Erythema Infectiosum (Fifth Disease)

Parvovirus B19
- single-stranded DNA virus that targets red cells in the bone marrow

Incubation Period: – 21 days
Ages 4-10
Route of transmission
- Person to person through direct contact with respiratory secretions and hand-mouth
- contact
- From mother to fetus
- Transfusion of blood and blood products

Clinical Features :
- 30 – 40 % of infection is sub-clinical
- Often mild symptoms – fever, headaches, stomach upset, achs, pain
- Contagious until 24 hours after fevers resolved
- Rubella-like rash
  - Like rubella, can cause
    - arthralgia or arthritis – particularly in adults (the hands are most frequently affected, followed by the knees and wrists)
    - Arthralgia may develop a few weeks after infection
  - red rash on cheeks
    - Bright red cheeks are a defining symptom of the infection in children (hence the name “slapped cheek disease“).
    - Occasionally the rash will extend over the bridge of the nose or around the mouth.
Complications:
- Polyarthropathy in infected adults
- Aplastic crisis
- potentially dangerous low blood cell count in patients with haemolytic blood disorders such as autoimmune haemolytic anaemia and sickle cell disease
No Treatment

Fetal effects of Parvovirus B19

can lead to spontaneous miscarriage and stillbirth
- loss rate before 20 weeks’ gestation is 13% and after 20 weeks’ gestation is 0.5%.
associated with hydrops fetalis.
- ultrasound signs include ascites, skin oedema, pleural and pericardial effusions, and placental oedema.
- parvovirus B19 infection accounts for 8% to 10% of non-immune hydrop
Thrombocytopaenia

Antenatal diagnosis and management

IgM is detectable within 1-3 weeks of exposure and usually remains detectable for 2-3
months, but sometimes longer

The absence of IgM does not exclude recent infection
Routine antenatal screening for parvovirus is not recommended As the risk of an adverse outcome is low
Women exposed to parvovirus during pregnancy should have maternal serology for IgG and IgM.
Women who are IgG negative should have repeat serology taken 2-4 weeks after exposure or if
symptoms occur.
Women who are IgM positive and/or IgG positive up to 20 weeks gestation should be monitored by
serial ultrasound every 1-2 weeks for 12 weeks to assess for fetal hydrops / anaemia.
PCR for parvovirus can be performed on plasma but is generally unlikely to be positive
after onset of rash (myalgias, fever and malaise coincide with peak viraemia)
Amniocentesis for diagnosis of asymptomatic intrauterine fetal infection is not routinely
recommended

Management plan for recent maternal Parvovirus infection

Confirmed maternal infection based on serology before 20 weeks gestation
No intervention is available to prevent fetal infection or damage
The fetus should be monitored by serial ultrasound every 1-2 weeks for 12 weeks to
assess for hydrops / fetal anaemia
Refer to Maternal Fetal Medicine specialist experienced in fetal ultrasound, blood sampling
and transfusion if signs of fetal hydrops