Which virus is transmitted by blood, semen or body fluids and causes immune system breakdown?

• A. Human Immunodeficiency Virus
• B. Hepatitis B
• C. Influenza
• D. Herpes

Answer: (A)

The key idea is identifying a virus that not only spreads through blood and body fluids but also compromises the body's immune defenses. HIV fits this exactly: it is transmitted through blood, semen, vaginal fluids, rectal fluids, and breast milk, and it attacks the immune system by infecting CD4+ T cells, gradually reducing their numbers. This weakening of the immune system leads to Acquired Immunodeficiency Syndrome, making the body far less able to fight infections and cancers.

Hepatitis B also travels through blood and body fluids but primarily damages the liver, not the immune system in a way that causes the global immunodeficiency seen with HIV. Influenza spreads mainly through respiratory droplets and doesn’t cause lasting immune-system breakdown. Herpes is sexually transmitted and can cause local sores, but it doesn’t produce the systemic immune deficiency characteristic of HIV.