VIH, or Virus de Inmunodeficiencia Humana, is a virus that attacks the immune system, specifically targeting CD4 cells, which are crucial for fighting infections. If left untreated, VIH can lead to SIDA (Síndrome de Inmunodeficiencia Adquirida), a condition where the immune system becomes severely weakened, making the body more susceptible to infections and diseases. The virus is primarily transmitted through blood, semen, vaginal fluids, and breast milk. Common ways of transmission include unprotected sexual contact, sharing needles, and from mother to child during childbirth or breastfeeding. Early detection and treatment with antiretroviral therapy can help manage the virus and improve quality of life.