What is the primary mode of transmission for HIV?

The primary mode of transmission for HIV is through sexual contact, blood transfusions, and sharing needles. This virus is primarily spread through bodily fluids, particularly blood, semen, vaginal fluids, and breast milk.

Sexual contact is a significant route, as unprotected sex with an infected partner can easily facilitate the transfer of the virus. Blood transfusions present another risk, especially if contaminated blood is transfused, although the risk has been greatly minimized in many countries due to screening protocols. Sharing needles is a critical transmission route among individuals who inject drugs, as it allows for direct entry of infected blood into the bloodstream.

The other modes of transmission listed, such as airborne particles, contaminated food and water, or direct contact with infected skin lesions, are not typical for HIV. The virus does not spread through the air, nor is it transmitted via food or water, as it does not survive long outside the human host. Direct contact with infected skin lesions may pose some risk, but it is not a common mode of HIV transmission. Thus, the options provided do not encompass the established primary transmission pathways of HIV as effectively as the correct answer.