B19V Infections Research Articles

Differential diagnosis on measles and rubella discarded cases highlights a sharp increase in parvovirus B19 infections in Milan, Northern Italy, in the first months of 2024.

In line with European trends, since 2023 Lombardy (Northern Italy) is experiencing a resurgence of measles and an increased number of reported cases of fever and rash. Measles discarded cases observed in our region within the context of measles and rubella surveillance from the first few months of 2024 (N = 30) were investigated for parvovirus B19 (B19V) and other rash-associated viruses. Thirteen cases tested positive for B19V DNA, representing a significant increase from previous years (on average 3 cases per year, p < 0.001) and ~40% of all B19V DNA-positive patients we detected since 2017. In 2024, B19V DNA-positive subjects spanned all ages, and the virus was predominant among adolescents and adults (84.6%). Two B19V infected patients were hospitalised, and likely cross-reacting anti-measles virus IgM were found in both. Our data align with the recent reports from the ECDC and various European countries, which are experiencing a surge in B19V infections, and underline the importance of comprehensive measles and rubella surveillance systems that can adapt to changing epidemiological trends.

Changing epidemiology of parvovirus B19 in the Netherlands since 1990, including its re-emergence after the COVID-19 pandemic

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.

The epidemiological and genetic characteristics of human parvovirus B19 in patients with febrile rash illnesses in China

To understand the epidemiological and genetic characteristics of B19V, a multiple-province surveillance of patients with febrile rash illnesses (FRIs) were conducted in China during 2009 ~ 2021. The clinical specimens of 3,820 FRI patients were collected and tested for B19V DNA. A total of 99 (2.59%) patients were positive for B19V, and 49 (49.49%) were children under 5 years old. B19V infections occurred throughout the year without obvious seasonal pattern. Ten NS1-VP1u sequences and seven genome sequences were obtained in this study, identified as subgenotype 1a. Combined with the globally representative genome sequences, no temporal and geographic clustering trends of B19V were observed, and there was no significant correlation between B19V sequences and clinical manifestations. The evolutionary rate of the B19V genome was 2.30 × 10–4 substitutions/site/year. The number of negative selection sites was higher than that of positive selection sites. It was the first to comprehensively describe the prevalence patterns and evolutionary characteristics of B19V in FRI patients in China. B19V played the role in FRI patients. Children under 5 years old were the main population of B19V infection. Subgenotype 1a was prevalent in FRI patients in China. B19V showed a high mutation rate, while negative selection acted on the genome.

Clinical and immune features of human parvovirus B19 infection in allogeneic stem cell transplantation recipients: A retrospective monocentric study.

Human parvovirus B19 (B19V) infection is associated with pure red cell aplasia (PRCA) in immunocompromised patients; however, the spectrum of manifestations associated with B19V in allogeneic hematopoietic stem cell transplantation recipients (alloHSCT) has rarely been reported. In this study, we aimed to report clinical and immune features of B19V infection after alloHSCT. We retrospectively collected and analyzed clinical and microbiological data of all transplanted patients with B19V DNAmia or tissue infection detected by polymerase chain reaction (PCR) in our center from 2010 to 2021. We report 35 cases of B19V infections in 33 patients. Median time from transplant to B19V first PCR positivity was 6.9 months (interquartile range (IQR) [1.6-18.9]). No preferential immune profile, type of transplantation or conditioning was identified. Hematological impairment was the most frequent sign, followed by rash and fever. Unconventional clinical forms were also detected, such as acute myelitis and myositis. For some cases, the direct relationship between symptoms and B19V infection was difficult to prove but was suggested by targeted tissue PCR positivity. When hematological impairment was not at the forefront, reticulocytopenia helped to diagnose B19V infections. Treatment was mainly based on high dose intravenous immunoglobulin. Although hematological impairment was the most frequent sign, B19V can affect multiple targets and lead to atypical manifestations. Because of its heterogeneous clinical presentation, B19V infection is likely under-diagnosed. Diagnosis of unusual B19V organ involvement needs combination of arguments which can include targeted tissue PCR.

Parvovirus B19 in Morocco: Seroprevalence of Immunoglobulin G Antibody in Pregnant Women in Marrakesh

Background: Parvovirus B19 (B19V) infection is ever-present and contagious. It is acquired during childhood and adolescence, but can occur at any age. B19V infection occurs in endemic epidemic mode in temperate zones in winter and spring. B19V infections, although often asymptomatic in pregnant women, can be responsible for hydrop fetalis, fetal anemia, and death in utero. This study will evaluate the seroprevalence of immunoglobulin G (IgG) antiparvovirus in pregnant women in Marrakesh city in Morocco, and to find out the possible risk factors associated with B19V infections. Methods: We randomly selected 100 pregnant women from the Zerktouni hospital in Marrakesh. Socio-demographic characteristics and background were collected using a questionnaire. Serologic tests were carried out by searching for immunoglobulin G antibodies via the ParvovirusVirclia® IgG Chemiluminescencemonotest kits (Vircell Microbiologist, Granada, Spain) at the Bacteriology-Virology laboratory of the Avicenna Military Hospital in Marrakesh. Results: The median age of study participants was 27 (interquartile range (IQR): 17–43) years. Of 100 pregnant women 8%, 38% and 54% were in the first, second and third trimester respectively. The majority 96% of women were from urban areas. Nineteen percent (19%) of them had a history of spontaneous abortion. Of 100 pregnant women, the overall prevalence of IgG was 51 (51%). The average age of participants with positive serology was 26.45 years, and the mean age of those with negative serology was 28.98 years. The immunity against the virus was higher in young pregnant women. Twenty five (25%) women tested positive for B19V antibodies in the third trimester of pregnancy, implying immunity for the virus. The results of logistic regression showed insignificant association between the prevalence of B19V IgG antibodies and the demographic and obstetrical factors except for the having a child under 6 years factor (χ2 = 12.33, p = 0.001). Conclusions: Infection with B19V remains important in pregnant women in our region and virological diagnosis must be sought before any suggestive context.

Beyond arboviruses: A multicenter study to evaluate differential diagnosis of rash diseases and acute febrile illness cases in Rio de Janeiro, Brazil.

IntroductionA wide variety of viruses can cause rash diseases (RDs) or acute febrile illness (AFIs) in children, adolescents and adults; however, approximately 19% of RD cases and 40% of AFI cases remain without a defined etiology. Parvovirus B19 (B19V) and herpesvirus infection can also cause RD and/or AFI, and in some risk groups, these infections can become persistent (or latent) and may require hospital treatment. Since these infections do not have mandatory reporting, they can be hidden by other diseases, such as those caused by arboviruses (e.g., dengue virus). In this context, the aim of this study was to pursue the differential laboratory diagnoses of B19V and herpesvirus infections in patients with RD and AFI, without a defined etiology, seen in hospitals and/or reference centers for infectious diseases in Rio de Janeiro.MethodsA total of 114 participants were enrolled in the study, including 54 children and 60 adults. B19V infection was assessed by real-time PCR (qPCR) and ELISA (anti-B19V IgM and IgG). EBV was assessed through qPCR, and betaherpesviruses (HCMV, HHV-6 and HHV-7) were assessed through multiplex qPCR. Sociodemographic and clinical data were obtained from the medical record data of these participants.ResultsThe median age of children with RD was 2 years (interquartile range (IQR): 5), and 55.6% were male. Among adults with AFI, the median age was 38 years (IQR: 21), and 56.7% were female. Regarding RD patients, viral prevalence (and load) were 5.5%(104IU/mL), 3.4%(104IU/mL), 5.5%(104IU/mL) and 11.1%(105IU/mL) for B19V, EBV, HCMV and HHV-6 infection, respectively, and in AFI patients they were 6.6%(105IU/mL), 1.6%(103IU/mL), 3.3%(104IU/mL) for B19V, HCMV and HHV-6, respectively. HHV-7 was not detected in RD or AFI patients.ConclusionThese results suggest the importance of including B19V and herpesviruses in the differential laboratory diagnoses for patients with RD and AFI, not only for epidemiological purposes but also for the proper management of the patient.

Parvovirus B19 infection in kidney transplant recipients: A prospective study in a teaching hospital in Shanghai, China

BackgroundThere is a lack of epidemiological studies on the course and clinical characteristics of Parvovirus B19 (B19V) infections in kidney transplant (KT) recipients. This study was undertaken to provide recommendations for clinical B19V infection diagnosis and treatment. MethodsSerum samples of KT recipients were regularly collected and tested for B19V-DNA copies, B19V-IgG/IgM levels, as well as hematological parameters and functions of kidney and liver. The course of B19V infection was described according to the results of serology and DNA testing, and the clinical and epidemiological data were combined for analysis. Results75% B19V infections occurred within 2 weeks after KT(n = 9). The infection rate of B19V in KT recipients was high, namely 10.17% (n = 12). The number of 10 patients IgM antibodies against B19V (IgM+) and theDNA B19V (DNA+), whereas 2 patients were IgM negative (IgM-) but DNA+. The B19V infected KT patients showed several symptoms, including anemia (100%), reduction of platelets (8.33%), and damage to liver (75%) and kidney function (16.67%) Patients with progressive anemia in the first two weeks after KT, which combined with the decrease of reticulocytes, are more likely to have B19V infection. Associations of four main therapeutic risk factors for B19V infections in KT patients have been analyzed. B19V infection was associated with use of basiliximab (OR = 1.19; 95%- CI: 1.08–1.32; P = 0.003) and use of thymoglobulins (OR = 0.84; 95%-CI: 0.76–0.93; P = 0.003). ConclusionsDoctors should be alert to B19V infection, especially in the immunodeficient patients within the first two weeks after transplantation.

Primate Erythroparvovirus 1 Infection in Patients with Hematological Disorders.

Primate erythroparvovirus 1, commonly referred to as Parvovirus B19 (B19V), is a DNA virus that normally results in a mild childhood infection called “erythema infectiosum”. Besides respiratory spread, B19V can also be transmitted through transfusions, which may result in persistent anemia in immunodeficient hosts. Dialysis patients often face acute or chronic anemia after infection with B19V. Here, we describe the laboratory investigation of 21 patients with hematological disorders for B19V infections. B19V DNA was detected in 13 (62%) of them, with specific IgM antibodies in three of the DNA positives. All 13 patients received treatment and were laboratory-monitored over a period of one year. In only two patients (a 14-year-old child with a kidney transplantation and a 39-year-old patient with aplastic anemia), markers of recent B19V infection were still detectable in follow-up samples. For four B19V DNA positive samples, short sequences could be obtained, which clustered with genotype 1a reference strains. Our findings suggest that all cases of hematological disorders should be examined for specific B19V antibodies and DNA for accurate diagnosis and appropriate patient management.

Identification and Genomic Characterization of Parvovirus B19V Genotype 3 Viruses from Cases of Meningoencephalitis in West Bengal, India.

ABSTRACTBrain infections are a major public health problem in India and other parts of the world, causing both mortality and lifelong disability. Even after a thorough investigation, many cases remain without an etiological diagnosis. Primate erythroparvovirus 1 (B19V) has been identified as a pathogen associated with undiagnosed meningoencephalitis in other settings, including the United Kingdom, France, and Latvia. Here, we reported 13/403 (3.2%) B19V PCR positive cases of meningoencephalitis in West Bengal, India. The positive samples were mostly from children (10/13, 76.92%) and presented as a spectrum consisting of acute encephalitis (7/13), acute meningoencephalitis (3/13), and meningitis (3/13). Of the 13 cases, 8/13 (61.5%) had no known etiology and 5/13 (38.5%) had a previous etiological diagnosis. The cases did not cluster in time or by location, suggesting sporadic occurrence rather than outbreaks. We were able to retrieve the complete B19V genomes from cerebrospinal fluid (CSF) in 12/13 cases. The sequences clustered into genotype 3b with complete genomes from Brazil, Ghana, and France, and partial genomes from India and Kyrgyzstan. This is the first report of B19V in cases of neurological infections from India. It highlights the need to evaluate the causal relationship between B19V with meningoencephalitis in the country. These were also the first complete genomes of genotype 3b from CSF and will be critical in the evaluation of the relationship between genotypes and disease.IMPORTANCE Cases of meningoencephalitis with no known etiology remain a major challenge to clinical management of brain infections across the world. In this study, we detected and characterized the whole-genome of primate erythroparvovirus 1 (B19V) in cases of meningoencephalitis in India. Our work highlighted the association between B19V and brain infections which has been reported in other countries. Our work also emphasized the need to examine the role of B19V in meningoencephalitis, specifically whether it caused or contributed to the disease together with other pathogens in India. Our study provided the first 12 genomes of B19V from cerebrospinal fluid. These genomes will contribute to an understanding of how the virus is changing across different locations and over time.

Donor-Derived Human Parvovirus B19 Infection in Kidney Transplantation.

BackgroundDonor-derived human parvovirus B19 (B19V) infections are rarely reported. Thus, its incidence in kidney transplantation is still unknown due to lack of surveillance studies. Similarly, whether the donor needs to be routinely screened for B19V and whether the kidneys from those with B19V DNAemia could be accepted also remain unknown.MethodsThis retrospective study aims to evaluate the donor-derived B19V infections occurring in 823 living and 1,225 deceased donor kidney transplantations from January 2016 to December 2020. The serum viral load of living donors and their corresponding recipients was evaluated before and after transplantation. Meanwhile, for the deceased donor kidney transplantation, the serum viral load of recipients was only tested after transplantation; if recipients of a deceased donor subsequently developed B19V infection, the serum viral load of recipients and their corresponding donors before transplantation would then be further traced.ResultsA total of 15 living donors were B19V DNAemia positive before the donation, of which B19V DNAemia occurred in three corresponding recipients. In deceased donor kidney transplantation, DNAemia occurred simultaneously in 18 recipients and their corresponding nine donors. A progressive decline in hemoglobin and reticulocyte count could be observed in one living donor recipient and other 11 deceased donor recipients, which were all well controlled by treatment eventually.ConclusionThe incidence of donor-derived B19V infection was 0.4% and 1.5% in living and deceased kidney transplantations, respectively. B19V was seemingly unnecessary to be routinely screened for the donor. Moreover, kidneys of the donors with B19V infection were acceptable.

Parvovirus B19 DNA detectable in hearts of patients with dilated cardiomyopathy, but absent or inactive in blood.

AimsParvovirus B19 (B19V) is often assumed to be a cause of dilated cardiomyopathy (DCM), based on the quantification of B19V DNA in endomyocardial biopsies (EMB). Whether the presence of B19V DNA correlates with active infection is still debated. Application of the enzyme endonuclease to blood samples results in degradation of B19V DNA remnants but leaves viral particles intact, which enables differentiation between active and past infection. In this study, the susceptibility to degradation by endonuclease of B19V DNA in blood was compared between DCM patients and a control group of recent B19V infections.Methods and resultsTwenty blood samples from 20 adult patients with DCM, who previously tested positive for B19V DNA in EMB and/or blood, were tested with B19V PCR before and after application of endonuclease to the samples. Six blood samples tested positive for B19V DNA with a mean viral load of 2.3 × 104 IU/mL. In five samples, B19V DNA became undetectable after endonuclease (100% load reduction); in one sample DNA load showed a 23% log load reduction (viral load before endonuclease: 9.1 × 104 IU/mL; after: 6.5 × 103 IU/mL). Presence of cardiac inflammation did not differ between patients with B19V DNAemia (1/4) and patients without B19V DNAemia (6/14) ( P value = 1.0). In all 18 control samples of proven recent B19V infections, DNA remained detectable after application of endonuclease, showing only a mean log load reduction of 2.3% (mean viral load before endonuclease: 8.1 × 1011 IU/mL; after: 8.0 × 1011 IU/mL). Load reduction differed significantly between the DCM group and the control group; indicating the presence of intact viral particles in the control group with proven active infection and the presence of DNA remnants in the DCM group (P value = 0.000).ConclusionDuring recent B19V infection, viral DNA levels in blood were unaffected by endonuclease. In contrast, B19V DNA in blood in patients with DCM became undetectable or strongly reduced after application of endonuclease. Circulating viral DNA in this subset of patients with presumed parvovirus‐associated DCM does not consist of intact viral particles. Viral replicative activity cannot be assumed from demonstrating B19V DNA in cardiac tissue or in blood in DCM patients.

Human parvovirus B19 frequency among blood donors after an epidemic outbreak: relevance of the epidemiological scenario for transfusion medicine

A retrospective, cross-sectional study was conducted to determine the frequency of human parvovirus B19 (B19V) infected individuals, viral loads and immunity among blood donors from Argentina, in a post-epidemic outbreak period. B19V DNA and specific IgG were tested in minimum study samples of donors attending a blood bank at Córdoba, Argentina, in 2014. Anti-B19V IgM and viral loads were determined in B19V-positive plasma samples. Seven of 731 samples (0.96%) resulted positive, corresponding to individuals aged 32–53 years, four of them repeat donnors and three first-time donors. Viral loads were <103 IU/mL. None had IgM and 6/7 had IgG, one of them at a high level (in the range of 100–200 IU/ml, and the remaining 5 at low to medium level, 5–50 IU/ml). Thus one case was classified as acute infection (DNA+/IgM-/IgG-) and six as potentially persistent infections (DNA+/IgM-/IgG+). No coinfections with other pathogens of mandatory control in the pre-transfusion screening were detected. Prevalence of IgG was 77.9% (279/358). This study provides the first data of B19V prevalence in blood donors in Argentina, demonstrating high rates of acute and persistent B19V infections and high prevalence of anti-B19V IgG in a post-epidemic period. Further research is needed to elucidate mechanisms/factors for B19V persistence as well as follow-up of recipients in the context of haemo-surveillance programs, contributing to the knowledge of B19V and blood transfusion safety.

Oral fluid: Non-invasive alternative for parvovirus B19 diagnosis?

BackgroundInfections with parvovirus B19 (B19V) have been associated with a wide range of disease manifestations of which erythema infectiosum (fifth disease) in children is most common. Clinical signs following infection of children with B19V can be similar to measles and rubella. Laboratory detection of B19V infections is based on detection of B19V-specific IgM antibodies by enzyme immunoassay (IgM-EIA) and/or B19V DNA by quantitative PCR (qPCR) on blood samples. The need for invasive sampling can be a barrier for public health diagnostics. ObjectivesTo evaluate the use of a dual target B19V-qPCR directed against the NS1 and VP2 of B19V on oral fluid samples as a non-invasive alternative for laboratory diagnosis of B19V infections in children below 12 years of age with exanthema. Study designOral fluid and serum samples were collected from 116 children with exanthema. All serum samples were tested by IgM-EIA/IgG-EIA, while all oral fluid and 56 serum samples were tested by B19V-qPCR. ResultsB19V-specific IgM antibodies were detected in 25 of 116 children in the study. B19V DNA was detected in oral fluid in 17 of the 25 children who were IgM positive, as well as two children who were IgM-equivocal or negative. The child with the equivocal IgM had a high quantity of B19V DNA in oral fluid (7 log IU/ml), compatible with an acute B19V infection. The IgM-negative child was IgG-positive and 4 log IU/ml B19V DNA was detected in the oral fluid sample, suggesting an acute infection and a falsely negative IgM. Sample size calculations indicated that oral fluid samples for qPCR should be collected from 2 to 3 children during outbreaks of exanthema to achieve similar sensitivity as IgM-EIA for one child (≥0.9) to confirm or exclude B19V. ConclusionsResults indicate that oral fluid samples are a suitable public health alternative for detection of B19V infections, potentially lowering the barriers for sampling.

Parvovirus B19: What Is the Relevance in Transfusion Medicine?

Parvovirus B19 (B19V) has been discovered in 1975. The association with a disease was unclear in the first time after the discovery of B19V, but meanwhile, the usually droplet transmitted B19V is known as the infectious agent of the “fifth disease,” a rather harmless children’s illness. But B19V infects erythrocyte progenitor cells and thus, acute B19V infection in patients with a high erythrocyte turnover may lead to a life-threatening aplastic crisis, and acutely infected pregnant women can transmit B19V to their unborn child, resulting in a hydrops fetalis and fetal death. However, in many adults, B19V infection goes unnoticed and thus many blood donors donate blood despite the infection. The B19V infection does not impair the blood cell counts in healthy blood donors, but after the acute infection with extremely high DNA concentrations exceeding 1010 IU B19V DNA/ml plasma is resolved, B19V DNA persists in the plasma of blood donors at low levels for several years. That way, many consecutive donations that contain B19V DNA can be taken from a single donor, but the majority of blood products from donors with detectable B19V DNA seem not to be infectious for the recipients from several reasons: first, many recipients had undergone a B19V infection in the past and have formed protective antibodies. Second, B19V DNA concentration in the blood product is often too low to infect the recipient. Third, after the acute infection, the presence of B19V DNA in the donor is accompanied by presumably neutralizing antibodies which are protective also for the recipient of his blood products. Thus, transfusion-transmitted (TT-) B19V infections are very rarely reported. Moreover, in most blood donors, B19V DNA concentration is below 1,000 IU/ml plasma, and no TT-B19V infections have been found by such low-viremic donations. Cutoff for an assay for B19V DNA blood donor screening should, therefore, be approximately 1,000 IU/ml plasma, if a general screening of blood donors for single donation blood components is considered at all: for the overwhelming majority of transfusion recipients, B19V infection is not relevant as well as for the blood donors. B19V DNA screening of vulnerable patients after transfusion seems to be a more reasonable approach than general blood donor screening.

Clinical impact & pathogenic mechanisms of human parvovirus B19: A multiorgan disease inflictor incognito.

Human parvovirus B19 (B19V) causes myriads of clinical diseases; however, owing to lack of awareness and undetermined clinical impact, it has failed to become a virus pathogen of global concern. Cryptically, B19V causes significant morbidity and mortality. Half of the world population and 60 per cent of Indians are known to be serologically naive and are at risk of acquiring B19V infections. Cumulatively, our data showed 21.3 per cent B19V-infected patients with juvenile chronic arthropathy, recurrent abortions, multi-transfused thalassaemia and leukaemia. In addition, B19V-infected cases that ended fatally included patients with pure red cell aplasia, fulminant hepatitis and haemophagocytic syndrome. Novel clinical associations of B19V observed were amegakaryocytic thrombocytopaenia, myositis and non-occlusive ischaemic gangrene of bowel. B19V possesses multiple receptors which are distributed widely in human tissues. Vascular endothelial cell infection by B19V causes endothelialitis and vasculitic injuries besides antibody-dependent enhancement which empowered B19V to cause multiorgan diseases. Owing to lack of suitable animal model for B19V, true causal role remains to be determined, but numerous reports on B19V infections substantiate a causal role in multiorgan diseases. Hence, B19V infections need to be recognized, investigated and treated besides making efforts on vaccine developments.

High incidence of maternal parvovirus B19 infection in a large unselected population-based pregnancy cohort in Norway

BackgroundAround 40% of pregnant women in Norway are parvovirus B19 (B19V) seronegative and thus at risk for B19 V infection. Studies on samples from women with symptomatic disease or known exposure have shown that nucleic acid amplification assays combined with serology increase the sensitivity and improves the diagnostic procedure. ObjectivesThe aim was to investigate the seroprevalence of B19V infection, the occurrence of new infections and vertical transmission in a population-based pregnancy cohort, with special emphasis on the diagnostic methods. Study designWe randomly selected 1350 pregnant women from the Norwegian Mother and Child Cohort Study (MoBa), using an algorithm for the detection of B19V infection, including both serology and PCR. ResultsMaternal infection was confirmed in 50 subjects (3.7% of 1349 women), of which 35(70%) were viremic. Of the initially seronegative 33(6.8%) seroconverted. The estimated average annual seroconversion rate was 15.5%, with the highest estimated annual seroconversion rate of 31.6%. The rates of yearly seroconversion followed the pattern found in reports from Norwegian microbiology laboratories. Among all women, 31 (2.3%) had an inconclusive serological profile and 17 (54.8%) had detectable virus. Of the 16 women with virus detectable at gestational week 17–18, seven were still seronegative with absent seroconversion in the second sample taken at birth. All together 10 children were vertically infected. ConclusionsHigh incidence of viremic B19V infections and high estimated annual seroconversion rates were found. Lack of seroconversion despite longstanding viremia emphasizes the importance of including PCR when testing for B19V infection during pregnancy.

Impact of Parvovirus B19 Viremia in Liver Transplanted Children on Anemia: A Retrospective Study.

Acute parvovirus B19 (B19V) infection in immunocompromised patients may lead to severe anemia. However, in adult transplant recipients, B19V reactivations without anemia and low-level viremia are common. The impact of B19V in pediatric transplant patients, with high risk of primary infection, is investigated here. In a six-month period, 159 blood samples of 54 pediatric liver transplant recipients were tested for B19V DNA by quantitative real-time PCR. Viremia was correlated with anemia and immunosuppression and compared with rates in adult transplant recipients. B19V DNA was detected in 5/54 patients. Primary B19V infections were observed in four patients prior to and in one patient after transplantation. Rates of viremia were significantly higher in pediatric recipients than in adults. Prolonged virus shedding after primary infection prior to transplantation accounts for most viremic cases. Anemia was significantly more frequent in samples from viremic patients, but remained mild. In 15% of anemic samples, B19V DNA was detected. Therefore, in anemic pediatric transplant recipients, diagnostics for B19V seem reasonable.

Insights into epidemiology of human parvovirus B19 and detection of an unusual genotype 2 variant, Bulgaria, 2004 to 2013.

The present study aimed to determine the role of human parvovirus В19 (B19V) as an aetiological agent in measles and rubella negative fever/rash patients from Bulgaria between 2004 and 2013. A total of 1,266 sera from all over the country were tested for B19V IgM antibodies and all positives were further investigated by polymerase chain reaction (PCR). Overall, 280 sera (22%) were B19V IgM positive and 227 of these (81%) were also PCR positive. The highest number of IgM positives was found among five to nine year-old children (27%). Eight infected women gave birth to healthy children; one fetus was aborted with hydrops fetalis. Of the 55 genetic sequences obtained, 54 belonged to genotype 1a and one grouped as a genotype 2 outlier. Phylogenetic analysis of all available genotype 2 sequences covering the 994 nucleotide non-structural protein 1(NS1)/capsid viral protein 1 (VP1) unique region junction, showed that only one other sequence grouped with the outlier strain, forming a clearly distinct and well-supported cluster of genotype 2 (between-group genetic distance: 3.32%). In accordance with B19V nomenclature, this cluster may represent a new subgenotype 2b. The study showed that B19V infections may be falsely identified as rubella or measles in ca 22% of cases, emphasising the need for laboratory confirmation.

Prevalence and genotypic characterization of Human Parvovirus B19 in children with measles- and rubella-like illness in Iran.

Human Parvovirus B19 (B19V) is a prototype of the Erythroparvovirus genus in Parvoviridae family. B19V infections are often associated with fever and rash, and can be mistakenly reported as measles or rubella. Differential diagnosis of B19V illness is necessary for case management and also for public health control activities, particularly in outbreak situations in which measles or rubella is suspected. To investigate the causative role of B19V infection in children with measles- and rubella-like illness, a total of 583 sera from children with exanthema were tested for presence of B19V by determining anti-B19V IgG and IgM antibodies by ELISA as well as B19V DNA detection by nested PCR. DNA positive samples were assessed further for determination of viral load and sequence analysis by Real-Time PCR and Sanger sequencing method, respectively. Out of 583 patients, 112 (19.21%) patients were positive for B19V-IgM antibody, 110 (18.87%) were positive for B19V-IgG antibody, and 63 (10.81%) were positive for B19V viral DNA. The frequency of B19V-IgG antibodies were increased with age; that is children under 6 year old showed 7.11% seroprevalence for B19V-IgG as compared to 18.39% and 28.91% for age groups 6 to >11 and 11-14 years old, respectively. Phylogenetic analysis of the NS1-VPu1 overlapping region revealed that all sequenced B19V-DNA belonged to genotype 1. The results of this study may aid the surveillance programs aiming at eradicating measles/rubella virus in Iran, as infections with B19V can be mistakenly reported as measles or rubella if laboratory testing is not conducted.

Increased number of parvovirus B19 infections in southeast Scotland in 2012–2013

Parvovirus B19 (B19V) infections are a common but under-investigated and under-reported cause of intrauterine infections. An increased number of acute B19V infections was identified in the Edinburgh area in 2012–2013, with 123 infections diagnosed in 33 pregnant women, 76 non-pregnant women and 14 men. All except one pregnant woman were asymptomatic. An overall infection rate of 18% was measured in pregnant women who were tested following B19V exposure (26/141). Furthermore, a 7% seroconversion rate was recorded in non-immune pregnant women who were re-tested after exposure (7/104). A high fetal loss rate (25%; 3/12) was observed in those who had acute B19V infection in early pregnancy (<11 weeks) whereas all pregnancies progressed to term in those where acute infection occurred after a gestational age of 12 weeks. These results suggest that more efforts should be targeted to investigate suspected B19V infections in early pregnancy during epidemic seasons.