Parvovirus B19 infection: association with third-trimester intrauterine fetal death

An Outbreak of Parvovirus B19 in Israel

Human parvovirus B19 (B19V) has a wide clinical spectrum, ranging from an asymptomatic infection to a life threatening one. During pregnancy, it can lead to fetal loss and hydrops fetalis. This retrospective study examined the incidence rates of B19V in Israel, analyzing anonymized electronic medical records of 2.7 million individuals between January 2015 and September 2023. A generalized linear model with a Poisson distribution was fit to the data, adjusting for potential confounders. A marked increase in B19V was observed in 2023, with an adjusted incidence rate ratio (IRR) of 6.6 (95% CI 6.33-6.89) when comparing 2023 to previous years. When specifically comparing 2023 to COVID-19 years (2020-2022), adjusted IRR climbs to 9.21 (8.66-9.80). Moreover, in 2023, previously existing seasonality has largely disappeared. High SES characterized most infected individuals with a marked discrepancy in social sectors; the Arab population was significantly less likely to be found B19V positive, even when adjusting for SES. Most infections occurred in school-aged children (6-11 years old). Pregnant women experienced the most significant rise in B19V, with an adjusted IRR of 11.47 (9.44-13.97) in 2023 compared to previous years; most cases were diagnosed in the first trimester. This study demonstrates that Israel is currently experiencing the largest and longest reported outbreak of B19V to date. Policymakers should consider setting screening policies in place, at least for populations at risk, while specifically studying and potentially targeting low socioeconomic populations and specific social sectors to avoid health inequalities.

Seroprevalence and geographical distribution of parvovirus B19 antibodies in pregnant women: A-meta analysis

Parvovirus B19 has been identified to infect pregnant women and cause anemia, spontaneous abortion, and fetal death. Given the significance of parvovirus B19 complications, this study aims to determine the seroprevalence and geographical distribution of parvovirus B19 antibodies in pregnant women to improve health control policies in the community. Online international databases and national Persian databases were used to define appropriate studies published between 2000 and January 2021. The quality of all papers was determined by a Newcastle-Ottawa Scale (NOS) checklist. The statistical analyses were performed using the Stata version 11 package (StataCorp, College Station, TX, USA) software. Heterogeneity among the primary studies was calculated using Cochran's Q-test and I2 index. The Egger test and the funnel plot chart with a significance level of less than 0.1 were used to evaluate the publishing bias. The seroprevalence of parvovirus B19 IgG antibodies among pregnant and non-pregnant women in Iran was assessed in 12 primary studies. Our finding showed that the seroprevalence of parvovirus B19 IgG antibodies among pregnant women varies from 21% to 76%. Combining the results of 5 primary studies based on the random effect model, the seroprevalence of parvovirus B19 IgG antibody among pregnant women in Iran was estimated to be 54% (95% CI:33-76). The seroprevalence of parvovirus B19 IgM antibodies has been reported in 9 studies. By combining the results of these studies using a random effect model, the seroprevalence of parvovirus B19 IgM antibody among pregnant women was estimated to be 3% (95% CI: 1-6). Generally, it is suggested that appropriate screening programs should be performed for the treatment and prevention of diseases. According to this point, the prevalence of parvovirus B19 is low among pregnant women, but it can cause serious manifestations such as hydrops fetalis and severe anemia, therefore, antibody determination using ELISA can be recommended for all pregnant women.

Parvovirus B19 DNAemia in pregnant women in relation to perinatal death: A nested case-control study within a large population-based pregnancy cohort

INTRODUCTION

Parvovirus B19 (B19V) is the infectious cause of exanthema infectiosum. In Europe around 40% of pregnant women are susceptible to infection. Having small children at home is the main risk factor for contracting an infection during pregnancy. The association between B19V-infection and perinatal death is not yet settled. The aims of the study were to estimate the association between maternal parvovirus B19 infection in pregnancy and perinatal death, and to assess the significance of a positive B19V PCR in pregnancy.

MATERIAL AND METHODS

The study population consists of women included in the Norwegian Mother and Child Cohort Study, a prospective population-based pregnancy cohort of nearly 100 000 women. Blood samples were obtained during weeks 17-18 in pregnancy (M1), at birth, and in umbilical cord blood. Within participants in the pregnancy cohort, 138 cases of perinatal death and 1350 controls with live-born children were included in a nested case-control study. Samples were analyzed with B19V serology and B19V PCR according to a predefined test algorithm. For cases, medical records and laboratory results from hospitals were combined with the results of B19V serology and PCR. The reported causes of perinatal death were categorized using the classification system: Causes Of Death and Associated Conditions (CODAC).

RESULTS

The B19V seroconversion rates were 9.8% for cases and 6.8% for control mothers. The odds ratio for maternal B19V infection in cases compared with controls was 1.28 (95% CI 0.35-4.70), adjusted for age, parity, body mass index and tobacco use. B19V-PCR-positive samples were detected at weeks 17-18 of gestation in both cases and controls. The proportion of positive samples was similar in cases and controls, 24% and 28.2%, respectively. Mothers with PCR-positive M1 samples transmitted B19V vertically in 9.1% of cases and in 11.9% of the controls. Of all perinatal deaths, 53% were attributed to placental pathology or unknown causes.

CONCLUSIONS

B19V PCR positivity was high and similar in both cases and controls. In our study B19V DNAemia was not seen to be associated with fatal outcome of pregnancy. The clinical significance of B19V DNA detection during pregnancy is uncertain. Caution is needed when diagnosing a B19V infection based only on B19V DNAemia.

Parvovirus B19 infection during pregnancy and risks to the fetus

Parvovirus B19 infects 1 to 5% of pregnant women, generally with normal pregnancy outcomes. During epidemics, the rate of infection is higher. Major congenital anomalies among offspring of infected mothers are rare, as the virus does not appear to be a significant teratogen. However, parvovirus B19 infection may cause significant fetal damage, and in rare cases, brain anomalies and neurodevelopmental insults, especially if infection occurs in the first 20 weeks of pregnancy. Parvovirus B19 is also an important cause of fetal loss, especially in the second half of pregnancy when spontaneous fetal loss from other causes is relatively rare. Parvovirus B19 infection may affect many fetal organs and can cause severe anemia, following fetal erythroid progenitor cells infection and apoptosis, especially in fetuses, that have shortened half-life of erythrocytes. Severe anemia may cause high output cardiac failure and nonimmune hydrops fetalis. In addition, parvovirus B19 may directly infect myocardial cells and produce myocarditis that further aggravates the cardiac failure. Intrauterine fetal transfusion is commonly used for the treatment of severe fetal anemia with survival rates of 75 to 90% and significant reduction of fetal morbidity. Only 66 cases were evaluated neurodevelopmentally, of which 10 (16%) had slight or severe neurodevelopmental problems. Because parvovirus B19 infection can cause severe fetal morbidity and mortality, it should be part of the routine work-up of pregnant women who have been exposed to the virus or of pregnancies with suspected fetal hydrops. Assessment for maternal infection during pregnancy is especially important during epidemics, when sero-conversion rates are high. Birth Defects Research 109:311-323, 2017. © 2017 Wiley Periodicals, Inc.

Human Parvoviruses

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

[Parvovirus B19 infection and pregnancy]

"Small virus" contagious during spring, parvovirus B19 is responsible for fifth disease of children. The prevalence of infection is very high before 10 years old and children are especially responsible for transmission to pregnant women. Approximately 50% of women old enough to procreate have stigmas serologic of old infection. Acquired immunity is long hasting and solid. During pregnancy, this virus is responsible for abortion, fetal anemia. Severe anemia can cause hydrops fetalis or fetal mortality in utero or neurologic damage. We are going to start again point by point of the contage has the care the situations with which the doctor can be confronted during the pregnancy.

Parvovirus infection: an immunohistochemical study using fetal and placental tissue

Parvovirus B19 infection causes 5% to 15% of cases of nonimmune hydrops fetalis. The aim of our study was to evaluate the use of immunohistochemistry in diagnosing parvovirus infection in fetal and placental tissue during routine fetal and perinatal autopsies. Histology slides of 20 cases of confirmed parvovirus infection were reviewed, and immunohistochemistry was applied to selected blocks of fetal and placental tissue. Immunohistochemistry was positive in all 20 cases, and histologic viral inclusions were seen in 19 cases. Immunohistochemical staining was closely correlated with histology and was more sensitive than histology in detecting virally infected cells, especially in autolyzed tissue. All cases also had confirmatory evidence of parvovirus infection by polymerase chain reaction of fetal liver and positive maternal serology, where it was available. We conclude that parvovirus immunohistochemistry is a reliable method for diagnosing parvovirus infection, especially in autolyzed tissue where histologic assessment may be suboptimal.

Intrauterine infection with parvovirus B19 and CMV: implications in early and late gestation fetal demise

In utero viral infections have been associated with an adverse pregnancy outcome and may have a causative role in the unexplained fetal death file. Parvovirus B19 and cytomegalovirus are among the most common pathogens implicated in fetal loss cases. Parvovirus B19 has been reported to account for cases of spontaneous abortions, intrauterine fetal death and nonimmune hydrops fetalis, whereas cytomegalovirus accounts for nonimmune hydrops fetalis, intrauterine growth retardation and congenital anomalies. This review aims to summarize the current literature in an attempt to underline the need for routine screening, close follow-up and prevention. A better understanding of the pathogenetic mechanisms of viral infections during the crucial time of organogenesis, along with early detection, may contribute to the reduction in stillbirth rate.

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.

Diagnosis of in utero Parvovirus B19 infection and maternal immune response - the relevance of linear epitopes and advanced serologic testing

IMPORTANCE OF THE FIELD

Parvovirus B19 (B19V) infection in utero causing fetal anemia and non-immune hydrops fetalis (NIHF) is a potentially life-threatening event for the fetus. Postexpositional non-invasive diagnosis is based on maternal IgG/IgM response and detection of viral genome in maternal blood. Serologic testing directs prenatal follow-up. Fetal infection is confirmed by polymerase chain reaction or in situ hybridization in fetal blood and/or amniotic fluid cells. The performance of serologic tests is significant in order to direct pre- and perinatal care at rational use of resources. Timing of diagnostic procedures and knowledge of the time course of infection in pregnant, asymptomatic women are critical. IgM negative testing in the presence of prolonged viremia may complicate individual risk analysis in pregnancy. Recently, advanced IgG avidity assays and epitope-type specific assays (IgG ETS EIA) have been re-evaluated.

AREAS COVERED IN THIS REVIEW

Epidemiology, clinical relevance and management of B19V infection in pregnancy. A review of the current literature (November 1984 - May 2009) and evaluation of current information on performance and predictive value of molecular and VP1/VP2 antigen-based IgG tests directed at the diagnosis of materno-fetal B19V infection and detection of past immunity. New aspects of B19V-associated fetal disease other than anemia/NIHF are also covered.

WHAT THE READER WILL GAIN

An overview of immunology and clinical relevance of B19V infection in pregnancy, of the potential value of advanced serologic testing and fields of future research.

TAKE HOME MESSAGE

In the absence of a commercially available vaccine, serologic tests remain important tools in individual risk analysis of pregnant women exposed to B19V. Sequential application of IgG avidity and IgG ETS EIAs may improve risk stratification and timing of invasive testing in B19V-exposed pregnancies, in particular with IgM-negativity and/or persistent DNAemia. Prospective evaluation of these test systems correlated to fetal outcome in order to reduce fetal morbidity and mortality as well as the overall burden of disease of B19V with regard to fetal malformation may be subject to future research.

The lack of routine surveillance of Parvovirus B19 infection in pregnancy prevents an accurate understanding of this regular cause of fetal loss and the risks posed by occupational exposure

In Europe, fetal loss due to Parvovirus B19 (B19V) is under-reported and a poorly addressed occupational risk to pregnant women. This is exemplified internationally, where it was unmentioned in the last two European Centre for Disease Prevention and Control (ECDC) annual surveillance reports or its 2009 special report on infections in pregnancy. To assess this potential for underestimating B19V fetal loss in pregnancy, we undertook a systematic review of practice in Northern Ireland in the management and reporting of B19V infections over a 12-month period of heightened transmission, one of six observed in a span of 9 years. Pregnant and non-pregnant women presented with symptomatic infection in 24 and 93 % of confirmed B19V infections, respectively, with no difference in viral loads. There was underinvestigation of viral causes of fetal loss, with only 143/2739 (5 %) tested for B19V, and a failure to follow up most non-immune women tested following rash contact. Occupational exposure was recorded in 31/60 (51.6 %) of pregnancies audited following rash exposure, the majority teachers or day care workers. Against a background seroprevalence of 66.5 % immunity in women of child-bearing years, two patterns of infection were identified. Firstly, pregnant women investigated for a rash or exposure to slapped cheek syndrome, where an infection incidence of 18 % was observed, resulted in 42 confirmed infections, all proceeding to healthy term deliveries. Secondly, pregnant women with unsuspected infection had six cases of confirmed B19V fetal loss, including four of 22 (18 %) diagnosed at autopsy, of which three were non-hydropic. While many studies have reported B19V fetal loss in pregnancy, there are no robust public health surveillance figures to draw on. That all six confirmed fetal losses came from the small number of miscarriages/stillbirths investigated, 143 out of 2739, suggests inadequate follow-up of those pregnancies where B19V-related fetal loss may be most common, and supports the need for enhanced surveillance pilots to address this significant gap in public health knowledge.

Diagnosis, management and possibilities to prevent parvovirus B19 infection in pregnancy

Human parvovirus B19 (B19V) infection in pregnancy can cause severe fetal anemia and nonimmune hydrops fetalis, which may be associated with spontaneous abortion and fetal death. Approximately 30–40% of women of child-bearing age are not immune to B19V infection. The risk to fetal life is particularly high if maternal infection occurs during the first 20 weeks of gestation. In this article we intend to give an overview on the molecular biology, epidemiology and management of B19V infection during pregnancy. These data will be combined with an assessment of the clinical situation of the infected fetus and the possibilities for avoiding and/or preventing B19V infection in pregnant women. Currently B19V infection is the causative agent of one of the most frequently occurring infectious complications in pregnancy that endangers fetal life, and so the necessity to develop a preventive vaccine is discussed.

Parvovirus B19 antibodies and correlates of infection in pregnant women attending an antenatal clinic in central Nigeria

Human parvovirus B19 infection is associated with spontaneous abortion, hydrops foetalis, intrauterine foetal death, erythema infectiosum (5th disease), aplastic crisis and acute symmetric polyarthropathy. However, data concerning Nigerian patients with B19 infection have not been published yet. The purpose of this study was to establish the prevalence of B19 IgG and IgM antibodies, including correlates of infection, among pregnant women attending an antenatal clinic in Nigeria. Subsequent to clearance from an ethical committee, blood samples were collected between August-November 2008 from 273 pregnant women between the ages of 15-40 years who have given their informed consent and completed self-administered questionnaires. Recombinant IgG and IgM enzyme linked immunosorbent assay kits (Demeditec Diagnostics, Germany) were used for the assays. Out of the 273 participants, 111 (40.7%) had either IgG or IgM antibodies. Out of these, 75 (27.5%) had IgG antibodies whereas 36 (13.2%) had IgM antibodies, and those aged 36-40 years had the highest prevalence of IgG antibodies. Significant determinants of infection (p < 0.05) included the receipt of a blood transfusion, occupation and the presence of a large number of children in the household. Our findings have important implications for transfusion and foeto-maternal health policy in Nigeria. Routine screening for B19 IgM antibodies and accompanying clinical management of positive cases should be made mandatory for all Nigerian blood donors and women of childbearing age.

Parvovirus B19 infection in human pregnancy

Human parvovirus B19 infection is widespread. Approximately 30-50% of pregnant women are nonimmune, and vertical transmission is common following maternal infection in pregnancy. Fetal infection may be associated with a normal outcome, but fetal death may also occur without ultrasound evidence of infectious sequelae. B19 infection should be considered in any case of nonimmune hydrops. Diagnosis is mainly through serology and polymerase chain reaction. Surveillance requires sequential ultrasound and Doppler screening for signs of fetal anaemia, heart failure and hydrops. Immunoglobulins, antiviral and vaccination are not yet available, but intrauterine transfusion in selected cases can be life saving.

Unexpected intrauterine fetal death in parvovirus B19 fetal infection

Parvovirus B19 infection during pregnancy can be transmitted to the fetus through the placenta. The consequences for the health of the fetus are very variable and can be very serious. They include intrauterine fetal death (IUFD) and miscarriage, which can lead to medico-forensic questions. For the most part, cases of IUFD take place during the second trimester of gestation and present an anatomopathologic picture characteristic of fetal infection with hydrops, placental edema, serous effusion, and erythroblastosis with nuclear inclusions. Endocardial fibroelastosis, medullar and thymic hypoplasia, and hepatic hemosiderosis are frequently present. In the third trimester, the cases are less frequent, not accompanied by hydrops, and can depend more on placental compromise than on direct infection of the fetus. We present 5 cases of IUFD resulting from parvovirus B19 and we discuss the pathogenetic and anatomopathologic aspects and obstetric liability. In 4 cases, the IUFD took place suddenly, in the absence of symptoms, in women who had not previously shown any symptom of the viral infection. In one case, the patient was hospitalized following an ultrasound diagnosis of fetal hydrops and IUFD took place 5 days after admission. Of these cases 3 were verified in the second trimester and 2 in the third trimester. Only the cases of the second trimester and one of the 2 cases of the third trimester presented the characteristic aspects of fetal infection. The other case of third trimester was characterized by placental involvement.

The role of fetal autopsy and placental examination in the causes of fetal death: a retrospective study of 132 cases of stillbirths

PURPOSE

To investigate the most plausible cause of stillbirth by evaluating clinical records and postmortem examination findings including placental analysis.

METHODS

A retrospective cohort study concerning 132 stillbirths from 124 pregnancies occurred in the Mother-Infant Department of the University Hospital of Modena, Italy, from January 2000 to December 2004. Collected data were reviewed and classified according to the Gardosi ReCoDe system.

RESULTS

A reasonable cause of fetal death was identified in 99/124 pregnancies (79.84%). No associated relevant factors were disclosed in 25 fetuses (20.16%) classified as unexplained stillbirths. A succeeding scrupulous analysis of the placenta and an accurate clinical record review were useful to detect other conditions in 82 cases, including 5 cases of unexplained stillbirth. The major relevant conditions associated to stillbirths were feto-placental infection especially in the early fetal gestation age, under the 24th week of gestation, and placental insufficiency occurred both in early and late gestation age fetuses and mainly associated with a IUGR (<10th customized percentile). The main frequent secondary conditions were represented by placental anomalies including cluster of avascular villi with stromal fibrosis associated to thrombosis in minor and/or major vessel(s). Through the further analysis of the placenta, we were able to reduce the unexplained stillbirth rate from 20.16 to 15%.

CONCLUSION

Accurate fetal autopsy and placental examination related to meticulous clinical collecting data are requisites in the valuation of stillbirth and could play an important role in reduction of unexplained stillbirth rate.

Infection and stillbirth

Infection may cause stillbirth by several mechanisms, including direct infection, placental damage, and severe maternal illness. Various organisms have been associated with stillbirth, including many bacteria, viruses, and protozoa. In developed countries, between 10% and 25% of stillbirths may be caused by an infection, whereas in developing countries, which have much higher stillbirth rates, the contribution of infection is much greater. In developed countries, ascending bacterial infection, both before and after membrane rupture, with organisms such as Escherichia coli, group B streptococci, and Ureaplasma urealyticum is usually the most common infectious cause of stillbirth. However, in areas where syphilis is prevalent, up to half of all stillbirths may be caused by this infection alone. Malaria may be an important cause of stillbirth in women infected for the first time in pregnancy. The two most important viral causes of stillbirth are parvovirus and Coxsackie virus, although a number of other viral infections appear to be causal. Toxoplasma gondii, Listeria monocytogenes, and the organisms that cause leptospirosis, Q fever, and Lyme disease have all been implicated as etiologic for stillbirth. In certain developing countries, the stillbirth rate is high and the infection-related component so great that achieving a substantial reduction in stillbirth should be possible by reducing maternal infections. However, because infection-related stillbirth is uncommon in developed countries, and because those that do occur are caused by a wide variety of organisms, reducing this etiologic component of stillbirth much further will be difficult.

Parvovirus B19 infection

Human parvovirus B19 (B19) is common in society. Among adults, more than 50% have contracted the infection and immunity is believed to last lifelong. Infection occurs in a few percent of pregnancies, and albeit rare it can then cause fetal anemia, non-immune fetal hydrops and fetal death. Among cases with fetal demise, B19 is found in significant numbers, especially in the second and third trimesters of pregnancy. There is no specific treatment or prophylaxis available against B19 infection, but counseling of non-immune mothers and active monitoring of confirmed maternal infections with intervention to correct fetal anemia is likely to decrease mortality. Passive immunization also has potential to resolve fetal complications, but needs further study.

Parvovirus b19 infection in fetal deaths

BACKGROUND

Parvovirus B19 infection during pregnancy can lead to nonimmune fetal hydrops, miscarriage, and intrauterine fetal death (IUFD). Some studies have suggested that parvovirus B19 infection may surprisingly often result in nonhydropic fetal death during the third trimester, in the absence of maternal serological evidence of acute infection. This study was conducted to investigate the prevalence of parvovirus B19 DNA among fetuses from miscarriages and IUFDs.

METHODS

We retrospectively studied 535 unborn fetuses, including 120 fetuses from miscarriages and 169 from IUFDs. The control fetuses were 246 fetuses from induced abortions. All fetuses were autopsied from July 1992 through December 1995 and from January 2003 through December 2005 in Helsinki, Finland. The period included a major epidemic of parvovirus B19 infection in 1993. Formalin-fixed, paraffin-embedded fetal tissues were studied with use of a highly sensitive and specific PCR that was capable of detecting all 3 parvovirus B19 genotypes and by histologic examination. In addition, maternal parvovirus B19 serological status was determined.

RESULTS

Parvovirus B19 DNA was detected in 5 fetuses with gestational ages of 14, 22, 23, 30, and 39 weeks; these included fetuses from 4 (2.4%) of the 169 IUFDs and 1 (0.8%) of the 120 miscarriages. During the epidemic year 1993, the prevalence of parvovirus B19 DNA-positive fetal deaths was 6 times the prevalence during nonepidemic years. All 5 mothers of the parvovirus B19 DNA-positive fetuses had serological signs of acute parvovirus B19 infection close to the time of fetal death. The only nonhydropic fetus was full-term.

CONCLUSIONS

Our findings indicate that the prevalence of parvovirus B19 infection among fetuses from IUFDs is low. In particular, our findings did not verify the claimed high prevalence of third-trimester nonhydropic IUFDs associated with parvovirus B19.

Infection with Parvovirus B19 and Herpes viruses in early pregnancy and risk of second trimester miscarriage or very preterm birth

We investigated whether infections with Parvovirus B19 and Herpes viruses in early pregnancy increase risks of second trimester miscarriage or delivery before 32 gestational weeks. Blood samples taken in early pregnancy were analyzed for Parvovirus B19 or Herpes viruses. Viremia was found in blood samples of 11 (4.7%) women with second trimester miscarriage and 10 (3.7%) women with very preterm birth, compared to 5 (1.7%) women who delivered at term, corresponding to adjusted odds ratios [95% CI] of 3.32 [0.93, 11.8] and 2.21 [0.71, 6.84], respectively. In stratified analyses, Parvovirus B19 viremia was associated with adjusted odds ratios of 3.76 [0.77, 18.3] for second trimester miscarriage and 2.66 [0.64, 11.1] for very preterm birth. Corresponding odds ratios for Human Herpes virus 6 viremia was 2.52 [0.33, 19.5] and 1.08 [0.14, 8.08], respectively. In conclusion, this study lends some support to the hypothesis that women with viremia in early pregnancy may face an increased risk of second trimester miscarriage or very preterm birth. Studies with larger sample sizes are needed.

Simultaneous persistence of multiple genome variants of human parvovirus B19

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

Identifying the etiologic role of Parvovirus B19 in non-immune hydrops fetalis by histopathology, immunohistochemistry and nucleic acid testing: a retrospective study

Intrauterine Parvovirus B19 infections may cause fetal anemia, non-immune hydrops fetalis or abortion. This study focuses on the pathogenic role of Parvovirus B19 in non-immune hydrops fetalis at Hacettepe University, a major reference hospital in Turkey. Twenty-two cases of non-immune hydrops fetalis were retrospectively selected out of a total of 431 hydrops fetalis specimens from the Department of Pathology archieves. Paraffine embedded tissue sections from placental and liver tissues from each case were evaluated by histopathology, immunohistochemistry, nested PCR and commercial quantitative Real-time PCR. Viral DNA was detected in placental tissues by Real-time PCR in 2 cases (2/22, 9.1%) where histopathology also revealed changes suggestive of Parvovirus B19 infection. No significant histopathologic changes were observed for the remaining sections. Nested PCR that targets the VP1 region of the viral genome and immunohistochemistry for viral capsid antigens were negative for all cases. As a result, Parvovirus B19 is identified as the etiologic agent for the development of non-immune hydrops fetalis for 9.1% of the cases in Hacettepe University, Turkey. Real-time PCR is observed to be an effective diagnostic tool for nucleic acid detection from paraffine embedded tissues. Part of this study was presented as a poster at XIIIth International Congress of Virology, San Francisco, USA (Abstract V-572).

Relevance of parvovirus B19, herpes simplex virus 2, and cytomegalovirus virologic markers in maternal serum for diagnosis of unexplained recurrent abortions

CONTEXT

The impact of viral infections during pregnancy on adverse pregnancy outcomes is not understood fully.

OBJECTIVE

To assess the frequency of parvovirus B19, herpes simplex 2, and cytomegalovirus infections in relation to late abortions, in sera from Egyptian pregnant women to establish basic knowledge for future pregnancy care. In addition, to study the diagnostic value of specific immunoglobulin M (IgM) against those viruses compared with their genomes detection by polymerase chain reaction in maternal serum as a noninvasive method of laboratory diagnosis.

DESIGN

Patients were recruited at the Women's Clinic, Mansoura University. One group of patients with recurrent spontaneous abortions (RSA) and a second group of pregnant women without a history of RSA were evaluated including demographic, medical, and clinical data. Virologic markers were evaluated for specific IgM and for viral DNA to cytomegalovirus, herpes simplex virus 2, and parvovirus B19.

RESULTS

There was a statistically significant difference between the RSA group and the pregnant women without RSA group in frequency of parvovirus IgM (84% and 16.7%, respectively) (P < .001) and herpes simplex IgM (40% for RSA) (P = .001). Parvovirus B19 viremia was positive in 48% RSA, herpes simplex virus 2 was positive in 32% RSA, and cytomegalovirus was positive in 12% RSA patients. For RSA patients with parvovirus viremia, the mean +/- SD of IgM value was 78.5 +/- 30.12 IU/mL, and for RSA patients with negative viremia it was 30.02 +/- 17.64 IU/mL with statistically significant difference between both levels (P < .001).

CONCLUSIONS

From this study, we conclude that viral infections with parvovirus B19 and herpes simplex 2 were frequently associated with recurrent abortions, and careful investigation for this condition must include evaluating these patients for the previously mentioned viruses. Serologic study by specific IgM for parvovirus and herpes simplex seem to be reliable as screening tests for high-risk pregnancy.

Work-up of stillbirth: a review of the evidence

Despite improvements in antenatal and intrapartum care, stillbirth, defined as in utero fetal death at 20 weeks of gestation or greater, remains an important, largely unstudied, and poignant problem in obstetrics. More than 26,000 stillbirths were reported in the United States in 2001. Although several conditions have been linked to stillbirth, it is difficult to define the precise etiology in many cases. This paper reviews known and suspected causes of stillbirth including genetic abnormalities, infection, fetal-maternal hemorrhage, and a variety of medical conditions in the mother. The proportion of stillbirths that have a diagnostic explanation is higher in centers that conduct a defined and systematic evaluation. The evidence for recommended diagnostic tests for stillbirth are discussed. The ongoing work of the National Institute of Child Health and Human Development Stillbirth Collaborative Research Network, a consortium of 5 academic centers in the United States that are studying the scope and causes of stillbirth, is presented.

Fetal Death

The death of a formed fetus is one of the most emotionally devastating events for parents and clinicians. With improved care for conditions such as RhD alloimmunization, diabetes, and preeclampsia, the rate of fetal death in the United States decreased substantially in the mid twentieth century. However, the past several decades have seen much greater reductions in neonatal death rates than in fetal death rates. As such, fetal death remains a significant and understudied problem that now accounts for almost 50% of all perinatal deaths. The availability of prostaglandins has greatly facilitated delivery options for patients with fetal death. Risk factors for fetal death include African American race, advanced maternal age, obesity, smoking, prior fetal death, maternal diseases, and fetal growth impairment. There are numerous causes of fetal death, including genetic conditions, infections, placental abnormalities, and fetal-maternal hemorrhage. Many cases of fetal death do not undergo adequate evaluation for possible causes. Perinatal autopsy and placental examination are perhaps the most valuable tests for the evaluation of fetal death. Antenatal surveillance and emotional support are the mainstays of subsequent pregnancy management. Outcomes may be improved in women with diabetes, hypertension, red cell alloimmunization, and antiphospholipid syndrome. However, there is considerable room for further reduction in the fetal death rate.

Association of hypospadias and cardiac defect in a Parvovirus B19-infected stillborn: A causality relation?

Parvovirus B19 intrauterine infection is a known cause of hydrops fetalis and fetal death. It is also associated with congenital malformations, although the teratogenic potential seems to be low. Postmortem examination of a male stillborn of 29 gestational weeks revealed mild subcutaneous edema, malformed micropenis, perineoscrotal hypospadias and atrial septal defect, along with fetal erythroblastosis and villitis. Polymerase chain reaction detected Parvovirus B19 DNA genome in tissues from the fetus and the placenta, confirming the hypothesis of an intrauterine infection.

Clinical aspects of parvovirus B19 infection

Parvovirus B19 is a significant human pathogen that causes a wide spectrum of clinical complications ranging from mild, self-limiting erythema infectiosum in immunocompetent children to lethal cytopenias in immunocompromised patients and intrauterine foetal death in primary infected pregnant women. The infection may also be persistent and can mimic or trigger autoimmune inflammatory disorders. Another important clinical aspect to consider is the risk of infection through B19-contaminated blood products. Recent advances in diagnosis and pathogenesis, new insights in the cellular immune response and newly discovered genotypes of human parvoviruses form a platform for the development of modern therapeutic and prophylactic alternatives.

Stillbirth and Bereavement: Guidelines for Stillbirth Investigation

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Etiology and prevention of stillbirth

OBJECTIVE

This is a systematic review of the literature on the causes of stillbirth and clinical opinion regarding strategies for its prevention.

STUDY DESIGN

We reviewed the causes of stillbirth by performing a Medline search limited to articles in English published in core clinical journals from January 1, 1995, to January 1, 2005. Articles before this date were included if they added historical information relevant to the topic. A total of 1445 articles obtained, 113 were the basis of this review and chosen based on the criterion that stillbirth or fetal death was central to the article.

RESULTS

Fifteen risk factors for stillbirths were identified and the prevalence of these conditions and associated risks are presented The most prevalent risk factors for stillbirth are prepregnancy obesity, socioeconomic factors, and advanced maternal age. Biologic markers associated with increased stillbirth risk are also reviewed, and strategies for its prevention identified.

CONCLUSION

Identification of risk factors for stillbirth assists the clinician in performing a risk assessment for each patient. Unexplained stillbirths and stillbirths related to growth restriction are the 2 categories of death that contribute the most to late fetal losses. Late pregnancy is associated with an increasing risk of stillbirth, and clinicians should have a low threshold to evaluate fetal growth. The value of antepartum testing is related to the underlying risk of stillbirth and, although the strategy of antepartum testing in patients with increased risk will decrease the risk of late fetal loss, it is of necessity associated with higher intervention rates.

Non-hydropic intrauterine fetal death more than 5 months after primary parvovirus B19 infection

AIMS

Clinical follow-up of possible fetal complications associated with maternal parvovirus B19 infection is usually recommended during the 2-3 months after primary infection.

RESULTS

A case of late intrauterine fetal death associated with at least 5 months of maternal parvovirus B19 viremia and in the presence of B19 IgG and IgM is described.

CONCLUSIONS

The time of clinical and laboratory follow-up after maternal parvovirus B19 infection may need to be revised if prolonged viremia is more common than previously described.

High frequency of parvovirus B19 DNA in bone marrow samples from rheumatic patients

BACKGROUND

Human parvovirus B19 (B19) polymerase chain reaction (PCR) is now a routine analysis and serves as a diagnostic marker as well as a complement or alternative to B19 serology. The clinical significance of a positive B19 DNA finding is however dependent on the type of tissue or body fluid analysed and of the immune status of the patient.

OBJECTIVES

To analyse the clinical significance of B19 DNA positivity in bone marrow samples from rheumatic patients.

STUDY DESIGN

Parvovirus B19 DNA was analysed in paired bone marrow and serum samples by nested PCR technique. Serum was also analysed for B19-specific IgG and IgM antibodies and the results were compared with clinical and epidemiological data.

RESULTS AND CONCLUSIONS

B19 IgG was found in 41 of 50 patients (82%) whereas none was B19 IgM positive. The serologic evaluation showed that none of the patients had acute B19 infection. However, B19 DNA was detected by PCR in 13 of 50 (26%) bone marrow samples from these patients indicating a high frequency of persistent infection compared with previous reports of patient groups and healthy controls. In the study, 22 patients had rheumatoid arthritis (RA) and 7 of these RA patients were B19 DNA positive in bone marrow. Rheumatoid factor was positive in 4 of the 7 B19 DNA positive RA patients as compared with Rheumatoid factor positivity in all of the 15 B19 DNA negative RA patients. Erosive arthritis in X-ray was less common in the B19 DNA positive group than in the B19 DNA negative group. A high frequency of parvovirus B19 DNA was thus detected in bone marrow samples in rheumatic patients. The clinical data does not support a direct association between B19 PCR positivity and rheumatic disease manifestation. Therefore, the clinical significance of B19 DNA positivity in bone marrow samples from rheumatic patients must be interpreted with caution.

Detection of parvovirus B19, cytomegalovirus and enterovirus infections in cases of intrauterine fetal death

AIMS

Maternal infections with parvovirus B19, cytomegalovirus (CMV) and enterovirus have been associated with intrauterine fetal death (IUFD), but the incidence of these infections is not clear. This prospective study was conducted to estimate this incidence.

METHODS

A prospective study of 38 months was conducted on cases of IUFD referred to Huddinge University Hospital, Stockholm, Sweden. Placental biopsies, fetal blood and amniotic fluid were collected from cases of IUFD (n=52). Placental biopsies from normal pregnancies at term (n=53) were used as controls. These tissues were examined for parvovirus B19 DNA, CMV DNA and enterovirus RNA using polymerase chain reaction (PCR). Maternal viral serology was measured in 46 cases and virus isolation for enterovirus in maternal stool samples was performed in 31 cases.

RESULTS

Viral nucleic acid was recovered in at least one tissue sample from six cases of fetal death (parvovirus B19 in two cases, CMV in three and enterovirus in one), while all placental biopsies from controls were found negative. Serological signs of primary maternal infection were found in two of the cases, and virus isolation for enterovirus was negative in all samples examined.

CONCLUSION

Parvovirus B19, CMV and enterovirus may be considered as etiologic agents in cases of fetal death. PCR on placental and/or fetal tissue improves diagnostic accuracy for these infections.

Advances in the biology, diagnosis and host-pathogen interactions of parvovirus B19

Increased recognition of parvovirus B19 (B19), an erythrovirus, as a significant human pathogen that causes fetal loss and severe disease in immunocompromised patients has resulted in intensive efforts to understand the pathogenesis of B19-related disease, to improve diagnostic strategy that is deployed to detect B19 infection and blood-product contamination and, finally, to elucidate the nature of the cellular immune response that is elicited by the virus in diverse patient cohorts. It is becoming clear that at least three related erythrovirus strains (B19, A6/K71 and V9) are circulating in the general population and that viral entry into target cells is mediated by an expanding range of cellular receptors, including P antigen and beta-integrins. Persistent infection by B19 is emerging as a contributory factor in autoimmune disease, a hypothesis that is constrained by the detection of B19 in the skin of apparently healthy individuals. B19 infection during pregnancy may account for thousands of incidences of fetal loss per annum in Europe, North America and beyond, yet there is currently only minimal screening of pregnant women to assess serological status, and thereby risk of infection, upon becoming pregnant. Whilst major advances in diagnosis of B19 infection have taken place, including standardization of serological and DNA-based detection methodologies, blood donations that are targeted at high-risk groups are only beginning to be screened for B19 IgG and DNA as a means of minimizing exposure of at-risk patients to the virus. It is now firmly established that a Th1-mediated cellular immune response is mounted in immunocompetent individuals, a finding that should contribute to the development of an effective vaccine to prevent B19 infection in selected high-risk groups, including sickle-cell anaemics.

The prognostic virtue of inflammatory markers during late-onset sepsis in preterm infants

AIM

Late-onset sepsis (occurring after the first three days of life) is a serious complication in preterm infants. In order to assess the possible prognostic virtues of the acute phase inflammatory response in the disease, we compared the inflammatory response of preterm infants who died within 72 hours (h) (fulminant sepsis) to infants who recovered from the disease (non-fulminant sepsis).

METHODS

Of 42 preterm infants that were evaluated: 10 had fulminant sepsis and 32 non-fulminant sepsis. Acute phase inflammatory response markers-C-reactive protein (CRP), serum amyloid A (SAA), interleukin (IL)-6 levels and white blood cell (WBC) counts were measured at the first suspicion of LOS and after 8, 24 and 48 h.

RESULTS

Small for gestational age (SGA) infants who were treated with fewer days of antibiotics characterized the fulminant sepsis group. The initial high levels of inflammatory markers were similar in both groups, but as early as 8 h after onset significantly lower levels of SAA, CRP and WBC counts were documented in the fulminant sepsis group. The inflammatory response remained low at 24 and 48 h in the fulminant sepsis group, while in the survivors, significantly increased inflammatory markers were measured. Decreases in the levels of the inflammatory markers preceded episodes of metabolic acidosis and arterial hypotension that were more common in the fulminant sepsis group. Infant mortality correlated inversely with SAA levels at 8 h and with CRP and WBC counts at 24 h after onset.

CONCLUSION

SAA, CRP and WBC counts can be used as prognostic markers in LOS in preterm infants, with SAA being the earliest prognostic marker.

Human parvovirus B19 DNA is not detected in Guthrie cards from children who have developed acute lymphoblastic leukemia

BACKGROUND

There has been much speculation about the cause of childhood acute lymphoblastic leukemia (ALL). It has been suggested, on the basis of findings in epidemiological studies, that ALL may be initiated by an in utero infection of the fetus. The human parvovirus B19 (B19) is etiologically related to human diseases, including erythema infectiosum and aplastic crisis, but it has not yet been considered to be involved in the development of ALL. Therefore, the aim of this study was to investigate, whether prenatal B19 infection could still be indirectly correlated with the development of childhood ALL.

PROCEDURES

Fifty-four Guthrie cards, collected at 3-5 days of age, from Swedish children who subsequently developed ALL, as well as from 50 healthy controls, were investigated by nested PCR for the presence of B19 DNA.

RESULTS

B19 DNA was not detected in any of the Guthrie cards from ALL patients or from healthy controls, although all tested samples had amplifiable cellular DNA as confirmed by an HLA DQ specific PCR.

CONCLUSION

B19 DNA was not found in any of the Guthrie cards from children who later developed ALL or in the healthy controls. These findings suggest that it is less likely that childhood ALL is associated with an in utero in fection with B19.

The infectious origins of stillbirth

OBJECTIVE

Our objective was to determine the relationship between various types of perinatal infections and stillbirths.

STUDY DESIGN

By use of various textbooks on perinatal infections, multiple MEDLINE searches, and the reference list of all appropriate manuscripts, the appropriate English language literature was reviewed to define the relationship between various perinatal infections and stillbirths.

RESULTS

Infection may cause stillbirth by a number of mechanisms, including direct infection, placental damage, and severe maternal illness. A large variety of organisms have been associated with stillbirth, including many bacteria, viruses, and protozoa. In developed countries, between 10% and 25% of stillbirths may be caused by an infection, whereas in developing countries, which often have much higher stillbirth rates, the contribution of infection is much greater. Ascending bacterial infection, both before and after membrane rupture, with organisms such as Escherichia coli, group B streptococci, and Ureaplasma urealyticum is usually the most common infectious cause of stillbirth. However, in areas where syphilis is very prevalent, up to half of all stillbirths may be caused by this infection alone. Malaria may be an important cause of stillbirth in women infected for the first time in pregnancy. The two most important viral causes of stillbirth are parvovirus and Coxsackie virus, although a number of other viral infections appear to be causal. Toxoplasma gondii, leptospirosis, Listeria monocytogenes, and the organisms that cause leptospirosis, Q fever, and Lyme disease have all been implicated as etiologic for stillbirth.

CONCLUSION

Because infection-related stillbirth is relatively rare in developed countries, and those that do occur are caused by a wide variety of organisms, reducing this etiologic component of stillbirth much further will be difficult. However, in certain developing countries, the stillbirth rate is so high and the infection-related component so great that achieving a substantial reduction in stillbirth should be possible simply by reducing maternal infections.

Ex vivo cytokine responses against parvovirus B19 antigens in previously infected pregnant women

Parvovirus B19 infection is a significant cause of fetal death. The aim of this study was to investigate the role of maternal immune status in modulating susceptibility to fetal B19 infection. Peripheral blood was obtained from pregnant women (n = 199) with no clinical evidence of recent B19 infection. Evaluation of ex vivo T cell responses from 149/199 individuals showed significantly higher interferon-gamma levels for seropositive individuals following VP1 (268 +/- 36 versus 103 +/- 19 pg/ml; P = 0.003) and VP2 (242 +/- 42 versus 91 +/- 16 pg/ml; P = 0.01) antigen stimulation. Significantly higher levels of interleukin-2 were also observed in seropositive individuals following both VP1 (P = 0.0003) and VP2 (P = 0.0005) stimulation. The observed Th1 cellular response is lower than that documented previously for non-pregnant individuals and strongly suggests that diminution of the maternal anti-viral immune response may increase susceptibility to fetal B19 infection.

Long term follow up of serostatus after maternofetal parvovirus B19 infection

BACKGROUND

Maternofetal parvovirus B19 infection may result in fetal hydrops or abortion. Chronic infection has been associated with long term complications (polyarthritis, persistent aplastic anaemia, hepatitis). In pregnancy maternal immunosuppression caused by a TH2 dominant response to viral antigens has been observed. There is little information on long term reactivity to intrauterine infection.

AIMS

To assess the serological status in children and their mothers after maternofetal parvovirus B19 infection and development of fetal hydrops.

METHODS

A total of 18 children and their mothers, and 54 age matched control infants were studied. Main outcome measures were parvovirus B19 DNA, specific IgM and IgG against the virus proteins VP1/VP2, and NS-1 in venous blood.

RESULTS

Parvovirus B19 DNA and antiparvovirus B19 (IgM) were undetectable in all sera. A significant larger proportion of maternal sera compared to study children's sera contained IgG against the non-structural protein NS-1. Mean levels of VP1/VP2 IgG antibodies were significantly lower in the children than in their mothers (48 (36) v 197 (95) IU/ml). There was no history of chronic arthritis in mothers and children. Five women had subsequent acute but transient arthritis postpartum, which was not correlated with antibodies against NS-1.

CONCLUSIONS

Serological evidence of persistent infection after maternofetal parvovirus B19 disease could not be detected. Increased maternal prevalence of anti NS-1 (IgG) and increased levels of antiparvovirus B19 (IgG) may reflect prolonged viraemia compared to fetal disease.

Human fetal infection with parvovirus B19: maternal infection time in gestation, viral persistence and fetal prognosis

OBJECTIVE

To clarify the relation between the time of parvovirus B19 (B19) infection in pregnancy and fetal outcome, including the viral persistence in the fetus.

METHODS

Among 57 pairs showing serologic and/or virologic evidence of maternal and fetal B19 infection between 1986 and 1999 in Japan, 13 maternal-fetal pairs with the time of maternal B19 infection documented were retrospectively evaluated for fetal outcome and viral persistence.

RESULTS

Nonimmune hydrops occurred at 23, 21 and 26 gestational weeks (gw) in three fetuses as a result of their mothers' symptomatic infection (erythema infectiosum) at 3, 16 and 19 gw, respectively. Spontaneous abortion without hydrops and intrauterine growth retardation resulting in small-for-gestational age (SGA) classification occurred in two fetuses whose mothers had developed erythema infectiosum at 5 and 16 gw, respectively. Eight fetuses were asymptomatic as a result of their mothers' infection at 6, 9, 12, 15, 18, 23, 23 and 33 gw, respectively. B19 DNA was detected in neonatal serum in all nine cases tested.

CONCLUSION

Maternal B19 infection throughout gestation including the early stage after fertilization caused fetal infection that persisted until intrauterine fetal death with or without nonimmune hydrops or until the neonatal period after birth.