This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Least concentration of human immunodeficiency virus is seen in 
Select and explain. 
A. Saliva, B. CSF, C. Blood, D. Semen
A: Saliva
Answer: A: Saliva 
Explanation: Viral load of HIV is maximum in blood, genital secretions like semen, and CSF

It also found in breast milk, saliva, lymphocytes, cell-free plasma, cervical secretions, saliva, tears, & minimal in urine

Saliva can contain fibronectin & glycoproteins, which prevent transmission of the virus.
A salivary protein called secretory leucocyte protease inhibitor also has anti-HIV activity