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.

Prevalence and incidence of erythrovirus B19 infection in children with sickle cell disease: The impact of viral infection in acute clinical events.

B19V infection is common during childhood. It is self-limited in healthy individuals, but is often associated with transient aplastic crisis in children with sickle cell disease. The aim of this study was to estimate the prevalence and incidence of B19V infection in children with sickle cell disease screened by the Newborn Screening Program of Minas Gerais, Brazil, and followed-up at Fundação Hemominas. Serum or plasma samples from 278 patients were tested for anti-B19V IgG and IgM using commercial ELISA and for viral DNA using in-house real-time PCR assays; 127 negative-children were retested about 1 year later. The median age of children at first testing was 5.9 years (0.8-12.3). The estimated prevalence of B19V was 29.5 % (95%CI 24.1-34.9 %). The incidence of B19V in those 127 negative-children was 18.2 cases/100 patient-years. All DNA-positive samples were identified as genotype 1, except one sample, in which both genotypes 1 and 3 were identified. It was observed that the higher the child's age, the higher the probability of B19V infection. The analysis of clinical and hematological data showed a significant association of B19V infection with transient aplastic crisis and acute splenic sequestration, higher frequency of transfusions, and higher rate of hospitalization, but not with acute chest syndrome or stroke. These results emphasize the impact of B19V infection on the course of sickle cell disease. Strategies to prevent and monitor B19V infection in children with sickle cell disease should be considered to diminish its morbidity in this susceptible population.

Infection and persistence of erythrovirus B19 in benign and cancerous thyroid tissues.

Human erythrovirus B19 (EVB19) is a small, pathogenic DNA virus that has been associated with a wide range of illnesses. The primary site of replication is in bone marrow-derived erythroid progenitor cells, but EVB19 DNA has been detected in a wide range of organs. Recently, studies have linked EVB19 to thyroid cancers and other thyroid diseases. Previous studies from multiple laboratories have detected EVB19 capsid proteins in Graves' disease, Hashimoto's thyroiditis, and thyroid cancer tissues. Data on viral gene expression and mechanism of infection in the thyroid are lacking. To investigate EVB19 infection and persistence in the thyroid, previously archived adult and pediatric tissue sections were examined for EVB19 DNA, RNA, and capsid proteins, as well as EVB19 receptor P-antigen and co-receptor α5ß1 integrin. EVB19 DNA and protein were detected in a majority of tissues examined (87% and 68%, respectively). Detection was similar in adult and pediatric samples. Quantification of viral genomes revealed no significant difference in the amount of viral DNA in benign, cancerous, or metastatic thyroid tissues. EVB19 capsid RNA was detected in 67% of the tissues examined, confirming at least low-level viral gene expression. Immunohistochemical staining for P-antigen and α5ß1 detected the receptor and co-receptor most frequently on normal thyroid epithelial cells. EVB19 capsid staining could be detected in tumors lacking viral receptors. These results suggest that normal thyroid epithelial cells are the initial target for EVB19 infection in the thyroid and allow for continued persistence in both normal and cancerous thyroid tissues.

Detection of erythrovirus B19 in thyroidectomy specimens from Graves' disease patients: a case-control study.

Environmental factors, such as viruses, are thought to contribute to the development of thyroid autoimmunity. Erythrovirus B19 (EVB19) is suspected to be involved in Hashimoto's thyroiditis, but no direct evidence is available concerning the role of EVB19 infection in Graves' disease. The objective of this study was to investigate whether the presence of EVB19 is more frequent in thyroidectomy specimens of patients undergoing thyroidectomy for Graves' disease (cases) than for multinodular thyroid (controls). Serum and thyroidectomy specimens were prospectively collected from 64 patients referred for total thyroidectomy over a 5-year period (2007-2011) and were investigated retrospectively and blindly for circulating EVB19 DNA by q-PCR (Qiagen), and for EVB19 thyrocyte infection by immunochemistry (VP2-Antibody, Dako). EVB19 serology was also determined. General clinical and laboratory data were collected. Twenty patients were referred for Graves' disease and 44 patients were referred for non-autoimmune multinodular thyroid. Patients with thyroid cancer were excluded. Ten percent of Graves' disease patients and 27.7% of control patients had positive staining of thyrocytes for EVB19 antibodies (ns). EVB19-positive and EVB19-negative cases did not differ. EVB19-positive controls were older than EVB19-negative controls (mean age: 57.5 [35-74] vs. 45 [28-80] years, P=0.03) No case of acute EVB19 infection was identified. EVB19-positive serology was more frequent in controls than in Graves' disease patients (88% vs. 45%, P<0.0001). EVB19 was detected in thyrocytes, but not more frequently in Graves' disease patients than in controls. Further studies are needed to determine the role of EVB19 infection in thyroid diseases.

Other viral infections in solid organ transplantation.

Viral infections are a major cause of morbidity and even mortality in solid organ transplant recipients. This article reviews key aspects of infections in solid organ transplant recipients from respiratory viruses, such as influenza, polyomavirus, erythrovirus B19 and measles.

Other viral infections in solid organ transplantation

Viral infections are a major cause of morbidity and even mortality in solid organ transplant recipients. This article reviews key aspects of infections in solid organ transplant recipients from respiratory viruses, such as influenza, polyomavirus, erythrovirus B19 and measles (AU)

Las infecciones víricas constituyen una causa importante de morbilidad y, en ocasiones, también de mortalidad en el receptor de un trasplante de órgano sólido. En este artículo se revisan aspectos fundamentales acerca de las infecciones por virus respiratorios, incluyendo el virus de la gripe, poliomavirus, erythrovirus B19 y sarampión en el receptor de un trasplante de órgano sólido (AU)

Diagnóstico de infección congénita / Diagnosis of congenital infection

El diagnóstico de la infección congénita está basado en: a) serología materna; b) estudio microbiológico del líquido amniótico y sangre fetal, y c) serología en el neonato y detección del agente etiológico por cultivo o PCR. La infección congénita por citomegalovirus, virus herpes simple, virus varicela-zóster, Toxoplasma gondii y erythrovirus B19 suele ser el resultado de la infección primaria en la madre. Por lo tanto, la detección de anticuerpos IgG antes del embarazo permite descartar las infecciones por estos agentes. El diagnóstico serológico definitivo de infección aguda en la embarazada requiere la demostración de seroconversión. En tales casos, debe realizarse el estudio de infección congénita intrauterina en muestras de líquido amniótico y sangre fetal.Las infecciones por citomegalovirus, virus de la rubéola y T. gondii pueden diagnosticarse por detección de IgM en sangre fetal. Sin embargo, la PCR en líquido amniótico ha desplazado a las técnicas convencionales en el diagnóstico de estas infecciones. En el recién nacido, el diagnóstico puede confirmarse mediante detección de IgM específica.Erythrovirus B19 puede detectarse por PCR en líquido amniótico o sangre fetal.En la infección congénita por el virus varicela-zóster, la persistencia de IgG después del nacimiento permite establecer el diagnóstico.La detección directa del virus herpes simple en vesículas o muestras orofaríngeas es la técnica de elección para el diagnóstico de infección congénita por este agente(AU)

In general, congenital diagnosis is based on: a) maternal serologic assays; b) microbiologic study of amniotic fluid or fetal blood sampling; and c) serology in children and microorganism detection by polymerase chain reaction (PCR) or culture.Congenital infections due to cytomegalovirus, herpes simplex, varicella, B19 erythrovirus and toxoplasmosis are usually the result of primary infection in the mother. Therefore, when IgG antibodies are detected before pregnancy, these infections are ruled out. Definitive serologic diagnosis of acute infection in pregnant women requires the demonstration of seroconversion (i.e., from seronegative to seropositive). In these cases, amniotic fluid or fetal blood sampling should be performed to determine the presence of intrauterine congenital infection.Cytomegalovirus, rubella and toxoplasmosis can be diagnosed by detection of specific IgM antibodies in fetal blood. However, PCR in amniotic fluid has replaced conventional prenatal diagnostic techniques, including fetal blood sampling, in the diagnosis of these infections. In the newborn, these infections may be confirmed by measuring IgM specific antibodies.B19 erythrovirus can be detected by PCR in amniotic fluid or fetal blood. Congenital varicella-zoster infection may be diagnosed on the basis of persistence of IgG antibodies after birth. Definitive diagnosis of herpes simplex virus infection requires viral isolation. Swabs or scraping from clinical specimens can be inoculated into susceptible cell lines for isolation(AU)

The detection of parvoviruses.

Parvovirus B19 is a single-stranded DNA virus which causes severe disease in immunocompromised patients and foetal loss in pregnant women. It is classified as an Erythrovirus and this genus also comprises two related viral genotypes (so-called LaLi/A6 (genotype 2) and V9 (genotype 3)) which appear to be immunologically indistinguishable from Parvovirus B19. Serological and nucleic acid test (NAT) systems to detect Parvovirus B19-mediated infection are commercially available; however, some NAT systems are genotype-specific. International standard preparations of Parvovirus B19 IgG and DNA have been produced for assay standardisation purposes, and to ensure consistency of assay manufacture and performance. Immunological assays, such as B-cell ELISpot, T-cell stimulation, and cytokine detection can also be used to confirm exposure to Parvovirus B19. Immunohistochemical techniques, employing commercially available monoclonal antibodies, are used to localise the virus in infected tissue and Parvovirus B19 viral antigen can also be detected in serum and plasma using antigen-specific ELISA. NAT systems have also been described to detect newly identified parvoviruses such as human bocavirus (HBoV), PARV4, and PARV5, although absolute confirmation of clinical diseases associated with these agents is required. This chapter describes the current status of detection systems for all the aforementioned parvoviruses, with particular emphasis on Erythrovirus detection by serological, NAT, and immunological approaches.

Chipmunk parvovirus is distinct from members in the genus Erythrovirus of the family Parvoviridae.

The transcription profile of chipmunk parvovirus (ChpPV), a tentative member of the genus Erythrovirus in the subfamily Parvovirinae of the family Parvoviridae, was characterized by transfecting a nearly full-length genome. We found that it is unique from the profiles of human parvovirus B19 and simian parvovirus, the members in the genus Erythrovirus so far characterized, in that the small RNA transcripts were not processed for encoding small non-structural proteins. However, like the large non-structural protein NS1 of the human parvovirus B19, the ChpPV NS1 is a potent inducer of apoptosis. Further phylogenetic analysis of ChpPV with other parvoviruses in the subfamily Parvovirinae indicates that ChpPV is distinct from the members in genus Erythrovirus. Thus, we conclude that ChpPV may represent a new genus in the family Parvoviridae.

Infrequent replication of parvovirus B19 and erythrovirus genotypes 2 and 3 among HIV-infected patients with chronic anemia.

We investigated the role that erythroviruses (parvovirus B19 and erythrovirus genotypes 2 and 3) play in the lives of immunosuppressed HIV-infected patients with chronic anemia. We screened the serum samples of 428 patients by specific ultrasensitive real-time polymerase chain reaction assay. Sixteen patients had circulating DNA, with no apparent clinical impact. Erythrovirus-associated anemia is an extremely rare event in HIV-infected patients.

[Genetic diversity of human erythroviruses. Consequences on infectious safety of plasma derivatives]. / Impact de la diversité génétique des erythrovirus humains sur la sécurité infectieuse des médicaments dérivés du sang.

The B19 Parvovirus (B19V) has for a long time been considered as the unique human virus belonging to the genus Erythrovirus. The genetic diversity of B19V isolates has been shown to be very low. The isolation of a variant (V9 strain), with a sequence markedly distinct from that of B19V which led to attributing this classification to this family of viruses. Phylogenetic analysis of sequences of V9-related isolates indicates an organization into three well-individualized genotypes. The B19V infection can be transmitted by transfusion. In immunocompetent recipients, B19V exposure by transfusion is most often inconsequential, since a large proportion is immunized. Such an infection may have serious clinical outcome in not immunized patients with shortened red cell survival, seronegative pregnant women and immunocompromised patients. In cellular products, viral DNA detection is not performed, but a preventive strategy could be discussed for at-risk recipients. Whereas in plasma derivatives, B19V screening is performed with a threshold of 10(4)IU/ml using molecular assays. With recent data of a new classification of three genotypes within human erythrovirus, nucleic acid testing assays would be validated in accordance with the genetic variability, in order to guarantee optimal safety. 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.

Phylogenetic analysis of a near-full-length sequence of an erythrovirus genotype 3 strain isolated in Brazil.

Human parvovirus B19 is the only member of the genus Erythrovirus that causes human disease. Recent findings of several strains with considerable sequence divergence from B19 have suggested a new classification for parvovirus genotypes as 1 (B19), 2 (A-6 and LaLi) and 3 (V9). In their overall DNA sequence, the three genotypes differ by approximately 10%. Here, we report the isolation of a genotype-3-related strain named BR543 during a prospective study conducted in Sao Paulo, Brazil. Analysis of the nearly full-length genome sequence of BR543 indicates that this B19 variant sequence clusters with Gh2768, a strain from Ghana belonging to subtype 3b, and showed mostly synonymous substitutions.

Seroprevalence of erythrovirus B19 IgG antibody among paediatric patients in Makkah and Jeddah, Kingdom of Saudi Arabia.

OBJECTIVE: To estimate the prevalence of IgG antibodies against B19 virus (B19V) in Makkah and Jeddah, Saudi Arabia. METHODS: B19V-specific IgG antibodies were detected by a commercial indirect enzyme-linked immunosorbent assay in sera of 400 paediatric patients (185 males and 215 females) aged 1-17 years. RESULTS: Of the 400 patients, 80 (20%) had sera positive for B19V-specific IgG. The difference in the prevalence of the antibodies between genders was not statistically significant (p = 0.9). The prevalence of anti-B19V antibodies increased significantly in the age group of 12-17 years as compared to younger patients (37.5 vs. 18% in those aged 1-11 years; p = 0.006). CONCLUSION: This study indicated a high prevalence of IgG antibodies against B19V in paediatric patients with an increase in age.

[Genetic diversity of human Erythroviruses]. / Diversité génétique des Erythrovirus humains.

B19 Parvovirus (B19V) has been considered for a long period of time as the unique human virus belonging to the genus Erythrovirus. The genetic diversity of B19V isolates has been shown to be very low (<2% nucleotide divergence). The isolation of a variant (V9 strain), with a sequence markedly distinct from that of B19V (>13% nucleotide divergence) led to specify the classification of this virus family. Phylogenetic analysis of partial sequences of V9-related isolates combined with Erythrovirus sequences in sequences banks indicates an organization into three well-individualized genotypes. Analysis of the nearly full-length genome sequences show an ancient separation between the three genotypes lineages. Genotype 3 (the most ancient lineage) could have originated in Africa. The functional regions of major proteins are conserved in the three genotypes. The frequency of these genotypes is various according to studies. Genotype 1 is predominant, except in Ghana where all the described isolates were genotype 3. A prospective French study performed between 1999 and 2001 indicated that genotypes 2 and 3 viruses circulated with a significant frequency (10%). Pathogenic properties might not differ according to the genotype.

Prevalence of erythrovirus genotypes in the myocardium of patients with dilated cardiomyopathy.

Parvovirus B19 (PVB19) is a member of the human erythrovirus family detected frequently in endomyocardial biopsies from patients with dilated cardiomyopathy. Human erythroviruses cluster into three genotypes 1-3 which share a high degree of homology between major structural proteins and may cause indistinguishable infections clinically and serologically. In human cardiac tissue erythrovirus genotypes other than PVB19 have not yet been reported. Three hundred seventeen consecutive patients with symptomatic dilated cardiomyopathy (median left ventricular ejection fraction: 28.6%, range 5-45%) who underwent endomyocardial biopsy for the elucidation of the etiology, were analyzed using a new consensus PCR assay designed for the detection of the three erythrovirus genotype sequences. Endomyocardial biopsies of 151 (47.6%) patients were erythrovirus-positive. Genotype 1 specific sequences were detected in 43/151 (28.5%) of positive biopsy samples, whereas genotype 2-specific sequences so far considered rare in human disease and not yet been described in human heart tissue was identified in 108/151 (71.5%) of virus-positive endomyocardial biopsies with a preference in patients above 50 years of age. In spite of younger age, systolic left ventricular dysfunction of genotype 1-positive patients was significantly reduced as compared to genotype 2-positive patients (24.4+/-10.4% vs. 31.0+/-9.5%, P=0.0001) at the initial presentation. The data show that two genetically distinct erythrovirus variants with a different age distribution are detectable in endomyocardial biopsies of patients with dilated cardiomyopathy. The erythrovirus genotype 2, not described previously in human heart tissue, is highly prevalent in the heart but the less prevalent genotype 1 is associated with more severe disturbed cardiac function.

Surveillance epidemiological: parvovirus B19 genotype 1

O parvovirus humano B19 foi isolado e caracterizado de amostra clínica de um paciente, infectado no Japão, e que apresentou os sintomas de febre e erupção cutânea após sua chegada ao Brasil. A infecção por parvovírus foi confirmada por meio de seguintes ensaios: Elisa para detecção de anticorpos IgM antiparvovirus B19 e técnica de polymerase chain reaction (PCR). Um fragmento da região NS1-VP1 foi diretamente submetido ao seqüenciamento do nucleotídeo. A análise filogenética parcial do B19, frente às várias seqüências disponíveis no GenBank, indicou que PV B19 isolado correspondeu ao genótipo 1.

Human parvovirus B19 was identified and characterized in sample collected from a patient who was infected in Japan, and the symptoms as fever and rash appeared after arriving to Brazil. The occurrence of virus infection was confirmed by both assays: Elisa parvovirus B19-specific IgM antibody detection andpolymerase chain reaction (PCR). A fragment of NS1-VP1 region was directly submitted to nucleotide sequencing. Partial phylogenetic analysis of B19 sequences, including several sequences available in GenBank, indicated that the isolated HPV B19 corresponded to genotype 1.

Heteroduplex mobility assay and single-stranded conformation polymorphism analysis as methodologies for detecting variants of human erythroviruses.

Variant samples from the three genotypes of erythroviruses have already been detected using sequencing as methodology for analysis. This study aimed to investigate the efficacy of single-stranded conformation polymorphism (SSCP) analysis and heteroduplex mobility assay (HMA) as methodologies to detect human erythrovirus variants, using their VP1 unique region sequences. Clinical samples and plasmids of PVBAUA, A6, LaLi, V9Gh3051, and D91.1 erythrovirus variants as prototypes of the three genotypes were used. SSCP analysis was able to distinguish all divergences among the plasmids, including the two mutation points between LaLi and A6 plasmids that led to distinct electrophoresis mobility patterns. Although HMA analysis was unabled to detect two mutation points between LaLi and A6, it enabled the differentiation among all other plasmids that revealed specific electrophoresis patterns, with high-enough sensibility to detect 1.5% nucleotide substitutions. When 57 clinical samples were analyzed, 33 of them presented an identical pattern to PVBAUA by HMA and SSCP analyses, two of them were sequenced and presented an identical sequence in relation to PVBAUA. Another pattern was found for 21 samples. Among these, two samples were sequenced, revealing one mutation point in relation to PVBAUA, while each one of the three remaining samples presented a distinct pattern, showing two or three mutations in relation to PVBAUA by sequencing. HMA and SSCP analyses were suggested as methodologies suited for detecting genetic mutations of human erythroviruses in developing countries because of their practicability and minor costs for reagents and equipment.

Bioportfolio: lifelong persistence of variant and prototypic erythrovirus DNA genomes in human tissue.

Human erythrovirus is a minute, single-stranded DNA virus causing many diseases, including erythema infectiosum, arthropathy, and fetal death. After primary infection, the viral genomes persist in solid tissues. Besides the prototype, virus type 1, two major variants (virus types 2 and 3) have been identified recently, the clinical significance and epidemiology of which are mostly unknown. We examined 523 samples of skin, synovium, tonsil, or liver (birth year range, 1913-2000), and 1,640 sera, by qualitative and quantitative molecular assays for the DNA of human erythroviruses. Virus types 1 and 2 were found in 132 (25%) and 58 (11%) tissues, respectively. DNA of virus type 1 was found in all age groups, whereas that of type 2 was strictly confined to those subjects born before 1973 (P < 0.001). Correspondingly, the sera from the past two decades contained DNA of type 1 but not type 2 or 3. Our data suggest strongly that the newly identified human erythrovirus type 2 as well as the prototype 1 circulated in Northern and Central Europe in equal frequency, more than half a century ago, whereafter type 2 disappeared from circulation. Type 3 never attained wide occurrence in this area during the past > or =70 years. The erythrovirus DNA persistence in human tissues is lifelong and represents a source of information about our past, the Bioportfolio, which, at the individual level, provides a registry of one's infectious encounters, and at the population level, a database for epidemiological and phylogenetic analyses.