Sunday, December 21, 2008
Intro on Methods of Study of Viruses
This topic gives ideal for people seeking a solid understanding of the basic principles in this rapidly developing field; it also offers a comprehensive introduction to the fundamentals of virology. The study of viruses is known as virology, and is a branch of microbiology. Viruses consist of two or three parts: all viruses have genes made from either DNA or RNA, long molecules that carry genetic information; all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell.
Viruses spread in many ways; different species of virus use different methods. The methods of studying the viruses such as Plaque Assay, ELISA, etc
Studying of viruses is to help find out the cure for the diseases.
Four main methods for diagnosis of viral infections
1) Culture
2) Serology: test for immune response to virus
3) Detection of viral antigens
4) Detection of viral nucleic acids
Cultivation:
- Laboratory animals-Apes and Monkeys, Mouse
- Chick Embryo
- Tissue Cell Culture
1. Primary cell cultures
– Heterogeneous – many cell types
– Closest to animal
– Technical hassle
2. Diploid cell strains
–Relatively homogeneous – fewer cell types
– Further from animal
– Technically less hassle
3. Continuous cell lines
– Immortal
– Most homogeneous
– Genetically weird – furthest from animal
– Hassle free
– Suspension or monolayer
l Tissue Culture Methods for Detection
1. Cytopathic effect (CPE)
2. Plaque Assay
Physical Methods
- Hemagglutination
- Immunological tests for proteins
- Assay for nucleic acid (Southern, PCR)
- Enzymatic (reverse transcriptase for retroviruses)
- Comparison of quantitative methods
- Serological/ Immunological Methods
- Hemagglutination (HA)
- Hemagglutination Inhibition (HI)
- Virus Neutralization,
- Complement Fixation
- ELISA, RIA, LA, western blot
Specimens for viral diagnosis
From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Table 51-1.
Blogged @ 6:10 PM