Hepatitis A Virus (HAV)
🔸Causes: Hepatitis A 🔸Transmission: Through ingestion of food or water contaminated with feces from an infected person (fecal-oral route) Disease Characteristics 🔸Acute phase: Most cases resolve spontaneously 🔸Does not become chronic 🔸Prevention: Vaccination provides effective immunity and is widely used Laboratory Testing 1.Serological Tests 🔸Anti-HAV IgM: Detects acute infection. Appears 1–2 weeks before symptom onset and persists for about 3–6 months. 👉A Positive result indicates an ongoing acute HAV infection. 🔸Anti-HAV IgG: Indicates immunity to HAV. Appears after infection or vaccination and persists lifelong. 👉A Positive result indicates previous infection or successful vaccination and provides long-term immunity. Summary : 🔸Anti HAV IgM → Recent infection 🔸Anti HAV IgG → Long-term immunity 2. Molecular Tests 🔸HAV RNA detection (RT-PCR): Detects viral genetic material in blood or stool. 🔸Used to confirm acute infection, especially when IgM is not yet dete...