Week 3 - Lecture 1 & 2 Flashcards
What are the purposes of viral disease diagnosis?
• Surveillance of viral diseases among certain population
• Identify the causative agent of certain suspected clinical cases of viral origin
• To monitor the progress of some viral diseases
• To monitor the antigenic/genetic variations of certain virus
• To help in the design of the right vaccine against the homologous circulating strains of viruses
What is the direct approach to viral diagnosis?
Identifying the virus or viral products (such as proteins, nucleic acids) in clinical samples or after virus isolation from clinical samples.
What is the indirect approach to viral diagnosis?
Detecting an immunological response to the virus (detect antibodies)
What tests can be used to detect a virus and the virus’ effect on cells?
**Make more **
Electromicroscopy (TEM, SEM), Immunoelectronmicroscopy, Light microscopy
skipped
Make questions from this chart
I-Diagnosis of viral infections at the individual animal or individual Herd level
- Management of the animal or its prognosis is influenced by the _______
- ______ and _______ diagnosis of the causative virus can be the basis for establishing the _______ plan (?)
diagnosis, Rapid, accurate, management, Biosecurity, vaccination, antimicrobial treatment
II- Certification of freedom from specific viral life long infections or proof of vaccination (BLV, BVDV, EIAV)
-These certificates or vaccines are mandatory for animal _______, participation in certain ______, or show for ____
-Artificial ________, _____ transfer, and blood ______
-Male used for _____ collection, female used for _____ transfer, blood _____ animals should be screened for wide range of viral infections (EAV, EIAV, BLV, etc)
- _______ viruses: (RVfV, Rabies, WNV, EEEV, Hendra virus, etc)
- All these animals require _______ and _______ as well as veterinary care
traveling, exhibition, sale, insemination, embryo, transfusion, semen, embryo, donor, Zoonotic, screening, testing
III- Diagnosis of virus infection at the State, country and International level
- ____ and _____ programs for some viruses such as (MDV, EIAV, BHV-1, BVDV)
-Surveillance programs in support to _______ diseases research control activates
-Surveillance programs in support to ______ diseases research control activates
Test, removal, enzootic, exotic
IV- Prevention of new emerging and re-emerging diseases
?
If it is a respiratory virus, what types of specimens would you collect antemortem?
If it is a respiratory virus, what types of specimens would you collect postmortem?
If it is an enteric virus, what type of samples would you collect antemortem?
If it is an enteric virus, what type of samples would you collect postmortem?
If it is a genital virus, what type of samples would you collect antemortem?
If it is a genital virus, what type of samples would you collect postmortem?
If it is a nervous system virus, what type of samples would you collect postmortem?
If it is a nervous system virus, what type of samples would you collect antemortem?
If it is a systemic virus, what type of samples would you collect antemortem?
If it is a systemic virus, what type of samples would you collect postmortem?
What should be considered during sample collection?
-Proper site of collection
- Right time
-Suitable volume/quantity
What should be considered during transportation of viral samples?
-Viral transport media (VTM)
-Antibiotic/antifungal cocktail
-Sterile containers
What should be considered for sample preservation?
-Proper preservation temperature
-Avoid freezing and thawing
Light microscopy is used to/for:
1. Monitor the ____ and ______ of cell culture
2. Monitor the viral infection in ____ ______ (____)
3. Detect ____ ______ ______ (TBDL)
4. Study the _______ changes of some viral infected ____
5. Immuno-histo-chemistry: ____ virus antigen (___ ____)
growth, multiplication, cell culture, CPE, viral inclusion bodies, histopathological, tissues, Rabies, brown dots
In most other cases viruses are _______ in cell culture before they can be visualized by ____
isolated, EM
Virus is surrounded by ______ ____ (electron ____) material, including: ?
This results in electrons being ______ from regions covered with stain thus creating a _____ which outlines viral _____
electron, dense, opaque, -2% uranyl acetate, 1-3% sodium or potassium tungstate, scattered, contrast, structures
What are the advantages of EM in diagnostic virology?
-Can detect the virus in body _______ and _______
-Do not require special _____ such as proteins standard, etc
-No ____ reaction with other ____ viruses
- _____ technique
secretions, excretions, reagents, cross, similar, Rapid
What are the disadvantages of diagnostic virology?
- ______ sensitive than other tests: requires ____ virus concentration
-The EM machine is ______
-Requires ______ _______ to do interpretation
Less, high, expensive, expert personnel
Scanning electron microscope uses a ________ resolution of tens of nm.
lower
Scanning electron microscope shows only _______ of specimens.
morphology
Scanning electron microscope is a ________ way to prepare specimens.
simple
Scanning electron microscopy is ______ and relatively _____ to use.
cheap, safe
Transmission electron microscope uses a ___________ resolution of ?
higher, 1nm or less
Transmission electron microscope shows multiple ________ of objects such as ________, _________, _____, and many more.
characteristics, crystallization, morphology, stress
When using transmission electron microscope, you must prepare your specimen by ________ your sample which is ______ and _______ consuming.
thinning, tiring, time
Transmission electron microscope is ________ and relatively _______ to human health.
expensive, harmful
What does this image show?
Transmission EM- SARS-CoV-2
Spike proteins are shown as protrusions from the surface of the virus and attach to the host cell receptors
virus is circulating and spikes embeds and attaches to receptor. Based on this –> develop vaccine, antiviral therapy, diagnosis, etc.
What does this image show?
EM
- one of the drawbacks is less viral sensitivity; need a large sample
What does this image show
Virus + Abs
IEM (Immuno-electron microscopy)
Serum specific to virus to clump viral particle together so you can better see the virus.
Ab captures virus -> clumps together
kind of modification to overcome one of the drawbacks to EM
Immuno-electron microscopy (IEM) is the _______ of viral-____ _______ will allow the ______ of virus particles that can be seen under EM easily.
addition, specific antibodies, concentration
Viral Diagnostic-Direct method-Virus isolation
1. Nasal swabs (in ________ media containing ______)
2. _____ (homogenize), ____ coat cells and _____
- Make __- ___% solution in cell culture medium – sonicate* homogenized tissues and buffy coat cells or freeze/thaw to ___ the cells (release the virus)
•_______ (3,000X g) or filter (0.2 µ)
- In most cases inoculation of sample (supernatant/ filtrate) onto cells of tissue culture – incubate at 37˚C in a CO2 incubator
* Feces – no sonication
transport, antibiotics, Tissue, buffy, feces, 10, 20, lyse, Centrifuge
**What are the methods of virus isolation?
Embryonated chicken egg innoculation (ECE)
Cell culture
Laboratory animals inoculation
What are the routes of inoculation for chicken eggs?
- Yolk sac
- Amniotic sac
- Allantoic Sac
- CAM Corio??
Each virus req. and likes certain routes compared to others.
Like/love = tropism
What are the types of cell culture used for virus isolation?
- Primary cell culture
- Secondary cell culture
- Established cell line
What are the routes of inoculation for laboratory animals?
- IM
- IV
- IP
- SC
- ID
ECE
we need to get a fertile egg.
Embryo with different tissues, live tissue, that can support viral repliction.
We need to candle egg to see if fertile or not.
If see B = live eg, C = can not support viral rep
Clean egg with 70% isopropol alcohol before puncturing
Describe the process of inoculating the Chorioallantoic Membrane (CAM) of a chicken egg.
Quite difficult, but very common
** Use older embryos (10 - 12 days)**
1. Drill hole at air space and then drill 2nd hold at top
2. Apply suction to 1st hole, then inoculate 0.1 ml of sample (to be tested) with syringe and needle in the 2nd hole.
3. Incubate & look for membrane edema or focal necrosis
4. Harvest the CAM
5. Preparation of artificial air sac
CAM is best to isolate Pox and herpesvirus
suctioning separates membranes so you can insert needle into CAM
List the methods of harvesting inoculated materials
• Open the inoculated eggs with sterile scissors
• Remove the egg shell and the egg shell membranes
• Pour the content of the egg into a clean, sterile petri dish
• Examine the inoculated embryos and the embryonic
membranes
List and describe the pathological changes of the virus on the ECE.
1-Curling: and dwarfing of embryos: IBV
2-Death: of the embryo: some viruses induce the death of the embryo such as NDV
3-Deformities: dwarfing, and hemorrhage of the embryo such as IBV
4-Hemorrhage: and thickening of the Chorioallantoic membranes as in case of Pox and Herpesviruses
5-Detection of hemagglutinin: in the egg fluids as in the case of NDV and AIV, which can be detected by the HA test.