Viral infection- Human immunodeficiency virus

Types of HIV

• The two main types of HIV are–

             HIV-1 (the common one) and HIV-2 (uncommon and less infectious).

HIV-1 and HIV-2

• The two different viruses are HIV-1 and HIV-2. Only one antibody test currently available can specifically differentiate between antibodies to HIV-1 or HIV-2, although tests that are sensitive to both types of viruses are widely available.
• Worldwide, the most important virus is HIV-1. HIV-1 accounts for around 95% of all infections worldwide. HIV-2 is supposed to be more than 55% genetically distinct from HIV-1
• Almost uncommon HIV-2 virus is concentrated in West Africa but has been seen in other countries with links to West Africa. As compared to HIV-1, it is less infectious and progresses more slowly, leading to fewer deaths. Yet, most people living with HIV-2 will ultimately progress to AIDS and die from the disease if not taken treatment.
• The commonly used antiretroviral drugs are active against HIV-2, non-nucleoside reverse transcriptase inhibitors (NNRTIs) like nevirapine and efavirenz do not work against it. The way to treat HIV-2 has been less clearly defined than HIV-1.

Key Features about HIV-1 and HIV-2

• Like many viruses, the capability of HIV is to mutate and change over time – there are many genetically distinct subgroups, within the most main types of HIV.
• To diagnose HIV Tests and monitor the level of the virus within the body that are sensitive to the full range of subtypes do exist, but might not be readily available in all settings.
• Both produce the same patterns of illness. SAS compared to HIV-1, HIV 2 causes a slower progression of the disease.
• It is important for tests to detect the HIV subtypes that are present within the region. Alternatively, testing may lead to false-negative results.