The patient was a 32-year-old male who presented to the emergency room with a 3-day history of fever (maximum temperature, 40EC), malaise, and back pain. Laboratory data revealed a WBC count of 4,700/mm³ and abnormal liver function test results. Blood cultures were done and were subsequently reported as negative. He developed anorexia and jaundice in addition to fevers and malaise. He denied a history of intravenous drug use, sexual contact (for 2 months), and transfusions. Five weeks ago he was visiting friends in New York City, and they ate raw oysters. Recent telephone contact with one of the friends revealed that he had a similar illness.

On examination the patient was mildly icteric (jaundiced). There was no rash or lymphadenopathy. The abdominal examination revealed a tender liver, which was slightly enlarged. The spleen tip was nonpalpable. Laboratory tests showed an AST level of 2,501 U/liter, and alkaline phosphatase level of 298 U/liter, a bilirubin level of 2.2 mg/dl, and a lactate dehydrogenase (LDH) level of 1,102 U/liter. Serum Hepatitis A IgM antibody was positive. Over the next month his symptoms resolved and the liver function test results returned to within normal limits.

1. How is the virus transmitted?  Answer
   

2. Describe how the HAV infection was detected?  Answer
   

3. Why was liver function so abnormal and then returned to normal? Explain the differences in clinical presentation between adults and children?  Answer

4. What are the long term consequences for HAV infection?  Answer
   

5. There is now a vaccine available for HAV. What type of vaccine is this and who should receive it?  Answer
   

6. What should be done for household contacts of the patient?  Answer