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.

Healthcare-Associated Transmission of Parvovirus B19 Arthropathy

Human parvovirus B19 (B19V) is well known for its infectivity. However, the risk for communicability to previously unexposed healthcare professionals is controversial. We report here a small outbreak of B19V infection among physicians and family members in an adult rheumatology practice that occurred after providing care for a patient with B19V arthropathy. As B19V-infected patients who demonstrate findings of erythema infectiosum or viral arthritis are generally beyond the period of transmissability, strict handwashing and droplet precautions remain imperative when there is contact with potentially pre-symptomatic family members.

Pure Red Cell Aplasia and Antibody-Mediated Rejection: Double Trouble in 1 Kidney Transplant Recipient Solved by Intravenous Immunoglobulin Infusion: A Case Report

Acquired pure red cell aplasia (PRCA) is characterized by severe normocytic (rarely macrocytic) and normochromic anemia, a low reticulocytes count in peripheral blood, and near absence of erythroid precursors in the bone marrow, with a normal level of erythropoietin. We describe a case of the kidney transplant recipient, diagnosed with PRCA induced with parvovirus B19 infection. Our case demonstrates that although this complication is rare, it should be considered in a differential diagnosis of anemia diagnostics in immunocompromised patients. In our case reduced immune response resulted from post-transplant immunosuppressive therapy. In our patient, apart from infection by parvovirus B19, graft dysfunction due to polyomavirus BK virus infection was also detected together with histologic and serologic features of antibody-mediated renal graft rejection. Considering the entire clinical picture, intravenous immunoglobulin therapy (IVIg) was successfully introduced.

The Role of Human Parvovirus B19 in the Pediatric Patients with Pancytopenia?

BACKGROUND

Parvoviruses are small DNA viruses causing erythema infectiosum, which is known as the fifth disease. The aim of this study was to investigate the presence of Parvovirus B19 DNA by Real-Time-PCR retrospectively in clinical samples of children diagnosed as acute leukemia and aplastic anemia when investigating the cause of pancytopenia and to investigate its relationship with the clinical manifestations.

METHODS

The study samples were collected between March 2014 and March 2018 in Gazi University, Faculty of Medicine, Department of Pediatric Hematology. Sixty pediatric patients; 37 males and 23 females, were included in the study. Nucleic acid isolation was performed by using MagNA-Pure Compact Nucleic Acid Isolation Kit (Roche, Germany). Extracted DNA was studied with LightCycler® 2.0 using the Real-Time PCR method and LightCycler® Parvovirus B19 Quantification Kit (Roche, Germany), and the results were evaluated quantitatively. Parvovirus B19 DNA detection interval of the kit was 101 - 106 copies/mL.

RESULTS

Sixty serum samples were investigated and 8.3% (5/60) Parvovirus B19 DNA positivity was determined. Of the five patients with Parvovirus B19 DNA positivity, three had acute lymphoblastic leukemia and two were diagnosed as aplastic anemia. Regarding viral load; 2/5, 1/5, 1/5, and 1/5 of the samples had a viral load of 102, 103, 104, and 105 copies/mL, respectively. Parvovirus B19 DNA positivity was detected in samples from March (2/5), April (2/5), and August (1/5).

CONCLUSIONS

Patients with acute leukemia and aplastic anemia in childhood using immunosuppressive drugs, blood, and blood products during chemotherapy, encounter Parvovirus B19 infections in the follow-up period and are diagnosed by serological and molecular methods. As a result of the study, we suggest that the detection of Parvovirus B19 DNA by Real-Time PCR method in children being admitted with pancytopenia and diagnosed as acute leukemia and aplastic anemia is useful in the follow-up and treatment.

Advances in the Development of Antiviral Strategies against Parvovirus B19

Parvovirus B19 (B19V) is a human pathogenic virus, responsible for an ample range of clinical manifestations. Infections are usually mild, self-limiting, and controlled by the development of a specific immune response, but in many cases clinical situations can be more complex and require therapy. Presently available treatments are only supportive, symptomatic, or unspecific, such as administration of intravenous immunoglobulins, and often of limited efficacy. The development of antiviral strategies against B19V should be considered of highest relevance for increasing the available options for more specific and effective therapeutic treatments. This field of research has been explored in recent years, registering some achievements as well as interesting future perspectives. In addition to immunoglobulins, some compounds have been shown to possess inhibitory activity against B19V. Hydroxyurea is an antiproliferative drug used in the treatment of sickle-cell disease that also possesses inhibitory activity against B19V. The nucleotide analogues Cidofovir and its lipid conjugate Brincidofovir are broad-range antivirals mostly active against dsDNA viruses, which showed an antiviral activity also against B19V. Newly synthesized coumarin derivatives offer possibilities for the development of molecules with antiviral activity. Identification of some flavonoid molecules, with direct inhibitory activity against the viral non-structural (NS) protein, indicates a possible line of development for direct antiviral agents. Continuing research in the field, leading to better knowledge of the viral lifecycle and a precise understanding of virus–cell interactions, will offer novel opportunities for developing more efficient, targeted antiviral agents, which can be translated into available therapeutic options.

Clinical Case of Parvovirus B19 Infection in Pregnant Woman with Β-Thalassemia in Bulgaria

A pregnant 30-year-old female in the 34th gestational week was admitted at University "Maichin Dom" Hospital prior to childbirth. The patient is diagnosed with β-thalassemia. During laboratory screening hemoglobin of 98 g/L was established. Blood smear shows mild microcytic hypochromic anemia: RBC 5.15 x 1012/L, HGB 98 g/L, MCV 65.8 fL, MCH 19.4 pg, MCHC 295 g/L. Serum iron concentration is 12.9 µmol/L and ferritin 17.5 µg/L. For the delivery process cesium was considered. Two days after procedure a rash presented on face, hands and breasts. Although the mother was positive for parvovirus B19 infection, the baby was negative. This was confirmed by se-rological and molecular investigations. We discovered only the mother's B19V IgG antibodies in the newborn. In connection to the main disease, namely β-thalassemia, acute virus infection could cause aplastic crisis. After consultation with a hematologist, serum hepcidin concentration (an iron homeostasis regulator) was quantified: 19.4 µg/L. ELISA test was used to prove B19V IgM antibodies in the mother. PCR analysis shows the presence of B19V DNA. During infection, inflammatory cytokines increase hepcidin secretion, leading to iron deposition into cells.

Outcome of fetuses with congenital parvovirus B19 infection: systematic review and meta-analysis

OBJECTIVE

To explore the outcome of fetuses affected by congenital parvovirus B19 (PB19) infection, with or without signs of hydrops on ultrasound.

METHODS

PubMed, EMBASE and CINAHL databases were searched for studies reporting on prenatal diagnosis and outcome of fetal PB19 infection. The outcomes explored were miscarriage, perinatal death (PND), intrauterine death, neonatal death, spontaneous resolution of hydrops or fetal anemia, need for intrauterine transfusion (IUT), resolution of hydrops or anemia after transfusion, fetal loss following transfusion, abnormal brain scan after birth and abnormal neurodevelopmental outcome. Outcomes were reported according to the presence or absence of signs of hydrops on ultrasound. A subgroup analysis was performed including hydropic and non-hydropic fetuses diagnosed at < 20 weeks and ≥ 20 weeks of gestation. Meta-analyses of proportions and meta-analyses using individual-data random-effects logistic regression were performed to analyze the data.

RESULTS

Thirty-five observational studies were included, involving 611 fetuses affected by PB19 infection. The risks of miscarriage (odds ratio (OR), 11.5; 95% CI, 2.7-49.7) and PND (OR, 4.2; 95% CI, 1.6-11.0) were higher in fetuses with PB19 infection presenting, compared with those not presenting, signs of hydrops on ultrasound. In fetuses affected by hydrops, spontaneous resolution of the infection, defined as disappearance of hydrops without need for IUT, occurred in 5.2% (95% CI, 2.5-8.8%) of cases whereas, in the group of fetuses not affected by hydrops, infection resolved in 49.6% (95% CI, 20.7-78.6%) of cases. IUT was performed in 78.7% (95% CI, 66.4-88.8%) of hydropic and in 29.6% (95% CI, 6.0-61.6%) of non-hydropic fetuses affected by congenital PB19 infection and resolution of the infection after IUT occurred in 55.1% (95% CI, 34.0-75.3%) and in 100% (95% CI, 57.3-100%) of cases, respectively. The risk of fetal loss after IUT was higher in fetuses affected compared with those not affected by hydrops (OR, 9.8; 95% CI, 2.8-34.6). The prevalence of abnormal brain imaging was 9.8% (95% CI, 2.5-21.0%) in fetuses affected and 0.0% (95% CI, 0.0-7.0%) in those not affected by hydrops, whilst the corresponding figures for abnormal neurodevelopmental outcome were 9.5% (95% CI, 2.6-20.2) and 0.0% (95% CI, 0.0-7.5), respectively; however, statistical power to assess these outcomes was inadequate due to the small number of included cases.

CONCLUSIONS

Hydrops is the main determinant of mortality and adverse perinatal outcome in fetuses with PB19 infection. Perinatal outcome in non-hydropic fetuses is generally favorable. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Diagnostic and prognostic value of molecular and serological investigation of human parvovirus B19 infection during pregnancy

To define diagnostic and prognostic markers of parvovirus B19 (B19V) fetal infection, two groups were investigated: 1) pregnant women with specific symptoms or contacts with symptomatic households (n=37); 2) mothers with pathological ultrasound findings and the relevant fetus at the time of prenatal diagnosis (n=16). In the first group, diagnosis of B19V infection was achieved using IgM detection in 29/37 (78.3%) of patients, while B19V DNA was detected in 36/37 (97.3%) of infected women. In the second group, intrauterine infection was investigated by amniocentesis (n=5), cordocentesis (n=3) or both (n=5). Median B19V DNA load in amniotic fluid was 8.2x107 copies/ml and in fetal blood was 2x109 copies/ml. Maternal blood was positive for B19V DNA (median 3.8x104 copies/ml) in 14/16 (87.5%) women examined. At time of fetal US investigation, all mothers were B19V IgG positive and B19V IgM were detected in 10/16 (62.5%), while fetal B19V IgG and IgM were detected in 1/8 (12.5%) and 5/8 (62.5%), respectively. Phylogenetic analysis revealed that all B19V maternal and fetal strains belonged to genotype 1A. Diagnosis of maternal, fetal and neonatal B19V infection should be based on both IgM and DNA detection. Prognostic markers of congenital B19V infection need to be defined.

Polymicrogyria in a fetus with human parvovirus B19 infection: a case with radiologic-pathologic correlation

We report the prenatal magnetic resonance imaging (MRI) appearance of polymicrogyria with pathologic correlation in a fetus with congenital parvovirus B19 infection. Prenatal ultrasound revealed non-immune hydrops, but detected no fetal brain abnormalities. A subsequent fetal MRI scan performed at 23 weeks' gestation demonstrated bilateral polymicrogyria, which was confirmed at autopsy. To our knowledge, prenatal diagnosis of polymicrogyria in association with congenital parvovirus B19 infection has not been previously described. This case provides further evidence for brain abnormalities resulting from congenital parvovirus B19 infection, and suggests that fetal neuroimaging with MRI would be of value in suspected cases of congenital parvovirus infection.

Global co-existence of two evolutionary lineages of parvovirus B19 1a, different in genome-wide synonymous positions

Parvovirus B19 (B19V) can cause infection in humans. To date, three genotypes of B19V, with subtypes, are known, of which genotype 1a is the most prevalent genotype in the Western world. We sequenced the genome of B19V strains of 65 asymptomatic, recently infected Dutch blood donors, to investigate the spatio-temporal distribution of B19V strains, in the years 2003-2009. The sequences were compared to B19V sequences from Dutch patients with fifth disease, and to global B19V sequences as available from GenBank. All Dutch B19V strains belonged to genotype 1a. Phylogenetic analysis of the strains from Dutch blood donors showed that two groups of genotype 1a co-exist. A clear-cut division into the two groups was also found among the B19V strains from Dutch patients, and among the B19V sequences in GenBank. The two groups of genotype 1a co-exist around the world and do not appear to differ in their ability to cause disease. Strikingly, the two groups of B19V predominantly differ in synonymous mutations, distributed throughout the entire genome of B19V. We propose to call the two groups of B19V genotype 1a respectively subtype 1a1 and 1a2.

Productive parvovirus B19 infection of primary human erythroid progenitor cells at hypoxia is regulated by STAT5A and MEK signaling but not HIFα

Human parvovirus B19 (B19V) causes a variety of human diseases. Disease outcomes of bone marrow failure in patients with high turnover of red blood cells and immunocompromised conditions, and fetal hydrops in pregnant women are resulted from the targeting and destruction of specifically erythroid progenitors of the human bone marrow by B19V. Although the ex vivo expanded erythroid progenitor cells recently used for studies of B19V infection are highly permissive, they produce progeny viruses inefficiently. In the current study, we aimed to identify the mechanism that underlies productive B19V infection of erythroid progenitor cells cultured in a physiologically relevant environment. Here, we demonstrate an effective reverse genetic system of B19V, and that B19V infection of ex vivo expanded erythroid progenitor cells at 1% O(2) (hypoxia) produces progeny viruses continuously and efficiently at a level of approximately 10 times higher than that seen in the context of normoxia. With regard to mechanism, we show that hypoxia promotes replication of the B19V genome within the nucleus, and that this is independent of the canonical PHD/HIFα pathway, but dependent on STAT5A and MEK/ERK signaling. We further show that simultaneous upregulation of STAT5A signaling and down-regulation of MEK/ERK signaling boosts the level of B19V infection in erythroid progenitor cells under normoxia to that in cells under hypoxia. We conclude that B19V infection of ex vivo expanded erythroid progenitor cells at hypoxia closely mimics native infection of erythroid progenitors in human bone marrow, maintains erythroid progenitors at a stage conducive to efficient production of progeny viruses, and is regulated by the STAT5A and MEK/ERK pathways.

[Clinicopathologic study of parvovirus B19 infection in perinatal period]

OBJECTIVE

To characterize the risks and histopathological features of parvovirus B19 infection of infants in perinatal period.

METHODS

Routine pathological examination was performed on 1 neonate, 2 dead fetuses and 2 placentas using either autopsy or biopsy materials.

RESULTS

The diagnostic intranuclear inclusions were found in erythroblasts in the bone marrow, liver, spleen and lungs in one case, in the spleen and liver in one case, in the spleen in one case, and in the placentas in two cases.

CONCLUSIONS

Severe hemolytic anemia or fetal hydrop or hemophagocytosis caused by the infection of parvovirus B19 can lead to death of infected neonates and fetus. Pathological confirmation of parvovirus B19 infection relies on the identification of erythroblasts containing the diagnostic intranuclear inclusions.

[A family outbreak of parvovirus B19 atypical exanthemas: report of two cases]

Two atypical cases of parvovirus B19 infection occurred consecutively within a family. A 14 year-old patient presented an extended papular-purpuric "gloves and socks" syndrome and two weeks later his mother developed a predominantly unilateral purpuric rash in the limbs with severe malaise. Specific IgM antibodies in the boy and polymerase chain reaction (PCR) and serology in the mother, confirmed parvovirus B19 infection. We emphasize the variable presentation of B19 infection within a family. The importance of etiologic studies in the presence of atypical exanthemas and the utility of PCR in the diagnosis of B19 are underscored.

Detection of IgE anti-parvovirus antibodies in human breast milk

Breast milk is a complex fluid, rich in nutrients and non-nutritional bioactive components, including antimicrobial factors, immunoglobulins, cytokines, and anti-inflammatory substances. Although IgE is implicated in viral immunity, its role in breast milk in parvovirus B19 immunity has not been studied. Total immunoglobulin levels of IgE, IgG, and IgE anti-parvovirus B19 antibodies were determined by ELISA and Western blot analysis in breast milk and in sera from a mother and her nursing infant (female, 10 mo). For specific IgE protein determination, breast milk was fractionated by chromatography on G-100 Sephadex; 3 peaks were collected and separated by SDS PAGE. The levels of total IgE in breast milk and its fractions were low (<2.4 ng/ml), and those of maternal and infant serum were negligible (18 and 4.3 IU/ml, respectively). Nevertheless, the breast milk and maternal and infant sera contained IgE anti-parvovirus B19 antibodies, even though the infant was never infected with parvovirus B19. Total serum levels of maternal IgG were within the normal range and those of infant IgG were low (473 mg/dl); total IgG in breast milk was not determined. Maternal serum contained some detectable IgG anti-parvovirus antibodies that were not present in infant serum or breast milk. Total maternal and infant serum levels of IgM and IgA were within the normal ranges. The presence of IgE anti-parvovirus B19 antibodies in breast milk suggests that IgE anti-viral antibodies are transmitted in breast milk and may provide protective responses in nursing children.

The "pressure pan" evolution of human erythrovirus B19 in the Amazon, Brazil

To understand the evolutionary dynamics of human parvovirus B19, we analyzed VP1 and VP2 gene sequences of B19 sampled from Belém (Amazon), the city of São Paulo, Brazil and globally. Our analysis revealed a strikingly different pattern of evolutionary change for those viral lineages introduced into Belém, which exhibited a higher rate of nonsynonymous substitutions compared to those viruses sampled from other locations. We propose that difference this is due to the high prevalence of B19 in Belém (up to 85%) compared to other locations (prevalences of approximately 50%), which imposes a more intense selection pressure. Hence, those B19 lineages introduced into Belém experienced an elevated rate of amino acid change, driven by positive selection, in order to generate serial re-infections in a small web of transmission, which can be thought of as an evolutionary "pressure pan".

Sensitive and rapid diagnosis of human parvovirus B19 infection by loop-mediated isothermal amplification

BACKGROUND

Human parvovirus B19 (B19) infections exhibit various skin manifestations that are similar to and hence hard to distinguish from many other skin diseases. The virological diagnosis of B19 infection is usually based on time-consuming serological tests and polymerase chain reaction (PCR).

OBJECTIVES

In this study, a DNA amplification method, loop-mediated isothermal amplification (LAMP), was used for the diagnosis of B19 infection and was compared with PCR.

METHODS

Ten patients with acute B19 infection and 16 patients with other skin diseases were enrolled. Sera and pharyngeal swabs were used directly as the templates in LAMP. The LAMP reaction was carried out at 63 degrees C for 1 h in a heat block. The reaction products were judged visually, by adding SYBR Green I into the tubes, and by gel electrophoresis.

RESULTS

B19 DNA was detected by LAMP in 10 sera and all of seven tested pharyngeal swabs of 10 patients with acute B19 infection but not in samples from 16 patients with other skin diseases. The results were in agreement with those obtained by PCR except for one case. The reason for the single discrepancy may be that the sensitivity of LAMP is 10(2) times higher than PCR.

CONCLUSIONS

Detection of B19 DNA by LAMP in serum and especially in the pharynx is a rapid and convenient method for the diagnosis of acute B19 infection.

Detection of parvovirus B19 in a case of erythema infectiosum with myositis

A well documented case of erythema infectiosum is being reported here for the first time from India which was associated with myositis that has not been reported globally. A 9-year-old child presented with moderate to high grade fever, mild anemia, and erythematous rash involving face, trunks and limbs associated with arthralgia, myalgia and myositis. Parvovirus B19 infection was confirmed by detection of IgM antibodies (inhouse ELISA) and DNA (nested PCR) in patient's serum.

Papular-purpuric "gloves and socks" syndrome caused by parvovirus B19 infection in Brazil: a case report

Papular-purpuric "gloves and socks" syndrome (PPGSS) is a novel, rare, self-limiting dermatosis caused by human parvovirus B19. It consists of pruritic edema and erythema of the hands and feet in a gloves-and-socks distribution, and it is associated with oral lesions and fever. We present a case of PPGSS in a 22-year-old Brazilian woman. Clinical and laboratory evaluation, including serological tests, PCR and gene sequencing, confirmed the presence of human parvovirus B19.

Erythema infectiosum following generalized petechial eruption induced by human parvovirus B19

Parvovirus B19 is a DNA virus responsible for a wide spectrum of clinical illnesses. Among dermatological manifestations, the most common is erythema infectiosum, also known as the fifth disease. In 1990 Harms et al first described a papular-purpuric gloves and socks syndrome (PPGSS) due to parvovirus B19. It is an acute acral dermatosis characterized by an eruption of petechiae and small purpuric papules affecting the hands and feet in a gloves-and-socks distribution. Recently it was observed that PPGSS may be associated with involvement of the peri-oral region and the chin (acropetechial syndrome) and other sites provoking unusual presentation of the rash. We describe a patient with an acral purpura with the features of the "acropetechial syndrome" involving the buttocks, genital and axillary regions who subsequently developed a maculopapular eruption with the characteristics of the fifth disease. Parvovirus B19 DNA was detected by polymerase chain reaction (PCR) both in skin vasculitic lesions and in the serum during the petechial eruption, before the onset of antibodies. The immune response coincided with the development of the exanthem, suggesting a direct role of parvovirus B19 in the pathogenesis of endothelial cell injury.

Presença de parvovírus B19 em Manaus, AM

A investigação de 1.107 casos de doenças exantemáticas em Manaus permitiu a identificação dos primeiros 47 casos de parvovírus humano B19 na cidade. O parvovírus B19 foi caracterizado por uma combinação de sinais e sintomas como febre, cefaléia, artralgia, mialgia e exantema. A freqüência de exantema foi maior em indivíduos menores de quinze anos e, no adulto, prevaleceram a febre e artropatias. O maior número de casos foi registrado em 1999. Quanto à faixa etária, nos menores de 15 anos, predominou o sexo masculino e, entre os adultos, o feminino. Este estudo, portanto, ressalta a necessidade de se elucidar a causa de doenças exantemáticas que ocorrem no Estado do Amazonas e indica que estudos são necessários, no que concerne à atividade viral.

Recurrent Erythema in Patients with Long-Term Parvovirus B19 Infection

We describe 3 patients with long-term parvovirus B19 infection (defined as detectable parvovirus B19 DNA load for >6 months after the onset of symptoms), which we monitored by serial testing for parvovirus B19 load and the presence of parvovirus B19-specific antibodies in blood. The patients showed recurrent erythema at intervals of several months.

Quantification of parvovirus B19 DNA using COBAS AmpliPrep automated sample preparation and LightCycler real-time PCR

The COBAS AmpliPrep instrument (Roche Diagnostics GmbH, D-68305 Mannheim, Germany) automates the entire sample preparation process of nucleic acid isolation from serum or plasma for polymerase chain reaction analysis. We report the analytical performance of the LightCycler Parvovirus B19 Quantification Kit (Roche Diagnostics) using nucleic acids isolated with the COBAS AmpliPrep instrument. Nucleic acids were extracted using the Total Nucleic Acid Isolation Kit (Roche Diagnostics) and amplified with the LightCycler Parvovirus B19 Quantification Kit. The kit combination processes 72 samples per 8-hour shift. The lower detection limit is 234 IU/ml at a 95% hit-rate, linear range approximately 10(4)-10(10) IU/ml, and overall precision 16 to 40%. Relative sensitivity and specificity in routine samples from pregnant women are 100% and 93%, respectively. Identification of a persistent parvovirus B19-infected individual by the polymerase chain reaction among 51 anti-parvovirus B19 IgM-negative samples underlines the importance of additional nucleic acid testing in pregnancy and its superiority to serology in identifying the risk of parvovirus B19 transmission via blood or blood products. Combination of the Total Nucleic Acid Isolation Kit on the COBAS AmpliPrep instrument with the LightCycler Parvovirus B19 Quantification Kit provides a reliable and time-saving tool for sensitive and accurate detection of parvovirus B19 DNA.

Oral manifestations of papular-purpuric 'gloves and socks' syndrome due to parvovirus B19 infection: the first case presented in Greece and review of the literature

Papular-purpuric 'gloves and socks' syndrome (PPGSS) is a novel, rare, self-limited dermatosis initially described in 1990. It is characterized by painful, pruritic edema and erythema, rapidly evolving to papular-purpuric lesions on the distal extremities, in a gloves-and-socks distribution, accompanied by fever and oral lesions such as petechiae, vesiculopustules and small erosions. Parvovirus B19 has been implicated in most cases as the etiological factor. Herein we present the first case of PPGSS in a 42-year-old Greek man with von Willebrand disease. On admission the patient was febrile, and presented acral edema and erythema rapidly followed by purpuric lesions on the same sites, and palatal petechiae. Complete remission of the exanthem occurred 7 days after hospitalization. Clinical and laboratory evaluation including serologic tests and PCR, confirmed the presence of parvovirus B19. Review of the existing literature on this novel syndrome and its association with parvovirus B19 is also presented.

Frontal lobe seizures and uveitis associated with acute human parvovirus B19 infection

We report a 5-year-old girl who developed repeated episodes of behavioral alterations shortly after human parvovirus B19 infection and uveitis. Video-electroencephalographic study demonstrated that these brief episodes were frontal lobe seizures. Seizures responded promptly to antiepilepsy medications. Further diagnostic testing did not reveal any rheumatologic disorders. Human parvovirus B19 infections in children are more commonly associated with febrile seizures and meningoencephalitis. Our case demonstrates that, rarely, it may be associated with the development of partial epilepsy.

[Exanthematous outbreak caused by human parvovirus B19 in a school in Banderaló, Argentina]

We report an exanthematic outbreak in a school of Banderaló town, located in the district of General Villegas, Buenos Aires province, Argentina. This outbreak affected 21 individuals, with a wide range of age (out of a total population of 1400). The observed clinical manifestations were exanthema and in some cases fever, asthenia, arthropathies and myalgia. The presence of specific IgM antibodies against measles, rubella and human parvovirus B19 were investigated. Analysis of IgM antibodies to parvovirus B19 by ELISA was positive in 90.8% of the cases and viremia was detected in 66.7% of the patients by nested PCR. These results indicate that human parvovirus B19 was the etiologic agent of the outbreak and they confirm its circulation in Argentina. Moreover, this study demonstrates that PCR may be useful for the study of transmission foci and of individuals with prolongued clinical manifestations. We consider that it is necessary to include the differential diagnosis of human parvovirus B19 in the surveillance of exanthematic virosis.

[Parvovirus B19 outbreak in a rural community in Alicante]

BACKGROUND

Parvovirus B19 (PVB19) has been identified as the cause of erythema infectiosum. The epidemiology of PVB19 has not been extensively studied in Spain or in the autonomic community of Valencia. The aim of this work is to describe an outbreak of PVB19 infection occurring in the area of Monforte del Cid, Alicante.

METHODS

A probable case was defined as: all subjects living in Monforte who presented a rash (mainly facial) and/or arthralgia starting from November 1999. A confirmed case was defined as: a probable case confirmed by laboratory analysis or a case having an epidemiological link. Laboratory confirmation included specific IgG or IgM antibodies to PVB19. Cases were mainly detected through the Monforte del Cid Primary Health Care Center.

RESULTS

The outbreak occurred from November 1999 to August 2000. A total of 118 cases were detected, giving an overall attack rate (AR) of 23.2 cases per 1,000 inhabitants. The highest rates were in the age groups of 0-4 years old (AR 5 114.5 per 1,000) and 5-9 years old (AR 5 180.3 per 1,000). By gender, the AR per 1,000 inhabitants was 26.9 in men and 16.7 in women. Two of the cases were pregnant women and one of them had a miscarriage.

CONCLUSIONS

The outbreak of erythema infectiosum lasted 10 months and mainly affected children under 14 years old. Active surveillance was focussed on women in the first three months of pregnancy.

Parvoviruses and blood products

Erythrovirus B19 (B19), a small isocahedral, non-enveloped virus (18-26 nm), is a ubiquitous infection agent in industrialised countries. Depending on the infected host, B19 has a wide range of disease manifestations from asymptomatic (the majority) to severe, including persistent infection. The risk of B19 transmission by blood products is enhanced by a high virus titre in the infected donor, by pooling of a large number of donations, and by the virus's resistance to effective inactivation methods such as heat and solvent-detergent treatments. B19-DNA has been detected in single donations, in manufacture plasma pools and in plasma derivatives (clotting factors, albumin, antithrombin III and immunoglobulins) produced by different processes. B19 transmission is mostly found in patients treated with clotting factors, as shown by a higher seroprevalence in treated haemophiliacs, by the presence of B19 DNA, and by active seroconversion. Chronic B19 infection can successfully be treated with polyvalent intravenous immunoglobulins. The key role of neutralising anti-B19 antibodies and of the virus titre has been demonstrated by B19 transmission after infusion of several B19-positive plasma batches treated with solvent-detergent. Two strategies can be followed to reduce the B19 risk: (1) reducing the viral load in the manufacture plasma pool by discarding B19-DNA-positive donations; (2) developing new strong virus inactivation methods. The physico-resistant properties of B19 make it a good model for new emergent viruses capable of infecting blood products.

Antibody responses in parvovirus B19 infected patients

Parvovirus B19 is the causative agent of erythema infectiosum. In addition, the infection may be associated with other disease manifestations: anemia and aplastic crisis, thrombo- or granulocytopenies; spontaneous abortion or hydrops fetalis in pregnant women; acute and chronic arthritis in adults and children, myocarditis and hepatitis. Both acute and persistent courses of B19-infections have been reported. All patients develop IgG against the capsid proteins VP1 and VP2, the majority of virus neutralizing antibodies that offer life-long protection against reinfections are directed against the VP1-unique region. IgM is mainly directed against VP2-specific epitopes. These antibodies may be present for only a rather short period of two to ten weeks after acute infection. IgG-antibodies against the nonstructural protein NS1 are preferentially found in patients which are unable to eliminate the virus and develop persisting viremia or virus persistence in distinct organs, e.g. synovial fluid, liver, bone marrow.

Simultaneous detection of measles virus, rubella virus, and parvovirus B19 by using multiplex PCR

We describe here a multiplex reverse transcription-PCR (RTMNPCR) assay designed to detect and differentiate measles virus, rubella virus, and parvovirus B19. Serial dilution experiments with vaccine strains that compared cell culture isolation of measles in B95 cells and rubella in RK13 cells showed sensitivity rates of 0.004 50% tissue culture infective dose (TCID(50)) for measles virus and 0.04 TCID(50) for rubella virus. This RTMNPCR can detect as few as 10 molecules for measles virus and rubella virus and one molecule for parvovirus B19 in dilution experiments with plasmids containing inserts of the primary reaction amplification products. Five pharyngeal exudates from measles patients and 2 of 15 cerebrospinal fluid samples from measles-related encephalitis were found to be positive for measles virus by this RTMNPCR. A total of 3 of 27 pharyngeal exudates from vaccinated children and 2 pharyngeal exudates, plus one urine sample from a case of congenital rubella syndrome, were found to be positive for rubella virus by RTMNPCR, whereas 16 of 19 sera from patients with erythema infectiosum were determined to be positive for parvovirus B19 by RTMNPCR. In view of these results, we can assess that this method is a useful tool in the diagnosis of these three viruses and could be used as an effective surveillance tool in measles eradication programs.

Fatal myocarditis associated with acute parvovirus B19 and human herpesvirus 6 coinfection

We report on the case of a healthy young boy who developed a fulminant myocarditis due to acute coinfection with erythrovirus (parvovirus B19) and human herpesvirus 6 (HHV-6) in the absence of an antiviral immune response. We suggest that the HHV-6-induced immunosuppression enhanced dissemination of parvovirus B19, which led to fatal myocarditis.

Acute parvovirus B19 infection during anti-retroviral therapy

Human parvovirus B19 (B19) has been described as a causative agent of chronic anemia in human immunodeficiency virus type-1 (HIV-1)-infected patients. We report an HIV-1 infected patient who had been receiving anti-retroviral therapy who showed sudden pancytopenia. Primary B19 infection was confirmed by the detection of plasma viremia and seroconversion. Although clearance required a prolonged period of time, the patient eventually cleared the B19 viral DNA from the plasma. More than likely, highly active anti-retroviral therapy (HAART), including a protease inhibitor, played a role in clearing the virus.

Fifth (human parvovirus) and sixth (herpesvirus 6) diseases

Fifth (erythema infectiosum) and sixth (roseola infantum) diseases are common rash illnesses of childhood that have long been recognized in clinical medicine. The discovery of the viruses that cause these illnesses has revealed relationships with other syndromes. Primary infection with the agent of erythema infectiosum, human parvovirus B19, is associated with transient aplastic crisis in hemolytic anemia, arthropathy in adults, chronic anemia in immunocompromised patients, and nonimmune fetal hydrops in pregnant women. The only documented illness associated with primary infection with human herpesvirus 6 is roseola or exanthema subitum in young children. However, reactivated infections in adults and immunocompromised patients may be associated with serious illness such as encephalitis/encephalopathy, and bone marrow suppression leading to transplant failure or graft-versus-host disease. Diagnostic studies for both viruses have been limited, although reliable serologic tests for human parvovirus B19 have recently become available. Diagnosis of human herpesvirus 6 remains problematic, because current tests cannot differentiate primary from reactivated disease. This is more of an issue for the putative relationship of these viruses to more chronic conditions, such as rheumatologic disease for human parvovirus B19 and multiple sclerosis for human herpesvirus 6. The relationship between the viruses and these conditions remains controversial, and better diagnostic tests and further information on viral pathogenesis for both viruses are required in order to make a reliable judgment in this regard.

Impaired gamma interferon responses against parvovirus B19 by recently infected children

Parvovirus B19 is the causative agent of "fifth disease" of childhood. It has been implicated in a variety of conditions, including unsuccessful pregnancy and rheumatoid arthritis, and is a potential contaminant of blood products. There has been little study of immunity to parvovirus B19, and the exact nature of the protective humoral and cell-mediated immune response is unclear. Immune responses to purified virus capsid proteins, VP1 and VP2, were examined from a cohort of recently infected children and compared with responses from long-term convalescent volunteers. The results demonstrate that antibody reactivity is primarily maintained against conformational epitopes in VP1 and VP2. The unique region of VP1 appears to be a major target for cell-mediated immune responses, particularly in recently infected individuals. We confirm that antibody reactivity against linear epitopes of VP2 is lost shortly after infection but find no evidence of the proposed phenotypic switch in either the subclass of parvovirus B19-specific antibody or the pattern of cytokine production by antigen-specific T cells. The dominant subclass of specific antibody detected from both children and adults was immunoglobulin G1. No evidence was found for interleukin 4 (IL-4) or IL-5 production by isolated lymphocytes from children or adults. In contrast, lymphocytes from convalescent adults produced a typical type 1 response associated with high levels of IL-2 and gamma interferon (IFN-gamma). However, we observed a significant (P<0.001) deficit in the production of IFN-gamma in response to VP1 or VP2 from lymphocytes isolated from children. Taken together, these results imply that future parvovirus B19 vaccines designed for children will require the use of conformationally preserved capsid proteins incorporating Th1 driving adjuvants. Furthermore, these data suggest novel mechanisms whereby parvovirus B19 infection may contribute to rheumatoid arthritis and unsuccessful pregnancy.

Screening of blood donors for human parvovirus B19 and characterization of the results

BACKGROUND AND OBJECTIVES

Human parvovirus B19 (B19 virus) can be transmitted through blood transfusion and plasma-derived products. In a previous report, we utilized the simple hemagglutination method based on the interaction between the B19 virus and P antigen on human erythrocytes in order to screen the blood donors. We called this method receptor-mediated hemagglutination (RHA) [Lancet 1995;346:1237-1238]. In this paper, we report on a large-scale screening of the B19 virus by RHA and discuss the results.

MATERIALS AND METHODS

Donor sera from September 1995 to March 1997 and seroconversion panels were enrolled. Donor sera were examined by RHA for large-scale screening. The positive sera in the first screening were then further investigated by the RHA inhibition test, countercurrent immunoelectrophoresis (CIE), an enzyme-linked immunosorbent assay, and polymerase chain reaction (PCR). We also evaluated the infectivity and neutralizing activity of various kinds of sera by the erythroid colony forming unit (CFU-e) assay. To examine the detection limits of the B19 virus by RHA, B19-viremic sera were purified by sucrose gradient ultracentrifugation.

RESULTS

Among 257,710 sera specimens, 293 sera (0.11%) gave a positive reaction in the first screening using RHA. Out of these 293 sera specimens, 31 were positive for PCR, of which 28 were also RHA inhibition-positive, and 25 of the 28 CIE-positive. In the CFU-e injury assay, all the RHA inhibition (+) sera showed a decrease in the number of erythroid colonies. The RHA inhibition (-) PCR (+) B19 antibody (+) sera did not affect the erythroid colony formation and protected CFU-e from injury by the B19 virus. By measuring the amount of purified B19 protein and its RHA titer, the detection limit of the B19 virus by RHA was calculated to the 0.37+/-0.03 ng/ml.

CONCLUSION

These results suggest that the RHA(+) RHA inhibition (+) sera were infectious in vitro. The combination of RHA and the RHA inhibition test is considered to be useful for the large-scale screening of infectious B19 virus in blood donors with high specificity.