Advances in human B19 erythrovirus biology

Parvovirus B19 in Pregnancy

Importance

Although the risk of parvovirus B19 infection during pregnancy and subsequent risk of adverse fetal outcome are low, understanding management practices is essential for proper treatment of fetuses with nonimmune hydrops fetalis. In addition, continued investigation into delivery management, breastfeeding recommendations, and congenital abnormalities associated with pregnancies complicated by parvovirus B19 infection is needed.

Objective

This review describes the risks associated with parvovirus B19 infection during pregnancy and the management strategies for fetuses with vertically transmitted infections.

Evidence Acquisition

Original articles were obtained from literature search in PubMed, Medline, and OVID; pertinent articles were reviewed.

Results

Parvovirus B19 is a viral infection associated with negative pregnancy outcomes. Up to 50% of people of reproductive age are susceptible to the virus. The incidence of B19 in pregnancy is between 0.61% and 1.24%, and, overall, there is 30% risk of vertical transmission when infection is acquired during pregnancy. Although most pregnancies progress without negative outcomes, viral infection of the fetus may result in severe anemia, congestive heart failure, and hydrops fetalis. In addition, vertical transmission carries a 5% to 10% chance of fetal loss. In pregnancies affected by fetal B19 infection, Doppler examination of the middle cerebral artery peak systolic velocity should be initiated to surveil for fetal anemia. In the case of severe fetal anemia, standard fetal therapy involves an intrauterine transfusion of red blood cells with the goal of raising hematocrit levels to approximately 40% to 50% of total blood volume. One transfusion is usually sufficient, although continued surveillance may indicate the need for subsequent transfusions. There are fewer epidemiologic data concerning neonatal risks of congenital parvovirus, although case reports have shown that fetuses with severe anemia in utero may have persistent anemia, thrombocytopenia, and edema in the neonatal period.

Conclusions and Relevance

Parvovirus B19 is a common virus; seropositivity in the geriatric population reportedly reaches 85%. Within the pregnant population, up to 50% of patients have not previously been exposed to the virus and consequently lack protective immunity. Concern for parvovirus B19 infection in pregnancy largely surrounds the consequences of vertical transmission of the virus to the fetus. Should vertical transmission occur, the overall risk of fetal loss is between 5% and 10%. Thus, understanding the incidence, risks, and management strategies of pregnancies complicated by parvovirus B19 is essential to optimizing care and outcomes. Further, there is currently a gap in evidence regarding delivery management, breastfeeding recommendations, and the risks of congenital abnormalities in pregnancies complicated by parvovirus B19. Additional investigations into optimal delivery management, feeding plans, and recommended neonatal surveillance are needed in this cohort of patients.

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.

RELATIONSHIP BETWEEN PARVOVIRUS B19 AND OSTEOARTHRITIS: LITERATURE REVIEW

Osteoarthritis and Parvovirus B19 infection present silent and gradual evolution, since the former is a degenerative process while the latter is often asymptomatic and may persist in the individual's body during their life. This study aims to analyze clinical studies that establish a correlation between degenerative osteoarthritis and Parvovirus B19 infection. Of the 62 studies found, 25 were chosen for reading in full. Analyzing only the studies that establish the correlation between the pathologies, seven confirm this relationship between Parvovirus B19 and Osteoarthritis, while one reports no relationship. No objective correlation could be found between the other articles studied. Our findings suggest that there is a close relationship between Parvovirus B19 and Osteoarthritis, with a higher prevalence of acquired causes, women and older adults, but it can manifest during life. However, it is essential to carry out new studies involving family history of patients with Osteoarthritis with positivity of Parvovirus B19, cohort studies between childhood and adult-old adult, so that it can elucidate this duality of congenital-acquired cause and, finally, raise treatment alternatives. Level of Evidence II, Systematic Review of Level II Studies.

Parvovirus В19 infection: lecture

Parvovirus B19 infection is best known as erythema infectiosum. However, infection with parvovirus B19 can lead to damage to various organs and systems, the development of severe complications up to death. The infection is most dangerous for people with immunodeficiency and hematological diseases. Serious consequences are possible with intrauterine infection of the fetus. Knowledge about the characteristics of the pathogen, the pathogenesis of the disease, the variety of clinical manifestations will allow the doctor to avoid diagnostic errors and provide the patient with timely medical care.

Parvovirus Infection in a Child Presenting with Erythema Multiforme and Vasculitis after a Yellow Jacket Bee Sting

Parvovirus B19 has a wide spectrum of clinical manifestations. Erythema multiforme and vasculitis are rarely reported with parvovirus B19 infections. Reactions to insect stings can range from local swelling to life-threatening systemic reactions. There have been rare reports of unusual reactions, such as vasculitis, occurring in a temporal relationship with insect stings. We report an 8-year-old patient having Parvovirus B-19-related erythema multiforme and vasculitis after a yellow jacket bee sting.

Prevalence and Phylogenetic Analysis of Parvovirus (B19V) among Blood Donors with Different Nationalities Residing in Qatar

Human parvovirus (B19V) is the causative agent of erythema infectiosum in children and is linked to a wide range of clinical manifestations. Studies related to B19V prevalence in the Middle East and North Africa (MENA) region and other parts of Asia are very scarce. The objectives of this study were to estimate the seroprevalence (anti-B19V IgM and IgG), the viremia rate (B19V DNA), and the circulating genotypes of B19V among blood donors in Qatar. Methods: Donors’ blood samples (n = 5026) from different nationalities, mainly from the MENA region and South East Asia, were collected from 2014–2016. Samples were tested for the B19V DNA using RT-PCR. Furthermore, 1000 selected samples were tested to determine the seroprevalence of B19V antibodies using enzyme-linked immunosorbent assay (ELISA). Genotyping was performed on 65 DNA positive samples by sequencing of nested PCR fragments (NS1-VP1u region, 927 nt). Results: Only 1.4% (70/5026) of the samples had detectible B19V DNA in their blood. B19V DNA prevalence statistically decreased with age (p = 0.03). Anti-B19V IgG was detected in 60.3% (561/930) of the tested samples, while only 2.1% (20/930) were IgM-positive and 1.2% (11/930) were both IgM- and IgG-positive. B19V genotyping showed a predominance of Genotype 1 (100%). Sequence analysis of the NS1-VP1u region revealed 139 mutation sites, some of which were amino acid substitutions. Conclusion: Our results indicated a relatively high seroprevalence of B19V in Qatar. Most importantly, B19 DNA was detected among Qatari and non-Qatari blood donors. Therefore, blood banks in Qatar might need to consider screening for B19V, especially when transfusion is intended for high-risk populations, including immunocompromised patients.

Human parvovirus B19: a review of clinical and epidemiological aspects in Brazil

Since the first evidence of human parvovirus B19 (B19V) infection in late 80s, several studies have been conducted to clarify the spectrum of clinical diseases in Brazil. B19V infection is prevalent in the general population and has exhibited a cyclical pattern of occurrence every 4-5 years, with the predominance of genotype 1 over 3b. During epidemic periods the wide range of clinical conditions, such as ertythema infectiosum, arthropathy, transient aplastic crisis, nonimmune hydrops fetalis and B19V-hepatitis were diagnosed. However, many infections are likely asymptomatic or have a self-limiting clinical course and are not readly diagnosed. Besides, the similarity of the symptoms of ertythema infectiosum to other rash diseases and the broadly circulation of arboviruses makes differential diagnosis more difficult. In this article, we provide a historical comprehensive overview of the research on parvovirus B19 conducted in Brazil, with a focus on the clinical and epidemiological aspects of the infection.

Upregulation of Pro-inflammatory Cytokine Genes by Parvovirus B19 in Human Bone Marrow Mesenchymal Stem Cells

Chronic inflammation plays a prominent role in cancer initiation and development. On the other hand, the Inflammation can be established by a number of factors such as viral infections. Parvovirus B19 (B19V) is a pathogen with widespread infection, which infects bone marrow erythroid progenitor cells. It has been shown that B19V can also enter human bone marrow mesenchymal stem cells (BM-MSCs). In this study, we hypothesized that BM-MSCs as the main cellular component of bone marrow niche may be induced to secret pro-inflammatory cytokines after B19V infection. BM-MSCs were cultured up to passage 3. The cells were then subjected to nucleofection to transfer a plasmid containing B19V genome. After 36 h, total RNA was extracted and the expression levels of IL-1β, IL-6, TNF-α and NF-κB genes were examined using qRT-PCR. Data analysis showed the significant increase in expression levels of all studied genes in the B19V-transfected cells (P < 0.05). Although further researches are required, our findings for the first time suggest the importance of B19V infection to establish an inflammatory microenvironment in the bone marrow and its involvement in inflammation-related diseases. Finally, based on our results, molecular assay to diagnose B19V infection of BM-MSCs prior to stem cell therapy is strongly recommended.

Human parvovirus B19 infection in patients with or without underlying diseases

BACKGROUND/PURPOSE

The clinical presentations of parvovirus B19 in patients with underlying diseases have greater diversity than previously healthy patients. We retrospectively identified patients with polymerase chain reaction (PCR)-confirmed parvovirus B19 infection in attempt to describe its clinical features especially in these populations.

METHODS

From 2009 to 2018, patients with real-time PCR-confirmed parvovirus B19 infection were collected. Comparisons were done between previously healthy patients and patients with preexisting diseases, as well as patients with high (>5.5 × 10⁵ copies/mL sera) and low viral loads.

RESULTS

Parvovirus B19 DNA was detected in 31 patients. Fourteen (45%) patients had underlying diseases, including six (19%) with immunologic diseases, five (16%) with hematologic diseases, and three (10%) with cardiopulmonary diseases. Only seven (23%) patients received an initial impression of erythema infectiosum prior to positive PCR. A higher proportion of patients with underlying diseases presented with fatigue and pallor, and suffered from tachycardia and hepatosplenomegaly compared to previously healthy patients. Among patients with a high viral load, a substantial proportion were of older age, suffered fatigue, and anemia. There was a trend of patients with immunologic comorbidity having a higher viral load.

CONCLUSION

The classical parvovirus B19 manifestations were less frequently observed in patients with a preexisting disease compared with previously healthy patients. Depending on host factors, the symptoms of parvovirus B19 infection can be multifaceted.

Evolutionary aspects of Parvovirus B-19V associated diseases and their pathogenesis patterns with an emphasis on vaccine development

Parvovirus B-19, a single human pathogenic member of the Parvoviridae family with it's small ssDNA and non-enveloped structure, is known to cause diseases in erythroid progenitor cells. But a wide range of clinical association of this virus with cells of non-erythroid origins has recently been discovered and many of those are being investigated for such association. Higher substitution rates in due course of evolution has been suggested for this cellular tropism and persistence. In this report, we have summarized the different disease manifestations of B-19 virus and have tried to find out a pattern of pathogenesis. Finally, we have focused on the vaccination strategies available against B-19 virus to correlate these with the mechanisms involved in various diseases caused by this virus.

Parvovirus B19 seroprevalence, viral load, and genotype characterization in volunteer blood donors from southern Brazil

Usually transmitted via respiratory droplets, parvovirus B19 (B19V) can also be acquired by blood transfusion especially because of viral persistence, resistance to blood treatment procedures, and high viral load during the early infection phase. This is particularly problematic in immunocompromised or anemic patients where the infection can have a severe outcome. As B19V DNA was detected in blood donations from South Brazil during a viral metagenomic survey performed by Next-Generation Sequencing, the objective of this retrospective study was to evaluate the seroprevalence, B19V DNA presence and circulating genotypes in a Hospital Blood Transfusion Service in Santa Maria city in South Brazil (Rio Grande do Sul state). Among 480 volunteer blood donors, 53.9% (n = 258 of 479) were anti-B19V IgG-positive, and 9 (1.9%) plasma samples presented B19V DNA. In almost all cases (n = 7 of 9, 77.8%), B19V DNA load was accompanied by the presence of anti-B19V IgG suggesting a persistent infection. The sequencing of the strains demonstrated that all belong to genotype 1 which is the most prevalent worldwide. The analysis of the recipient information of the positive for B19V DNA units revealed no related posttransfusion adverse effects. Our results demonstrate for the first time, B19V seroprevalence, viral load, and genotypes among blood donors from South Brazil and give a light for the circulation and impact of this B19V in this part of the country.

Parvovirus B19 in South African blood donors

BACKGROUND

Parvovirus B19 (PVB19) is transmitted via transfusion of blood and blood products. PVB19 is resistant to viral inactivation methods, which poses a threat to blood safety. We investigated the prevalence of PVB19 antibodies and DNA in healthy blood donors from the South African National Blood Bank Service to evaluate the necessity of PVB19 DNA testing.

STUDY DESIGN AND METHOD

A retrospective analysis of 1500 residual plasma specimens from healthy blood donors from the SANBS repository were screened in mini-pools of 20 for PVB19 DNA using a quantitative polymerase chain reaction (PCR). Positive pools were resolved by individual viral load testing and screened for PVB19 immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies to correlate viral loads with serological status. PVB19 IgG prevalence was determined by testing 90 randomly selected specimens from the 1500 plasma specimens.

RESULTS

The prevalence of PVB19 IgG, IgM and IgG, and DNA was 62.2%, 0.06%, and 0.9%, respectively. Fourteen of the 1500 blood donor specimens received, had detectable PVB19 viral loads. Nine of the fourteen donors with detectable viral loads were PVB19 IgG seropositive. The PVB19 viral loads ranged from 1.81 to 5.32 log IU/mL. Four of the fourteen viraemic donors had a viraemia >10 ⁴ IU/mL.

CONCLUSION

We have demonstrated a low prevalence of PVB19 DNA in SANBS blood donors. The predominance of low-level viraemia and the presence of PVB19 antibodies, suggests that the risk of transfusion transmission of PVB19 among SANBS donors may be relatively low.

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.

Parvovirus B19 in HIV+ adult patients with different CD4+ lymphocyte counts

PURPOSE

Human parvovirus B19 (B19V) can cause anemia in immunocompromised patients. We aimed to investigate the presence of B19V in HIV+ adults with different CD4+ T cell counts, to recognise the frequency of B19V in these different conditions and its possible association with anemia.

METHODOLOGY

We studied B19V specific IgM, IgG and DNA in 98 HIV+ patients and in 52 healthy individuals. HIV load, CD4+ counts and haemoglobin level were also determined in the patients.

RESULTS

No individual in the control group had detectable IgM, 41/52 (78.8 %) had IgG and 5/52 (9.6 %) had B19V DNA. Among HIV+ patients, we found 5/98 (5.1 %) IgM+, 66/98 (67.3 %) IgG+ and 15/98 (15.3 %) had B19V DNA (no significant differences between the two groups compared). Considering the CD4+ cell range in HIV patients, 37 had <200 CD4+ cells ml^-1, 31 had 200-500, and 30 had >500. Anti-B19V IgG prevalence in patients with >500 CD4+ cells ml^-1 was significantly higher than in the rest (P=0.004) and compared to the control (P=0.046). B19V DNA concentration was always <10³ IU ml^-1, including 5 healthy individuals and 15 HIV+ patients. There was no significant association between B19V IgM or DNA and anemia nor between B19V DNA and HIV load.

CONCLUSIONS

The results indicate that B19V is not a high-risk factor for anemia in adult HIV+ patients under HAART treatment. Further studies will contribute to elucidate the mechanisms and significance of B19V DNA prevalence/persistence in adults, independently of the CD4+ cell status.

Parvovirus B19 integration into human CD36+ erythroid progenitor cells

The pathogenic autonomous human parvovirus B19 (B19V) productively infects erythroid progenitor cells (EPCs). Functional similarities between B19V nonstructural protein (NS1), a DNA binding endonuclease, and the Rep proteins of Adeno-Associated Virus (AAV) led us to hypothesize that NS1 may facilitate targeted nicking of the human genome and B19 vDNA integration. We adapted an integration capture sequencing protocol (IC-Seq) to screen B19V infected human CD36+ EPCs for viral integrants, and discovered 40,000 unique B19V integration events distributed throughout the human genome. Computational analysis of integration patterns revealed strong correlations with gene intronic regions, H3K9me3 sites, and the identification of 41 base pair consensus sequence with an octanucleotide core motif. The octanucleotide core has homology to a single region of B19V, adjacent to the P6 promoter TATA box. We present the first direct evidence that B19V infection of erythroid progenitor cells disrupts the human genome and facilitates viral DNA integration.

Genotype 1 of human parvovirus B19 in clinical cases

Summary Introduction: Virus surveillance strategies and genetic characterization of human parvovirus B19 (B19V) are important tools for regional and global control of viral outbreak. In São Paulo, Brazil, we performed a study of B19V by monitoring the spread of this virus, which is an infectious agent and could be mistakenly reported as a rash and other types of infection. Method: Serum samples were subjected to enzyme immunoassay, real time polymerase chain reaction, and sequencing. Results: From the 462 patients with suspected cases of exanthematic infections, the results of the 164 serum samples were positive for B19V immunoglobulin M. Among these cases, there were 38 patients with erythema infections and B19-associated with other infections such as encephalitis, hydrops fetalis, chronic anemia, hematological malignancies. These samples were sequenced and identified as genotype 1. Conclusion: This study showed patients with infections caused by B19V and sequencing genotype 1. Continuous monitoring is necessary to detect all known genotypes, and the emergence of new genotypes of these viruses for case management in public health control activities.

Contemporary infectious exanthems: an update

An exanthem is a skin rash that may be associated with mucous membrane eruption, fever or other symptoms. It may develop as manifestation of an infectious disease or as adverse reaction to drugs. Beside the ‘classical exanthems’ commonly occurring in childhood, other exanthems, defined as ‘atypical’ for the different morphology and causal agents, may occur. Among the atypical exanthems with infectious etiology, viral, bacterial, parasitic and helminth infections are implicated. We describe herein etiology and epidemiology of the atypical exanthems caused by infectious agents. In case of exanthem, to make a correct etiological diagnosis is crucial for both the patient and community concerning issues such as time off school, immunizations and risk in pregnancy and immunocompromised individuals.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.

Molecular diversity of human parvovirus B19 during two outbreaks of erythema infectiosum in Brazil

This study was conducted to provide information on the genetic diversity of human parvovirus B19 (B19V) circulating in the municipality of Niterói, Rio de Janeiro, Southeast Brazil during 1996–2006, a period with two distinct outbreaks of B19V infection: 1999–2000 and 2004–2005. A total of 27 sera from patients with erythema infectiosum and five sera from HIV-infected patients that tested positive for B19V DNA during the study period were analyzed. To genotype B19V strains, a semi-nested PCR for partial amplification of the capsid gene was performed and sequence analysis revealed that 31 sequences belonged to subgenotype 1a (G1a) of the main genotype 1 and one sequence was characterized as subgenotype 3b (G3b). The phylogenetic tree supported the division of the G1a into two well-defined clades with 1.3% of divergence. The low diversity of the G1a strains may be explained by the fact that all patients had acute B19V infection and 30/32 sera were collected during two distinct outbreaks. The G3b strain was from an HIV-infected patient who seroconverted to anti-B19 IgG antibodies in September/2005. This is the first report of G3b in the state of Rio de Janeiro.

Substitution rate and natural selection in parvovirus B19

The aim of this study was to estimate substitution rate and imprints of natural selection on parvovirus B19 genotype 1. Studied datasets included 137 near complete coding B19 genomes (positions 665 to 4851) for phylogenetic and substitution rate analysis and 146 and 214 partial genomes for selection analyses in open reading frames ORF1 and ORF2, respectively, collected 1973–2012 and including 9 newly sequenced isolates from Serbia. Phylogenetic clustering assigned majority of studied isolates to G1A. Nucleotide substitution rate for total coding DNA was 1.03 (0.6–1.27) x 10⁻⁴ substitutions/site/year, with higher values for analyzed genome partitions. In spite of the highest evolutionary rate, VP2 codons were found to be under purifying selection with rare episodic positive selection, whereas codons under diversifying selection were found in the unique part of VP1, known to contain B19 immune epitopes important in persistent infection. Analyses of overlapping gene regions identified nucleotide positions under opposite selective pressure in different ORFs, suggesting complex evolutionary mechanisms of nucleotide changes in B19 viral genomes.

[Seroprevalence of human parvovirus B19 in children with fever and rash in the North of Tunisia]

The aim of the study is to evaluate the prevalence of specific antibodies anti-human parvovirus B19 (PVB19) immunoglobulin M (IgM) and IgG in children with fever and rash. This study involved 257 children aged from 7 months to 15 years with febrile rash unrelated to measles and rubella (seronegative for IgM). The sera were examined by immunoenzymatic assay. Detection of antibodies of PVB19 was done by enzyme-linked immunosorbent assay (Elisa). In our study, prevalence of immunoglobulin G (IgG) and IgM were 44 and 11.3%, respectively. Clinically, children with positive IgM serology had submitted an erythema infectiosum (13/29 cases), myocarditis (1 case), encephalitis (1 case), severe sickle cell anemia (7 cases), and immunocompromised (7 cases). The incidence rate of viral infection was 11.3%; most of the cases of PVB19 infection occurred between the months of May and August. Incidence was higher in the 10-15 years age group (21%). The prevalence of IgG antibody varied and increased with age, it rises from 38.2% in preschool children (19 months-4 years) to 53.5% in those aged between 4.5 and 15 years, reaching 58% in the 10-15 years age group. The four risk factors of PVB19 infection are: (1) those aged between 4.5 and 9 years, which is the most affected age group (P = 0.0018); (2) female gender in children aged between 19 months and 4 years (P = 0.037); (3) transfusion and (4) immune deficiency (P = 0.022 and P = 0.001, respectively). The study of the prevalence of PVB19 infection shows that viral infection is acquired early in childhood, increases with age; viral transmission is favored by the community life. Because of the widespread vaccination program against measles and rubella, the systematic search of PVB19 in front of eruptive fevers becomes important.

Genotype 3b of human parvovirus B19 detected from hospitalized children with solid malignancies in a North Indian tertiary care hospital

Human parvovirus B19 (B19V) infection is known to cause serious consequences in immuno-compromized individuals. The present cross sectional study was designed to estimate the prevalence and genotype distribution of B19V in children receiving chemotherapy for solid malignancies at a tertiary care hospital in North India during October 2013 to May 2015. Serum samples from all the patients were tested for anti-B19V IgM and IgG antibodies and for B19V-DNA as soon as received. Samples testing positive for B19V-DNA were subjected to viral load estimation and to genotype determination by sequencing. Total 96 children were enrolled of which 9 (9.3%), 32 (33.3%), and 25 (26%) tested positive for anti-B19V IgM, anti-B19V IgG, and B19V-DNA, respectively. The viral load of B19V-DNA positive children ranged from 5.5 × 10(2) to 3.5 × 10(12) copies/ml. Accordingly children were divided into three groups: group I, with acute infection (n = 25); group II, previously exposed (n = 27), and group III, negative for B19V infection or with inappropriate antibody response (n = 44). B19V positivity was significantly associated (P-value < 0.0001) with a history of blood transfusion in the past 6 months, severe anemia (hemoglobin levels <6 gm%) and thrombocytopenia (platelets <150,000/cu.mm.). Sequence analysis of 21 of 25 DNA positive samples showed that all of them were Genotype 3b that clustered into three groups. All the sequences within each cluster were identical. The nucleotide identity of the sequences suggests a nosocomial outbreak of B19V during the study period. Children on chemotherapy for solid tumors should be routinely screened for B19V infection by both serology and PCR. J. Med. Virol. 88:1922-1929, 2016. © 2016 Wiley Periodicals, Inc.

Clinical features and laboratory findings of human parvovirus B19 in human immunodeficiency virus-infected patients

Immunocompromised patients may develop severe chronic anaemia when infected by human parvovirus B19 (B19V). However, this is not the case in human immunodeficiency virus (HIV)-infected patients with good adherence to highly active antiretroviral treatment (HAART). In this study, we investigated the clinical evolution of five HIV-infected patients receiving HAART who had B19V infections confirmed by serum polymerase chain reaction. Four of the patients were infected with genotype 1a strains and the remaining patient was infected with a genotype 3b strain. Anaemia was detected in three of the patients, but all patients recovered without requiring immunoglobulin and/or blood transfusions. In all cases, the attending physicians did not suspect the B19V infections. There was no apparent relationship between the infecting genotype and the clinical course. In the HAART era, B19V infections in HIV-positive patients may be limited, subtle or unapparent.

Update of the human parvovirus B19 biology

Since its discovery, the human parvovirus B19 (B19V) has been associated with many clinical situations in addition to the prototype clinical manifestations, i.e. erythema infectiosum and erythroblastopenia crisis. The clinical significance of the viral B19V DNA persistence in sera after acute infection remains largely unknown. Such data may constitute a new clinical entity and is discussed in this manuscript. In 2002, despite the genetic diversity among B19V viruses has been reported to be very low, the description of markedly distinct sequences showed a new organization into three genotypes. The most recent common ancestor for B19V genotypes was estimated at early 1800s. B19V replication is enhanced by hypoxia and this might to explain the high viral load detected by quantitative PCR in the sera of infected patients. The minimum infectious dose necessary to transmit B19V infection by the transfusion of labile blood products remains unclear. At the opposite, the US Food and Drug Administration proposed a limit of 10(4)IU/mL of viral DNA in plasma pools used for the production of plasma derivatives. Recently, a new human parvovirus (PARV4) has been discovered. The consequences on blood transfusion of this blood-borne agent and its pathogenicity are still unknown.

Human parvovirus B19 VP1u Protein as inflammatory mediators induces liver injury in naïve mice

Human parvovirus B19 (B19V) is a human pathogen known to be associated with many non-erythroid diseases, including hepatitis. Although B19V VP1-unique region (B19-VP1u) has crucial roles in the pathogenesis of B19V infection, the influence of B19-VP1u proteins on hepatic injury is still obscure. This study investigated the effect and possible inflammatory signaling of B19-VP1u in livers from BALB/c mice that were subcutaneously inoculated with VP1u-expressing COS-7 cells. The in vivo effects of B19-VP1u were analyzed by using live animal imaging system (IVIS), Haematoxylin-Eosin staining, gel zymography, and immunoblotting after inoculation. Markedly hepatocyte disarray and lymphocyte infiltration, enhanced matrix metalloproteinase (MMP)-9 activity and increased phosphorylation of p38, ERK, IKK-α, IκB and NF-κB (p-p65) proteins were observed in livers from BALB/c mice receiving COS-7 cells expressing B19-VP1u as well as the significantly increased CRP, IL-1β and IL-6. Notably, IFN-γ and phosphorylated STAT1, but not STAT3, were also significantly increased in the livers of BALB/c mice that were subcutaneously inoculated with VP1u-expressing COS-7 cells. These findings revealed the effects of B19-VP1u on liver injury and suggested that B19-VP1u may have a role as mediators of inflammation in B19V infection.

Hereditary Spherocytosis Unmasked by Human Parvovirus B19 Induced Aplastic Crisis in a Family

Human parvovirus (HPV) B19 induced aplastic crisis in a family leading to the diagnosis of hereditary spherocytosis (HS) is a very rare condition being barely reported in the literature. We herein report a 4-year-old girl, her brother, and their mother who all presented with progressive pallor and jaundice after a febrile illness. The HPV B19 was diagnosed using polymerase chain reaction (PCR) and positive serology for specific anti-HPV B19 IgM. They were further diagnosed with having HS. The clinical importance of this report is that in the case of an abrupt onset of unexplained severe anemia and jaundice, one should consider underlying hemolytic anemias mostly hereditary spherocytosis complicated by HPV B19 aplastic crisis. Herein, we report the occurrence of this condition, simultaneously in three members of a family. The distinguished feature of this report is that all affected family members developed some degrees of transient pancytopenia, not only anemia, all simultaneously in the course of their disease.

Remitting seronegative symmetrical synovitis with pitting edema associated with parvovirus B19 infection: two new cases and review of the comorbidities

BACKGROUND

Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) is a rare syndrome consisting of acute symmetrical tenosynovitis of the hands and wrists associated with pain and marked pitting edema of the dorsum of the hands or the feet. Persistent rheumatoid factor seronegativity and elevated acute phase reactants are the rule, while radiographic findings are characterized by the absence of bony erosions. The syndrome has occasionally been associated with a wide range of diseases including solid and hematological malignancies, polymyalgia rheumatica, and other inflammatory rheumatic diseases.

METHODS

Two patients with skin eruption on hands and feet associated with arthromyalgias have been investigated to confirm diagnosis of RS3PE and to detect comorbidities. A revision of all the possible medical conditions correlated to RS3PE has been performed.

RESULTS

We report two cases of RS3PE associated with Parvovirus B19 infection/reactivation. There are very few reports on the association between RS3PE and infectious agents, and in only one case the syndrome has been correlated to parvovirus infection.

CONCLUSIONS

We want to underline the importance for patients with RS3PE to be seen by dermatologists who should become familiar with this syndrome and remark that Parvovirus B19 infection may be a potential cause of RS3PE.

Spectrum of adult Parvovirus B19 infection according to the underlying predisposing condition and proposals for clinical practice

The virological diagnosis of Parvovirus B19 (PvB19) infection is currently based on sero-diagnosis, molecular methods or both, yet without clear recommendations. We retrospectively identified patients with polymerase chain reaction-positive PvB19 and/or positive serological assay between 2007 and 2013. Eighty-two adults with at least one diagnostic criterion of recent PvB19 infection (IgM antibodies, viral DNA in blood and/or in marrow) were included and classified into three homogeneous groups: 30 patients had no underlying predisposing condition, 25 a hereditary haemolytic anaemia, 27 an underlying immunodeficiency. The classical PvB19-related manifestations were less frequent in immunocompromised than in immunocompetent patients (arthromyalgia: 5 vs. 14; erythema: 4 vs. 17, respectively). Only 41·4% of patients with no underlying disease were anaemic. Bicytopenia and pancytopenia were observed mainly in immunocompromised patients. Classical pure red cell aplasia was observed in only 9 of the 27 marrow smears performed. Specific IgM were found in 93% of immunocompetent patients, whereas only 58% had detectable viral DNA in blood. IgM and DNA were present alone or together in all patients with hereditary haemolytic anaemia. In immunocompromised patients, the diagnosis was confirmed by marrow analysis in 91% of cases. We make some proposals based on this large series of PvB19-infected patients.

Congenital Parvovirus B19 Infection: Persistent Viremia and Red Blood Cell Aplasia

We describe a case of fetal parvovirus B19 infection resulting in preterm birth and leading to hydrops fetalis requiring multiple in utero transfusions. The infant developed chronic postnatal anemia responsive to intravenous immunoglobulin therapy. Serum viral load decreased after immunoglobulin treatment but remained detectable for over 1 year.

Parvovirus B19 infection presenting with severe erythroid aplastic crisis during pregnancy in a woman with autoimmune hemolytic anemia and alpha-thalassemia trait: a case report

Introduction

Parvovirus B19 virus commonly causes subclinical infection, but it can prove fatal to the fetus during pregnancy and cause severe anemia in an adult with hemolytic diseases. We present the case of a woman with autoimmune hemolytic anemia who was diagnosed with parvovirus B19-induced transient aplastic crisis during her second trimester of pregnancy and faced the high risk of both fetal and maternal complications related to this specific viral infection. To the best of our knowledge, the experience of successful intravenous immunoglobulin treatment for B19 virus infection during pregnancy, as in our case, is limited.

Case presentation

A 28-year-old and 20-week pregnant Chinese woman with genetically confirmed alpha-thalassemia trait was diagnosed with cold antibody autoimmune hemolytic anemia and suffered from transient aplastic crisis caused by B19 virus infection. She received intravenous immunoglobulin treatment to reduce the risk of hydrops fetalis. Her peripheral blood reticulocyte percentage recovered, but anemia persisted, so she underwent several courses of high dose intravenous dexamethasone for controlling her underlying hemolytic problem. Finally, her hemoglobin levels remained stable with no need of erythrocyte transfusion, and a healthy baby boy was naturally delivered.

Conclusions

Parvovirus B19 virus infection should be considered when a sudden exacerbation of anemia occurs in a patient with hemolytic disease, and the possible fetal complications caused by maternal B19 virus infection during pregnancy should not be ignored. Close monitoring and adequate management can keep both mother and fetus safe.

Parvovirus B19 at the culprit coronary stenosis predicts outcome after stenting

BACKGROUND

Parvovirus (PV) B19 DNA is detected in endothelial cells and may cause endothelial dysfunction, which is involved in in-stent restenosis. We aimed at performing an exploratory analysis that evaluated if PVB19 DNA at the culprit coronary stenosis would be associated with an increased rate of major adverse cardiac events (MACE) after coronary stenting.

MATERIALS AND METHODS

Consecutive patients undergoing stent implantation for stable or unstable coronary artery disease were enroled. Serology for PVB19 infection and presence of DNA for PVB19 on balloons used for predilatation were assessed in all patients. MACE rate, as a composite of cardiac death, myocardial infarction (MI) or clinically driven target lesion revascularization (TLR) was obtained at 24 month follow-up. Adjusted hazard ratio (HR) with 95% confidence interval (CI) was calculated for variables associated with MACE.

RESULTS

One hundred and nine patients [age 66 ± 10, male sex 89 (82%)] were enroled. At 24-month follow-up, 18 patients experienced a MACE. Two patients (2%) experienced MI, while 16 patients (15%) experienced clinically driven TLR. At multiple Cox regression analysis, the presence of PVB19 DNA on the balloon and the use of bare-metal stents were independent predictors of MACE [HR 3·30, 95% CI (1·12-10·08), P = 0·03 and HR 4·19, 95% CI (1·60-10·94), P = 0·003].

CONCLUSIONS

PVB19 DNA detected on the balloon used for dilatation of coronary stenosis before stent implantation is associated with MACE rate at follow-up, mainly due to clinically driven TLR. The results of this exploratory analysis should be confirmed in a larger population.

Identification of past and recent parvovirus B19 infection in immunocompetent individuals by quantitative PCR and enzyme immunoassays: a dual-laboratory study

Parvovirus B19 (B19V) is a member of the family Parvoviridae, genus Erythrovirus. B19V-specific IgG and IgM react differently against conformational and linear epitopes of VP1 and VP2 antigens, leading to the development of IgG avidity and epitope type specificity (ETS) enzyme immunoassays (EIAs) for distinguishing past from recent infection. Additionally, B19V viral load determination (by quantitative PCR [qPCR]) is increasingly used in the staging of B19V infection. In this study, the utility of these methods is compared. A panel of 78 sera was jointly tested by the Virus Reference Department (VRD), London, United Kingdom, and the Haartman Institute (HI), Helsinki, Finland, using a number of EIAs, e.g., B19V-specific IgG and IgM, IgG avidity, and ETS EIAs. At VRD, the sera were also tested by a B19V viral load PCR (qPCR). By consensus analysis, 43 (55.1%) sera represented past infection, 28 (35.9%) sera represented recent infection, and 7 (9.0%) sera were indeterminate. Both VRD B19V qPCR and HI B19V VP2 IgM EIA gave the highest agreement with consensus interpretation for past or recent infection, with an overall agreement of 99% (95% confidence interval [CI], 92 to 100) and positive predictive value (PPV) of 100% (95% CI, 87 to 100). Nine sera designated as representing past infection by consensus analysis were B19V IgM positive by a commercial VRD B19V IgM EIA and B19V IgM negative by a new HI in-house B19V VP2 IgM EIA. A new VRD B19V IgG avidity EIA showed good (>95%) agreement (excluding equivocal results) with consensus interpretations for past or recent infection. Correct discrimination of past from recent B19V infection was achieved through application of qPCR or by appropriate selection of EIAs.

Measles, mumps, rubella, and human parvovirus B19 infections and neurologic disease

While the systemic disorders associated with measles, mumps, and rubella viruses and human parvovirus B19 tend to be mild, each virus can produce potentially life-threatening neurologic disease in human hosts, especially when these viruses infect young children. Two of the viruses, rubella and parvovirus B19, can be vertically transmitted to fetuses during maternal infection and cause congenital infection. Neurologic complications are common after intrauterine infection with the rubella virus, a condition known as the congenital rubella syndrome. Two, measles and rubella viruses, can induce "slow viral" infections, serious, disorders that can occur several years after the initial exposure to the virus and typically have fatal outcomes.

Parvovirus b19 infections and blood counts in blood donors

OBJECTIVES

Parvovirus B19 (B19V) is a transfusion-transmissible virus. To obtain data about the prevalence, incidence, the course of B19V infection in blood donors and whether B19V might impair their blood counts, samples from blood donors with B19V infection were investigated.

METHODS

Blood donations were screened for B19V DNA using the Cobas TaqScreen DPX Test® in mini-pools. B19V DNA concentration, anti-B19V IgG antibody titer and blood counts were determined in positive donors.

RESULTS

157/23,889 (0.66%) donors provided 347 B19V DNA-positive samples. Prevalence of B19V infection was 0.45%, incidence 0.20%. B19V DNA concentrations were predominantly low; only in 8 samples were viral loads of ≥10(5) IU B19V DNA/ml plasma detectable. Besides a slight decrease in hemoglobin, hematocrit, mean corpuscular volume, mean cellular hemoglobin and mean hemoglobin concentration, no major differences in blood counts occurred in B19V DNA-positive samples. In samples with a low B19V DNA concentration, anti-B19V IgG titers were rather high. 98 donors provided at least 1 B19V DNA-positive follow-up sample, indicating a prolonged viremia.

CONCLUSIONS

B19V infection induced no major impairment in the blood counts. In donors with low-level viremia, infectivity through their donations is probably reduced by high antibody titers. Low-level viremia is prolonged, probably exceeding 1 year in many cases.

Antigenic variation and transmission fitness as drivers of bacterial strain structure

Shifts in microbial strain structure underlie both emergence of new pathogens and shifts in patterns of infection and disease of known agents. Understanding the selective pressures at a population level as well as the mechanisms at the molecular level represent significant gaps in our knowledge regarding microbial epidemiology. Highly antigenically variant pathogens, which are broadly represented among microbial taxa, are most commonly viewed through the mechanistic lens of how they evade immune clearance within the host. However, equally important are mechanisms that allow pathogens to evade immunity at the population level. The selective pressure of immunity at both the level of the individual host and the population is a driver of diversification within a pathogen strain. Using Anaplasma marginale as a model highly antigenically variable bacterial pathogen, we review how immunity selects for genetic diversification in alleles encoding outer membrane proteins both within and among strains. Importantly, genomic comparisons among strains isolated from diverse epidemiological settings elucidates the counterbalancing pressures for diversification and conservation, driven by immune escape and transmission fitness, respectively, and how these shape pathogen strain structure.

Novel B19-like parvovirus in the brain of a harbor seal

Using random PCR in combination with next-generation sequencing, a novel parvovirus was detected in the brain of a young harbor seal (Phoca vitulina) with chronic non-suppurative meningo-encephalitis that was rehabilitated at the Seal Rehabilitation and Research Centre (SRRC) in the Netherlands. In addition, two novel viruses belonging to the family Anelloviridae were detected in the lungs of this animal. Phylogenetic analysis of the coding sequence of the novel parvovirus, tentatively called Seal parvovirus, indicated that this virus belonged to the genus Erythrovirus, to which human parvovirus B19 also belongs. Although no other seals with similar signs were rehabilitated in SRRC in recent years, a prevalence study of tissues of seals from the same area collected in the period 2008-2012 indicated that the Seal parvovirus has circulated in the harbor seal population at least since 2008. The presence of the Seal parvovirus in the brain was confirmed by real-time PCR and in vitro replication. Using in situ hybridization, we showed for the first time that a parvovirus of the genus Erythrovirus was present in the Virchow-Robin space and in cerebral parenchyma adjacent to the meninges. These findings showed that a parvovirus of the genus Erythrovirus can be involved in central nervous system infection and inflammation, as has also been suspected but not proven for human parvovirus B19 infection.

Expression of chicken parvovirus VP2 in chicken embryo fibroblasts requires codon optimization for production of naked DNA and vectored meleagrid herpesvirus type 1 vaccines

Meleagrid herpesvirus type 1 (MeHV-1) is an ideal vector for the expression of antigens from pathogenic avian organisms in order to generate vaccines. Chicken parvovirus (ChPV) is a widespread infectious virus that causes serious disease in chickens. It is one of the etiological agents largely suspected in causing Runting Stunting Syndrome (RSS) in chickens. Initial attempts to express the wild-type gene encoding the capsid protein VP2 of ChPV by insertion into the thymidine kinase gene of MeHV-1 were unsuccessful. However, transient expression of a codon-optimized synthetic VP2 gene cloned into the bicistronic vector pIRES2-Ds-Red2, could be demonstrated by immunocytochemical staining of transfected chicken embryo fibroblasts (CEFs). Red fluorescence could also be detected in these transfected cells since the red fluorescent protein gene is downstream from the internal ribosome entry site (IRES). Strikingly, fluorescence could not be demonstrated in cells transiently transfected with the bicistronic vector containing the wild-type or non-codon-optimized VP2 gene. Immunocytochemical staining of these cells also failed to demonstrate expression of wild-type VP2, indicating that the lack of expression was at the RNA level and the VP2 protein was not toxic to CEFs. Chickens vaccinated with a DNA vaccine consisting of the bicistronic vector containing the codon-optimized VP2 elicited a humoral immune response as measured by a VP2-specific ELISA. This VP2 codon-optimized bicistronic cassette was rescued into the MeHV-1 genome generating a vectored vaccine against ChPV disease.

Human parvovirus B19 NS1 protein aggravates liver injury in NZB/W F1 mice

Human parvovirus B19 (B19) has been associated with a variety of diseases. However, the influence of B19 viral proteins on hepatic injury in SLE is still obscure. To elucidate the effects of B19 viral proteins on livers in SLE, recombinant B19 NS1, VP1u or VP2 proteins were injected subcutaneously into NZB/W F1 mice, respectively. Significant expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were detected in NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Markedly hepatocyte disarray and lymphocyte infiltration were observed in livers from NZB/WF 1 mice receiving B19 NS1 as compared to those mice receiving PBS. Additionally, significant increases of Tumor Necrosis Factor -α (TNF-α), TNF-α receptor, IκB kinase -α (IKK-α), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) and nuclear factor-kappa B (NF-κB) were detected in livers from NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Accordingly, significant increases of matrix metalloproteinase-9 (MMP9) and U-plasminogen activator (uPA) were also detected in livers from NZB/W F1 mice receiving B19 NS1 as compared to those mice receiving PBS. Contrarily, no significant variation on livers from NZB/W F1 mice receiving B19 VP1u or VP2 was observed as compared to those mice receiving PBS. These findings firstly demonstrated the aggravated effects of B19 NS1 but not VP1u or VP2 protein on hepatic injury and provide a clue in understanding the role of B19 NS1 on hepatic injury in SLE.