August 23, 2012

Coinfection of a RNA virus with a DNA virus

A lecturer is giving a talk about a ribonucleic acid virus that causes hepatitis. He is describing how this virus requires coinfection with a deoxyribonucleic acid virus to support its replication. This virus has been confined primarily to populations with frequent percutaneous exposures, such as drug addicts and hemophiliacs.

Which virus or viral agent is he talking about?

a) Recombinant hepatitis B vaccine
b) Hepatitis C virus
c) Hepatitis B surface antigen
d) Hepatitis C vaccine
e) Hepatitis D
f) Hepatitis B immune globulin (HBIG)
g) Hepatitis B virus DNA
h) Hepatitis B e antigen
i) Hepatitis A
j) Atopic dermatitis






ANSWER
The correct answer is E

Explanation
Hepatitis D is a ribonucleic acid (RNA) virus that requires coinfection with hepatitis B (a deoxyribonucleic acid [DNA] virus) to support its replication. Infection with this agent occurs either simultaneously with acute hepatitis B infection or is superimposed on chronic hepatitis B. Like hepatitis B, hepatitis D is transmitted by percutaneous inoculation and intimate contact.

In nonendemic areas, such as the United States and western Europe, hepatitis D has been confined primarily to populations with frequent percutaneous exposures, such as drug addicts and hemophiliacs. In endemic areas, such as the Mediterranean countries, hepatitis D is transmitted primarily through intimate contact.

Hepatitis D (delta hepatitis) is being recognized with increasing frequency. Its incubation period is similar to that for hepatitis B, and, when both hepatitis B and hepatitis D infections are acquired simultaneously, a single clinically apparent episode of hepatitis may ensue. There is a slight increase in the risk of fulminant hepatitis when the two infections occur simultaneously, but, in general, the outcome of simultaneous acute hepatitis B and D is no different from the outcome of hepatitis B alone.

In contrast, among patients with chronic hepatitis B infection, superimposed hepatitis D may lead to severe, fulminant hepatitis, convert a mild or asymptomatic chronic hepatitis B infection into a severe form of chronic hepatitis ( chronic active hepatitis), or accelerate the course of chronic active hepatitis. A diagnosis of delta hepatitis is made by demonstrating the appearance of antibody to hepatitis D (anti-HDV).

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