Erythema infectiosum, also known as fifth disease, is a clinical manifestation of infection with parvovirus B19, a virus that infects only humans and is distinct from animal parvoviruses [1].
Disease overview
Erythema infectiosum (Fifth disease)
传染性红斑（第五病）
Evidence-backed informationEN 5/7 applicable sections · ZH 5/7 applicable sectionsUpdated Sep 4, 2026
Erythema infectiosum (fifth disease) is a clinical presentation of parvovirus B19 infection that primarily spreads via respiratory particles and follows a seasonal and cyclical pattern in temperate settings. Because no vaccine exists, control relies on general hygiene and environmental measures that reduce respiratory virus transmission [1]. School-aged children are the most commonly affected group, and outbreaks tend to recur every few years [1].
Read the full clinical and epidemiological profile6
Illness typically begins with nonspecific early symptoms during which a patient is contagious, followed later by characteristic features such as a rash and joint pain. Patients are usually no longer contagious once later symptoms such as the rash appear, and it is generally considered safe to return to work or school after the rash develops [1]. Because the manifest does not detail the appearance or course of the rash or other signs beyond contagion timing, further clinical detail is not provided here.
In the United States, parvovirus B19 infection occurs more often in late winter, spring, and early summer, with minor outbreaks occurring roughly every three to four years [1]. Evidence provided in the manifest is restricted to these surveillance-relevant distribution patterns.
Parvovirus B19 spreads from person to person through respiratory particles and can also be transmitted through blood or blood products [1]. The virus can additionally cross the placenta during pregnancy from mother to baby [1]. Because parvovirus B19 infects only humans, it is not acquired from dogs or cats, and animals cannot contract it from an infected person, although other parvoviruses circulate separately in animal populations [1].
No vaccine or specific treatment exists to prevent parvovirus B19 infection, so prevention relies on good hygiene, cleaner air, and general actions that reduce the spread of respiratory viruses [1]. Returning to work or school after the rash appears is usually considered safe because contagiousness has typically waned by that stage, although individuals with anemia or weakened immune systems may remain contagious for longer periods and should follow clinical guidance [1].
- 1US Centers for Disease Control and Prevention. Preventing Parvovirus B19 | Parvovirus B19 and Fifth Disease | CDC [Internet]. cited 4 Sept 2026.Available from: https://www.cdc.gov/parvovirus-b19/prevention-treatment/index.html
Coverage
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Trends by reporting country
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Data access
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Official sourcesAuthority, cadence, notes1
JP NIID Weekly
Japan
Japan weekly infectious disease surveillance via NIID/JIHS.