Microbiology Demystified

such as in the bodies of AIDS patients or in infants whose immune sys-

tems are not fully developed. This virus can be fatal to some infants.

• Epstein-Barr Virus (EBV). Epstein-Barr virus causes infectious mono-
  nucleosis.


• Papovaviridae—Papovaviruses such as the human papilloma virus (HPV),
  which causes warts (papillomas) and tumors (polyomas).


• Poxviridae. Poxviridae causes pox (pus-filled lesions) diseases such as
  smallpox.


• Adenoviridae. Adenoviruses cause acute respiratory disease, which is the
  common cold virus.

RNA virus

An RNA virus is a virus that contains RNA but not DNA. Common RNA

viruses are:

• Flaviviridae. Flaviviruses, such as the Dengue virus that causes Break
  Bone Fever, are carried by mosquitoes. Break Bone Fever results in
  skin lesions, fever, and muscle and joint pain, and is often fatal. Other
  Flaviviruses include:
  
  
  • St. Louis encephalitis virus. St. Louis encephalitis viruscauses an infec-
    tion that is not easily recognized. Wild birds and mosquitoes carry St.
    Louis encephalitis virus. Monkeys carry a form of this virus called yel-
    low fever virus, which is transmitted to humans by mosquitoes and
    leads to severe liver damage.
  
  
  • Hepatitis C virus (HCV). Hepatitis C Virus is called non-A Hepatitis
    virusand non-B Hepatitis virusand results in chronic infection. Humans
    contract this virus from needle pricks and blood transfusions.
  
  
  
  


• Picornavirus. Picornavirussuch as the Polioviruscauses Poliomyelitis and
  kills motor neurons resulting in weakness and loss of muscle tone (flaccid
  paralysis). Others include:
  
  
  • Hepatitis A Virus (HAV).Hepatitis A virus (HAV) is also known as
    infectious hepatitis and is transmitted through a fecal-oral route.
  
  
  • Rhinovirusis the most frequent cause of the common cold. It causes
    localized upper respiratory tract infections.
  
  
  
  


• Retroviridae. Retroviruses are a group of RNA viruses that include the fol-
  lowing commonly recognized viruses:
  
  
  • Human immunodeficiency virus (HIV). (Lentivirus) human immunod-
    eficiency virus is a virus that often results in acquired immunodeficiency
  
  
  
  

(^190) CHAPTER 12 Viruses, Viroids, and Prions