Virus

• Viruses


  Obligatory intracellular parasites
• Virus Characteristics

  • Contain only one form of nucleic acid, either DNA or RNA.
  • Contain a protein coat that covers the nucleic acid
  • Multiply inside living cells by utilizing the cell's synthesis mechanism
  • Causes the formation of specialized structures capable of transferring viral nucleic acid to cells.
• Viral genes carried in the genomes of other organisms provide a record of viral evolution characteristics
• Viruses infect a wide range of hosts, including invertebrates, Vertebrates, Plants, Protosis, Fungi, Bacteria
• Virus Contains a protein coat that covers the nucleic acid
• Smallest Size of a virus 


  20 nm
• Normal size of influenza and human immunodeficiency virus 


  100 nm
• Viruses are classified by:

  •Nucleic acid

  • Differences in structures of coats
• capsid 


  Is a protein shell that encloses the viral genome.
• Common shapes of capsids  

  Icosahedral, prolate and Helical
• Measles


  Skin viral infection caused by the measles virus (also known as rubeola virus)
• Measles Symptoms 


  • Fever
  • Conjunctivitis
  • Cough
  • Koplik spots in the mouth
  • Red blotchy skin rash
• Pathogen of measles

  Measles virus (also known as rubeola virus)
• Measles

  RNA virus, in the family Paramyxoviridae
• German Measles (Rubella)


  Mild febrile viral disease
• German Measles (Rubella)


  • Fine, pinkish flat rash appears
• Pathogen of German Measles

  Rubella virus
• Roseola Infantum also knows as:

  Exanthem Subtium or sixth disease
• Roseola Infantum 


  Sixth disease caused by human herpes virus 6
• Symptoms of Roseola Infantum :

  Sudden onset high-grade fever

  Generalized rash that lasts for 2 days
• Erythma infectiosum 


  Slapped cheek appearance, rash
• Erythma Infectiosum 


  Fifth disease caused by Parvovirus B 19
• Chickenpox also known as Varicella is caused by varicella-zoster virus (VZV)
• Chickenpox

  Acute, generalized viral infection with fever and skin rash
• Smallpox

  • Fever
  • Malaise
  • Headache
  • Prostration
  • Severe backache
  • Distinctive skin rash
• Smallpox is caused by 2 strains of variola virus
• Warts

  • Common warts (verrucae vulgaris)
  • Venereal warts
  • Plantar warts
• Warts are harmless but some become cancerous
• Adenoviral conjunctivitis and keratoconjunctivitis


  • Inflammation of conjunctiva
  • Edema of the eyelid
  • Periorbital tissue
  • Pain
  • Photophobia
  • Blurred vision
• Adenoviral conjunctivitis and keratoconjunctivitis are caused by various types of adenovarious: Herpes Simplex and Varicella
• Herpes simplex


  Viral infection
• Hemorrhagic conjunctivitis


  • Sudden onset
  • Redness
  • Swelling
  • Pain in the eyes
• Varicella (Chickenpox)


  Acute, generalized viral infection with fever and skin rash
• Herpes zoster (Shingles)


  • Reactivation of varicella virus
  • Inflammation of sensory ganglia of cutaneous sensory nerves
  • Fluid-filled blisters
  • Pain
  • Paresthesia