Exam 1: Laboratory Diagnosis of Viral Infections Flashcards
When do you collect virus?
During acute stage of illness before antibodies form
Where do you take samples from?
Blood Nasal swabs Feces Urine Pus Vesicular fluid Skin lesions Spinal fluid Biopsy Necropsy tissues
When do you collect tissue specimens?
Immediately after death
What are used for isolation of a virus?
Embryonated eggs, cell cultures, or live animals
What are the only animals used for isolation of a virus?
10 day old neonate mice for rabies diagnostics
What do many media used for viral growth contain?
Antibiotics to remove bacteria/mycoplasmas
How should you store fresh tissues?
At -60 degrees C after collection
How should viruses be transported?
Air tight if on dry ice or else you could inactivate some viruses due to pH change from CO2 in dry ice
What is the direct method of detection of viruses?
Virus itself, or component antigens/molecules of virus is detected
What is the indirect method of detection of viruses?
Serological evidence from specific antibodies is sought as a consequence of viral infection
What is used almost exclusively to replicate viruses?
Chicken embryos
What is the best chanve for successful propagation of an unknown virus?
In the natural host
The inoculation route is also critical with certain viruses
What is the method used for rabies virus?
Intracerebral inoculation
What are the direct method tests?
Electron microscopy Direct (and indirect) fluorescent antibody test ELISA Radioimmunoassay PCR
How do you morphologically characterize viral particles?
Electron microscopy
