Test 2 - Practice Questions Flashcards
Describe PCR.
Used to make multiple copies of DNA. Each new DNA has one old strand and one new strand.
- Denaturation
- Annealing: Primers attached
- Extension/Elongation: taq polymerase synthesizes two new strands of DNA using the original strands as templates.
What is real-time PCR?
Also known as Quantative PCR.
Allows monitoring and quantification of increasing accumulation of PCR products/nucleic acid load as the reaction progreses.
Describe Metagenomics.
The study of the collective set of microbial populations in a sample by analyzing its entire nucleotide sequence content. Used for random detection of existing/new pathogens.
What is the importance of Genome sequencing?
- Pathogen detection
- Studies genetic variation
- ID of novel/undiscovered strains
- Development of diagnostics
- ID of genes associated with drug resistance
- Development of therapeutics
- Judging the efficacy of current vaccines and formulating new vaccine strategies.
Phylogenetic Analysis
The use of virus genome sequence data to study evolution of viruses and genetic relationships among viruses.
Microarray
The use of several thousands of known DNA probes to analyze target/sample DNA via hybridization on a glass/silicon chip. The sample DNA has a fluorescent signal that flouresces at intensities relative to the degree of hybridization.
It can be used to analyze hundreds of pathogens on a single chip.
Acyclovir is used to treat primarily what kind of viruses?
Herpes viruses
Herpesvirus in humans, Feline herpes virus 1 induced corneal ulcers and Equine Herpesvirus-1 enduced encephalomyelitis.
Describe the mechanism of action of Zidovudine or Axidothymidine (ZDV/AZT).
What kind of viruses is it used to treat?
It is a nucleoside analog of thymine. It uses reverse transcriptase to cleave it (after it has been phosphorylated by endogenous kinases) and is then inserted into the cDNA being synthesized. There is competitive inhibition for reverse transcriptase. It also has an azide group instead of a OH group on the pentose sugar, which blocks further nucleotide attachment.
It is a type of Anti-retroviral therapy. It is used to treat HIV and FIV. It slows the virus but does not eradicate it.
What is DIVA?
Differentiative Infected from Vaccinated Animals
Subunit markers are aded to the vaccine to be able to differentiate vaccinated animals from immunity developed through natural infection.
Describe the difference between isolation and quarantine.
Isolation applies to animals known to be ill with a contagious disease. It reduces contact with a susceptible host but relies on sensitivy of diagnostic tool.
Quarantine applies to those who have been exposed to a contagious disease and is enforced for the duration of the incubation period. It is not effective for chronically infected healthy shedders.
Which of the following is a sterilization method?
A. Disinfection
B. Moist Heat
C. Antisepsis
B. Moist Heat (e.g. Autoclave)
List the different sterilization methods.
- Moist heat (e.g. autoclave)
- Dry Heat (e.g. hot air oven)
- Chemical methods (e.g. ethylene oxide, ozone, hydrogen peroxide)
- Radiation (e.g. nonionizing UV and ionizing gamma/X-rays)
- Steril filtration (pore size <0.2 um)
TRUE/FALSE.
Antisepsis and disinfection are synonymous.
FALSE.
Disinfection refers to the elimination of many pathogenic organisms on inaminate objects. It is less effective than sterilization.
Antisepsis is the application of antimicrobial to skin or living tissue to inhibit/destroy microorganisms.
TRUE/FALSE.
All viruses of the poxvirus family are pleomorphic and brick-shaped.
FALSE.
Parapoxviruses are ovoid and covered with long thread-like surface tubules, which appear to be arranged in a criss-cross fashion.
What are the two types of infectious poxvirus particles?
Intracellular mature virus -IMV- (lysis; one membrane) & Extracellular enveloped virus-EMV- (budding, more virulent)
The virion outlayer of poxviruses encloses a dumbell-shaped core and two structures which contain enzymes crucial for replication. These structures are known as ______.
Lateral bodies
Replication of poxviruses occurs predominantly in the _____ of host cells.
Cytoplasm.
TRUE/FALSE.
Because poxviruses are enveloped, they are not stable in the environment.
FALSE.
Their envelopes have a low lipid content, which makes them capable of surviving in dried scabs for many months/years.
Describe the pathogenesis of poxviruses.
They are epitheliotropic (cause cutaneous skin lesions) and many are host specific. Exception: orthopoxviruses affect a wide range of host species.
After infection, they gain access to systemic circulation via lymphatics. Secondary viremia disseminates the virus back to the skin and other target organs.
Macule –> Papule –> Vesicle –> Scab –> Scar
*Ulceration may develop.
I wanna play a game……
ZOONOTIC vs. NOT.
- Cowpox
- Swinepox
- Sheeppox
- Cowpox –> Zoonotic
- Swinepox –> NOT
- Sheeppox –> REPORTABLE
What are the species that can be infected by cowpox?
Cattle, Cats, humans
Describe what happens when cats are infected with cowpox.
There are primary lesions (mostly head, neck or forelimb; small or large abscess), followed by widespread secondary lesions (turn into ulcerated pauples and become covered in scabs).
Many cats should no signs but skin lesions. Maydevelop mild coryza or conjunctivities.
Complications can result from secondary bacterial infections.
TRUE/FALSE.
Humans get cowpox from cows.
FALSE.
Cuddly cats are the culprits.
What are the CS of monkeypox in humans?
Same as smallpox.
Infasion period (generalized symptoms) followed by skin eruption (rash from lesions, follwed by scabs/crusts)
______ is characterized by horseshoe-shaped ring-like lesions.
Pseudocowpox.
These are left behind after the scab drops off and it surrounds a wartlike granuloma.
______ is responsible for Milker’s nodules in humans.
Pseudocowpox
TRUE/FALSE.
Contagious Ecthyma (ORF) has a high case fatality (5-15%) and his zoonotic. Because of this, all farms should be vaccinated.
FALSE.
only farms that do not have a problem with it.
What kind of disease is caused by sheeppox?
Systemic disease
What is the difference between malignant vs. benign forms of sheeppox?
Malignant: initially begins with general symptoms (depression, fever, salivation/lacrimation edema of the eyes) and after 1-2 days skin lesions develop all over (skin, spleen, abomasum, vagina, etc) with secondary pneumonia. Cutaneous nodules are distributed widely over the body and leave a star-shaped scar.
Benign: ONLY SKIN LESIONS. Little to no systemic reaction.
What is the most common route of transmission for sheeppox?
Aerosol
Lumpy skin disease is caused by……
Capripoxvirus
Arthropod transmission is most common.
It affects cattle.
What occurs as a sequel to swinepox?
Exduative epidermitis (greasy pig disease) and secondary bacterial dermatitis occasionaly occur as a sequel to swine pox.
What happens in severe infections with swinepox?
Especially congenitally acquired pox infections (biglets are born with lesions all over the body shortly after birth. Lesions may occur in upper respiratory and digestive tracts.
