Tuesday, 28 October 2014

Why Ebola virus is not human immunodeficiency virus (HIV)

I'm not an HIV expert and only an Ebola virus hobbyist but let's see if we can list some things that are similar and different about these two viruses.

Some ways that Ebola virus and HIV are similar...
  1. Both are harder to catch than a cold. They do not spread through an airborne route.
  2. Both have lipid envelopes - Ebola virus is about 904-
    1,100nm long x 80nm wide whereas HIV is about 120nm around
  3. Both can be transmitted in blood, breast milk, and through sexual contact, being present in seminal fluid (HIV also in female genital secretions). For HIV the extent of the frequency of exposure and the viral load play during that exposure, play a role in the likelihood of infection; this is not well defined for Ebola virus.[1]
Some ways that Ebola virus and HIV differ...
  1. HIV is an RNA virus that goes through a DNA phase which allows it to hide in our cells while Ebola virus is strictly an RNA virus
  2. Ebola virus infects dendritic cells, monocytes, macrophages, endothelial cells, endocardium, kidney and liver cells but not peripheral lymphocytes while HIV primarily infects CD4+ lymphocytes and also dendritic cells
  3. They differ in the mechanics underpinning the way that they replicate themselves
  4. Ebola virus disease occurs very quickly whereas acquired immunodeficiency syndrome (AIDS) has a long latent period (although there is an earlier more acute disease)
  5. At writing, no antiviral or vaccines exist on the market for Ebola virus or Ebola virus disease; a range of drugs exist to slow or suppress HIV
  6. Ebola virus acutely kills cells, causes coagulation, organ damage and disrupts the immune response without lingering; HIV eventually becomes latent in the cells it infects, integrating with the genome
  7. Ebola virus has 7 genes, HIV has 9 and overlapping reading frames.
References...
  1. Principles of virology. Flint SJ, Enquist LW, Racaniello VR, Skalka AM.3rd Edition. Vol 2. Chap 6.