![](/olcweb/styles/shared/spacer.gif) | ![](/sites/dl/free/0072320427/title/cover_image.JPG) Foundations in Microbiology, 4/e Kathleen Park Talaro,
Pasadena City College Arthur Talaro
RNA Viruses
Chapter Overview- RNA viruses are responsible for a large number of human infections, and are especially prominent causes of emerging diseases.
- RNA viruses may be enveloped or not; most contain single-stranded RNA, but one group has double-stranded.
- The influenza viruses are highly variable viruses that cause influenza, an epidemic respiratory disease.
- Miscellaneous respiratory infections caused by enveloped RNA viruses are parainfluenza, mumps, measles, and croup.
- Zoonotic RNA viruses are spread by animal vectors:
- Bunyaviruses (hantaviruses) are spread by rodents and are involved in serious respiratory infections.
- Arenaviruses are carried by rodents and can cause hemorrhagic fevers.
- The arthropod-borne arboviruses are the agents of yellow and dengue fever.
- Lyssavirus (rabies virus) is a fatal brain infection acquired from contact with mammals.
- Retroviruses are unusual viruses that can use single-stranded RNA to synthesize double-stranded DNA using a reverse transcriptase enzyme.
- One prominent example is the human immunodeficiency virus (HIV), the cause of acquired immunodeficiency syndrome (AIDS), a devastating infection of the white blood cells.
- AIDS is spread through sexual intercourse and contact with blood.
- The destruction of specific immune function by HIV leads to opportunistic infections, cancers, and metabolic dysfunction.
- Picornaviruses are very small nonenveloped RNA viruses that may be spread through close contact and orofecally in food and water.
- Examples of picornaviruses are:
- enteric viruses, including poliovirus, an infection of the central nervous system that can cause paralysis, and hepatitis A, an acute form of liver infection;
- rhinoviruses and coxsackieviruses, which are major agents of the common cold syndrome.
- Rotavirus is the only double-stranded RNA virus and a common cause of viral gastroenteritis.
- Prions are very unusual infectious proteins transmitted by infectious tissues and secretions. They cause slow, progressive neurological diseases called spongiform encephalopathies (Creutzfeldt-Jakob disease).
|
|