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VIRAL SHAPES
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VIRUSES There are presently 20 recognized families of viruses that affect humans and/or animals CLASSIFIED BY: –By whether they contain DNA or RNA –By structure –Also by type of capsid and or envelope
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Viral Vocabulary The CAPSID = the protein shell that encloses the (DNA or RNA). ENVELOPE may contain material from the host cell as well as the virus
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Bacteriophage Bacteriophage = A virus that infects bacteria
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Viral Replication
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Lytic vs. Lysogenic
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Lytic – “Fast & Furious” 4 Stages: 1.Penetration: DNA or RNA injected into host cell 2.Biosynthesis: Virus has hijacked the host cell uses it to make copies of itself 3.Maturation: puts the viral pieces back together 4.Lysis: cell membrane breaks open and releases virus
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Lysogenic – “Slow & Steady” Integration of DNA/RNA into hosts bacterium’s genome (chromosome) When virus copies itself – new genetic material is copied also – then it can convert to the lytic cycle This is how viruses mutate
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http://www.youtube.com/watch?v =_J9-xKitsd0 http://www.youtube.com/watch?v =_J9-xKitsd0 http://www.youtube.com/watch?v =TVLo2CtB3GA http://www.youtube.com/watch?v =TVLo2CtB3GA
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DNA VIRUSES The following are a few of the more common DNA Viruses
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Adenovirus
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Adenoviruses Cause colds Conjunctivitis ("pink eye")
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HPV - Papillomavirus Often causes warts Warts may go away spontaneously Human genital warts may become malignant if they last for a long time.
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Herpesvirus Seven different species are known to infect humans –Including herpes simplex virus (HSV) –Cytomegalovirus (CMV) –Zoster (VZV); and –Epstein Barr virus (EBV)
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Hepatitis B Virus
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Hepatitis B Can be acute or chronic It can last for up to several months in acute infections Many years (even for life) in chronic infections.
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RNA Viruses
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Influenza virus
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Rotavirus Intestine – causes diarrhea, especially in children. The term "rota", meaning wheel
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Paramyxoviruses measlesmumpsencephalitis
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VIRAL CLASSIFICATION - review RNA or DNA Retrovirus single-stranded or double- stranded shape enveloped or not
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A couple of “strange bugs” Hard to classify …
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Rickettsia These organisms are small Pleomorphic (can change shape) coccobacilli Their structure similar to Gram-negative bacteria
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Rickettsia
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Mycoplasmas Mycoplasma are the smallest organisms lacking cell walls that are capable of self- replication Seven different species infect humans Pneumonia for example
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H1N1
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1918 Flu Killer Flu Spanish Flu
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Killed somewhere between 20 – 50 million; infected 500 million
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Viral Hemorrhagic Viruses Ebola
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Ebola hemorrhagic fever The Ebola virus was first identified in Sudan and in a nearby region of Zaire (now Democratic Republic of the Congo) in 1976. Ebola is one of the most virulent (deadly) viral diseases known to humankind, causing death in 50-90% of victims cases.
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Ebola The Ebola virus is transmitted by direct contact with the blood, body fluids and tissues of infected persons. Transmission of the Ebola virus has also occurred by handling ill or dead infected chimpanzees.
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Ebola outbreak contained in Uganda 22 February 2008 (article from WHO) In November 2007: the Ministry of Health in Uganda confirmed an outbreak of Ebola in Bundibugyo. In all, 149 cases were detected and 37 patients died.
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CDC – Ebola - Current http://www.cdc.gov/vhf/ebola/index.html Case Counts: http://www.cdc.gov/vhf/ebola/outbreaks/20 14-west-africa/case-counts.html http://www.cdc.gov/vhf/ebola/outbreaks/20 14-west-africa/case-counts.html http://www.cdc.gov/vhf/ebola/outbreaks/20 14-west-africa/case-counts.html
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