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Parvovirus B19V (B19V) infection during pregnancy can be complicated by potentially life-threatening fetal hydrops, which can be managed by intrauterine transfusion (IUT). This study investigates the long-term temporal patterns in the epidemiology of B19V and evaluates the impact on fetal hydrops, by combining data on B19V infections from the Dutch Sentinel Surveillance system in the period 1990 to 2023, Dutch blood banking data and hospital data on fetal hydrops. Using wavelet analysis, we identified annual epidemic cycles in the Netherlands in the period 1990–2019 and we identified superimposed multiannual cycles in the period 1990–2009. After 2009, no multiannual cycle could be identified, although the incidence fluctuated and correlates with number of IUT performed. As of 2020, weekly reports of B19V infection demonstrated a historically low incidence and B19V-DNA positive blood donors were nearly absent. From May 2020 to May 2023, no IUT for B19V-related hydrops was performed. In the spring of 2023, B19V infections re-emerged, reaching pre-pandemic epidemic levels. Due to the changes in B19V epidemiology over the last 30 years and the near-absence of B19V during the COVID-19 pandemic, the resulting low immunity levels may lead to rebound outbreaks. Alertness to severe complications such as fetal hydrops is warranted. [ABSTRACT FROM AUTHOR]

Abstract Parvovirus B19 (B19V) is one of the major viral pathogens that infect only human beings. This study's aim is to determine which genotypes of the B19V are present in Turkey and to perform a phylogenetic analysis. Twelve B19V positive serum specimens already diagnosed by real-time PCR amplifying a partial region of the NS gene were included in this study. The serological markers and viral loads of the patients were determined. The positivity of the specimens was confirmed using semi-nested PCR. To determine the genotype of the B19V, PCR-positive amplicons were sequenced directly and compared to GenBank-referenced strain sequences. The phylogeny of the 12 sequenced strains was constructed with the maximum likelihood method. Two different genotypes of B19V were identified in our study. Genotype 2 of B19V was not detected. All of the B19V genotype 1 sequences were clustered in the common genotype 1a cluster (10/12, 83.3%). The average quantification of the B19V strains was determined to be 2.1 × 107 IU/ml. The nucleotide identities between our strains and those isolated in other countries were 85.8%–99.5%. Compared to the Turkish strains identified in our study, at the nucleotide level, the closest strains based on genotypes 3b and 1a were the Germany and Netherlands isolates respectively. This study was the first to provide the genotypic variation of B19V circulated in Turkey. We determined two distinct subtypes of B19V, including subtype 3b and 1a. While the genotype 1 is common all over the world, genotype 3 has begun to spread outside of Africa. Highlights • Primate erythroparvovirus 1 identified for the first time in Turkey. • Genotype 1 sequences were clustered in the common genotype 1a group. • The Genotype 3 generally known as African type of primate erythroparvovirus 1 was determined. [ABSTRACT FROM AUTHOR]

• After intrauterine infection, parvovirus B19 is detectable in neonatal blood samples. • Height of viral load in postnatal samples correlates with timing of infection. • Sensitivity is low when infection takes place in early pregnancy. Diagnosis of congenital viral infection at birth is generally attempted by direct detection of the virus by PCR in various neonatal materials. How to reliably diagnose intrauterine infection with parvovirus B19 (B19 V) at birth is unknown. To evaluate the performance of B19 V DNA detection in cord blood (CB) or neonatal dried blood spots (DBS) in diagnosing fetal infection. Two cohorts of children diagnosed prenatally with an intrauterine B19 V infection were included in this study. CB samples of intrauterine B19 V infections that were sent to a reference laboratory for congenital infections in Stuttgart, Germany in the period 1995–2014 were tested in triplicate for B19 V DNA by quantitative PCR. DBS from children with intrauterine B19 V infection that underwent IUT at the LUMC, Leiden, the Netherlands in the period 2009–2014 were tested for B19 V DNA by quantitative B19 V PCR in triplicate. Fourteen of twenty (70 %) CB samples tested positive for B19 V DNA. The positivity rate was 40 % (4/10) in those with a prenatal diagnosis <20 weeks gestation. When intrauterine B19 V infection was diagnosed thereafter, 100 % (10/10) samples were B19 V DNA positive. Of the thirteen available DBS, twelve (92 %) tested positive. Viral load in CB and DBS corresponded inversely with time from fetal diagnosis to birth. B19 V DNA can be detected in neonatal blood samples of children following intrauterine B19 V infection, although the possibility of false-negatives, even in severe infections, should be considered. B19 V viral load at birth correlates with timing of infection. [ABSTRACT FROM AUTHOR]

Plasma derivatives and blood components with low levels of parvovirus B19 (B19) seem not infectious, but recently infected, highly viraemic donors may transmit B19. We studied the incidence of high-level B19 viraemia (B19 DNA > 10 IU/ml) in 6·5 million Dutch blood donations. Between 2003 and 2009, all Dutch blood and plasma donations were screened for the presence of B19 DNA, via pools of 480. Reactive pools were resolved and demographic parameters were obtained for all donors with B19 viraemia > 10 IU/ml. In a subset, IgG and IgM antibodies to B19 were determined. Four hundred and eleven donations (1/15815) were identified with B19 DNA levels above 10 IU/ml, predominantly (83%) occurring in donors aged 18-47 years. Each year infection rates were elevated between December and July, with April accounting for 16% of infections. The years 2004 and 2009 were epidemic, with up to 1/4880 highly viraemic donations in May 2004. In a subset of 67 viraemic donations, 47/67 (70%) tested negative for IgG and IgM antibodies to B19; 16/67 (24%) showed isolated IgM and 4/67 (6%) contained IgG and IgM antibodies. The seasonal pattern of asymptomatic B19 infection in blood donors followed the notification rate of clinical cases. Geographically, B19 infection was randomly spread over the Netherlands. In epidemic seasons, blood donations with high levels of parvovirus, without concurrent antibodies, are common. They may infect immunocompromised and parvovirus-naïve recipients. The feasibility of preventive measures should be studied. [ABSTRACT FROM AUTHOR]