Diagnosis of Viral Infections 1 & 2 Flashcards
How many risk groups are there of infective micro organisms
4
What is risk group 1?
Zero to low individual and community risk
What is risk group 2?
Moderate individual risk, low community risk
What is risk group 3?
High individual risk, low community risk
T/F: A pathogen in risk group 3 causes serious human/animal disease but does not ordinarily spread from one individual to another. They have effective treatment measures and preventatives
True
What is risk group 4?
High individual and community risk
T/F: Pathogens in risk group 4 usually cause serious human/animal diseases and is readily transmitted , directly and indirectly. There is usually no effective treatment or preventative methods
True
What risk group(s) belongs to BSL-4?
Risk group 4
What is a biohazard?
Biological substance that pose a threat to health of living organism, primarily humans
What is biosafety?
The containment principles, technologies and practices that are implemented to prevent unintentional exposure to pathogens and toxins, or accidental release
Aerosol are very small droplets of fluid that spread via _____
Air
For virus isolation, when should specimens be collected? Why?
Soon after the onset of symptoms because there is maximal amounts of viruses present at onset of signs
How many blood specimens are usually collected for serological tests and when are they collected?
Two; one during acute phase and second during convalescence period
How so some specimens be collected for molecular diagnostics?
Early part of illness
What is associated with viral transport medium (VTM)?
Swabs
What packing system should be followed while transporting infectious materials?
Basic triple packaging system
T/F: Clinical signs, necropsy, and histopathology are ways to DX viral infections
True
Cultivation/isolation in cell/tissue culture and inoculation in eggs can be used for _________ of viruses
Detection
What method could be used to demonstrated and detect viruses that cannot be grown in-vitro?
Electron microscopy
What are two types of electron microscopy that can be used?
- Scanning electron microscope (SEM)
2. Transmission electron microscope (TEM)
The method of TEM is based on what type of electrons?
Transmitted
The method of SEM is based on what type of electrons?
Scattered
Which electron microscopic method seeks to see what is inside and beyond the surface?
TEM
Which method of electron microscopy produces 3D images?
SEM
Which method of electron microscopy has higher magnification and greater resolution?
TEM
What is a gold standard test?
Diagnostic test considered to be most accurate and best available under particular condition or set of conditions
Sensitivity is the probability that cases _______ the infection will have __________test result and specificity is probability that cases _________ the infection will have ________ result
- With
- Positive
- Without
- Negative
What color and type of tube is used or serum collection?
Red-top vacutainer tube
What color and type of tube is used for plasma collection?
Lavender-top EDTA vacutainer tube
What are the 4 type of ELISAs?
- Direct ELISA
- Indirect ELISA
- Sandwich ELISA
- Competitive ELISA
T/F: For direct ELISA, the specificity of primary antibody is very important
True
T/F: Enzyme-conjugated secondary antibodies are used to detect or quantify antigen concentration
False; enzyme-conjugated PRIMARY antibodies
For indirect ELISA, enzyme-conjugated __________ antibodies are used to recognize __________ antibodies
- Secondary
2. Primary
An antigen is measured between what to layers for a sandwich ELISA?
A layer of capture antibodies and layer of detection antibodies
For a competitive ELISA, will a decrease or increase in signal indicate the presence of antigen in a sample?
A decrease
What are two types of fluorescence antibody tests (FAT)?
- Direct FAT
2. Indirect FAT
What is a direct FAT?
Labeled Ab are added to sample
What is an indirect FAT?
Use fluorescent labeled secondary Ab to recognize primary antibody bound to antigen
What is immunohistochemistry?
Antibody tagged with enzyme and enzyme reacts with substrate to produced colored product that be seen in infected cell under light microscope
What is immunochromatography?
A form of point-of-care (POC) test/assay
Agglutination is a method using the property of specific _______ to bind to many _________ into single clumps resulting in large complexes
- Antibodies
2. Antigens
What property of the pathogen does hemagglutination and hemagglutination inhibition test rely on?
The pathogens ability to nonspecifically agglutinate erythrocytes
What kind of assay is an agar gel immunodiffusion test?
Serological assay
In a compliment fixation test, if a patient has antibodies against virus A and the intact RBCs settle at the bottom, is that a positive or negative reaction?
Positive reaction
In a compliment fixation test, if a patient is negative to virus A with no antibodies and the sheep RBCs have undergone destruction/hemolysis, is that a positive or negative reaction?
Negative reaction
What is the neutralization of viruses?
Loss of infectivity through reaction of virus with specific antibody
