Erythema infectiosum, also known as fifth disease, is a viral illness caused by human parvovirus B19, a single-stranded DNA virus belonging to the *Parvoviridae* family. The disease primarily affects children aged 5–15 years and is defined clinically by a biphasic presentation: initial flu-like symptoms followed by a characteristic erythematous rash. The rash classically begins on the cheeks as a bright red, “slapped-cheek” appearance and later spreads to the trunk and extremities in a lacy pattern. No specific ICD-10 or ICD-11 codes are provided in the source material.
Disease Profile
Erythema infectiosum (Fifth disease)
传染性红斑（第五病）
Erythema infectiosum (fifth disease) is a viral exanthem commonly seen in children, characterized by a distinctive 'slapped-cheek' rash and mild systemic symptoms. It is caused by parvovirus B19 and typically follows a self-limited course with low morbidity. Surveillance remains limited due to its benign nature and lack of mandatory reporting in most jurisdictions.
The clinical syndrome is generally mild and self-limiting. Initial prodromal symptoms may include low-grade fever, malaise, headache, and mild upper respiratory symptoms, occurring approximately 4–14 days after exposure. The hallmark cutaneous manifestation—erythema infectiosum—is typically non-pruritic and appears 1–3 days after the onset of systemic symptoms. In immunocompetent individuals, the illness resolves without complications. However, in immunocompromised patients or pregnant women, parvovirus B19 infection may lead to severe anemia or fetal hydrops, respectively. Source snippets do not provide details on duration of rash, recurrence patterns, or long-term sequelae.
Epidemiological data are sparse in the provided sources; no geographic distribution, seasonal trends, or surveillance burden metrics are specified. The disease is reported globally but is more frequently recognized in temperate regions during late winter and early spring. Outbreaks have been documented in school settings, suggesting close contact transmission among children. No reservoir or animal host information is available in the source material beyond the human-specific nature of parvovirus B19. The source does not indicate whether this condition is reportable or monitored through sentinel systems beyond the mention of ‘JP weekly sentinel surveillance concept’.
Transmission occurs via respiratory droplets from infected individuals, particularly during the pre-rash phase when viremia is highest and symptoms are mild or absent. Vertical transmission from mother to fetus is possible and poses significant risk in pregnancy. The source does not specify environmental persistence, fomite transmission, or exact infectious period beyond the general incubation context. No data on asymptomatic carriage or duration of infectivity post-rash onset are provided.
Children aged 5–15 years are the primary demographic affected. Pregnant women are considered a high-risk group due to potential for fetal infection and associated complications such as hydrops fetalis. Individuals with chronic hemolytic disorders (e.g., sickle cell disease, thalassemia) are at increased risk for transient aplastic crisis following infection. Source snippets do not provide additional risk stratification or data on adult susceptibility or severity.
No vaccine is currently available for parvovirus B19. Preventive measures focus on standard hygiene practices—including handwashing and respiratory etiquette—to reduce transmission in communal settings such as schools and daycare centers. Pregnant women with potential exposure should be counselled and tested if indicated. No other targeted interventions are described in the source material.
Given the benign clinical course and absence of mandatory reporting, erythema infectiosum is rarely captured in routine surveillance unless investigated in the context of congenital infection or hemolytic complications. Its inclusion in ‘JP weekly sentinel surveillance concept’ suggests it may be monitored in Japan’s pediatric sentinel network, though no further detail on case definitions or reporting thresholds is available. Surveillance interpretation should prioritize cases with atypical presentations or high-risk exposures (e.g., pregnancy, immunosuppression).
Figure 1 | Full historical trajectories across all reporting countries.
Figure 2 | Year-over-year monthly comparison for seasonality and structural shifts.
Dataset Archive
Supplementary Data | Multi-country disease dataset
Machine-readable multi-country disease dataset (JSON/CSV) with source metadata.
Source Register
Official sources and update cadences used to construct the downloadable dataset.
JP
JP NIID Weeklyweeklyweb
Japan
Japan weekly infectious disease surveillance via NIID/JIHS.
Official sourceSuggested presentation pattern: cite the data version and coverage window when exporting charts or tables for publication.