Virus nomenclature classification and properties

virus
nomenclature
classification
properties
types of virus

1. virus contents Nomenclature classification properties of virus

2. INTRODUCTION & DEFINATION Virus are living or non living They can only multiply in another living cell DEFIN ATI ON Virus are noncellular particles made up og genetic material and protein that can invade living cells. A virus is an infectious agent of small size and simple composition that can only multiply only in living cells of animals or bacteria.

3. DISCOVERY OF VIRUS Bejernik [1897] coined the latin name virus meaning poison Tobecco mosaic virus Wendell Stanley[1935] discovered viruses were made up of nucleic acid and protein Smallpox Edward jenner [1796] developed a smallpox vaccine using milder cowpox viruses Smallpox has been eradicated in the world today

4. TYPES OF VIRUS Helical virus Polyhedral virus Spherical virus Complex virus

5. NOMENCLATURE OF VIRUS 1. name after the disease e.g - smallpox virus 2.Name after the place where the disease first reported e.g - newcastle disease virus, Ebola virus 3. Host and signs of disease e.g - tobacco mosaic virus 4. Latin and Greek words eg - corona viridae - crown parvo viridae - small

6. NOMENCLATURE OF VIRUS 5. Virus discovers e.g - Epstein- barr virus 6. How they were originally throught to be controlled e.g dengue virus [evil spirit] influenza virus [bad air] 7. Combination of above e.g Rous sacrom virus

7. CLASSIFICATION Viruses are classified on the basis of habitat[host] . Which is trivial system beside thevirus are classified on criteria. -Structure -Chemical composition -similarities in genetic makeup -International committee on the taxonomy of virus 3 orders 63 families - viridae 263 genera – virus 1- baltimor classification 2- classical system classification 3- genetic classification

8. Baltimore classification Suggested by David Baltimore – seven Baltimore classes The division of viruses into classes based on genome type & mode of replication &transcription RNA and DNA viruses can be single-stranded or double-stranded

9. Genetc classification Group 1:Double stranded DNA genome All member of viruses that contain double stranded DNA it will be directly transcribe to mRNA. Double stranded DNA one strand is template and it will transcribed directly to mRNA. Group 2:Single stranded DNA genome It is haploid because the DNA have single strand. DNA one strand is template. First of all DNA convert into the double stranded DNA with the help of transcription DNA is convert into mRNA with the help of DNA depended RNA polymerase .

10. Genetic classification Group 3:Double stranded RNA genome In this group the RNA is positive or negative sense of RNA. In this negative sense RNA is template and it convert into the positive sense and it will directly synthesis mRNA with the help of RNA depended RNA polymerase. Group 4:Single stranded RNA genome positive sense The virus have positive sense of RNA. That positive sense one strand is template and it will convert into negative sense RNA. Then so many copy of the mRNA will be formed with the help of nagative sence RNA while nagative sense of RNA one strand is template

11. Genetic classification Group 5:single stranded RNA genome negative sense In negative sense RNA one strand is template. with the help of RNA depended RNA ploymarse enzyme this nagative sense RNA directly transcripe into mRNA Group 6:Single stranded RNA genome that replicated with DNA intermediate In this type have reverse transcription enzyme that virus having RNA positive snse . That positive sense RNA by using the reverse transcribing enzyme that will converting partial haploid and partial diploid DNA. Then DNA template will be transcribe into mRNA

12. Genetic classification Group 7:Double stranded DNA genome that replicate with RNA intermediate The group that having partially haploid and partially diploid DNA. That virus by using partially haploid DNA that will be convert with help of DNA depended DNA polymerase converted into DNA transcribe into mRNA.

13. Classification on basis of host Animal virus: -viruses of animal host - rabies,polio,mumps,smallpox,chickenpox,influenza Plant virus: -virus which show theirlive characteristics attached to plants - TMV,Banana strek virus,carrot thin leaf virus Bacterial virus: - Bacterio phages [T1 , T2 , T3, and T4

14. ICTV Classification Established in 1966 Only body to takes the task of developing refining and maintaining the universal virus taxonomy Governed by the virology division of the international union of microbiological societies.

15. ICTV Classification Virus classification starts at the level of order and continues as follows with the taxon suffixes. ORDER - virales FAMILY - viridae SUBFAMILY - virinae GENUS - virus SPECIES Species name generally take the form of [disease] virus.

16. Properties of virus Size 20-350 nm (smallest infectious agent) Obligate intracellular parasites. Only one kind of RNA or DNA contain as genome. Two primary shape : rod and spherical Rod shaped virus helical symmetry. Spherical virus icosahedrons

17. reference Virus texonomy
textbook of medical virology