Prenatal diagnosis of intrauterine infection with parvovirus B19 by the polymerase chain reaction technique

Postnatal IVIG treatment for persistent anaemia in neonate due to congenital parvovirus infection

Congenital parvovirus B19 infection is a rare but serious condition that can result in hydrops fetalis and fetal death. Due to the virus' cytotoxic effect on fetal red blood cell precursors, postnatal infection can cause a neonatal viremia and secondary pure red cell aplasia. Here, we describe a case of congenital parvovirus infection in a preterm infant complicated by hydrops fetalis and chronic anaemia that responded to postnatal treatment with intravenous immunoglobulin administered on day of life 44. After treatment, the anaemia resolved as the neonate exhibited interval increases in haemoglobin, haematocrit and reticulocyte count with no subsequent need for red blood cell transfusions.

Performance of a Multiplex Nested Polymerase Chain Reaction in Detecting 7 Pathogens Containing DNA in Their Genomes Associated With Congenital Infections

CONTEXT.—

Infections are the leading cause of perinatal and infant mortality in low-income and low-resource countries, which have a higher prevalence of infections. Definitive diagnosis of congenital and perinatal infections is largely dependent upon the results of laboratory tests.

OBJECTIVE.—

To develop a multiplex nested polymerase chain reaction (PCR) technique for the simultaneous detection of 7 pathogens containing DNA in their genomes in suspected cases of congenital infection.

DESIGN.—

Eligible participants were pregnant women with positive immunoglobulin M antibodies raised to one of the pathogens in the prenatal serologic screening, associated or not with fetal ultrasound abnormalities or positive fetal serology. Neonates whose mothers did not attend prenatal care were included when they presented with symptomatology and laboratory parameters suggestive of infection. The detection rate of the multiplex nested PCR was compared with maternal, fetal, and neonatal serology, as well as placental immunohistochemistry and noncommercial amplifications.

RESULTS.—

Of 161 suspected cases, the multiplex nested PCR detected 60 (37.3%), whereas the tests available in hospital laboratories detected 13 of 60 (21.7%) of the cases detected by the multiplex nested PCR, demonstrating a 4.6 times higher detection rate for the multiplex nested PCR (Fisher exact test, P < .001). Positive amplifications were to Toxoplasma gondii (32 cases), cytomegalovirus (14 cases), parvovirus B19 (5 cases), and adenovirus (5 cases). In 4 cases, 2 pathogens were simultaneously detected. All types of biological matrices were suitable for amplification. Sequencing of multiplex nested PCR products confirmed the molecular findings.

CONCLUSIONS.—

The multiplex nested PCR significantly increased the number of diagnosed congenital infections. Given the scarcity of DNA recovered from amniotic fluid and some neonatal samples, this multiplex nested PCR allows the simultaneous detection of 7 pathogens associated with congenital infections in a reliable, faster, cost-effective, and more sensitive way.

Diagnosis and management of human parvovirus B19 infection

Parvovirus B19 is a common infection in children occurring in winter and spring months that can affect pregnant women and their unborn fetuses. Adverse fetal sequelae may include red blood cell aplasia due to bone marrow suppression, anemia, myocarditis, nonimmune hydrops, and fetal death. Fortunately, several noninvasive testing schemes are available to assess the fetus, and invasive testing is reserved for fetuses with marked anemia.

Parvovirus B-19 infection during pregnancy

The development of an acute parvovirus B-19 infection during pregnancy can cause pregnancy complications ranging from early pregnancy loss to nonimmune hydrops. There is no treatment, but preventive measures can be used to decrease perinatal mortality. The diagnosis is made on the basis of clinical suspicion and serology. If the fetus exhibits hydrops in the latter part of pregnancy, the main treatment options include either correcting the associated anemia with intrauterine blood transfusion or birth with extrauterine management. Although the serious problems associated with this virus during pregnancy are uncommon, they can be fatal. In view of this, a pregnant woman who is antibody negative should try to avoid contact with large groups of young children in order to decrease contact with potential vectors.

Prenatal testing for infectious disease

Prenatal testing for infectious diseases is performed frequently and for a variety of indications. The purpose of this article is to review the maternal and fetal infections that pose diagnostic concerns. Recent advances in diagnostic testing (such as avidity testing) is included. Testing issues focus on the diagnosis of maternal and fetal infection.

Testing for hematologic disorders and complications

This review summarizes state-of-the-art and emerging techniques in the antenatal diagnosis of fetal anemia and hemoglobinopathies. Fetal anemia may result from hemolytic disease, hemorrhage, suppression of erythropoiesis, infection (eg, parvovirus B19), or trauma. The clinical laboratory plays an essential role in the evaluation of these disorders by way of the use of various hematologic, biochemical, serologic, cytometric, and molecular genetics methods. Hemoglobinopathies are the most common class of single gene disorders worldwide. The authors have used the example of homozygous alpha-thalassemia major (Hb Barts disease) as a paradigmatic case for antenatal hemoglobinopathy screening. Perhaps the most familiar indication for hematologic screening in pregnancy is HDFN, most commonly in pregnancies previously sensitized to the RhD antigen. All pregnant women, regardless of their past medical or obstetric history or previous antibody screens, should have ABO/Rh blood typing and a red cell antibody screen performed at the first prenatal visit. Long-established methods for assaying FMH (KB method), microcytosis (hemogram with red cell indices), and blood group incompatibility (direct antigen test, serologies) remain critical for rapid, sensitive diagnosis. Analysis of fetal free DNA in maternal plasma holds the promise for rapid, ultrasensitive, and noninvasive detection of many fetal hematologic disorders.

Parvovirus B19 infection in pregnancy: quantitative viral DNA analysis using a kinetic fluorescence detection system (TaqMan PCR)

Human parvovirus B19 infections are common in the general population, and infection during pregnancy may cause hydrops fetalis and fetal death. To initiate adequate treatment, accurate laboratory diagnosis is essential. The most sensitive tests are nested PCR systems, but these assays provide semiquantitative results at best. A parvovirus B19 DNA assay was developed based on the real time TaqMan PCR. This method was calibrated on the basis of serial plasmid dilutions and tested with an international parvovirus B19 standard. The assay was capable of quantifying parvovirus B19 DNA from one to about 5 x 10(7) genome equivalents per reaction (corresponding to 100 to 5 x 10(9) genome equivalents per ml serum). Samples from 51 pregnant women with suspected acute parvovirus B19 infection were tested, and positive PCR results were obtained in at least one of the materials investigated in 41 cases. The median viral DNA load in maternal blood samples was 1.3 x 10(4) copies/ml (range 7.2 x 10(2)-2.6 x 10(7)). Maternal virus DNA concentration was not associated with the presence of maternal symptoms and/or fetal complications. As the stage of infection was not known in the majority of cases, our data do not exclude an association between peak levels of parvovirus B19 DNA and the development of complications. Maternal sera and corresponding fetal material were available for concurrent testing from 15 DNA-positive cases: in most fetal samples, viral DNA concentrations were several orders of magnitude higher (up to 2.1 x 10(12) copies/ml) compared to the corresponding maternal blood samples.

[Viral infections and pregnancy: contribution of amniotic fluid and blood samples]

The main viral infections prenatally detected in fetuses are: cytomegalovirus, parvovirus B19, rubella virus and varicellazoster virus infections. Prenatal diagnosis is based on the direct detection of the virus by culture (CMV), of its antigens or of its genome, essentially by PCR. This direct detection can be done either on fetal blood or on amniotic fluid. Prenatal diagnosis can also be performed by detection of specific IgM in fetal blood (rubella). Non specific markers of viral infection can also help in diagnosis. At the present time, prenatal diagnosis is essentially based on the detection of the viral genome in amniotic fluid. In order to better appreciate the severity of fetal infections, some groups have tried to identify prognostic markers of these infections. The viral load as well as the level of specific IgM could play a role in certain infections (CMV).

Detection of parvovirus B19 IgM by antibody capture enzyme immunoassay: receiver operating characteristic analysis

Parvovirus B19 infection can cause severe effects in high-risk groups including pregnant women and immunocompromised individuals. Although serological detection of B19 infection is commonplace, minimal information is available on the absolute performance characteristics of various tests for the detection of B19 IgM. The performance of the first parvovirus B19 IgM enzyme immunoassay to be cleared by the US Food and Drug Administration (FDA) is described. The immunoassay cut-off has been established using receiver operating characteristic (ROC) analysis giving a sensitivity and specificity of detection of 89.1 and 99.4%, respectively. No cross-reactivity is observed with rubella or other viral disease IgM which cause similar symptomologies to parvovirus B19. Multi-site reproducibility studies have shown high immunoassay reproducibility with detection rates (observed/expected result) of 100% for nonreactive specimens (N=324) and strongly reactive (N=403), respectively. Immunoassay reproducibility ranged from 11.76 to 17. 46% coefficient of variation for all reactive specimens tested (N=12) whereby each specimen was assayed a total of 81 times. Parvovirus B19 IgM seroprevalence of 1% was observed in a US blood donor population (N=399). In the absence of international performance criteria, this study will be of major benefit to the clinical virologist in assessing immunoassay reliability for the detection of recent infection with parvovirus B19.

Dermatomyositis associated with the presence of parvovirus B19 DNA in muscle

We report a case of dermatomyositis associated with molecular evidence of parvovirus B19 DNA in two muscle biopsies collected 5 months apart. IgG- but not IgM-specific antibodies were detected in serum. None of four serum samples was positive for parvovirus B19 DNA. The two biopsies contained B19 VP1 sequences and the second one was also positive for NS1. This is the first report of viral parvovirus B19 DNA in muscle of a patient with dermatomyositis. Latent muscle infection may contribute to the clinical picture.

Detection of microorganisms in the tracheal aspirates of preterm infants by polymerase chain reaction: association of adenovirus infection with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is recognized as an important cause of morbidity and mortality in preterm infants. Because the role of congenital infections in BPD has been debated, the purpose of this study was to test the hypothesis that detection of infectious agents in tracheal aspirate samples was associated with the development of BPD. Tracheal aspirate samples were obtained within the 1st week of life and screened by polymerase chain reaction for adenovirus, cytomegalovirus, parvovirus, enteroviruses, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma pneumoniae, and Chlamydia species. BPD was defined as persistent oxygen dependence at 28 d of age and 36 wk postconceptional age (PCA). Infants that expired before these time points were excluded from statistical analysis. Out of 89 infants studied, at 28 d of life, 13 had expired, 45 had BPD, and 31 had no BPD (controls). At 36 wk PCA, 15 infants expired, 39 still had BPD, and 35 did not. A significant increase in the frequency of adenovirus genome was identified in BPD patients compared with controls, both at 28 d of life (12/45 = 27% versus 1/31 = 3%: p< or =0.01) and at 36 wk PCA (10/39 = 29% versus 2/35 = 6%: p = 0.01). Other microorganisms were rarely detected and not associated with the development of BPD. This is the first study reporting the frequency of detection of adenovirus DNA in tracheal aspirate samples obtained during the 1st week of life from infants with BPD and suggests that prenatal acquisition may be important in the development of BPD.

Prenatal diagnosis of parvovirus B19-induced hydrops fetalis by chemiluminescence in situ hybridization

Parvovirus B19 can be transmitted transplacentally from the infected mother to the fetus during pregnancy, and hydrops fetalis, abortion, or stillbirth can result. In our study we explored the use of chemiluminescence in situ hybridization to detect B19 DNA on cord blood cells, amniotic fluid cells, and pleuric fluid cells from several cases of hydrops fetalis. B19 DNA was detected by using digoxigenin-labeled probes immunoenzymatically visualized with the chemiluminescent adamantil-1,2-dioxetane phenyl phosphate substrate for alkaline phosphatase. The luminescent signal emitted from the hybridized probes was detected, analyzed, and measured with a high-performance, low-light-level imaging luminograph connected to an optical microscope and to a personal computer for the quantification and localization of the chemiluminescent emission inside individual cells.

Parvovirus B19 infection in thoracic organ transplant recipients

BACKGROUND

Clinical manifestations of parvovirus B19 infection in immunocompromised patients are mostly reported as acute or chronic hematologic disorders. More recently, respiratory or renal involvement has been described.

OBJECTIVE

We started in 1994 a prospective study of parvovirus B19 infection in a group of lung (LTP) and heart-lung (HLTP) transplanted patients, including occasionally heart transplanted (HTP) patients.

STUDY DESIGN

62 patients (49 LTP, 11 HLTP, 2 HTP) were included in a serological survey and DNA detection by PCR was performed on each serum sample of the first 29 patients; later we performed it only when serology could suggest an acute episode, or when parvovirus infection could be suspected on clinical or biological observations. A total of 1655 sera were examined by serological tests and DNA detection was done in 500 samples. Specific IgM, seroconversion, significant increase of specific IgG levels, and/or parvovirus B19 DNA detection, were considered as markers of viral infection.

RESULTS

We observed the presence of both markers of infection in 24 patients (39%), with an individual combination of positive antibody and PCR results. Acute or chronic anaemia, neutropenia were associated to these laboratory findings in 19 patients, but in five cases, an asymptomatic clinical infection suggested viral persistence.

CONCLUSIONS

We report parvovirus associated acute or chronic anaemia and pancytopenia in a group of LTP, HLTP and HTP patients, as well as asymptomatic cases of infection. In the hypothesis of a parvoviral persistent or latent infection, current diagnosis methods may be unreliable to identify any other clinical manifestations.

Parvovirus B19 infections in pregnancy

Parvovirus B19 is the viral agent that causes the childhood exanthum erythema infectiosum, or fifth disease. Approximately 50% of pregnant women are seropositive for this agent and thus immune to primary infection. However, acute infection may develop in seronegative pregnant women exposed to B19. Acute B19 infections during pregnancy have been associated with miscarriage and hydrops fetalis. This latter condition is amenable to fetal therapy via intrauterine transfusion.

Foetal intracardiac transfusion for the treatment of severe anaemia due to human parvovirus B-19 infection

Intra-uterine parvovirus infection may result in severe foetal anaemia and death. Ultrasound diagnosis of foetal parvovirus is presented, together with ultrasound-guided foetal transfusion to treat the anaemia.

Polymerase chain reaction in the detection of microbes in amniotic fluid

Intra-amniotic infection during pregnancy can be caused by bacteria, viruses or protozoa, Toxoplasma gondii for example. Bacterial intrauterine infections are connected with premature birth, premature rupture of fetal membranes, and infective complications of both the mother and the newborn. Viral infections and Toxoplasma gondii can cause fetal malformations and illness with serious sequelae to the infant or fetal death in utero. Determining the causative agent is important and often greatly affects the prognosis of the newborn. Amniotic fluid is in most cases easily and safely obtainable during the second and third trimester and can be used in several microbiological assays. These include bacterial and viral cultures, Gram staining, quantitative assays for immunoglobulins or cytokines, and polymerase chain reaction (PCR) for detecting microbial DNA. This review concentrates on broad-spectrum or universal bacterial PCR for detection of bacterial DNA in amniotic fluid and on PCR assays for certain clinically important viruses and for Toxoplasma gondii.

Serologic and virologic evidence for frequent intrauterine transmission of human parvovirus B19 with a primary maternal infection during pregnancy

OBJECTIVE

To define the intrauterine viral transmission rate during primary maternal parvovirus B19 infection and identify factors that may influence this rate.

METHODS

Forty-three pregnant women at two medical centers were identified with a primary B19 infection and followed to delivery. At delivery maternal and infant (umbilical cord) blood was obtained for B19 serologic and virologic PCR testing.

RESULTS

All of the women delivered healthy infants at term and none was hydropic. Overall 22 (51%) of the 43 infants had some evidence of a congenital B19 infection. B19-specific IgM was detected in 11 infants at delivery, B19 IgA was detected in 10 and B19 DNA was detectable by PCR in 11 infants. One infant was negative at birth but became positive for IgM, IgA and PCR at 6 weeks of age. No association was found between the likelihood of intrauterine infection and: maternal age; symptomatic maternal infection; method of delivery; maternal IgG titer at delivery; maternal IgG avidity at delivery; or maternal viremia at delivery. Intrauterine infection was associated with maternal IgM positivity at delivery; this association may have been a result of maternal infection occurring later in gestation.

CONCLUSION

Although the incidence of intrauterine hydrops and fetal demise after maternal infection is low, there is a high rate of intrauterine viral infection that occurs throughout gestation and yields newborns who, although infected in utero, are asymptomatic at birth.

Acute parvovirus B19 infection in pregnant women--an analysis of serial samples by serological and semi-quantitative PCR techniques

The serological and virological course of parvovirus B19 infection was followed in 14 women who suffered symptomatic or subclinical acute infection during pregnancy. Serial serum samples from the patients were tested for IgG and IgM antibodies and the levels of parvovirus B19 DNA were monitored using a semi-quantitative PCR assay. In addition, the outcome of the pregnancies was documented by clinical information and by testing cord blood for parvovirus B19 specific antibodies as well as for parvovirus B19 DNA by PCR. Levels of IgG antibodies rose steadily within 2 months of infection and in some cases began to decline at the end of pregnancy. IgM antibodies were usually detected for at least 2 months and persisted for as long as 9 months in one case. Viral DNA was detectable for at least 8 weeks following infection and semi-quantitative analysis revealed a gradual reduction in virus load during the viraemic phase of infection. There were no apparent differences in the course of antibody development and duration of viraemia in symptomatic versus subclinical infections.

A clinical and epidemiological study of human parvovirus B19 infection in fetal hydrops using PCR Southern blot hybridization and chemiluminescence detection

Ninety-eight samples from 80 cases of spontaneous abortions after fetal death or hydrops fetalis from 12,000 pregnant women were examined using PCR. DNA was extracted from amniotic fluid, fetal blood, ascitic fluid and fetal biopsies or placenta specimens using QIA amp kits (QIAGEN). A 270-bp length fragment located within the B19 gene NS1 was amplified using PCR followed by electrophoresis and southern-blot hybridization assay using a horseradish peroxidase-labelled probe and chemiluminescence detection. This assay was able to detect 1 to 10 DNA copies in a 10 microliters sample. Parvovirus B19 was identified in 11 cases (14% of fetal hydrops; 1 case for 1,100 pregnancies). Amniotic fluid was the most common and reliable sample to assess the diagnosis. Gestational age ranged from 17 to 28 weeks (mean 23 weeks). IgM antibodies were detected in 3 maternal sera, 2 patients of which reported an exposure to B19 infection during pregnancy. In 2 cases, intrauterine blood transfusions led to the cessation of symptoms and to birth of normal babies.

Detection of intrauterine viral infection using the polymerase chain reaction

Intrauterine viral infection commonly presents as nonimmune hydrops fetalis or intrauterine growth restriction. Cytomegalovirus (CMV) and parvovirus are commonly recognized causes of fetal infection using serology and cultures. We used the polymerase chain reaction (PCR) to evaluate the frequency of fetal viral infection and the associated clinical course and outcome. Specimens (amniotic fluid, fetal blood, pleural fluid, tissue) from 303 abnormal pregnancies at risk for viral infection and 154 controls were analyzed using primers for CMV, herpes simplex virus, parvovirus B19, adenovirus, enterovirus, Epstein-Barr virus, and respiratory syncytial virus. Viral genome was detected in 144/371 samples (39%) or 124/303 patients (41%), with adenovirus (n = 74 patients; 24%), CMV (n = 30 patients; 10%), and enterovirus (n = 22 patients; 7%) most common. Only 4/154 (2.6%), unaffected control patients' samples were PCR positive. We conclude that diagnosis of fetal viral infection by PCR is common in abnormal pregnancies. Adenovirus and enterovirus may cause fetal infection that have been previously unrecognized.

Higher prevalence of parvovirus B19 in Belgian as compared to Tunisian blood donors: differential implications for prevention of transfusional transmission

Serious anaemia can be induced by human parvovirus B19 (HPV) infection in immuno-compromised patients or subjects with an haemolytic disorder. Routine inactivation procedures are insufficient to neutralize the virus, but screening for HPV is an effective means to avoid transmission by transfusion of blood components. In the present study, we have compared for the first time the IgG and IgM seroprevalence in a North African (Tunisian) and Western European (Belgian) population of blood donors. The prevalence of HPV-specific IgM was less than 2% in both populations, pointing to the absence of an epidemic. The prevalence HPV IgG was significantly (p < 0.01) higher in Belgium (74%) than in Tunisia (65%), without any relationship with age or sex. This finding may suggest a south-north gradient of this infectious disease. Since the presence or absence of HPV-specific antibodies does not preclude transfusional transmission, screening for the virus itself should be done to avoid iatrogenic infection in HPV-naive subjects at risk. In view of the different transfusion policies in Belgium and Tunisia, a strategy for each of both countries is proposed.

Human parvovirus B19: immunity of Greek females and prenatal investigation of hydrops fetalis

Sera from 308 healthy Greek females of reproductive age were examined for specific IgG antibodies to human parvovirus B19 by recombinant-Elisa to determine the immunity rates of this part of population to parvovirus B19. Also paired maternal sera and amniotic fluids from nine pregnancies with hydrops fetalis were investigated for specific IgG and IgM antibodies and parvovirus DNA by polymerase chain reaction and southern hybridization analysis. The latter study was conducted to find out the participation of parvovirus B19 infection in hydrops fetalis cases in Greece. The overall prevalence of IgG antibodies in healthy Greek females was at a rate of 57.8% rising with age. One case of hydrops fetalis out of the nine examined, was diagnosed prenatally as parvovirus B19 maternal-fetal infection. It was a twin pregnancy with one fetus hydropic and the other growth retarded. Premature birth of liveborn infants was followed by neonatal death, 48 h after delivery. The contribution of parvovirus B19 in cases of non-immune hydrops fetalis was at 11% in this part of the world.

Infection by parvovirus B 19 during pregnancy: a review

Fetal infection by Parvovirus B 19 is a common cause of fetal anemia and nonimmune hydrops fetalis and may result in fetal death. Recent improvements in diagnosing parvovirus infections by sensitive molecular biology techniques now allow for a new insight into its pathogenic rule, immunology, and the varied clinical manifestations. The estimated overall risk of fetal loss after maternal exposure is about 6.5 percent, which is much less than previously thought. Inasmuch as complete spontaneous reversal of fetal hydrops has been commonly described, controversy exists regarding the management of the fetus with clinical signs of infection by Parvovirus B 19. According to the experience that has accumulated, it seems that only cases with severe fetal anemia or signs of fetal compromise should be managed by intrauterine transfusion. This procedure, however, is not without risk. Although an association between fetal viral infection and structural abnormalities has been described, it has not been proved yet. However, infection by Parvovirus B 19 has been recently proposed as a causative factor for congenital red blood cell aplasia.

Toxoplasmosis and parvovirus B19

Pregnant women might well improve their chances for a successful pregnancy outcome by following the advice of W. C. Fields: avoid contact with small children and animals whenever possible. Failing widespread acceptance of this philosophy, management of T. gondii and parvovirus B19 infections continues to be a challenge for the foreseeable future.

The elusive search for fetal infection. Changing the gold standards

Two percent to four percent of all newborns have a major structural malformation of which only a small percentage can be explained by either aneuploidy or a single-gene disorder. No other mammal has a similar reproductive problem. It is the suggestion that previously unrecognized viral infection accounts for a large percentage of these abnormalities by interfering with appropriate embryonic cell migration, reducing hyperplasia, or damaging the precursor structure by means of an inflammatory mechanism.

Human parvovirus B19 infection and hydrops fetalis in Rio de Janeiro, Brazil

Formalin-fixed paraffin embedded lung and liver tissue from 23 cases of non immune hydrops fetalis and five control cases, in which hydrops were due to syphilis (3) and genetic causes (2), were examined for the presence of human parvovirus B19 by DNA hybridisation. Using in situ hybridisation with a biotynilated probe one positive case was detected. Using 32P-labelled probes in a dot blot assay format, five further positives were obtained. These were all confirmed as positive by a nested polymerase chain reaction assay. Electron microscopy revealed virus in all these five positive cases. The six B19 DNA positive cases of hydrops fetalis were from 1974, 1980, 1982, 1987 and 1988, four of which occurred during the second half of the year, confirming the seasonality of the disease.

Comparative evaluation of virological and serological methods in prenatal diagnosis of parvovirus B19 fetal hydrops

Human parvovirus B19 infection in pregnancy represents a potential hazard to the fetus since fetal loss or fetal hydrops can occur. The risk of fetal loss due to transplacental B19 transmission has been evaluated in several studies using different diagnostic methods on maternal and fetal specimens. We analyzed the diagnostic value of virological and serological techniques on maternal serum, fetal cord blood, and amniotic fluid specimens obtained at the time of clinical diagnosis of fetal hydrops in 18 cases of B19 fetal hydrops. B19 DNA was detected by nested PCR, dot blot hybridization, and in situ hybridization assay. Anti-B19 immunoglobulin M and G antibodies were detected by immunoassays using recombinant B19 antigens. Our data suggest that for maternal sera, virological and serological methods have a complementary role in diagnosis, while for fetal specimens the in situ detection of B19 DNA in fetal cord blood is the most sensitive diagnostic system.

Sickle cell acute chest syndrome associated with parvovirus B19 infection: case series and review

Acute Chest Syndrome (ACS) continues to be a major source of morbidity and mortality among patients with sickle cell disease. It is characterized by the presence of pleuritic chest pain, fever, raises on lung auscultation, and pulmonary infiltrates on chest x-ray [Castro et all: Blood 84:643-649]. The pathophysiology of this disorder remains poorly understood leading to the descriptive term "Acute Chest Syndrome" designated by Charache et al. [Arch Intern Med 139:67-69, 1979]. Typical bacterial pathogens are seldom isolated in adults, although they play a significant role in the pathogenesis of this entity in children. Until recently, the technology to accurately study viral infection as a precipitating cause of ACS has been unavailable. Parvovirus B19 is being increasingly recognized as an important human pathogen, and has been established as the cause of transient "aplastic crisis" in patients with sickle cell diseases [Saarien et al: Blood 67:-11411-11417, 1986; Young: Sem Hematol 25:159-172, 1988]. We present three patients with hemoglobin SC variant of sickle cell disease who developed ACS in association with acute parvovirus B19 infection, one of which died of respiratory failure. Parvovirus B19 infection was established by polymerase chain reaction for parvovirus B19 DNA, and the presence of parvovirus B19 specific IgM antibodies. These cases suggest that parvovirus B19 may be associated with more than self-limited illness in patients with sickle cell disease, and that this ubiquitous virus may merit further study as a precipitating cause of ACS.

Fetal pathology in intrauterine death due to parvovirus B19 infection

OBJECTIVES

To study the pathological features of fetuses dying because of parvovirus B19 infection, with particular reference to the presence of hydrops; to assess the usefulness of immunochemistry as a screening method for the detection of parvovirus infection at post-mortem examination.

DESIGN

Review of clinical, sonographic, serological and pathological data; immunohistochemical staining of post-mortem tissue.

SAMPLE

Cases of intrauterine fetal death occurring during the 18-month period January 1993 to June 1994 inclusive, referred for post-mortem examination to the Pathology Department, Royal Victoria Infirmary, Newcastle upon Tyne.

RESULTS

Eleven cases of fetal death due to parvovirus infection were identified. Seven fetuses were less than 18-week size. Three fetuses showed conspicuous hydropic change. One of the 11 cases was detected for the first time by retrospective immunochemical screening. Of cases originating from the Newcastle district, parvovirus infection was responsible for about 10% of all non-malformed fetal deaths occurring between 10 and 24 weeks of gestation referred for pathological examination.

CONCLUSIONS

During the period of study, parvovirus infection was a relatively common cause of mid-trimester fetal death. Many fetuses dying because of this infection are not noticeably hydropic, and the possibility of parvovirus infection should be considered in any case of intrauterine fetal death. Immunochemistry can be used to confirm the histopathological diagnosis, and may be of particular help where there is advanced autolysis; immunohistochemical screening may detect occasional cases not initially identified by examination of routinely stained tissue sections.

Infectious causes of hydrops fetalis

A variety of infectious agents have been associated with nonimmune hydrops fetalis, most notably parvovirus B19, cytomegalovirus, herpes simplex virus, Toxoplasma gondii, and Treponema pallidum. These agents produce hydrops through effects on fetal bone marrow, myocardium, or vascular endothelium. Knowledge of the epidemiology and clinical characteristics of maternal and fetal infection can be used to select a diagnostic approach. Etiologic diagnosis will guide prognosis and the selection of specific chemotherapy.

Observational study of effect of intrauterine transfusions on outcome of fetal hydrops after parvovirus B19 infection

The role of intrauterine transfusion for fetal hydrops arising from maternal paravirus B19 infection is unclear. 66 cases of fetal hydrops arising from B19 infection were reported in England and Wales between June, 1992, and September, 1994. In 29 cases the fetus was dead at the time of the first abnormal ultrasound or a therapeutic abortion as performed; 12 of the 38 alive at the first abnormal scan received intrauterine transfusions and 3 of the 12 died. 26 did not receive intrauterine transfusions and 13 died. After adjustment for the severity of the hydrops as assessed by the ultrasound and for gestational age, the odds of death among those who received an intrauterine transfusion was significantly less than among those who did not (odds ratio 0.14, 95% CI 0.02-0.96). These findings suggest that intrauterine transfusion will benefit some fetuses with hydrops arising from parvovirus B19 infection.

Infectious diseases

Routine antenatal screening can detect some potentially serious infectious diseases or susceptibility to infection and allow intervention to prevent adverse outcomes. However, screening programmes can only be justified if appropriate criteria are met for the quality of laboratory tests and interventions. For many infections that are associated with adverse maternal or fetal effects, there are no suitable, cost-effective methods of screening or prevention. However, early diagnosis of infection in high-risk women or those with symptoms can allow preventive intervention. Acute febrile illness or other symptoms consistent with infection during pregnancy should be investigated more diligently than in a non-pregnant woman. Early diagnosis of an apparently trivial maternal infection may prevent serious fetal disease. When the diagnosis of maternal infection is made, appropriate action depends on the nature of infection and the stage of pregnancy at which it occurs. The results of serological test should be confirmed, preferably by a reference laboratory, by retesting the original specimen(s) and/or testing further specimens, as appropriate. Management decisions generally should be made in consultation with an infectious disease physician or clinical microbiologist with experience of infectious diseases in pregnancy.

The diagnosis of congenital infections: contemporary strategies

Congenital infections remain an important source of neurologic, ophthalmologic, and audiologic disability for thousands of children throughout the world. This review summarizes the clinical features and describes contemporary approaches to the microbiologic diagnosis of congenital infections. In particular, this review emphasizes the important roles that molecular methods, especially the polymerase chain reaction, have in detecting the many infectious agents capable of damaging the developing nervous system.

Fetal parvovirus B19 infection and liver disease of antenatal onset in an infant with Ebstein's anomaly

Fetal parvovirus B19 infection has been reported in association with hydrops and fetal demise, myocarditis, and congenital anomalies, as well as with normal outcome of pregnancy. One infant with liver disease of fetal onset associated with parvovirus B19 infection has been described. We have seen another such infant, in whom marked siderosis of the liver suggested accelerated destruction of erythrocytes and portal tract fibrosis with proliferation of bile ducts suggested intrauterine infection. Viral cytopathic effects were not seen. Maternal serum obtained postpartum contained IgM class antibodies against parvovirus B19, and parvovirus B19 nucleic acid sequences were identified in the infant's liver by polymerase chain reaction studies. We propose that recognition of this combination of siderosis with fibrosis and bile duct proliferation will permit identification of cases of fetal parvovirus B19 infection.

Determination of normal human fetal immunoglobulin M levels

Immunoglobulin M (IgM) levels were measured in 198 cord blood samples from 192 apparently normal pregnancies from 24 weeks of gestation to term. Simple linear regression analysis yielded a standard curve for IgM development during pregnancy showing a 0.5 mg/dl increase in IgM per week of gestation. This curve allows the comparison of fetal IgM levels from pregnancies considered to be at risk for intrauterine infection.

Estimation of serum concentration of parvovirus B19 DNA by PCR in patients with chronic anaemia

Parvovirus B19 DNA was detected in serum samples from 10 out of 42 patients with chronic anaemia, the majority of whom suffered from aplastic anaemia, haemolytic anaemia, pure red cell anaemia or myelodysplastic syndrome. Nested PCR methods with sensitivities of 0.005-0.05 fg DNA were developed. In nine patients, B19 DNA could only be detected by nested PCR. Conventional PCR with a sensitivity of 50 fg B19 DNA could only detect B19 DNA in one patient. In the majority of B19-DNA-positive patients, the DNA concentration was estimated at 0.005-0.05 fg per 5 microliters serum.