Exam 2 - Lab Diagnosis Flashcards
we can prove a virus causes disease by using ______________
Koch’s Postulates
what are the 4 rules to Koch’s Postulates?
- microorganism found in abundance in all organisms suffering
- microorganism must be isolated from a diseased organism and grown in pure culture
- cultured microorganism should cause disease when introduced into a healthy organism
- microorganism must be reisolated from the inoculated diseased experimental host and identified as being identical to the original specific causative agent
rivers causation criteria
A virus causes a disease if it is found in all cases, can be grown in host cells, passes through filters, causes the same disease in a healthy host, can be re-isolated, and triggers an immune response
Fredericks and Relman had ______________ based and _______________ based evidence
nucleic acid; biotechnology
over ___% of all infectious disease cases are caused by viruses
60%
when are specimens taken for testing?
before diagnosis
what are the 5 general approaches for lab diagnosis?
- Microscopy
- Viral antigen detection
- Culture
- Nucleic acid detection
- Antibody detection (serology)
methods for microscopy
- electron microscopy
- immunofluorescence
methods for viral antigen detection
- ELISA
- IFA
- Western Blot
methods for cell culture
- growth of live virus in cultured cells in vitro
- centrifugation (shell vial technique)
methods for nucleic acid detection
- PCR (DNA)
- RT-PCR (RNA)
- qPCR (all viruses)
methods for antibody detection (serology)
- ELISA
- IFA
- Western Blot
viruses need a _______ system
host
labs are classified by _____________
biosafety level (BSL)
why are biosafety levels important?
they determine the level of safety precautions needed within a lab setting
