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 big hazard to sure susceptible 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 by way of respiratory droplets and sometimes causes a gentle, two-phased sickness in youngsters. The primary section is marked by flu-like signs that may embrace fever, headache, malaise, muscle aches, cough, sore throat, and joint ache. Within the second section, a attribute “slapped cheek” rash develops, which can be known as Fifth Illness or Erythema Infectiosum. By age 20, about 50 % of individuals have been contaminated and have antibodies that may assist combat reinfection. And by age 40, the determine rises to 70 %.
However, for individuals who have compromised immune programs, are pregnant, or have sure situations, corresponding to sickle cell anemia, the virus may cause extreme issues, corresponding to extreme anemia, myocarditis, hepatitis, or encephalitis. In being pregnant, the virus can infect the fetus and trigger harmful issues and miscarriage.
Often, 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, as an example, well being researchers in Israel reported the nation’s largest and longest B19V outbreak up to now, 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 improve 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 prior to now 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 international locations have seen unusually giant will increase in B19V infections.
In response to the US CDC, the surge appeared to reach in North America in June, although the information is restricted. Given its sometimes gentle presentation, B19V just isn’t a nationally notifiable an infection within the US, that means instances usually are not tracked. Nonetheless, the CDC does passively acquire knowledge on the virus.
As an example, industrial 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 improve, going from 15 % between 2022 and 2024 to 40 % in June 2024. Amongst plasma donors, the prevalence of pooled samples with a threshold degree of B19V DNA went from 1.5 % in December 2023 to twenty % in June 2024. The CDC additionally stated 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, corresponding 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 illnesses have been disrupted, inflicting uncommon dips and spikes in transmission. B19V transmission could have likewise been affected.
