A typical seasonal respiratory virus that sometimes infects school-aged youngsters is inflicting an unusually giant spike in instances throughout Europe and the US this summer season. The surge in transmission is a major hazard to sure weak populations together with pregnant individuals, in accordance with a well being alert launched by the Facilities for Illness Management and Prevention on Tuesday.
The virus is parvovirus B19, aka B19V, which spreads through respiratory droplets and sometimes causes a gentle, two-phased sickness in youngsters. The primary part is marked by flu-like signs that may embody fever, headache, malaise, muscle aches, cough, sore throat, and joint ache. Within the second part, a attribute “slapped cheek” rash develops, which can be referred to as Fifth Illness or Erythema Infectiosum. By age 20, about 50 % of individuals have been contaminated and have antibodies that may assist struggle reinfection. And by age 40, the determine rises to 70 %.
However, for individuals who have compromised immune methods, are pregnant, or have sure situations, equivalent to sickle cell anemia, the virus may cause extreme problems, equivalent to extreme anemia, myocarditis, hepatitis, or encephalitis. In being pregnant, the virus can infect the fetus and trigger harmful problems and miscarriage.
Normally, the virus spreads with little discover, inflicting extreme illness solely not often. However, in latest months, B19V has risen above the din of seasonal viruses. On the finish of final yr, for example, well being researchers in Israel reported the nation’s largest and longest B19V outbreak to this point, with the speed of instances rising ninefold over the speed between 2020 and 2022, and 6.6-fold over earlier years. Pregnant individuals noticed a relative enhance in danger throughout the outbreak.
Worldwide surge
In June, researchers in Denmark reported a peak in instances earlier this yr that was the very best price of an infection previously 10 years, 3.5-fold increased than the subsequent highest peak from 2017. However Denmark just isn’t alone. Additionally in June, the European Centre for Illness Prevention and Management reported that 14 European nations have seen unusually giant will increase in B19V infections.
In keeping with the US CDC, the surge appeared to reach in North America in June, although the information is proscribed. Given its sometimes delicate presentation, B19V just isn’t a nationally notifiable an infection within the US, that means instances will not be tracked. Nevertheless, the CDC does passively acquire knowledge on the virus.
As an example, business laboratories have reported a rise in check positivity, and the proportion of individuals with IgM antibodies—an indicator of latest an infection—elevated amongst all ages from lower than 3 % between 2022 and 2024 to 10 % this June. Youngsters between the ages of 5 and 9 noticed the best enhance, going from 15 % between 2022 and 2024 to 40 % in June 2024. Amongst plasma donors, the prevalence of pooled samples with a threshold stage of B19V DNA went from 1.5 % in December 2023 to twenty % in June 2024. The CDC additionally mentioned it has gotten anecdotal studies of will increase in instances of B19V in pregnant sufferers.
The CDC requires clinicians to be extra conscious of the potential of B19V infections. For pregnant individuals and others at excessive danger, the CDC recommends taking precautions, like masking and vigilant hand hygiene. That is significantly necessary for any high-risk individuals in work settings that contain shut contact with youngsters, equivalent to colleges and daycares, the CDC notes.
It is unclear what’s driving the B19V, however researchers have famous that B19V tends to have small surges each three to 4 years. With the worldwide debut of SARS-CoV-2 on the finish of 2019, many seasonal and cyclical patterns of infectious ailments have been disrupted, inflicting uncommon dips and spikes in transmission. B19V transmission might have likewise been affected.