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Questions and Answers
Parvovirus B19's ability to induce transient aplastic anemia in individuals with pre-existing conditions like sickle cell anemia is primarily attributed to its:
Parvovirus B19's ability to induce transient aplastic anemia in individuals with pre-existing conditions like sickle cell anemia is primarily attributed to its:
- Preference for infecting and destroying red blood cell precursors (erythroblasts) in the bone marrow. (correct)
- Induction of a robust cytotoxic T-lymphocyte response that targets infected red blood cells.
- Inhibition of erythropoietin production, leading to reduced red blood cell synthesis.
- Disruption of iron metabolism, causing ineffective erythropoiesis and premature cell death.
The characteristic 'slapped cheek' rash associated with Fifth disease is LEAST likely to be confused with rashes caused by:
The characteristic 'slapped cheek' rash associated with Fifth disease is LEAST likely to be confused with rashes caused by:
- Scarlet fever.
- Rubella.
- Measles.
- Varicella-Zoster Virus. (correct)
Why is PCR preferred over antibody detection for diagnosing parvovirus B19 in immunocompromised patients?
Why is PCR preferred over antibody detection for diagnosing parvovirus B19 in immunocompromised patients?
- PCR is more sensitive in detecting past rather than current infections.
- Immunocompromised individuals often have reduced antibody production, making antibody detection unreliable. (correct)
- PCR assays are less expensive and more readily available than antibody tests.
- Antibody detection is more prone to false-positive results in immunocompromised individuals.
Transplacental transmission of parvovirus B19 is most dangerous to the fetus during the first trimester due to:
Transplacental transmission of parvovirus B19 is most dangerous to the fetus during the first trimester due to:
The joint pain (arthralgia) and arthritis observed in adults infected with parvovirus B19 are primarily attributed to:
The joint pain (arthralgia) and arthritis observed in adults infected with parvovirus B19 are primarily attributed to:
Given that parvovirus B19 lacks its own viral polymerase, its replication strategy necessitates:
Given that parvovirus B19 lacks its own viral polymerase, its replication strategy necessitates:
Why does parvovirus B19 only have one serotype?
Why does parvovirus B19 only have one serotype?
Although generally mild, erythema infectiosum poses a significant threat to individuals with sickle cell disease because it can trigger:
Although generally mild, erythema infectiosum poses a significant threat to individuals with sickle cell disease because it can trigger:
The seasonal prevalence of Fifth disease, with increased incidence in late winter and spring, is most likely related to:
The seasonal prevalence of Fifth disease, with increased incidence in late winter and spring, is most likely related to:
Even though there is no specific antiviral treatment for parvovirus B19 infection, intravenous immunoglobulin (IVIG) is sometimes used in immunocompromised patient due to it's ability to:
Even though there is no specific antiviral treatment for parvovirus B19 infection, intravenous immunoglobulin (IVIG) is sometimes used in immunocompromised patient due to it's ability to:
Flashcards
Parvovirus B19
Parvovirus B19
Nonenveloped single-stranded DNA virus causing Fifth Disease.
Slapped Cheeks Rash
Slapped Cheeks Rash
Bright red rash on cheeks, often seen in children with Fifth Disease.
Aplastic Anemia
Aplastic Anemia
Severe reduction in red blood cell production, possibly caused by Parvovirus B19 in susceptible individuals.
Arthralgia/Arthritis (B19)
Arthralgia/Arthritis (B19)
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Hydrops Fetalis (B19)
Hydrops Fetalis (B19)
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Parvovirus B19 Target Cells
Parvovirus B19 Target Cells
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Diagnosing Parvovirus B19
Diagnosing Parvovirus B19
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Parvovirus B19 Transmission
Parvovirus B19 Transmission
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Parvovirus B19 Treatment
Parvovirus B19 Treatment
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Immunity to Parvovirus B19
Immunity to Parvovirus B19
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Study Notes
- Fifth disease, also known as slapped cheek syndrome or erythema infectiosum, is caused by parvovirus B19
- Parvovirus B19 is a non-enveloped, single-stranded DNA virus
- Parvovirus B19 can trigger spontaneous miscarriages and sickle cell crises
- It can cause transient aplastic anemia in children with chronic anemia (sickle cell anemia, thalassemia, spherocytosis)
- Individuals with sickle cell disease and those who are immunocompromised are particularly at risk
- The virus lacks its own polymerase, relying on the host cell's DNA polymerase for replication and transcription within the nucleus
Properties and Structure
- The parvovirus capsid has icosahedral symmetry
- Parvovirus is the smallest non-enveloped virus, measuring 22nm
- There is only one serotype of parvovirus B19
Transmission and Epidemiology
- Primarily spread via respiratory droplets
- Can also be transmitted through blood transfusions and via transplacental transmission, leading to fetal infections
- First trimester infections can lead to fetal death
- Second trimester infections are associated with hydrops fetalis
- Third trimester infections typically do not result in major complications.
- Parvovirus B19 is not a common cause of congenital abnormalities
- About 50% of adults in the U.S. have antibodies to parvovirus B19 by age 18
- Erythema infectiosum is most common in children aged 4-15 years
- Adults may experience arthralgia or arthritis, especially in females (small joints of hands and feet bilaterally involved)
Pathogenesis
- Parvovirus B19 primarily infects RBC precursor erythroblasts in the bone marrow, leading to aplastic anemia
- Also targets endothelial cells, leading to the rash seen in erythema infectiosum
- IgM/IgG immune complexes contribute to the rash and arthritis in adults
- Infection confers lifelong immunity
Clinical Symptoms
- Causes a mild disease, primarily in children
- Characterized by a bright red rash on the cheeks ("slapped cheeks") with a less intense, "lacy" rash on the body
- May present with low-grade fever, runny nose, and sore throat
- Symptoms typically resolve within a week
Clinical Symptoms - Disease
- Characterized by bright red rash on cheeks
- Other conditions with similar rashes include measles, rubella, scarlet fever, and roseola
- Patients with chronic anemia can develop transient aplastic anemia upon infection
- First-trimester infections can lead to fetal death
- Second-trimester infections can lead to hydrops fetalis
- Infections in the third trimester are not a common cause of congenital abnormalities
- Adults, especially women, may experience arthritis, mainly affecting the small joints of the hands and feet
Diagnosis and Treatment
- Diagnosis is typically based on symptoms such as the slapped cheek rash
- IgM antibodies indicate Fifth disease and aplastic anemia
- PCR can detect viral DNA in the blood of immunocompromised patients
- There is no specific antiviral treatment or vaccine available
- Immunoglobulins (IVIG) may be helpful for chronic infections in immunocompromised patients
- Most common in late winter and spring and occurs worldwide
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