukaryotic, bacterial, or plant cells
- vaccines utilizing harmless viruses as vectors for expression of other viral antigens
- vaccines utilizing viral DNA
23
Q
Explain DIVA
A
- differentiating infected from vaccinated animals
- vaccination with only live attenuated vaccines leads to production of an antibody response identical to that produced after natural infection
- subunit marker vaccines DIVA vaccines have only a portion of the pathogen, so if antibodies to other parts of the pathogen are detected, the animal has been naturally infected
24
Q
What are the 6 methods of vector control?
A
- source reduction
- biological control
- chemical control
- reducing contact potential
- protection of portals of entry
- decontamination
25
Q
Explain isolation
A
- applies to animals/people who are known to be ill with a contagious disease
- reduces probability of contact with a susceptible host
- not effective is shedding does not occur
26
Q
Explain quarantine
A
- applies to those who have been exposed to a contagious disease
- enforced for longest incubation period of the disease
- not effective for chronically infected healthy shedders
27
Q
What are the 4 methods of reducing contact potential?
A
- isolation
- quarantine
- population control programs
- quarantine and culling
28
Q
Define decontamination
A
- a process of treatment that renders a medical device, instrument, or environmental surface safe to handle
- includes sterilization, disinfection, and antisepsis
29
Q
Define sterilization
A
- describes a process that destroys or eliminates all forms of microbial life/pathogens, including highly resistant pathogens, such as spores
- no degrees, all or nothing
30
Q
Define disinfection
A
- a process that eliminates many or all pathogenic microorganisms, except spores, on inanimate objects
31
Q
Define antisepsis
A
- the application of a liquid antimicrobial chemical to skin or living tissue to inhibit or destroy microorganisms
32
Q
What are the 5 sterilization methods?
A
- moist heat (autoclave)
- dry heat (oven)
- chemical methods
- radiation
- sterile filtration
33
Q
What are the 5 areas of prevention and control in animal farms?
A
- farm biosecurity
- housing and management
- vermin and bird control
- purchasing policy
- people
