Parvovirus B19 (also known as erythrovirus B19) causes a common childhood illness called erythema infectiosum or fifth disease. The disease is characterised by fever and a rash with erythematous cheeks, from which it derives its common name 'slapped cheek' disease. Parvovirus B19 infection generally results in a mild febrile illness, but can have more severe manifestations in patients at risk. In patients with increased red blood cell turnover (underlying haemolytic haemoglobulinopathies), infection can lead to a transient aplastic crises, and to pure red cell aplasia in the immunocompromised. Infection in the first 20 weeks of pregnancy is associated with an increased risk of intrauterine death and hydrops fetalis. For this reason, an observed increase in parvovirus B19 activity in Scotland warrants increased vigilance by clinicians and awareness of the relevant information and guidance on diagnosis and management of infection.1-4
Parvovirus B19 is a common infection, with approximately 50-60% of individuals having been infected by the time they reach adulthood. The disease is not notifiable in the UK and surveillance relies on laboratory reports of confirmed cases. Infection is most common in young children, but testing is largely focused on pregnant women (Figure 1), because of the potentially serious consequences, as well as the demonstration that complications of in-utero infection can be successfully treated with foetal transfusion. There is currently no licensed vaccine for parvovirus B19.1-3
In temperate countries like the UK a seasonal pattern in transmission can be observed, with increased numbers of cases reported in spring and early summer. A three to four year epidemic cycle of increasing case reports has been observed for parvovirus B19 in the UK.2
Despite the recognised ascertainment bias, the number of laboratory confirmed cases suggests an increase in parvovirus B19 activity in Scotland in the first quarter of 2013. An increase in parvovirus B19 activity was already noted in England and Wales in the first two quarters of last year (2012).5 Figure 1 shows that whilst the number of laboratory-confirmed cases reported in the first three months (weeks 1-12) of 2012 was within expected levels in Scotland, the number of cases reported increased in the summer and autumn of 2012. The number of reports received in the first three months of 2013 indicates a further increase in parvovirus B19 activity in Scotland to levels which are higher than at the same time in previous years. The increase in laboratory-confirmed infections can be seen across most NHS boards in Scotland, without apparent geographical focus. It should be noted that this increase may in part be related to increased numbers of tests performed due to increased awareness of the infection. However as negative test results for parvovirus B19 are not reported through the electronic laboratory reporting system (ECOSS), changes in testing strategy cannot be quantified.
This report is intended to draw attention to the current increased parvovirus B19 activity in Scotland and to highlight available NHS Clinical Knowledge Summaries, and guidance for managing the infection in health care settings, the community and in pregnant women.1-3
- HPA Rash Guidance Group. Guidance on viral rash in pregnancy: investigation, diagnosis and management of viral rash illness, or exposure to viral rash illness in pregnancy. HPA; 2011. Available from: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/Pregnancy/.
- Health Protection Agency. Parvovirus B19 (slapped cheek syndrome, fifth disease or erythema infectiosum). Available from: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/ParvovirusB19/....
- Crowcroft NS, Roth CE, Cohen BJ, Miller E. (1999). Guidance for control of parvovirus B19 infection in healthcare settings and the community. J Public Health 1999;21(4): 439-446. Available from: http://jpubhealth.oxfordjournals.org/content/21/4/439.abstract.
- NICE Clinical Knowledge Summaries. Parvovirus B19 infection. Available from: http://www.cks.nhs.uk/parvovirus_b19_infection.
- Health Protection Agency. Increased parvovirus B19 activity in England and Wales. Health Protection Report 2012:6(24). Available from: http://www.hpa.org.uk/hpr/archives/2012/news2412.htm#prvrs.