Phylogenetic analysis of human parvovirus B19, indicating two subgroups of genotype 1 in Vietnamese patients

Surveillance of Erythrovirus B19 (B19V) in patients with acute febrile illness suspected of arboviruses in Mato Grosso do Sul state, Brazil

Introduction

Human Erythrovirus (parvovirus) B19 infection can produce symptoms similar to those produced by Dengue, Chikungunya, and Zika viruses, making clinical diagnosis difficult. The importance of erythrovirus B19 in human pathology has been increased and reported in numerous studies published globally.

Methods

The B19V infection was investigated by real-time PCR in sera samples from patients with signs and symptoms related to classic arboviral symptoms. This study was conducted to provide information on the genetic diversity of Human Erythrovirus B19 (B19V) circulating in the state of Mato Grosso do Sul, Midwest region of Brazil, from 2017 to 2022. A total of 773 sera samples of patients with negative diagnostic results for Dengue, Chikungunya, and Zika, during the study period were analyzed.

Results

Erythrovirus DNA was found in 10.6% (82/773) of patients, among them 10 were pregnant women. Four samples were completely sequenced, and the other five partially, to genotype by phylogenetic reconstruction. All samples belong to worldwide dispersed genotype 1, subgenotype 1a.

Discussion

The findings of the study demonstrate the importance of including B19V in differential laboratory diagnosis for epidemiological purposes and appropriate patient management. The diagnosis for B19V should be performed, particularly among pregnant women, immunocompromised patients, and individuals with hemolytic diseases, given that the infection is more severe in these cases.

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.

Regional mutations in CHIKV-ECSA genomes and detection of other viruses in the serum of acute febrile patients by a metagenomic approach in Mato Grosso, Central-Western Brazil, 2018

Mato Grosso (MT) State is part of central western Brazil and has a tropical permissive environment that favors arbovirus outbreaks. A metagenomic approach was used to identify viral genomes in seven pools of serum from patients (n=65) with acute febrile disease. Seven chikungunya virus (CHIKV) genomes were determined, showing four amino acid changes found only in CHIKV genomes obtained in MT since 2018: nsP2:T31I, nsP3: A388V, E3:T201I and E3:H57R, in addition to other mutations in E1, nsP2 and nsP4. Six parvovirus B19 (B19V) genotype I genomes (4771-5131 nt) showed four aa alterations (NS1:N473D, R579Q; VP1:I716T; and 11 kDa:V44A) compared to most similar B19V from the USA. Coinfection between CHIKV and B19V was evidenced in 22/65 (33.8%) patients by RT‒PCR and PCR, respectively. Other viruses found in these pools include human pegivirus C, torque teno virus 3, an unclassified TTV and torque teno mini virus. Metagenomics represents a useful approach to detect viruses in the serum of acute febrile patients suspected of arbovirus disease.

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.

Comprehensive surveillance data suggest a prominent role of parvovirus B19 infection in Belarus and the presence of a third subtype within subgenotype 1a

Human parvovirus B19 (B19V) infection is not notifiable in Belarus and its most common clinical presentation erythema infectiosum (EI) is often difficult to distinguish from other exanthematous diseases. The objective of this study was to provide comprehensive data about EI epidemiology in Belarus based on the serological and molecular investigation of samples from measles and rubella discarded cases collected between 2005 and 2019. Overall, 4919 sera were investigated for IgM antibodies against B19V and the positive cases were analysed according to year, season and age. B19V DNA was amplified by PCR in a total of 238 sera from all over the country, and sequenced for phylogenetic analyses. B19V infection was confirmed in 1377 (27.8%) measles and rubella discarded cases. Two high incidence periods and a seasonal increase of EI between mid-February to mid-July were identified. Children from 4 to 6 and from 7 to 10 years of age represented the largest groups of patients (22.51% and 22.66% of all cases, respectively), followed by adults between 20 and 29 years of age (14.23%). Among the 238 B19Vs sequenced, one belonged to subgenotype 3b and 237 to subgenotype 1a with 81 (34.2%) clustering with subtypes 1a1 and 153 (64.6%) with 1a2. Three strains (1.2%) formed an additional, well-supported cluster suggesting the presence of another subtype of 1a, tentatively named 1a3. The epidemiological and molecular analyses highlighted not only the prominent role of B19V in exanthematous diseases in Belarus, but also suggested a previously underestimated diversity of subgenotype 1a sequences with a third subtype 1a3.

Genetic diversity of primate erythroparvovirus 1 between 2009 and 2016: First report from Turkey

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.

Ancient human parvovirus B19 in Eurasia reveals its long-term association with humans

Human parvovirus B19 (B19V) is a ubiquitous human pathogen associated with a number of conditions, such as fifth disease in children and arthritis and arthralgias in adults. B19V is thought to evolve exceptionally rapidly among DNA viruses, with substitution rates previously estimated to be closer to those typical of RNA viruses. On the basis of genetic sequences up to ∼70 years of age, the most recent common ancestor of all B19V has been dated to the early 1800s, and it has been suggested that genotype 1, the most common B19V genotype, only started circulating in the 1960s. Here we present 10 genomes (63.9-99.7% genome coverage) of B19V from dental and skeletal remains of individuals who lived in Eurasia and Greenland from ∼0.5 to ∼6.9 thousand years ago (kya). In a phylogenetic analysis, five of the ancient B19V sequences fall within or basal to the modern genotype 1, and five fall basal to genotype 2, showing a long-term association of B19V with humans. The most recent common ancestor of all B19V is placed ∼12.6 kya, and we find a substitution rate that is an order of magnitude lower than inferred previously. Further, we are able to date the recombination event between genotypes 1 and 3 that formed genotype 2 to ∼5.0-6.8 kya. This study emphasizes the importance of ancient viral sequences for our understanding of virus evolution and phylogenetics.

Genotypes of erythrovirus B19, their geographical distribution & circulation in cases with various clinical manifestations

Erythrovirus B19 (B19V) is one of the erythroviruses known to be pathogenic in humans. B19V is classified into three distinct genotypes; 1, 2 and 3, differing from each other by 2-13 per cent. Genotype 1 consists of the prototype B19V isolates, genotype 2 comprises the A6, LaLi and their related isolates while genotype 3 includes the V9- and V9-related isolates. The classification of genotype 1 into two subtypes (1A and 1B) and genotype 3 into two subtypes (3a and 3b) with an estimated nucleotide difference of about 5 per cent has been done. Predominance of genotype 1 across all the continents is seen followed by genotypes 2 and 3. There are no disease-specific genotypes. All the three genotypes have been found in symptomatic as well as asymptomatic individuals and have been reported from several countries across the world. The prevalence of genotype 2 in older populations and its absence from current circulation in Northern Europe has also been reported. The present review focuses on geographic distribution and association of genotypes of B19V with different clinical manifestations.

Serological and molecular analysis of parvovirus B19 infection in Mayan women with systemic lupus erythematosus in Mexico

Background:

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that mainly affects women, characterized by the production of autoantibodies. Its causal agent is unknown, but the combination of environmental, hormonal and genetic factors may favor the development of the disease. Parvovirus B19 has been associated with the development of SLE, since it induces the production of anti-single stranded DNA antibodies. It is unknown whether PV-B19 infection is an environmental factor that trigger or reactivate SLE in the Mexican Mayan population.

Aim:

A preliminary serological and molecular study of PV-B19 infection in Mayan women with established SLE was done.

Methods:

IgG and IgM anti PV-B19 were evaluated in 66 SLE patients and 66 control subjects, all women of Mayan origin. Viral DNA and viral load were analyzed by qPCR.

Results:

Insignificant levels of IgM were observed in 14.3% (4/28) of the patients and 11.4% (4/35) of control subjects. IgG was detected in 82.1% (23/28) of the patients and 82.9% (29/35) of control subjects, but were significantly higher in patients. Viral DNA was found in 86.0% (57/66) of the patients and 81.0% (54/66) of control subjects. Viral load, quantified in 28/66 patients and 31/66 controls which were positive for IgM and IgG, was significantly higher in controls.

Conclusion:

The high prevalence of PV-B19 in Yucatan, and the presence of IgM, IgG, and viral load in Mayan women with established SLE suggest that PV-B19 infection could be an environmental factor to trigger or reactivate SLE.

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.

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.

Existence of various human parvovirus B19 genotypes in Chinese plasma pools: genotype 1, genotype 3, putative intergenotypic recombinant variants and new genotypes

Background

Human parvovirus B19 (B19V) is a frequent contaminant of blood and plasma-derived medicinal products. Three distinct genotypes of B19V have been identified. The distribution of the three B19V genotypes has been investigated in various regions or countries. However, in China, data on the existence of different B19V genotypes are limited.

Methods

One hundred and eighteen B19V-DNA positive source plasma pool samples collected from three Chinese blood products manufacturers were analyzed. The subgenomic NS1/VP1u region junction of B19V was amplified by nested PCR. These amplified products were then cloned and subsequently sequenced. For genotyping, their phylogenetic inferences were constructed based on the NS1/VP1-unique region. Then putative recombination events were analyzed and identified.

Results

Phylogenetic analysis of 118 B19V sequences attributed 61.86 % to genotype 1a, 10.17 % to genotype 1b, and 17.80 % to genotype 3b. All the genotype 3b sequences obtained in this study grouped as a specific, closely related cluster with B19V strain D91.1. Four 1a/3b recombinants and 5 new atypical B19V variants with no recombination events were identified.

Conclusions

There were at least 3 subtypes (1a, 1b and 3b) of B19V circulating in China. Furthermore, putative B19V 1a/3b recombinants and unclassified strains were identified as well. Such recombinant and unclassified strains may contribute to the genetic diversity of B19V and consequently complicate the B19V infection diagnosis and NAT screening. Further studies will be required to elucidate the biological significance of the recombinant and unclassified strains.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0611-6) contains supplementary material, which is available to authorized users.

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.

Parvovirus B19 1A complete genome from a fatal case in Brazil

Parvovirus B19 (B19V) infects individuals worldwide and is associated with an ample range of pathologies and clinical manifestations. B19V is classified into three distinct genotypes, all identified in Brazil. Here, we report a complete sequence of a B19V genotype 1A that was obtained by high-throughput metagenomic sequencing. This genome provides information that will contribute to the studies on B19V epidemiology and evolution.

No evidence of persistent parvovirus B19 viremia among Iranian patients with HIV after a 1-year follow-up

Recent studies have demonstrated that, in common with other latent viruses, parvovirus B19 infection can be controlled by the host immune response but may persist in some places such as the bone marrow. Persistent B19 infection has been found in both immunocompetent and immunocompromised individuals, such as patients infected with human immunodeficiency virus (HIV). However, there is limited data regarding long-term B19 viremia in HIV patients. In this study, we investigated virological and hematological findings, and also the clinical outcome, of seven cases of HIV/B19 coinfection (confirmed by PCR) after one year. These cases were provided from a previous study on patients with HIV infection that found B19 DNA in 13 cases. Seven of these 13 patients were available after 1 year, and we retested them for B19 viremia and B19-specific antibodies. B19 IgG was tested by ELISA, and B19 DNA was assessed by nested PCR. Anemia was not observed in these cases. All subjects had cleared viremia, but B19 IgG seroconversion occurred in two cases. No significant changes in CD4 and hemoglobin occurred. The results of this study indicate that B19 infection in HIV patients is a subtle infection and that B19 viremia is not a long-term event.

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.

Epidemiologic study of human parvovirus B19 infection in East China

Human parvovirus B19 (B19V) infection causes a number of diseases in humans, and, in some circumstances, can be life threatening. To understand the epidemiology of B19V infection in the greater metropolitan area of Hangzhou, East China, we performed surveys of IgM and IgG antibodies against B19V and quantification of B19V DNA, by using enzyme-linked immunosorbent assay and quantitative PCR, respectively, in plasma samples from diverse groups. These groups included anemia patients, Mycoplasma pneumonia- and Treponema pallidum-infected patients, HIV-positive individuals, and healthy blood donor volunteers. Our results demonstrated a low level of B19V IgG antibody presence, ranging from 21.9% to 41.8% in all the groups tested, suggesting a low prevalence of B19V infection in the area. Of note, we found that two healthy blood donors and one Mycoplasma pneumonia-infected patient had B19V IgM antibody among 1,290 plasma samples tested. The Mycoplasma pneumonia-infected patient had viremia with viral genome copies of 2.86 × 10(6) per ml of plasma. We detected a high rate of B19V DNA (7.1%) in HIV-positive injection drug users. Importantly, an amino acid mutation of P558S in the large non-structural protein NS1 was identified to be conserved among 14 B19V isolates from the HIV-positive group but not in the B19V isolate of the Mycoplasma pneumonia-infected patient, representing a hallmark of B19V isolates that circulate in HIV1-positive patients in the greater metropolitan area of Hangzhou, East China.

Frequency and genotype of human parvovirus B19 among Iranian patients infected with HIV

The human parvovirus B19 (B19) usually causes a subclinical infection in immunocompetent individuals. Whereas immunocompromised individuals such as patients infected with HIV are at risk of persistent anemia due to B19 infection. Only few studies have been carried out on distribution and molecular epidemiology of B19 in Iran. We aimed to determine the frequency and genotype of B19 among Iranian patients infected with HIV. We conducted a survey on 99 HIV patients and 64 healthy controls. IgG and IgM antibodies against B19 were detected by ELISA and B19 DNA was assessed by nested PCR. PCR products were subjected to direct sequencing and classified after phylogenetic analysis. The prevalence of B19 immunoglobulin was 11.1% for IgG and 1% for IgM. B19 DNA was detected in 13.1% of cases. The prevalence of B19 IgG, IgM, and DNA in control group was 25%, 1.6%, and 9.4%, respectively. B19 IgG was significantly lower in HIV group than in normal controls. There was no significant difference regarding anemia between cases and controls. All sequenced B19 isolates belonged to genotype 1A with low genetic diversity. Our findings indicated that in the HAART era, the importance of B19 infections in HIV patients may be limited whereas persistent B19 viremia in the circulation of healthy controls raises a potential concern in blood donations.

Molecular phenotypes of human parvovirus B19 in patients with myocarditis

AIM: To investigate molecular phenotypes of myocardial B19V-infection to determine the role of B19V in myocarditis and dilated cardiomyopathy (DCM).

METHODS: Endomyocardial biopsies (EMBs) from 498 B19V-positive patients with myocarditis and DCM were analyzed using molecular methods and functional experiments. EMBs were obtained from the University Hospitals of Greifswald and Tuebingen and additionally from 36 German cardiology centers. Control tissues were obtained at autopsy from 34 victims of accidents, crime or suicide. Identification of mononuclear cell infiltrates in EMBs was performed using immunohistological staining. Anti-B19V-IgM and anti-B19V-IgG were analyzed by enzyme-linked immunosorbent assay (ELISA). B19V viral loads were determined using in-house quantitative real-time polymerase chain reaction (PCR). For B19V-genotyping a new B19V-genotype-specific restriction fragment length polymorphism (RFLP)-PCR was established. B19V-genotyping was verified by direct DNA-sequencing and sequences were aligned using BLAST and BioEdit software. B19V P6-promoter and HHV6-U94-transactivator constructs were generated for cell culture experiments. Transfection experiments were conducted using human endothelial cells 1. Luciferase reporter assays were performed to determine B19V-replication activity. Statistical analysis and graphical representation were calculated using SPSS and Prism5 software.

RESULTS: The prevalence of B19V was significantly more likely to be associated with inflammatory cardiomyopathy (iCMP) compared to uninflamed DCM (59.6% vs 35.3%) (P < 0.0001). The detection of B19V-mRNA replication intermediates proved that replication of B19V was present. RFLP-PCR assays showed that B19V-genotype 1 (57.4%) and B19V-genotype 2 (36.7%) were the most prevalent viral genotypes. B19V-genotype 2 was observed more frequently in EMBs with iCMP (65.0%) compared to DCM (35%) (P = 0.049). Although there was no significant difference in gender-specific B19V-loads, women were more frequently infected with B19V-genotype 2 (44.6%) than men (36.0%) (P = 0.0448). Coinfection with B19V and other cardiotropic viruses was found in 19.2% of tissue samples and was associated with higher B19V viral load compared to B19V-monoinfected tissue (P = 0.0012). The most frequent coinfecting virus was human herpes virus 6 (HHV6, 16.5%). B19V-coinfection with HHV6 showed higher B19V-loads compared to B19V-monoinfected EMBs (P = 0.0033), suggesting that HHV6 had transactivated B19V. In vitro experiments confirmed a 2.4-fold increased B19V P6-promoter activity by the HHV6 U94-transactivator.

CONCLUSION: The finding of significantly increased B19V loads in patients with histologically proven cardiac inflammation suggests a crucial role of B19V-genotypes and reactivation of B19V-infection by HHV6-coinfection in B19V-associated iCMP. Our findings suggest that B19V-infection of the human heart can be a causative event for the development of an endothelial cell-mediated inflammatory disease and that this is related to both viral load and genotype.

Keeping pace with parvovirus B19 genetic variability: a multiplex genotype-specific quantitative PCR assay

Three genotypes have been identified within the parvovirus B19 species (B19V), and such genetic diversity may have significant implications for the development of molecular detection assays. In the present study, B19V genetic variability has been examined on a subset of genomic sequences available in the NCBI nucleotide database, and a quantitative PCR (qPCR) assay able to detect, differentiate, and quantify all viral variants has been established. The designed primers and probes have been used for the development of alternative detection formats, based on a combined use of intercalating dye and genotype-specific hydrolysis probes. The qPCR assay analytical performances have been determined on the 1st WHO International Reference Panel for Parvovirus B19 Genotypes. The developed qPCR protocols allow for the detection of genotypes 1 to 3 with equal accuracy, and with a limit of detection (LOD) of 200 IU/ml. A comparison of routine performance was carried out with respect to a previously established assay specifically validated on B19V genotype 1. For 130 clinical samples analyzed, 126 showed concordant results (31 positive and 97 negative), while 4 showed discordant results. Overall, the genotype-specific qPCR assay showed a sensitivity of 93.94% and a specificity of 97.94%, with an agreement rate of 96.92%. The proposed qPCR assay and the alternative protocols developed, each with robust performance, may allow choice with respect to operational systems and diagnostic requirements and might contribute to provide a more reliable diagnostic service and epidemiological surveillance of B19 virus.

Co-infection of human parvovirus B19 with Plasmodium falciparum contributes to malaria disease severity in Gabonese patients

Background

High seroprevalence of parvovirus B19 (B19V) coinfection with Plasmodium falciparum has been previously reported. However, the impact of B19V-infection on the clinical course of malaria is still elusive. In this study, we investigated the prevalence and clinical significance of B19V co-infection in Gabonese children with malaria.

Methods

B19V prevalence was analyzed in serum samples of 197 Gabonese children with P. falciparum malaria and 85 healthy controls using polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and direct DNA-sequencing.

Results

B19V was detected in 29/282 (10.28%) of Gabonese children. B19V was observed more frequently in P. falciparum malaria patients (14.21%) in comparison to healthy individuals (1.17%) (P<0.001). Notably, the mild-malaria group revealed significantly lower hematocrit levels in B19V/P. falciparum co-infection than in P. falciparum mono-infection (P<0.05). Genetic analysis revealed a predominance of B19V genotype-1 (71.43%) in the studied population. However, B19V-genotype 2 was observed significantly more often in children with severe-malaria than in mild-malaria (P=0.04).

Conclusion

Our findings reveal that B19V-infection is frequent in Gabonese children with P. falciparum malaria and signifies a possible contribution of B19V on the clinical course of malaria in a genotype-dependent manner. B19V co-infection should be considered as a additional diagnostic measure in malaria patients with life threatening anemia.

Parvovirus B19 Achievements and Challenges

Parvovirus B19 is a widespread human pathogenic virus, member of the Erythrovirus genus in the Parvoviridae family. Infection can be associated with an ample range of pathologies and clinical manifestations, whose characteristics and outcomes depend on the interplay between the pathogenetic potential of the virus, its adaptation to different cellular environments, and the physiological and immune status of the infected individuals. The scope of this review is the advances in knowledge on the biological characteristics of the virus and of virus-host relationships; in particular, the interactions of the virus with different cellular environments in terms of tropism and ability to achieve a productive replicative cycle, or, on the contrary, to establish persistence; the consequences of infection in terms of interference with the cell physiology; the process of recognition of the virus by the innate or adaptive immune system, hence the role of the immune system in controlling the infection or in the development of clinical manifestations. Linked to these issues is the continuous effort to develop better diagnostic algorithms and methods and the need for development of prophylactic and therapeutic options for B19V infections.

Human immunodeficiency virus/human parvovirus B19 co-infection in blood donors and AIDS patients in Sichuan, China

BACKGROUND

Human parvovirus B19 (B19) is a common pathogen which causes a variety of diseases. Persistent B19 infection is related to the degree of host immunodeficiency in patients with human immunodeficiency virus (HIV) infection. However, the existence, loading, virus evolution and distribution of B19 in Chinese HIV-positive patients have not been determined.

MATERIALS AND METHODS

We investigated 573 HIV-positive blood donors and AIDS patients in Sichuan, China in the last two decades. Bl9-specific serology and quantitative polymerase chain reaction were used to determine the prevalence of B19/HIV co-infection. Viral genome fragments were subjected to phylogeny and haplotype analysis.

RESULTS

B19 genomic DNA was found in 26 of 573 (4.5%) HIV-positive individuals, a higher prevalence than in blood donors. DNA levels ranged from 5.3×10(2)-1.1×10(5) copies/mL. The seroprevalence of IgG was significantly lower in HIV-positive samples than in HIV-negative blood donors, indicating deficient production of B19-specific IgG in the former. The B19 isolates were genotype-1 subtype B19-1A which formed a monophyletic group; seven distinct haplotypes were discovered with 60% of the B19/HIV co-infected variants sharing one central haplotype.

DISCUSSION

This study on the prevalence, phylogeny and distribution of human parvovirus B19 in Sichuan, China, demonstrates the persistence of B19 in the circulation of both immunocompetent and immunocompromised subjects, with implications for blood safety.

Green fluorescent protein (GFP) color reporter gene visualizes parvovirus B19 non-structural segment 1 (NS1) transfected endothelial modification

Background

Human Parvovirus B19 (PVB19) has been associated with myocarditis putative due to endothelial infection. Whether PVB19 infects endothelial cells and causes a modification of endothelial function and inflammation and, thus, disturbance of microcirculation has not been elucidated and could not be visualized so far.

Methods and Findings

To examine the PVB19-induced endothelial modification, we used green fluorescent protein (GFP) color reporter gene in the non-structural segment 1 (NS1) of PVB19. NS1-GFP-PVB19 or GFP plasmid as control were transfected in an endothelial-like cell line (ECV304). The endothelial surface expression of intercellular-adhesion molecule-1 (CD54/ICAM-1) and extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) were evaluated by flow cytometry after NS-1-GFP or control-GFP transfection. To evaluate platelet adhesion on NS-1 transfected ECs, we performed a dynamic adhesion assay (flow chamber). NS-1 transfection causes endothelial activation and enhanced expression of ICAM-1 (CD54: mean±standard deviation: NS1-GFP vs. control-GFP: 85.3±11.2 vs. 61.6±8.1; P<0.05) and induces endothelial expression of EMMPRIN/CD147 (CD147: mean±SEM: NS1-GFP vs. control-GFP: 114±15.3 vs. 80±0.91; P<0.05) compared to control-GFP transfected cells. Dynamic adhesion assays showed that adhesion of platelets is significantly enhanced on NS1 transfected ECs when compared to control-GFP (P<0.05). The transfection of ECs was verified simultaneously through flow cytometry, immunofluorescence microscopy and polymerase chain reaction (PCR) analysis.

Conclusions

GFP color reporter gene shows transfection of ECs and may help to visualize NS1-PVB19 induced endothelial activation and platelet adhesion as well as an enhanced monocyte adhesion directly, providing in vitro evidence of possible microcirculatory dysfunction in PVB19-induced myocarditis and, thus, myocardial tissue damage.

Collaborative study to establish a World Health Organization International genotype panel for parvovirus B19 DNA nucleic acid amplification technology (NAT)-based assays

BACKGROUND AND OBJECTIVES

The aim of the collaborative study was to evaluate a panel of plasma samples containing different genotypes of parvovirus B19 (B19V) for use in nucleic acid amplification technology (NAT)-based assays.

MATERIALS AND METHODS

The panel of samples [Center for Biologics Evaluation and Research Parvovirus B19 Genotype Panel 1; National Institute for Biological Standards and Control (NIBSC) code number 09/110] comprises four different members, i.e. Member 1, Member 2, Member 3, and Member 4 (M1-M4); these represent genotypes 1, 2, 3a B19V, and a negative plasma control, respectively. Thirty-five laboratories from 13 different countries participated in the study. Participants assayed the panel members concurrently with the 2nd World Health Organization (WHO) International Standard for B19V DNA (NIBSC code 99/802) on four separate occasions.

RESULTS

A total of 44 sets of data were returned, 34 from quantitative assays and 10 from qualitative assays. The majority of assays used were in-house and based on real-time PCR. The results showed that all three genotypes were detected consistently by the majority of participants, although a small number of assays detected genotypes 2 and 3 less efficiently, or not at all. Real-time stability studies have indicated that the panel of B19V samples is stable under normal conditions of storage, i.e. ≤-70°C.

CONCLUSIONS

The four-member panel is intended for use in evaluating the ability of NAT assays to detect different B19V genotypes (M1-M3). Based on the results of the collaborative study, the panel was established as the 1st WHO International Reference Panel for parvovirus B19 genotypes.

Prevalence and association of human parvovirus B19V with hepatitis B and C viruses in Nigeria

Co-infection of parvovirus B19 with hepatitis B virus has been found in patients with acute and chronic hepatitis. The clinical significance of parvovirus B19 in hepatitis B co-infected patients is still controversial. In this study parvovirus B19 antibodies and DNA were investigated in serum samples from 76 patients with HBV infection, 17 with HBV/HCV co-infection and 44 healthy controls. In the sera from patients with HBV infection, anti-B19V IgM and IgG antibodies were detected in 24/76 (32%) and 25/76 (33%), in 6/17 (35%) and 8/17 (47%) of HBV/HCV co-infected patients, and in 14/44 (32%) and 12/44 (12%) of a non-hepatitis healthy controls, respectively. B19V DNA was detected in 8/76 (11%) of patients with HBV infection and in 3/17 (18%) of patients with a HBV/HCV co-infection, and in 4/44 (9%) healthy controls. The occurrence of parvovirus B19 DNA was significantly higher in patients with symptomatic HBV 4/20 (20%) compared to asymptomatic HBV carrier 4/56 (7%) (P<0.05). Ten of the positive B19V DNA sequences belonged to B19V genotype 1 while two belonged to genotype 3. The results of this study showed a significant difference in the prevalence of parvovirus B19 DNA in symptomatic HBsAg positive as compared to asymptomatic HBsAg positive individuals; however, the conclusion that parvovirus B19 infection increased the frequency of liver disease was not supported. Long-term longitudinal studies are, however, required to determine the synergistic effect of parvovirus B19 infection in HBV or HBV and HCV co-infected persons.

The prevalence of human parvovirus B19 DNA and antibodies in blood donors from four Chinese blood centers

BACKGROUND

Human parvovirus B19 is a common human pathogen that causes a variety of diseases with outcomes ranging from asymptomatic to severe, especially in immunocompromised patients. The B19 virus can be transmitted via blood and/or blood products and its resistance to common viral inactivation and/or removal methods raises the importance of B19-related blood safety. However, the existence, variation, and loading of B19 in Chinese blood donors have not been determined.

STUDY DESIGN AND METHODS

Quantitative polymerase chain reaction (PCR) was developed to detect all three genotypes of the human erythrovirus DNA in plasma samples. In total, 3957 donations from four Chinese blood centers were screened for B19 by real-time minipool nucleic acid amplification technology (NAT). The positive samples were then confirmed by nested PCR and subjected to sequence analysis and alignment for phylogenetic studies. An enzyme-linked immunosorbent assay-based experiment was also performed to identify the prevalence of immunoglobulin (Ig)G and/or IgM antibodies specific to the B19 structural proteins in acquired samples.

RESULTS

Of 3957 blood donors, 23 (0.58%) specimens were found positive for B19 DNA. The quantitative DNA levels ranged from 2.48 × 10(2) to 6.38 × 10(4) copies/mL. The phylogenic analyses showed that the prevalent genotypes in Chinese blood donors belong to B19 Genotype 1. A total of 448 samples from Chinese blood donors were investigated for the seroprevalence of B19 antibodies, among which 24.6 and 6.9% of specimens were seropositive for B19 IgG and IgM antibodies, respectively. A total of 2.5% of these samples were positive for both antibody isotypes.

CONCLUSIONS

Whether B19 NAT screening of blood and blood products should be launched in China, larger studies are needed to facilitate an informed decision.

Real-time polymerase chain reaction detection of parvovirus B19 DNA in blood donations using a commercial and an in-house assay

BACKGROUND

European regulations require testing of manufacturing plasma for parvovirus B19 (B19) DNA to limit the load of this virus to a maximum acceptable level of 10 IU/µL. To meet this requirement, most manufacturers introduced a test algorithm to identify and eliminate high-load donations before making large manufacturing pools of plasma units. Sanquin screens all donations using a commercial assay from Roche and an in-house assay.

STUDY DESIGN AND METHODS

Between 2006 and 2009, 6.2 million donations were screened using two different polymerase chain reaction (PCR) assays targeting B19 DNA. Donations with B19 DNA loads of greater than 1 × 10(6) IU/mL showing significant differences in viral load between the two assays were further analyzed by sequencing analysis.

RESULTS

A total of 396 donations with B19 DNA loads of greater than 1 × 10(6) IU/mL were identified. Fifteen samples (3.8%) had discordant test results; 10 samples (2.5%) were underquantified by the Roche assay, two samples (0.5%) were underquantified by the in-house assay, and three samples (0.8%) were not detected by the Roche assay. Sequencing analysis revealed mismatches in primer and probe-binding regions. Phylogenetic analysis showed that 12 samples were B19 Genotype 1. The three samples not detected by the Roche assay were B19 Genotype 2.

CONCLUSION

This study shows that 3.8% of the viremic B19 DNA-positive donations are not quantified correctly by the Roche or in-house B19 DNA assays. B19 Genotype 1 isolates showing incorrect test results are more common than B19 Genotype 2 or 3 isolates. Newly designed B19 PCR assays for blood screening should preferably have multiplexed formats targeting multiple regions of the B19 genome.

Investigation of the prevalence of human parvovirus B19 DNA in Korean plasmapheresis donors

BACKGROUND

To ensure the safety of plasma derivatives, some countries have been screening for the human parvovirus B19 (B19V) antigen or DNA in blood donors. We investigated the prevalence of B19V DNA and anti-B19V antibodies in Korean plasmapheresis donors to evaluate the necessity of B19V DNA screening test.

METHODS

Plasma samples were collected between March and July 2008 from 10,032 plasmapheresis donors. The B19V DNA test was performed using the LightCycler 2.0 (Roche, Germany) with quantification kits. Anti-B19V IgM and IgG were tested in 928 randomly selected samples from the 10,032 donors using recomWell Parvovirus B19 ELISA IgM, IgG assay (Mikrogen, Germany). RecomLine Parvovirus B19 LIA IgG, IgM assay (Mikrogen, Germany) was used to analyze the epitopes of antibodies in donors showing positive results for B19V DNA and anti-B19V antibodies. DNA sequencing was performed to identify the genotypes.

RESULTS

The prevalence of B19V DNA was 0.1% (10/10,032). Virus titers in B19V DNA positive donors were less than 10(5) IU/mL (range: 2.7 x 10(1)-3.2 x 10(4) IU/mL) except for 1 donor (1.33 x 10(8) IU/mL). All the isolated B19V DNAs from 6 donors were identified as genotype I. Nine out of 10 B19V DNA positive donors also possessed anti-B19V IgG only or IgG and IgM. The prevalence of anti-B19V IgG was 60.1% (558/928).

CONCLUSIONS

The prevalence of B19V DNA in Korean blood donors was not high and most donors also possessed neutralizing anti-B19V antibodies. Thus, the implementation of a B19V screening test for Korean blood donors does not appear to be imperative.

Genetic variants of human parvovirus B19 in South Africa: cocirculation of three genotypes and identification of a novel subtype of genotype 1

Parvovirus B19 comprises three distinct genotypes (1, 2, and 3). The distribution of B19 genotypes has not before been examined in South Africa. Two hundred thirty-nine laboratory samples submitted to a diagnostic virology laboratory for parvovirus DNA detection were analyzed retrospectively. Of the 53 PCR-positive samples investigated, 40 (75.4%) were identified as genotype 1 by genotype-specific PCR or consensus NS1 PCR and sequencing and 3 (5.7%) as genotype 2 and 10 (18.9%) as genotype 3 by analysis of NS1 sequences. Furthermore, phylogenetic analysis identified two genotype 1 sequences which were distinct from the previously described genotypes 1A and 1B. Interestingly, a genotype 2 virus was detected in the serum of an 11-year-old child, providing evidence for its recent circulation. This is the first study to demonstrate the concurrent circulation of all three genotypes of B19 in South Africa and the provisional identification of a novel subtype of genotype 1. The implications of parvovirus B19 variation are discussed.

Phylogenetic analysis of human parvovirus b19 sequences from eleven different countries confirms the predominance of genotype 1 and suggests the spread of genotype 3b

Phylogenetic analysis of 166 human parvovirus B19 sequences from 11 different countries attributed 91.57% to genotype 1, 5.42% to genotype 3b, and 3.01% to genotype 3a. Very similar viruses of genotype 1 circulated widely in Europe and Israel. Genotype 3b seems to show an increasing spread outside of Africa.

A proficiency testing study to evaluate laboratory performance for the detection of different genotypes of parvovirus B19

BACKGROUND AND OBJECTIVES

In Europe, it is a regulatory requirement that parvovirus B19 (B19V) DNA nucleic acid amplification technique-based testing is performed on plasma pools for certain classes of plasma-derived medicinal products. This proficiency testing study set out to examine the ability of public quality control laboratories and plasma fractionation organizations to detect different genotypes of B19V using nucleic acid amplification technique-based assays.

MATERIALS AND METHODS

Laboratories were supplied with cloned DNAs representing the main genotypes of B19V. All samples were adjusted to equivalent copy number and were distributed as part of a routine external quality assessment programme investigating the evaluation of B19V containing plasma samples by these laboratories. The plasmid clones were distributed to 25 laboratories, representing 13 quality control laboratories and 12 manufacturers of plasma derivatives. The criteria for acceptable detection of the different genotypes of B19V DNA was based upon the maximum theoretical efficiency for polymerase chain reaction amplification. Proficient laboratories were deemed to be those reporting results within 1 log(10) dilution for each of the different virus genotypes.

RESULTS

Data were returned by 23 of the participating laboratories. Some laboratories returned data for more than one type of assay and in total 27 data sets were analysed. Nine of the participating laboratories were able to successfully detect all the virus genotypes according to the applied criteria, all except one used in-house assays.

CONCLUSIONS

The results of the study highlight that there are still discrepancies in the detection of a broad spectrum of B19V genotypes, with implications for batch release testing.

Simultaneous persistence of multiple genome variants of human parvovirus B19

The species human parvovirus B19 (B19V) can be divided into three genotypes. In this study, we addressed the question as to whether infection of an individual is restricted to one genotype. As viral DNA is detectable in tissue for long times after acute infection, we examined 87 liver specimens from adults for the presence of B19V DNA. Fifty-nine samples were found to be positive, 32 of them for genotype 1, 27 for genotype 2 and four for genotype 3. In four samples, DNA of two genotypes was detected; samples from three individuals were positive for genotypes 1 and 2 and a sample from one individual was positive for genotypes 1 and 3. Surprisingly, significant sequence heterogeneity was observed at approximately 1 % of the nucleotides of the genotype 1 genomes from individuals with double genotype 1 and 2 infection. Controls using different enzymes for genome amplification and dilutions of the template verified that nucleotide heterogeneity was due to the presence of three or more genome variants of genotype 1. In summary, the evidence shows that individuals can be infected with two different genotypes, and B19V DNA can persist as a population of different genomes. The results may have implications for the understanding of the antiviral immune response and the development of vaccines against B19V.

Tissue persistence and prevalence of B19 virus types 1–3

Human parvovirus B19 is a minute ssDNA virus that causes a wide variety of diseases, including erythema infectiosum, arthropathy, anemias and fetal death. In addition to the B19 prototype, two new variants (B19 types 2 and 3) have been identified. After primary infection, B19 genomic DNA has been shown to persist in solid tissues of not only symptomatic but also of constitutionally healthy, immunocompetent individuals. The viral DNA persists as an intact molecule without persistence-specific mutations, and via a storage mechanism with life-long capacity. Thus, the mere presence of B19 DNA in tissue cannot be used as a diagnostic criterion, although a possible role in the pathology of diseases, for example through mRNA or protein production, cannot be excluded. The molecular mechanism, host-cell type and possible clinical significance of tissue persistence are yet to be elucidated.

Biological and immunological relations among human parvovirus B19 genotypes 1 to 3

The human parvovirus B19 is now divided into three genotypes: type 1 (prototype), type 2 (A6- and LaLi-like), and type 3 (V9-like). In overall DNA sequence, the three virus types differ by approximately 10%. The most striking DNA dissimilarity, of >20%, is observed within the p6 promoter region. Because of the scarcity of data on the biological activities and pathogenetic potentials of virus types 2 and 3, we examined the functional characteristics of these virus types. We found the activities of the three p6 promoters to be of equal strength and to be most active in B19-permissive cells. Virus type 2 capsid protein VP2, alone or together with VP1, was expressed with the baculovirus system and was shown to assemble into icosahedral parvovirus-like particles, which were reactive in the hemagglutination assay. Furthermore, sera containing DNA of any of the three B19 types were shown to hemagglutinate. The infectivities of these sera were examined in two B19-permissive cell lines. Reverse transcription-PCR revealed synthesis of spliced B19 mRNAs, and immunofluorescence verified the production of NS and VP proteins in the infected cells. All three genotypes showed similar functional characteristics in all experiments performed, showing that the three virus types indeed belong to the same species, i.e., human parvovirus B19. Additionally, the antibody activity in sera from B19 type 1- or type 2-infected subjects (long-term immunity) was examined with homo- and heterologous virus-like particles. Cross-reactivity of 100% was observed, indicating that the two B19 genotypes comprise a single serotype.