Question 1: Define HIV and explain how it causes AIDS.

Answer: HIV (Human Immunodeficiency Virus) is a virus that infects and destroys helper T cells of the immune system, leading to AIDS (Acquired Immunodeficiency Syndrome), which is the condition characterised by a severely weakened immune system.

Question 2: Describe how HIV is transmitted between individuals.

Answer: HIV is transmitted through exchange of infected body fluids such as blood, semen, vaginal fluids, and breast milk, typically via unprotected sexual contact, blood transfusions, sharing needles, or from mother to child during childbirth or breastfeeding.

Question 3: In forensic investigations, how can scientists detect the presence of HIV in a person's bodily fluids?

Answer: Scientists can detect HIV using techniques such as PCR (Polymerase Chain Reaction) to identify viral DNA or RNA, or enzyme-linked immunosorbent assay (ELISA) tests to detect antibodies against HIV in blood samples.

Question 4: Calculate the viral load if a forensic lab detects 1500 copies of HIV RNA per millilitre of blood. Express your answer in copies per millilitre.

Answer: 1500 copies/ml

Question 5: Why is it important for forensic scientists to understand the replication process of HIV?

Answer: Understanding HIV replication helps forensic scientists develop accurate detection methods, trace infection sources, and understand how the virus persists and spreads in individuals.

Question 6: Propose a basic experimental outline for detecting HIV in a forensic blood sample, including key steps and safety precautions.

Answer: The experiment involves collecting a small blood sample in a sterile environment, using PPE to prevent contamination, extracting nucleic acids from the sample, performing PCR amplification of HIV-specific genetic material, and analysing the results. Safety precautions include wearing gloves, lab coat, eye protection, and working in a biosafety cabinet to prevent exposure to infectious agents.

Question 7: A forensic scientist finds a blood sample containing 2.5 x 10^4 copies of HIV DNA. What does this suggest about the infection status of the individual?

Answer: It suggests the individual is infected with HIV and has a significant viral load, indicating active infection and potential for transmission.

Question 8: Explain the significance of detecting HIV-specific antibodies in forensic samples.

Answer: Detecting HIV-specific antibodies indicates that the person has been exposed to the virus and has mounted an immune response, which can be used as evidence in forensic investigations to determine infection status.

Question 9: Discuss one ethical consideration when using forensic evidence to detect HIV in individuals.

Answer: Ethical considerations include privacy and confidentiality, ensuring that sensitive health information is protected and only used for legal purposes, and obtaining consent where possible.

Question 10: In a forensic investigation, a sample shows a high viral load but no antibodies are detected. What could this imply about the stage of infection?

Answer: This could imply a very early stage of infection before the immune system has produced detectable antibodies, or an immunocompromised state where antibody production is impaired.

Question 11: Describe how advances in forensic science could help in controlling the spread of HIV in the community.

Answer: Advances such as rapid detection methods, genetic analysis of viral strains, and improved contact tracing can help identify sources of infection, monitor transmission patterns, and implement targeted interventions to reduce spread. Ethical use of forensic data ensures privacy while aiding public health efforts.