Viruses Flashcards
- Acellular
- Small obligate anaerobes intracellular prasites
- composed of proteins & nucleic acids
- DO NOT replicate
Virus
- obligate intracellular parasites
- “acellular”, “nonliving”
- protein and NAs composition
Viruses
- complete virus particle
- either DNA/ RNA encased in a capsid
- may or may not be surrounded by a lipoprotein
Virion
DNA or RNA
Nucleic Acid Core
– Protein component
– for protection
– basis if viral symmetry
Capsid
– Some are naked
– General Rule:
— Enveloped - more susceptible
— Naked - less susceptible
Viral envelope
Symmetry
- Cubic/ Icosahedral
- Helical
- Complex
Cubic/ Icosahedral
- Rhino
- Adeno
- Polio
Helical
- TMV: Tobacco Mosaic Virus
- Corona
Complex
- Pox
- Bacteriophage
- largest
- most complex
Pox
- smallest
- lipid containing virus
Hep B
Viral replication
- Attachment
- Penetration
- Uncoating
- Expressing viral gene
- Replication
- Virion synthesis
- Release
Lytic
- Virus invades
- Creates copies of itself
- Bursts cell to release its virions
Lysogenic
- Virus invades
- It incorporates its genetic material in the hosts DNA (Provirus/ Prophage)
- Bursts cell to release its virions
DNA virus
- DS
- Icosahedral
- Nucleus
EXCEPTIONS
- ssDNA: Parvo-
- complex: Pox
- Cytoplasm: Pox
RNA virus
- Helical
- Enveloped
- Cytoplasm
EXCEPTIONS
• Unenveloped: Picorna- Reo- Calici- • Nucleus: Retro- Orthomyxo- Influenza- • dsRNA: Reo-
Naked DNA
- Parvo
- Papova
- Adeno
Enveloped DNA
- Herpes
- Hep B
- Pox
- (+) Sense RNA
- May be directly translated into their viral proteins
- PiCoTCaFlaRe
- Picorna
- Corona
- Toga
- Calici
- Flav
- Retro/ Reo
- (-) Sense RNA
- needed to be converted by RNA polymerase before they can be translated into their viral proteins
- ParFABOR
- Paramyxo-
- Filo-
- Arena-
- Bunya-
- Orthomyxo-
- Rhabdo
Viral Exanthems
- German measles/ Rubella
- Measles/ Rubeola
- Erythema infectosum
- Rubivirus
- transmission: respiratory droplets
- “3 day fever”, 3rd fever
- incubation — already infectious
German Measles/ Rubella
- mental retardation
- deafness
- glaucoma
Congenital Rubella
Vaccine for German Measles
- MMR
— live attenuated
— 2 doses
- Morbillivirus (family Paramyxoviridae)
- transmission: respiratory
- FIRST DISEASE
- ✔️ 1 serotype
- characteristic: Koplik Spots
Measles/ Rubeola
Other members of Paramyxoviridae
- RSV
- Mumps virus
Pneumonia
RSV: Respiratory Syncytial Virus
- self limiting
- very contagious
- manifestations: Parotisis — inflamm. of parotid glands
Orchitis — testicles
Mumps virus
- “Slapped cheek syndrome”
- transmission: repsiratory
- FIFTH DISEASE/ Erythema Infectiosum
Parvovirus
Pox Virus
- Molluscum contagiosum
- Cowpox
- Smallpox
- Fleshy, dome-shaped papules
- transmission: skin contact
Molluscum contagiosum
Milker’s nodules
Cowpox
Variola virus
Small pox
- one serotype
- only humans are reservoir
- ✖️subclinical stage
Variola Virus
HHV 1
HSV 1 — Oral herpes
HHV 2
HSV 2 — Genital Herpes
HHV 3
VZV — Chickenpox
HHV 4
EBV — Infectious mononucleosis
HHV 5
CMV — Associated with Rhinitis
HHV 6, 7
Roseolovirus — Exanthem subitum
HHV 8
Kaposi Sarcoma Related
Herpes Simplex 1 & 2
- Herpetic whitlow – fingers
- Herpes keratitis – cornea
- Herpes gladiotorum – skin; wrestling
- Eczema herpeticum – blistery skin rash
Varicella Zoster Virus
• Chickenpox — shingles (reactivation)
— sharply demarcated in midline
— painful
- “kissing virus”
- transmission: saliva
- infectious mononucleosis
- Burkitt’s Lymphoma
- Assoc. w/ Nasopharyngeal carcinoma
Epstein Barr Virus