Parvovirus B19 in pregnancy: possible consequences of vertical transmission

Ensuring Transfusion Safety: Screening Blood Donors for Human Parvovirus B19

Ensuring the safety of blood and blood products is a vital aspect of healthcare. The potential for transmission of pathogens through blood and blood products makes transfusion safety a significant concern. Despite advancements in testing methodologies, donated blood products still pose a risk for infection transmission. Human parvovirus B19 (B19V) is a small, single-stranded, non-enveloped DNA virus transmissible parenterally by blood transfusion. B19V causes a wide range of clinical manifestations, which is generally harmless in healthy individuals. B19V infection may cause severe complications, such as aplastic crises, as it affects erythrocyte progenitor cells in individuals with increased erythrocyte turnover. Additionally, B19V can be transmitted from pregnant women to their foetus, potentially causing hydrops fetalis and foetal death. The potential for transmission through blood and blood products makes B19V a significant concern for transfusion safety. In response to the growing recognition of B19V's impact on transfusion safety, various international health organisations have introduced guidelines to minimise its transmission through blood and plasma products. However, the implementation of these guidelines varies globally, with some regions, such as India, still lacking formal protocols for B19V monitoring. This review article explores the existing methodologies for screening blood donors for B19V, assesses the associated transfusion risks, and considers the implications for public health and clinical practice. By emphasising advancements in diagnostic techniques and the challenges of their implementation, this article provides a comprehensive overview of efforts to reduce the transmission of B19V through blood transfusions, thereby ensuring safer blood supplies and improved patient outcomes.

Epidemic of parvovirus B19 and disease severity in pregnant people, Denmark, January to March 2024

We report an epidemic of parvovirus B19 infections in Denmark during the first quarter of 2024, with a peak incidence 3.5 times higher than during the most recent epidemic in 2017. In total, 20.1% (130/648) of laboratory-confirmed cases were pregnant. Severe adverse outcomes were observed among 12.3% (16/130) of pregnant people and included foetal anaemia, foetal hydrops and miscarriage. Parvovirus B19 infection is not systematically monitored, but a national laboratory-based surveillance system is currently being established in Denmark.

Parvovirus B19 in Pregnancy

Importance

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

Objective

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

Evidence Acquisition

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

Results

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

Conclusions and Relevance

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

Parvovirus B19 Infection and Pregnancy: Review of the Current Knowledge

Parvovirus B19, a member of the Parvoviridae family, is a human pathogenic virus. It can be transmitted by respiratory secretions, hand-to-mouth contact, blood transfusion, or transplacental transmission. Most patients are asymptomatic or present with mild symptoms such as erythema infectiosum, especially in children. In rare cases, moderate-to-severe symptoms may occur, affecting blood cells and other systems, resulting in anemia, thrombocytopenia, and neutropenia. Non-immune pregnant women are at risk for fetal infection by parvovirus B19, with greater complications if transmission occurs in the first or second trimester. Infected fetuses may not show any abnormalities in most cases, but in more severe cases, there may be severe fetal anemia, hydrops, and even pregnancy loss. Maternal diagnosis of intrauterine parvovirus B19 infection includes IgG and IgM antibody testing. For fetal diagnosis, PCR is performed through amniocentesis. In addition to diagnosing the infection, it is important to monitor the peak of systolic velocity of the middle cerebral artery (PVS-MCA) Doppler to assess the presence of fetal anemia. There is no vaccine for parvovirus B19, and fetal management focuses on detecting moderate/severe anemia by fetal PVS-MCA Doppler, which, if diagnosed, should be treated with intrauterine transfusion by cordocentesis. Prevention focuses on reducing exposure in high-risk populations, particularly pregnant women.

Diagnosis of congenital infections in premature, low-birthweight newborns with intrauterine growth restriction caused by cytomegalovirus (CMV), herpes simplex virus (HSV), Parvo-B 19, and Zika virus: a systematic review

OBJECTIVES

To identify the prevalence of viral congenital infections in newborns classified as premature, low-birthweight, small for gestational age or intrauterine growth restriction.

METHODS

The definition considered for selecting papers were: P as newborns younger than 28 days; V as low-birthweight, prematurity and intrauterine growth restriction; O as frequency of congenital infections with Cytomegalovirus, Parvovirus B19, Herpes Simplex, and Zika virus. The research was performed using EMBASE, LILACS, SCOPUS and MEDLINE databases, with no limitations on date and language.

RESULTS

Eight studies were included. Manuscripts including Herpes Simplex, Zika virus or Parvovirus B19 did not fulfill the defined criteria. A wide variation in the frequency of CMV congenital infection (0-4.8%) was found, which might be attributed to regional and methodological differences between investigations.

CONCLUSIONS

Newborn characteristics associated with CMV congenital infections may direct investigations towards these patients with a higher probability of infection. However, as data are controversial, studies concerning screening of infection are important to define recommendations of diagnosis.

Ultrasound Findings of Fetal Infections: Current Knowledge

Infectious diseases during pregnancy are still a major cause of fetal mortality and morbidity worldwide. The most common teratogenic pathogens are cytomegalovirus (CMV), varicella-zoster virus (VZV), rubeovirus, parvovirus B19, herpes simplex virus (HSV), Toxoplasma gondii, Treponema pallidum and the emergent Zika virus (ZIKV). Ultrasound findings include cerebral anomalies, orbital defects, micrognathia, cardiac defects, hepatosplenomegaly, liver calcifications, abdominal anomalies, skin and limb anomalies, edema, placental and amniotic fluid anomalies and altered Doppler analyses. The classification of ultrasound markers of congenital infections by anatomical region is reported to guide differential diagnosis and prenatal care.

Non-immune hydrops fetalis: Two case reports

BACKGROUND

Fetal hydrops is a serious condition difficult to manage, often with a poor prognosis, and it is characterized by the collection of fluid in the extravascular compartments. Before 1968, the most frequent cause was the maternal-fetal Rh incompatibility. Today, 90% of the cases are non-immune hydrops fetalis. Multiple fetal anatomic and functional disorders can cause non-immune hydrops fetalis and the pathogenesis is incompletely understood. Etiology varies from viral infections to heart disease, chromosomal abnormalities, hematological and autoimmune causes.

CASE SUMMARY

A 38-year-old pregnant woman has neck lymphoadenomegaly, fever, cough, tonsillar plaques at 14 wk of amenorrhea and a rash with widespread itching. At 27.5 wk a fetal ultrasound shows signs of severe anemia and hydrops. Cordocentesis is performed with confirmation of severe fetal anemia and subsequent fetal transfusion. The karyotype is 46, XX, array-comparative genome hybridization (CGH) negative, and infectious tests are not conclusive. In the following days there is a progressive improvement of the indirect signs of fetal anemia. At 33.6 wk, for relapse of severe fetal anemia, further fetal transfusions are necessary and an urgent cesarean section is performed. On the day 12 of life, for the detection of anemia, the newborn is subjected to transfusion of concentrated red blood cells and begins treatment with erythropoietin. Later there is a normalization of blood chemistry values and the baby does not need new transfusions. A 29-year-old pregnant woman, with Sjogren's syndrome and positive Anti-Ro/SSA antibodies, is subjected to serial fetal ecocardio for branch block. At 26.5 wk there is a finding of fetal ascites. Infectious disease tests on amniotic fluid are negative as well as quantitative fluorescent polymerase chain reaction, Array CGH. At cordocentesis Hb is 1.3 mmol/L, consequently fetal transfusion is performed. Also in this case, due to continuous episodes of relapse of fetal anemia with consequent transfusions, at 29.4 wk a cesarean section is performed. On day 9 of life, a treatment with erythropoietin is started in the newborn, but the baby needs three blood transfusions. The search for autoantibodies in the baby found SS-A Ro60 positive, SSA-Ro52 positive and SS-B negative. The hemoglobin values normalized after the disappearance of maternal autoantibodies.

CONCLUSION

An attempt to determine the etiology of hydrops should be made at the time of diagnosis because the goal is to treat underlying cause, whenever possible. Even if the infectious examinations are not conclusive, but the pregnancy history is strongly suggestive of infection as in the first case, the infectious etiology must not be excluded. In the second case, instead, transplacental passage of maternal autoantibodies caused hydrops fetalis and severe anemia. Finally, obstetric management must be aimed at fetal support up to an optimal timing for delivery by evaluating risks and benefits to increase the chances of survival without sequelae.

Single Uterine Access for Bilateral Pleuroamniotic Shunting in Fetuses with Severe Hydrothorax by an Internal Rotational Maneuver: Feasibility and Outcomes between Successful and Failed Procedures

OBJECTIVE

The objective of this study was to describe the feasibility of single percutaneous uterine access for bilateral pleuroamniotic shunting (PAS) in fetuses with severe hydrothorax by using an internal rotational maneuver and to compare perinatal outcomes between successful and failed procedures.

METHODS

A prospective cohort of 25 fetuses with isolated bilateral hydrothorax and hydrops were referred to our fetal surgery center in Queretaro, Mexico during an 8-year period. Bilateral PAS was first attempted through a percutaneous single uterine access by internal rotation of the fetus, which was achieved by using the blunt tip of the same cannula, and in case of a failed procedure, a second uterine port was used to place the second shunt. The perinatal outcomes between successful (single uterine port) and failed (2 uterine ports) fetal procedures were compared.

RESULTS

Placing of bilateral shunts through a percutaneous single uterine access was feasible in 15/25 (60%) cases. Overall, median GA at delivery was 35.2 weeks with a survival rate of 64.0% (16/25). Three cases were excluded due to shunt dislodgement, leaving a final population of 22 fetuses; 13/22 (59.1%) and 9/22 (40.9%) managed using 1 and 2 uterine ports, respectively. The group with bilateral PAS placement through a successful single uterine port showed a significantly higher GA at birth (36.5 vs. 32.8 weeks, p = 0.001), lower surgical time (11.0 vs. 19.0 min, p = 0.01), longer interval between fetal intervention and delivery (5.7 vs. 2.7 weeks, p = 0.01), lower risk of preterm delivery (46.2 vs. 100%, p < 0.01), and lower rate of perinatal death (15.4 vs. 55.6%, p < 0.05) than the failed procedures requiring 2 uterine ports.

CONCLUSION

In fetuses with severe bilateral hydrothorax and hydrops, bilateral pleuroamniotic shunting through a successful single percutaneous uterine access is feasible in up to 60% of cases and is associated with better perinatal outcomes.

Identification and management of congenital parvovirus B19 infection

Parvovirus B19 (B19V) infection is well known for its mild, self-limiting clinical presentations in children, such as erythema infectiosum. Approximately 40% of women of childbearing age are susceptible to B19V infection. While maternal B19V infection usually has a good prognosis, B19V can cause severe fetal anaemia and pregnancy loss due to its ability to suppress erythroid progenitor cells. Non-invasive ultrasound monitoring for fetal anaemia is usually performed if maternal seroconversion occurs in the first 20 weeks of gestation, with amniocentesis for fetal infection reserved for those who first present with fetal anaemia or hydrops of unknown cause. Intrauterine transfusion is the standard treatment for severe fetal anaemia and is associated with a significant improvement in survival. However, survivors of hydrops fetalis may have a higher rate of long-term neurodevelopmental complications compared with non-hydropic survivors. This review aims to synthesise published data on the diagnosis, surveillance and outcomes of congenital parvovirus infection to assist clinicians in diagnosing and managing this important condition.

No G-Quadruplex Structures in the DNA of Parvovirus B19: Experimental Evidence versus Bioinformatic Predictions

Parvovirus B19 (B19V), an ssDNA virus in the family Parvoviridae, is a human pathogenic virus, responsible for a wide range of clinical manifestations, still in need of effective and specific antivirals. DNA structures, including G-quadruplex (G4), have been recognised as relevant functional features in viral genomes, and small-molecule ligands binding to these structures are promising antiviral compounds. Bioinformatic tools predict the presence of potential G4 forming sequences (PQSs) in the genome of B19V, raising interest as targets for antiviral strategies. Predictions locate PQSs in the genomic terminal regions, in proximity to replicative origins. The actual propensity of these PQSs to form G4 structures was investigated by circular dichroism spectroscopic analysis on synthetic oligonucleotides of corresponding sequences. No signature of G4 structures was detected, and the interaction with the G4 ligand BRACO-19 (N,N'-(9-{[4-(dimethylamino)phenyl]amino}acridine-3,6-diyl)bis(3-pyrrolidin-1-ylpropanamide) did not appear consistent with the stabilisation of G4 structures. Any potential role of PQSs in the viral lifecycle was then assessed in an in vitro infection model system, by evaluating any variation in replication or expression of B19V in the presence of the G4 ligands BRACO-19 and pyridostatin. Neither showed a significant inhibitory activity on B19V replication or expression. Experimental challenge did not support bioinformatic predictions. The terminal regions of B19V are characterised by relevant sequence and symmetry constraints, which are functional to viral replication. Our experiments suggest that these impose a stringent requirement prevailing over the propensity of forming actual G4 structures.

Overall prevalence of human parvovirus B19 among blood donors in mainland China: A PRISMA-compliant meta-analysis

BACKGROUND

Human parvovirus B19 (B19V) infection exhibits a broad range of clinical outcomes. Blood transfusion is a common route of B19V transmission. However, information about the overall prevalence of B19V infection and B19V genotypes among blood donors in mainland China is lacking.

METHODS

This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search for studies reporting the B19V prevalence among blood donors in mainland China from 2000 to 2018 was performed. The prevalence of B19V was estimated through a meta-analysis of the relevant literature. A comprehensive meta-analysis program was used for data processing and statistical analysis.

RESULTS

Twenty-one eligible articles were included, involving 48,923 participants assessed for B19V-DNA, 12,948 participants assessed for anti-B19V immunoglobulin M (IgM), and 8244 participants assessed for anti-B19V immunoglobulin G (IgG). The analysis revealed the pooled estimates of the prevalence rates of B19V-DNA, anti-B19V IgM, and anti-B19V IgG among blood donors to be 0.7% (95% confidence interval [CI] 0.2-2.4%), 2.7% (95% CI 1.7-4.3%), and 33.6% (95% CI 28.2-39.4%), respectively. Moreover, phylogenetic analyses indicated that 142 of 169 (84.0%) B19V isolates belonged to Genotype 1.

CONCLUSIONS

The overall prevalence of B19V among blood donors is not high in mainland China, and most isolates belong to Genotype 1.

Tropism, pathology, and transmission of equine parvovirus-hepatitis

Equine parvovirus-hepatitis (EqPV-H) has recently been associated with cases of Theiler's disease, a form of fulminant hepatic necrosis in horses. To assess whether EqPV-H is the cause of Theiler's disease, we first demonstrated hepatotropism by PCR on tissues from acutely infected horses. We then experimentally inoculated horses with EqPV-H and 8 of 10 horses developed hepatitis. One horse showed clinical signs of liver failure. The onset of hepatitis was temporally associated with seroconversion and a decline in viremia. Liver histology and in situ hybridization showed lymphocytic infiltrates and necrotic EqPV-H-infected hepatocytes. We next investigated potential modes of transmission. Iatrogenic transmission via allogeneic stem cell therapy for orthopedic injuries was previously suggested in a case series of Theiler's disease, and was demonstrated here for the first time. Vertical transmission and mechanical vectoring by horse fly bites could not be demonstrated in this study, potentially due to limited sample size. We found EqPV-H shedding in oral and nasal secretions, and in feces. Importantly, we could demonstrate EqPV-H transmission via oral inoculation with viremic serum. Together, our findings provide additional information that EqPV-H is the likely cause of Theiler's disease and that transmission of EqPV-H occurs via both iatrogenic and natural routes.

Performance of Zika Assays in the Context of Toxoplasma gondii, Parvovirus B19, Rubella Virus, and Cytomegalovirus (TORCH) Diagnostic Assays

Infections during pregnancy that may cause congenital abnormalities have been recognized for decades, but their diagnosis is challenging. This was again illustrated with the emergence of Zika virus (ZIKV), highlighting the inherent difficulties in estimating the extent of pre- and postnatal ZIKV complications because of the difficulties in establishing definitive diagnoses. We reviewed the epidemiology, infection kinetics, and diagnostic methods used for Toxoplasma gondii, parvovirus B19, rubella virus, and cytomegalovirus (TORCH) infections and compared the results with current knowledge of ZIKV diagnostic assays to provide a basis for the inclusion of ZIKV in the TORCH complex evaluations. Similarities between TORCH pathogens and ZIKV support inclusion of ZIKV as an emerging TORCH infection. Our review evaluates the diagnostic performance of various TORCH diagnostic assays for maternal screening, fetal screening, and neonatal screening. We show that the sensitivity, specificity, and positive and negative predictive value of TORCH complex pathogens are widely variable, stressing the importance of confirmatory testing and the need for novel techniques for earlier and accurate diagnosis of maternal and congenital infections. In this context it is also important to acknowledge different needs and access to care for different geographic and resource settings.

Molecular screening of the human parvoviruses B19 and bocavirus 1 in the study of congenital diseases as applied to symptomatic pregnant women and children

Introduction

B19 virus (B19V) and bocavirus 1 (HBoV1) are human pathogenic parvoviruses that are prevalent worldwide and are responsible for a diverse and not yet fully established spectrum of clinical manifestations.

Objective

To screen B19V and HBoV1 in patients with clinical manifestations associated with acquisition of the infection during gestation.

Methods

A retrospective, observational study was performed that included serum samples from patients without a previous known aetiology. B19V and HBoV1 were determined by end-point PCR. Positive samples were genotyped.

Results

A total of 106 serum samples were analysed, 61 from pregnant women and 45 from neonates and paediatric patients. None were positive for HBoV1, while B19V was detected in 37/106 [34.9 %, 95 % confidence interval (CI): 26.5–44.4] of the samples studied. In the group of pregnant women, 28/61 (45.9 %, 95 % CI: 34.0–58.3) were B19V-positive, and 2 of them had foetal anaemia followed by hydrops and foetal death, 3 were associated with a history of recurrent pregnancy loss and there was 1 case of spontaneous abortion. B19V was also detected in cases of maternal febrile exanthema, polyhydramnios, oligohydramnios and foetal ascites. In the group of children, 9/45 (20.0 %, 95 % CI: 10.9–33.8) neonatal patients were B19V-positive, and this was associated with foetal hydrops, TORCH syndrome and cardiac alterations. The nucleotide sequences analysed confirmed the identity of B19V genotype 1.

Conclusions

We found no evidence to indicate the presence of HBoV1 in maternal blood or in the newborns/paediatric patients (hence providing no support for the supposed vertical transmission). On the other hand, the high frequency of B19V in the pathologies studied indicates the importance of molecular diagnosis in both the mother and the child. Future efforts should contribute to early detection and characterization of infections.

The risk of maternal parvovirus B19 infection during pregnancy on fetal loss and fetal hydrops: A systematic review and meta-analysis

BACKGROUND

Human parvovirus B19 (B19) is widespread infection in humans, yet the impact on adverse pregnancy outcomes is controversial.

OBJECTIVE

to evaluate the impact of B19 infection during pregnancy on adverse pregnancy outcome, and investigated the incidence of fetal loss and fetal hydrops after maternal B19 infection during pregnancy.

STUDY DESIGN

A systematic literature search was performed using Embase, Medline, PubMed, Web of science, and the Cochrane Library database for relevant publications up to 10^th August 2018. Cohort studies and case-control studies were included in analyses.

RESULTS

In total, 36 eligible studies were included. Of these, 18 studies reported the risk of maternal B19 infection during pregnancy on fetal loss and 20 studies reported the incidence of fetal loss or fetal hydrops after maternal B19 infection. Collectively, the results indicated that maternal B19 infection increased the risk of fetal loss, spontaneous abortion, and stillbirth with ORs of 2.68 (95% CI: 2.02-3.55), 2.42 (95% CI: 1.76-3.33), and 3.53 (95% CI: 1.91-6.54), respectively, when compared with uninfected pregnant women. In addition, the incidence of fetal loss and fetal hydrops in B19 infected pregnant women was 7.6% (95% CI: 5.5-9.5) and 9.3% (95% CI: 5.6-13.0), respectively.

CONCLUSIONS

maternal parvovirus B19 infection during pregnancy increased the risk of fetal loss, spontaneous abortion, and stillbirth. A high incidence of fetal loss and fetal hydrops was observed in pregnant women with parvovirus B19 infection.

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.

Seroprevalence of parvovirus B19 in blood donors: the risks and challenges of blood transfusion in Zambia in the era of HIV/AIDS at the Kitwe Central Hospital, blood bank

BACKGROUND

Human Parvovirus (B19V) is a small, single-stranded, non-enveloped DNA virus which is pathogenic to humans causing a wide array of clinical complications which include erythema infectiosum, aplastic crisis and hydrops foetalis. It is generally harmless in healthy individuals but may be life threatening in immunocompromised individuals such as patients with sickle cell disease, cancer, HIV and pregnant women. It has been shown to be transmissible by blood transfusion but donor screening for the virus is not yet mandatory in most sub-Saharan African countries including Zambia.

MATERIALS AND METHODS

This was a cross-sectional study undertaken at the Kitwe Central Hospital, blood bank and Tropical Diseases Research Centre at Ndola Central Hospital. A total of 192 blood samples were screened for Ig M antibodies against parvovirus B19 by ELISA.

OBJECTIVES

The general objective of the study was to determine the seroprevalence of parvovirus B19 infections among healthy blood donors at the Kitwe Central Hospital blood bank. Specific Objectives were to detect parvovirus B19 Ig M antibodies in donor blood using serology and to analyse the age and sex distribution of parvovirus among blood donors.

RESULTS

The prevalence of parvovirus B19 Ig M in this study was 15.6%. The majority of the positive cases were in the age group 15-22 years (17.8%) but there was no statistical significance between occurrence of parvovirus and age ( p value=0.703). Prevalence in males was higher than in females that is 16.4% and 13.8%, respectively. The relationship between gender and parvovirus B19 occurrence was however not significant either (p value=0.516).

CONCLUSION

This study showed a 15.6% prevalence rate of acute Parvovirus B19 infections in blood donors at the Kitwe Central Hospital, blood bank. Studies with larger sample sizes are needed to validate these results.

Parvovirus B19 infection in pregnancy-awareness and opportunities

Parvovirus B19 (B19V) is a human pathogenic virus associated with a wide range of clinical conditions. In pregnancy, B19V poses a potential hazard to the fetus as crossing the placental barrier and infecting erythroid progenitor cells in bone marrow and liver, it blocks fetal erythropoiesis leading to profound anemia, hydrops and/or fetal death. The virus is not regarded as a teratogen, however more scientific awareness is emerging on mechanisms and consequences of intrauterine infection and possible sequelae in the neonatal development. Reliable diagnostic procedures and fetal management strategies, including intrauterine transfusion, are established. In spite of being a recognized fetotropic agent possibly leading to fetal loss, testing for B19V is not routinely included in preconception or antenatal screenings, possibly delaying the management of B19V-complicated pregnancies. Continuous advances in B19V research will provide for better diagnostic methods and algorithms, as well as for the development of effective prophylactic interventions and novel therapeutic options.

Circulation of Porcine Parvovirus Types 1 through 6 in Serum Samples Obtained from Six Commercial Polish Pig Farms

Porcine parvoviruses are small non-enveloped DNA viruses, very resistant to inactivation, and ubiquitous in the global pig population. Porcine parvovirus type 1 (PPV1) has been known since the 1960s and is a major causative agent of reproductive failure in breeding herds. During the last decade, several new parvoviruses have been identified in pigs by molecular methods and have been consecutively designated as PPV2 through PPV6. Epidemiology data for these viruses are limited, and the impact of these newly recognized parvoviruses on pigs is largely unknown. To further generate knowledge on the distribution of PPVs in pigs, a total of 247 serum samples were collected from six commercial Polish pig farms during 2013-2015 and tested by PCR assays and ELISAs. The pigs ranged from two to 18 weeks of age at sample collection. Breeding herds supplying the investigated farms were routinely vaccinated against PPV1. While all growing pig samples were negative for PPV1 DNA, young pigs were frequently negative for PPV1 antibodies and seroconversion to PPV1 was commonly seen at 9-10 weeks of age. The PPV2 antibody detection was highest in young pigs (2-6-week-old) and decreased in older pigs indicating passively acquired antibodies. The DNA prevalence rates in the serum samples analysed were 19% for PPV2, 7.7% for PPV3, 2.4% for PPV4, 4.0% for PPV5 and 6.1% for PPV6. Most PPV DNA-positive samples were identified in 9- to 18-week-old pigs with no obvious association with disease on the farm. All recently emerging PPV genotypes were detected in Polish farms. Similar to previous reports in other pig populations, PPV2 was the most frequent PPV genotype circulating in Poland.

Parvovirus B19 Replication and Expression in Differentiating Erythroid Progenitor Cells

The pathogenic Parvovirus B19 (B19V) is characterized by a strict adaptation to erythroid progenitor cells (EPCs), a heterogeneous population of differentiating cells with diverse phenotypic and functional properties. In our work, we studied the dynamics of B19V infection in EPCs in dependence on the cell differentiation stage, in terms of distribution of infected cells, synthesis of viral nucleic acids and production of infectious virus. EPCs at early differentiation stage led to an abortive infection, without viral genome replication and a very low transcriptional activity. EPCs at later stages were permissive, with highest levels of viral replicative activity at day 9 (+3.0 Log from 2 to 48 hpi) and lower levels at day 18 (+1.5 Log from 2 to 48 hpi). B19V DNA increment was in accordance with the percentage of cells positive to flow-FISH assay (41.4% at day 9, 1.1% at day 18). Quantitation of total RNA indicated a close association of genome replication and transcription with viral RNA accumulation within infected cells related to viral DNA increase during the course of infection. Analysis of the different classes of mRNAs revealed two distinct pattern of genome expression profile with a fine regulation in the frequency utilization of RNA processing signals: an early phase, when cleavage at the proximal site leading to a higher relative production of mRNA for NS protein, and a late phase, when cleavage at the distal site was more frequent leading to higher relative abundance of mRNA for VP and 11 kDA proteins. Infectious virus was released from cells at day 6–15, but not at day 18. Our results, providing a detailed description of B19V replication and expression profile in differentiating EPCs, highlight the very tight adaptation of B19V to a specific cellular target defined both by its erythroid lineage and its differentiation stage.

No Definite Association between Human Parvovirus B19 Infection and Behçet Disease

BACKGROUND

The etiology of the Behçet disease (BD) has remained obscured. There have been studies to show the association of BD to infections like herpes simplex, hepatitis, and parvovirus B19 however, the findings are rather controversial.

MATERIALS AND METHODS

We selected 55 patients with the best matched symptoms of BD and measured the loads of B19 DNA in their plasma by quantitative real time PCR and verified their seropositivity by ELISA. All findings were compared to the results from 42 healthy persons.

RESULTS

Patients showed a wide spectrum of BD symptoms. Serologic studies showed high prevalence of B19 IgG among the tested patients which was not statistically different with the healthy population (72.7% vs. 85.7%, respectively). Similarly, the prevalence of B19 IgM between patients and controls was not different (18% vs. 11.9%, respectively). No correlation was found between the presence of anti-B19 antibodies and the clinical observations. Only one person from the patient and control groups had detectable levels of B19 DNA without any difference or correlation with the disease symptoms.

CONCLUSION

Our data could not establish an association between B19 parvovirus infection and Behçet disease, although there have been reports of such correlation. Nevertheless, there might be indirect relation in genetically susceptible individuals after viral infections. More studies on designed animal models and surveys on patients should be done to resolve this controversy.

The effects of co-infection with human parvovirus B19 and Plasmodium falciparum on type and degree of anaemia in Ghanaian children

OBJECTIVE

To determin the extent to which parvovirus B19 (B19V) and co-infection of B19V and malaria contribute to risk of anaemia in children.

METHODS

B19V DNA and malaria parasites were screened for 234 children at the PML Children's Hospital in Accra. The role of B19V and co-infection with B19V and malaria in anaemia was evaluated by analysing full blood cell counts, malaria and B19V DNA results from these children.

RESULTS

The prevalence of B19V, malaria and co-infection with B19V and malaria was 4.7%, 41.9% and 2.6%, respectively. Malaria posed a greater risk in the development of mild anaemia compared to severe anaemia (OR=5.28 vrs 3.15) whereas B19V posed a higher risk in the development of severe anaemia compared to mild anaemia (OR=4.07 vrs 1.00) from a non-anaemic child. Persons with co-infection with B19V and malaria had 2.23 times the risk (95% CI=0.40-12.54) of developing severe anaemia should they already have a mild anaemia. The degree of anaemia was about three times affected by co-infection (Pillai's trace=0.551, P=0.001) as was affected by malaria alone (Pillai's trace=0.185, P=0.001). B19V alone did not significantly affect the development of anaemia in a non-anaemic child. Microcytic anaemia was associated with B19V and co-infection with B19V and malaria more than normocytic normochromic anaemia.

CONCLUSIONS

B19V was associated with malaria in cases of severe anaemia. The association posed a significant risk for exacerbation of anaemia in mild anaemic children. B19V and co-infection with B19V and malaria may be associated with microcytic anaemia rather than normocytic normochromic anaemia as seen in cases of B19V infection among persons with red cell abnormalities.

The seroprevalence of parvovirus B19 infection in pregnant women in Sudan

Parvovirus B19 (B19V) infection during pregnancy may have serious consequences like fetal anaemia, hydrops fetalis, and fetal loss. Since epidemiological data on B19V infection are generally lacking in Sudan, the current study aimed to determine the seroprevalence of B19V in Sudanese pregnant women. Five hundred women, attending antenatal clinics in Khartoum state between November 2008 and March 2009, were enrolled and screened for B19V IgG and IgM antibodies by enzyme immunoassays. The study revealed a B19V IgG seroprevalence of 61·4%, with one subject positive for IgM. B19V DNA was not detected by PCR in any of the tested individuals. B19V IgG seroprevalence was significantly correlated with multigravidity (P = 0·046). Our data showed that B19V infection is prevalent in Sudan and we recommend further studies in Sudanese women, particularly in those with complications and adverse outcomes of pregnancy.

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.