INTRODUCTION TO VIROLOGY Lecture 16 Prepared by: Miss Norzawani Jaffar Bsc (Hons) Biomedical Sciences, UKM

Learning Outcomes At the end of learning season, the student must be able to; Understand virology in definition. Explain the general structure for virus Understand and describe the mode of virus transmission. Understand virus classification

Definitions Virology: The science which study the virus and viral diseases. Virus: A genitic material containing either DNA or RNA genome that is able to alternate between intra and extra cellular states. Is a microscopic infectious agent that can reproduce only inside a host cell.

General virology

Introduction The virus is usually very, very small compared to the size of a living cell (20 – 300 nm). Viral components are assembled and don’t replicate By “ division “. Viruses need to host cell to produce their components For replication. Viruses have a naked capsid or an envelope morphology.

Structure of virus

Structure of virus : 1- Nucleic acid(genome) : DNA or RNA not both. 2- Capsid(protein coat) : Which protect the genitic material. a)Helical. b) Icosahedral. 3- Envelope : That surrounds them then they are outside the cell.

HELICAL ICOSAHEDRAL

Viruses Transmission Viruses spread by coughing and sneezing (Influenza viruses). Viruses are transmitted by the faecal-oral route such as (Norovirus), via contact with contaminated hands, food, or water. HIV is one of several viruses that are transmitted through sexual contact.

Viruses classification DNA viruses remember HHAPPPy. Herpes. Hepadna. Adeno. Pox. Parvo. Papova=Polyoma+papilloma. *all DNA viruses replicate in the nucleus except POX replicate in the cytoplasm. *all DNA viruses are dsDNA except PARVO ssDNA. *all DNA viruses are icosahedral except POX is complex. *3 DNA viruses are naked PAP(Parvo, Adeno and Papova).

RNA viruses: *all RNA viruses are ssRNA except REO is ds RNA. *all RNA viruses replicate in the cytoplasm except ORB (Orthomyxo, Retro and Borna) replicate in the nucleus. *3 RNA viruses are non enveloped PCR (Picorna, Calici And Reo). *5 RNA viruses have icosahedral PCR+FT ( Flavi and Toga).

Parvovirus B19V cause Rash

Adeno Virus cause Conjuctivitis Red Eye

Pox Virus ; Smallpox

Rhabdo Virus

Treatment Drugs that use for viral infections are called antiviral drugs. Interferon: which stop or slow virus replication. Vaccines: for antibody formation, before exposure to disease. Immunoglobulins: are related to immune system and help to kill the virus.

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