**Question:** A nurse develops clinical symptoms consistent with hepatitis. She recalls sticking herself with a needle approximately 4 months ago after drawing blood from a patient. Serologic tests for HBsAg, antibodies to HBsAg, and hepatitis A virus (HAV) are all negative; however, she is positive for lgM core antibody. The nurse

A. IgM anti-HAV
B. HBV (hepatitis B virus)
C. HCV (hepatitis C virus)
D. HDV (hepatitis D virus)

**Correct Answer:** D. HDV (hepatitis D virus)

**Core Concept:** Hepatitis is a group of viral infections causing inflammation of the liver. Hepatitis viruses can be broadly classified into three types: A, B, and C. Hepatitis A virus (HAV) is usually acquired through the ingestion of contaminated food or water, while hepatitis B virus (HBV) and hepatitis C virus (HCV) are transmitted through blood or bodily fluids. Hepatitis D virus (HDV) is a satellite virus that requires the presence of hepatitis B virus (HBV) to cause infection, as it relies on HBV for its replication.

**Why the Correct Answer is Right:** The nurse's serologic test results indicate that she has antibodies for hepatitis B core antigen (HBcAg), suggesting a recent or past HBV infection. Hepatitis D virus (HDV) is a satellite virus that requires the presence of HBV to cause infection, as it relies on HBV for its replication. Therefore, the nurse is likely infected with HDV, which is why option D is the correct answer.

**Why Other Options are Incorrect:**

A. IgM anti-HAV: IgM anti-HAV is a specific antibody found in acute hepatitis A virus infection, which the nurse does not have.

B. HBV (hepatitis B virus): The nurse has antibodies for HBcAg, indicating a past or current HBV infection, but the question specifies that the nurse is infected with hepatitis D virus.

C. HCV (hepatitis C virus): Similar to option A, HCV-specific IgM antibodies are found in acute hepatitis C virus infection, which is not the case for the nurse.

**Clinical Pearl:** In healthcare settings, maintaining strict infection control measures is crucial to prevent transmission of hepatitis viruses, especially among healthcare professionals who may be at a higher risk due to occupational exposure.