Question
What is the difference between HIV-1 and HIV-2?
27 September 2006. Related: All topics, Other tests.
What is the difference between HIV1 and HIV2 with regards to structure, function, occurence and survival in the environment?
Answer
HIV-1 and HIV-2 are two different viruses. HIV-1 is the main family of HIV and accounts for 95% of all infections worldwide. HIV-2 is mainly seen in a few West African countries. The spread in the rest of the world is negligible.
Although HIV-2 generally progresses more slowly than HIV-1, some HIV drugs (NNRTIs like nevirapine and efavirenz) do not work against HIV-2.
On a structural level HIV-1 and HIV-2 have important genetic differences. A technical description of the difference is that the vpu gene found in HIV-1 is replaced by the vpx gene in HIV-2. In addition, the protease enzymes from the two viruses, which are aspartic acid proteases and have been found to be essential for maturation of the infectious particle, share about 50% sequence identity.
There are, however, differences in substrate and inhibitor binding between these enzymes. Most notably between the CGP 53820 inhibitory binding.
On functional level, there is a difference between the two viruses in terms of how easy it is for the virus to infect someone. HIV-1 enters the immune system by attaching onto the CD4+ receptor found on the surface of certain white blood cells. HIV-2 has a harder time gaining such a foothold.
So HIV-2 generally progresses much more slowly, with lower viral laod and slower risk of becoming sick. However, some HIV drugs (including NNRTIs) are not active against HIV-2.
Both viruses are fragile and highly susceptible to physical and chemical agents and therefore do not survive well outside the human body. HIV in blood or sexual fluid for example is not infectious after it has been outside the body for a few minutes.
Notes: this answer was updated in January 2018.
Hi Mercy, HIV is easy to treat. With treatment people live normal active lives.
can u have HIV and still live a normal life? and can it be treated?
Hi. HIV-2 can still be treated using other HIV meds. Your doctor can talk about this. None of the drugs in the NNRTI group work agains HIV-2 but NRTIs (nukes) and protease inhibitors (PIs) do.
If nevirapine can’t protect hiv2…….what drug we can use in a case of hiv 2 infected mother going to birth to her baby??
Not if they have access to treatment. HIV treatment is very effective.
does it mean a person with hiv-1 is at a high risk of dying
Transmission questions are already answer in the FAQ page:
http://i-base.info/qa/factsheets/hiv-transmission-and-testing
Or in this online guide:
HIV testing and risk of transmission
Hi, with regard to a patient being sent to the lab to test for hiv 1 + 2 al + p24 g does it already confirm that he/ is hiv positive?
Hi,
You can find an answer to a similar question here:
http://i-base.info/qa/36
Thanks for the information,but my question is,can HIV1 degenerate to HIV2, What is the origin of both of them,are they from different sources.