Viral Infections and Immune Response

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Questions and Answers

What is the characteristic symptom of the rash that appears on the cheeks of children infected with parvovirus B19?

Papular rash

Slapped cheek appearance (correct)

Butterfly-like rash

Maculopapular rash

What is the common symptom experienced by adults infected with parvovirus B19?

Polyarthritis with or without a rash (correct)

Aplastic crisis

Hydrops fetalis

Erythema infectiosum

What is the serious complication of parvovirus infection in people with chronic hemolytic anemia?

Erythema infectiosum

Aplastic crisis (correct)

Polyarthritis

Hydrops fetalis

What is the effect of parvovirus infection on hemoglobin levels during the prodromal period?

Slight decrease Signup and view all the answers

What is the duration of reticulocytopenia in patients with chronic hemolytic anemia infected with parvovirus B19?

7 to 10 days Signup and view all the answers

What is the risk of fetal death in a pregnant seronegative mother infected with parvovirus B19?

Significantly increased risk Signup and view all the answers

What is the effect of parvovirus infection on erythropoiesis in the bone marrow of patients with chronic hemolytic anemia?

Transient reduction Signup and view all the answers

What is the characteristic symptom of parvovirus infection in immunocompromised individuals?

Chronic disease Signup and view all the answers

What was the appearance of the daughter's face?

As if it had been slapped Signup and view all the answers

What symptom did the mother report having more of than usual?

Joint pain Signup and view all the answers

When was the child contagious?

During the initial disease signs and symptoms Signup and view all the answers

What causes the initial nonspecific disease signs?

Interferon and other innate responses to the infection Signup and view all the answers

What causes the rash?

Antibody and virion immune complexes Signup and view all the answers

Why are individuals with chronic hemolytic anemia at increased risk for serious disease after B19 infection?

Because B19 replicates in erythrocyte precursors and prevents development of new erythrocytes or shortens their lifetime Signup and view all the answers

Why is quarantine a poor means of limiting the spread of B19 parvovirus?

Because the virus is spread before the onset of the classic disease signs and symptoms of erythema infectiosum Signup and view all the answers

What is a risk factor for serious disease after B19 infection in pregnant women?

Hydrops fetalis and loss of the fetus Signup and view all the answers

What is a notable symptom of Parvovirus B19 infection?

Slapped-face rash Signup and view all the answers

What is a symptom of Parvovirus B19 infection in adults?

Arthralgia Signup and view all the answers

What is the typical course of Parvovirus B19 infection?

Biphasic disease Signup and view all the answers

What is the characteristic rash of Parvovirus B19 infection?

Slapped-face rash Signup and view all the answers

What is the time frame during which a child with Parvovirus B19 infection is contagious?

Before the onset of symptoms Signup and view all the answers

What is the underlying condition that increases the risk of serious disease after Parvovirus B19 infection?

Anemia Signup and view all the answers

What is the reason why quarantine is a poor means of limiting the spread of Parvovirus B19?

The child is contagious before the onset of symptoms Signup and view all the answers

What is the diagnostic method used to detect Parvovirus B19 DNA in clinical samples?

PCR Signup and view all the answers

Study Notes

Phases of Parvovirus B19 Infection

Large numbers of viruses are released in oral and respiratory secretions during the first phase, making the person contagious.
The second phase is immune-mediated, characterized by arthralgia and rash, which occur when specific antibodies react with B19 and form immunocomplexes that deposit and cause tissue injury.

Effects of Parvovirus B19 Infection

In children, B19 virus causes erythema infectiosum (fifth disease), characterized by a distinctive rash on the cheeks, which appears as if they have been slapped.
In adults, B19 infection causes polyarthritis (with or without a rash) that can last for weeks.
In patients with chronic hemolytic anemia (e.g., sickle cell anemia), serious complications can occur, including aplastic crisis, characterized by a transient reduction of erythropoiesis in the bone marrow, leading to reticulocytopenia, decreased hemoglobin levels, and systemic manifestations of fever, rash, and arthralgia.

Diagnosis and Treatment

Diagnosis is usually based on clinical picture, but definitive diagnosis can be made using serological techniques (ELISA for B19 IgM and IgG) and molecular techniques (PCR for detecting B19 DNA in clinical samples).
No specific antiviral treatment or human vaccine is available.

Case Study

The symptoms of the mother and daughter are related, as they are both caused by the presence of antibody, formation of immune complexes, and hypersensitivity reactions.
The biphasic nature of the disease and the slapped-face rash are notable symptoms of parvovirus B19 etiology.
Quarantine is a poor means of limiting the spread of B19 parvovirus because the virus is spread before the onset of the classic disease signs and symptoms of erythema infectiosum (fifth disease).

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Description

This quiz covers the two phases of a viral infection, including the contagious phase and the immune-mediated phase, and its symptoms such as rash and joint pain. Learn about the effects of the virus on children and normal individuals.