Parvovirus B19

Question 1

Define

Answer 1

“Fifth disease / erythema infectiosum / B19 / Slapped Cheek”

· Transmission via respiratory secretions, vertical transmission, infected blood products

o Infects erythroblastoid red cell precursors (RBC) precursors in BM

o Infectious period = 10 days before to 1 day after rash develops

Question 2

Signs and symptoms

Answer 2

1st: Asymptomatic OR coryzal illness for 2-3 days -> latent for 7-10 days…

2nd: Erythema infectiosum (most common):

• Red ‘slapped cheek’ rash on face (viraemic phase of fever, malaise, headache, myalgia)
• Progresses (1 week later) to maculopapular (lace) like rash in trunk and limbs
• Complications: rare in children, in adults: arthralgia and arthritis

Aplastic crisis (more serious)
* occurs in children with chronic haemolytic anaemia (sickle cell) because there is an increased rate of RBC turnover
* or immunodeficient who are unable to produce an antibody response to neutralise the infectious agent

o Fetal disease – maternal transmission – leads to fetal hydrops, death due to severe anaemia

Question 3

Investigation

Answer 3

B19 serology (IgG and IgM) à n.b. similar to rubella

RT-PCR (2nd line)

Question 4

Management

Answer 4

Supportive (virus; fluids, analgesia, rest) à will clear in ~3 weeks

No need to stay off school or avoid pregnant women (as not really infectious once the rash develops)

Safety net the complications – anaemia, lethargy, pregnancy, etc.

Secondary arthritis may be treated with ibuprofen