Human Immunodeficiency Virus

HIV, or human immunodeficiency virus, is the virus that causes AIDS (acquired immuno-deficiency syndrome).

It attacks the immune system by destroying CD4 positive (CD4+) T cells that are vital to fighting off infection. HIV belongs to a class of viruses known as retroviruses.

Within that class, HIV is in the lentivirus subgroup, the members of which are known for having a long time period between initial infection and the beginning of serious symptoms. This is why there are many people who are unaware of their HIV infection and can unknowingly spread the virus to others. Early detection of HIV infection is critical in helping to minimize further transmission of the disease.

The four main routes of infection are unsafe sex, contaminated needles, breast milk from an infected mother, and birth to an infected mother. Transmission through blood and blood products has largely been eliminated as a result of screening of blood donations.

Since the beginning of the epidemic, almost 70 million people have been infected with the HIV virus and about 35 million people have died of HIV. Globally, 36.7 million [34–39.8 million] people were living with HIV at the end of 2015 and within that year 1.1 million people died of AIDS-related illnesses.1

Data from 146 countries show that some have achieved declines in new HIV infections among adults of 50% or more over the last 10 years, while many others have not made measurable progress, and yet others have experienced worrying increase in new HIV infections.2

With the right tools for screening and monitoring the disease, and therapy such as antiretroviral drugs, HIV can be a manageable disease.

Coinfection of HIV and Syphilis 3

One of the major concerns associated with HIV and syphilis co-infection is that syphilis facilitates HIV acquisition and transmission.

Syphilis has been estimated to increase HIV transmission 2- to 9-fold and HIV acquisition 2- to 4-fold. The presence of genital ulcers can increase HIV acquisition through disruption of the natural mucosal and epithelial barriers. Syphilis can also increase HIV transmission by increasing viral shedding and seminal viral load.

Furthermore, infection with Treponema  pallidum has been shown to transiently decrease CD4 counts in HIV-infected patients and increase HIV viral load, both of which have been linked to an increase in HIV transmission.

The Human Immunodeficiency Virus

The Human Immunodeficiency Virus

  1. World Health Organization (WHO) Global Health Observatory (GHO) HIV/AIDS Global Situation and Trends [Online] Accessed: 14 Nov 2014 Available at:
  2. Prevention gap report, UNAIDS, 2016
  3. HIV Clinician, Spring 2010, Vol. 22, No. 2, 7-10