Inapparent congenital cytomegalovirus infection. Clinical and epidemiologic characteristics in early infancy

Congenital Cytomegalovirus Testing Outcomes From the ValEAR Trial

OBJECTIVE

To determine the positivity rate of congenital cytomegalovirus (cCMV) testing among universal, hearing-targeted CMV testing (HT-cCMV) and delayed targeted dried blood spot (DBS) testing newborn screening programs, and to examine the characteristics of successful HT-cCMV testing programs.

STUDY DESIGN

Prospective survey of birth hospitals performing early CMV testing.

SETTING

Multiple institutions.

METHODS

Birth hospitals participating in the National Institutes of Health ValEAR clinical trial were surveyed to determine the rates of cCMV positivity associated with 3 different testing approaches: universal testing, HT-cCMV, and DBS testing. A mixed methods model was created to determine associations between successful HT-cCMV screening and specific screening protocols.

RESULTS

Eighty-two birth hospitals were surveyed from February 2019 to December 2021. Seven thousand six hundred seventy infants underwent universal screening, 9017 infants HT-cCMV and 535 infants delayed DBS testing. The rates of cCMV positivity were 0.5%, 1.5%, and 7.3%, respectively. The positivity rate for universal CMV screening was less during the COVID-19 pandemic than that reported prior to the pandemic. There were no statistically significant drops in positivity for any approach during the pandemic. For HT-cCMV testing, unique order sets and rigorous posttesting protocols were associated with successful screening programs.

CONCLUSION

Rates of cCMV positivity differed among the 3 approaches. The rates are comparable to cohort studies reported in the literature. Universal CMV prevalence decreased during the pandemic but not significantly. Institutions with specific order set for CMV testing where the primary care physician orders the test and the nurse facilitates the testing process exhibited higher rates of HT-cCMV testing.

Progressive, Long-Term Hearing Loss in Congenital CMV Disease After Ganciclovir Therapy

BACKGROUND

Long-term hearing outcomes among children with symptomatic congenital cytomegalovirus (CMV) disease who received 6-week ganciclovir therapy early in life are unknown.

METHODS

Longitudinal study of 76 children with symptomatic congenital CMV disease, born 1983-2005, who were categorized into three groups: group A treated with ganciclovir; group B untreated who had microcephaly, chorioretinitis, or sensorineural hearing loss (SNHL; ≥25 dB) diagnosed in the first month of life (congenital); and group C untreated who did not meet criteria for group B.

RESULTS

Patients in groups A (n = 17), B (n = 27), and C (n = 32) were followed to median age of 13, 11, and 13 years, respectively. In group A, patients received ganciclovir for median of 40 (range, 11-63) days; 7 (41%) had grade 3 or 4 neutropenia. Congenital SNHL was diagnosed in 11 (65%) patients in group A, 15 (56%) in group B, and none in group C. Early-onset SNHL was diagnosed between ages ≥1-12 months in an additional 4 (24%), 6 (22%), and 8 (25%) patients in groups A, B, and C, respectively. By the end of follow-up, 12 (71%), 16 (59%), and 7 (22%) of patients in groups A, B, and C, respectively, had severe (>70 dB) SNHL in the better-hearing ear.

CONCLUSIONS

In this study, most patients with symptomatic congenital CMV disease and congenital or early-onset SNHL eventually developed hearing loss severe enough to have been potential candidates for cochlear implantation, with or without 6-week ganciclovir therapy. Understanding long-term hearing outcomes of patients treated with 6-month oral valganciclovir (current standard of care) is needed.

Congenital Cytomegalovirus Infection Burden and Epidemiologic Risk Factors in Countries With Universal Screening: A Systematic Review and Meta-analysis

IMPORTANCE

Congenital cytomegalovirus (cCMV) infection is the most common congenital infection and the leading acquired cause of developmental disabilities and sensorineural deafness, yet a reliable assessment of the infection burden is lacking.

OBJECTIVES

To estimate the birth prevalence of cCMV in low- and middle-income countries (LMICs) and high-income countries (HICs), characterize the rate by screening methods, and delineate associated risk factors of the infection.

DATA SOURCES

MEDLINE/PubMed, Scopus, and Cochrane Database of Systematic Reviews databases were searched from January 1, 1960, to March 1, 2021, and a total of 1322 studies were identified.

STUDY SELECTION

Studies that provided data on the prevalence of cCMV derived from universal screening of infants younger than 3 weeks were included. Targeted screening studies were excluded.

DATA EXTRACTION AND SYNTHESIS

Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline was followed. Extraction was performed independently by 3 reviewers. Quality was assessed using the Newcastle-Ottawa Scale for cohort studies. Random-effects meta-analysis was undertaken. Metaregression was conducted to evaluate the association of sociodemographic characteristics, maternal seroprevalence, population-level HIV prevalence, and screening methods with the prevalence of cCMV.

MAIN OUTCOMES AND MEASURES

Birth prevalence of cCMV ascertained through universal screening of infants younger than 3 weeks for CMV from urine, saliva, or blood samples.

RESULTS

Seventy-seven studies comprising 515 646 infants met the inclusion criteria from countries representative of each World Bank income level. The estimated pooled overall prevalence of cCMV was 0.67% (95% CI, 0.54%-0.83%). The pooled birth prevalence of cCMV was 3-fold greater in LMICs (1.42%; 95% CI, 0.97%-2.08%; n = 23 studies) than in HICs (0.48%; 95% CI, 0.40%-0.59%, n = 54 studies). Screening methods with blood samples demonstrated lower rates of cCMV than urine or saliva samples (odds ratio [OR], 0.38; 95% CI, 0.23-0.66). Higher maternal CMV seroprevalence (OR, 1.19; 95% CI, 1.11-1.28), higher population-level HIV prevalence (OR, 1.22; 95% CI, 1.05-1.40), lower socioeconomic status (OR, 3.03; 95% CI, 2.05-4.47), and younger mean maternal age (OR, 0.85; 95% CI, 0.78-0.92, older age was associated with lower rates) were associated with higher rates of cCMV.

CONCLUSIONS AND RELEVANCE

In this meta-analysis, LMICs appeared to incur the most significant infection burden. Lower rates of cCMV were reported by studies using only blood or serum as a screening method.

MRI findings in children with congenital cytomegalovirus infection retrospectively diagnosed with dried umbilical cord

PURPOSE

Brain MRI provides important information about suspected congenital CMV infection in neonatally underdiagnosed children. This study aimed to describe MRI findings in children in whom congenital CMV infection was not suspected during the neonatal period and was proven retrospectively.

METHODS

We enrolled 31 children referred to the pediatric neurology clinic with neurological symptoms who were proven to have congenital CMV infection based on dried umbilical cord samples. Upon diagnosis, MR and CT images were assessed using the van der Knaap scoring system integrated with additional variables. Two investigators independently assessed all images.

RESULTS

The age at diagnosis was < 12 months in 14, 12-24 months in 11, and > 24 months in 6 patients. The initial symptom triggering clinic referral was delayed development in 22, seizure in 5, deafness in 3, and hemiplegia in 1 patient. Of the 31 children, 30 had a white matter (WM) abnormality predominant in the deep WM of the parietal lobe (n = 25). Anterior temporal lesions were observed in 21 children. Cortical lesions were observed in 7 children, suggestive of polymicrogyria. No child had cerebellar or brainstem abnormalities. Brain CT was performed in 22 of 31 children, and 11 showed punctate cerebral calcification in the periventricular and/or deep WM.

CONCLUSION

Patients with congenital CMV infection with delayed neurological symptoms show a relatively uniform pattern of parietal-dominant multifocal WM lesions and anterior temporal lesions, with or without polymicrogyria.

Ocular cytomegalovirus latency exacerbates the development of choroidal neovascularization

Age-related macular degeneration (AMD) is a complex, multifactorial, progressive disease which represents a leading cause of irreversible visual impairment and blindness in older individuals. Human cytomegalovirus (HCMV), which infects 50-80% of humans, is usually acquired during early life and persists in a latent state for the life of the individual. In view of its previously described pro-angiogenic properties, we hypothesized that cytomegalovirus might be a novel risk factor for progression to an advanced form, neovascular AMD, which is characterized by choroidal neovascularization (CNV). The purpose of this study was to investigate if latent ocular murine cytomegalovirus (MCMV) infection exacerbated the development of CNV in vascular endothelial growth factor (VEGF)-overexpressing VEGF-A^hyper mice. Here we show that neonatal infection with MCMV resulted in dissemination of virus to various organs throughout the body including the eye, where it localized principally to the choroid in both VEGF-overexpressingVEGF-A^hyper and wild-type(WT) 129 mice. By 6 months post-infection, no replicating virus was detected in eyes and extraocular tissues, although virus DNA was still present in all eyes and extraocular tissues of both VEGF-A^hyper and WT mice. Expression of MCMV immediate early (IE) 1 mRNA was detected only in latently infected eyes of VEGF-A^hyper mice, but not in eyes of WT mice. Significantly increased CNV was observed in eyes of MCMV-infected VEGF-A^hyper mice compared to eyes of uninfected VEGF-A^hyper mice, while no CNV lesions were observed in eyes of either infected or uninfected WT mice. Protein levels of several inflammatory/angiogenic factors, particularly VEGF and IL-6, were significantly higher in eyes of MCMV-infected VEGF-A^hyper mice, compared to uninfected controls. Initial studies of ocular tissue from human cadavers revealed that HCMV DNA was present in four choroid/retinal pigment epithelium samples from 24 cadavers. Taken together, our data suggest that ocular HCMV latency could be a significant risk factor for the development of AMD. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Long-term outcomes of children with symptomatic congenital cytomegalovirus disease

OBJECTIVE

To assess long-term outcomes of children with symptomatic congenital cytomegalovirus (CMV) disease detected at birth.

STUDY DESIGN

We used Cox regression to assess risk factors for intellectual disability (intelligence quotient <70), sensorineural hearing loss (SNHL; hearing level ⩾25 dB in any audiometric frequency) and vision impairment (best corrected visual acuity >20 or based on ophthalmologist report).

RESULTS

Among 76 case-patients followed through median age of 13 (range: 0-27) years, 56 (74%) had SNHL, 31 (43%, n=72) had intellectual disability and 18 (27%, n=66) had vision impairment; 28 (43%, n=65) had intellectual disability and SNHL with/without vision impairment. Microcephaly was significantly associated with each of the three outcomes. Tissue destruction and dysplastic growth on head computed tomography scan at birth was significantly associated with intellectual disability and SNHL.

CONCLUSION

Infants with symptomatic congenital CMV disease may develop moderate to severe impairments that were associated with presence of microcephaly and brain abnormalities.

Prenatal exposures associated with neurodevelopmental delay and disabilities

Neurobehavioral teratology refers to the study of the abnormal development of the structure and the behavioral functions of the central nervous system, which result from exposure to exogenous agents during prenatal development. The focus of this review is the effects of various prenatal exposures on human neurodevelopment. Studies that deal with the adverse effects of infectious agents (rubella, cytomegalovirus, and toxoplasma), teratogenic drugs (e.g., antiepileptic drugs such as phenytoin, valproate, and carbamazepine, coumarin derivatives, and retinoids), alcohol, and other substances of abuse will be reviewed. Additionally, prenatal exposure to industrial or environmental chemicals (e.g., lead, methylmercury, and polycarbonated biphenyls) as well as exposure of the embryo or fetus to high amounts of ionizing radiation will be addressed. Possible mechanisms of selected neurobehavioral teratogens will also be discussed.

Neuroimaging of pediatric brain infections

Neuroimaging plays an important and growing role in the diagnosis and therapeutic management of pediatric brain infections. This article describes the spectrum of imaging findings associated with major pediatric viral and bacterial brain infections, outlining the role of current imaging technology in the differential diagnoses of brain injury, detection of complications and therapy monitoring. MRI is the tool of choice in the evaluation of brain infections and particular attention is devoted to the role of diffusion-weighted imaging and magnetic resonance spectroscopy. This article considers viral and bacterial infection in their different modalities of presentation as congenital, acute and subacute/chronic disease. With regard to congenital infections, the growing role of fetal MRI as a valuable complement to ultrasound in the prenatal assessment of brain damage is emphasized.

New estimates of the prevalence of neurological and sensory sequelae and mortality associated with congenital cytomegalovirus infection

Congenital CMV is a major cause of neurological and sensory impairment in children. Reliable estimates of the prevalence of permanent sequelae and mortality associated with congenital CMV are needed to guide development of education and prevention programmes and to gauge the financial costs associated with this disease. To calculate such estimates, this review used data solely from studies in which children with congenital CMV were identified through universal screening. Based on 15 studies with a total of 117 986 infants screened, the overall CMV birth prevalence estimate was 0.7%. The percentage of infected children with CMV-specific symptoms at birth was 12.7%. The percentage of symptomatic children with permanent sequelae was 40-58%. The percentage of children without symptoms at birth who developed permanent sequelae was estimated to be 13.5%. The true burden of congenital CMV infection is unclear because data on important outcomes, such as visual impairment, are lacking and follow-up of infected children has been too short to fully identify late-onset sequelae. Therefore, the estimates of permanent sequelae associated with congenital CMV presented here are likely underestimates. Future studies should extend follow-up of CMV-infected children identified through universal screening and include the evaluation of visual impairment.

Review and meta-analysis of the epidemiology of congenital cytomegalovirus (CMV) infection

We reviewed studies that reported results of systematic cytomegalovirus (CMV) screening on fetuses and/or live-born infants. The overall birth prevalence of congenital CMV infection was 0.64%, but varied considerably among different study populations. About 11% of live-born infants with congenital CMV infection were symptomatic, but the inter-study differences in definitions of symptomatic cases limit the interpretation of these data. Non-white race, low socioeconomic status (SES), premature birth, and neonatal intensive care unit admittance were risk factors for congenital CMV infection. Birth prevalence increased with maternal CMV seroprevalence. Maternal seroprevalence accounted for 29% of the variance in birth prevalence between study populations. Maternal seroprevalence and birth prevalence were both higher in study populations that were ascertained at birth rather than in the prenatal period. Thus, timing of ascertainment should be considered when interpreting birth prevalence estimates. Birth prevalence was inversely correlated with mean maternal age, but this relationship was not significant when controlling for maternal seroprevalence. The rate of transmission to infants born to mothers who had a primary infection or a recurrent infection during pregnancy was 32% and 1.4%, respectively. Possible maternal primary infections (i.e. seropositive mother with CMV IgM) resulted in congenital infections about 20% of the time, but are likely to represent a mixture of primary and recurrent infections. In summary, CMV is a common congenital infection worldwide that can lead to permanent disabilities. There is an urgent need for interventions that can reduce the substantial burden of this often overlooked disease.

Umbilical cord blood screening for cytomegalovirus DNA by quantitative PCR

BACKGROUND

Cytomegalovirus (CMV) infection, which is the most common congenitally transmitted infection, affects approximately 1% of neonates worldwide. Despite its prevalence, no convenient screening test for neonatal CMV infection has been implemented.

OBJECTIVE

The purpose of this pilot study was to evaluate the feasibility and yield of screening umbilical cord blood for CMV DNA emiaby quantitative PCR.

STUDY DESIGN

Umbilical cord blood was tested for CMV DNAemia using a commercial quantitative PCR assay. Maternal CMV serostatus at the time of delivery was assessed by testing for CMV IgG and IgM antibodies in serum.

CONCLUSIONS

Screening for congenital CMV infection with PCR is easily incorporated into routine labor and delivery care using discarded cord blood specimens to identify neonates whose infection is otherwise undiagnosed. Among 433 infants tested, two (0.5%) had DNAemia detected in cord blood, one of whom was symptomatic, and both of whose mothers were CMV IgG positive and IgM negative. Viremic neonates identified by screening with PCR may be at high risk of developing long-term neurological complications of CMV infection and cannot reliably be identified using clinical presentation or maternal serology. Because of its convenience, cord blood CMV screening with PCR should be further investigated for incorporation into neonatal screening protocols.

Routine CMV screening during pregnancy

Cytomegalovirus (CMV) screening during pregnancy has been widely discussed for several years, but still no consensus has been agreed. With a number of live births of 750,000 per year in France, we would expect 7500 infected infants at birth per year (rate of congenital infection of 1%). Among infected infants at birth, the number of severely infected foetuses would be approximately 75, the number of infants with severe sequelae would be 480, 675 approximately would present with hearing loss and the number of asymptomatic infants would be 6270. Five different preventive methods for congenital CMV infection are possible: (1) Routine CMV screening at the beginning of pregnancy for primary prevention. (2) Secondary prevention by antenatal diagnosis of congenital CMV infection complications. (3) Tertiary prevention by serological testing during pregnancy. (4) Tertiary prevention by serological screening at birth. (5) Tertiary prevention: Hearing loss screening at birth. The aims of this review are to define the advantages and disadvantages of these different methods of CMV screening during pregnancy and to determine if the current available information would make systematic testing acceptable.

Congenital cytomegalovirus infection in San Luis Potosi, Mexico

The incidence of congenital cytomegalovirus infection in Mexico is unknown. We evaluated the presence of cytomegalovirus infection in 560 newborn infants at a public general hospital. There were five (0.89%) infected newborns. Infants with congenital infection were more likely to be born to primigravid mothers (P = 0.01) and were more often from rural areas (P = 0.058) than were noninfected newborns.

Infection by cytomegalovirus in patients with neonatal cholestasis

BACKGROUND

Neonatal cholestasis syndrome with an intra or extrahepatic origin has been associated to viral infections. The participation of the cytomegalovirus in the etiopathogenesis of neonatal hepatitis has been already known for some time, but only recently there have been indications that this virus may be one of the possible etiological factors for extrahepatic biliary atresia.

AIMS

To assess the prevalence of infection by cytomegalovirus in patients with intrahepatic cholestasis and extrahepatic cholestasis. To compare the clinical characteristics of the intrahepatic cholestasis and extrahepatic cholestasis groups with the cytomegalovirus serological results. Patients and Methods - This study consisted of 76 patients with neonatal cholestasis who were admitted between January 1980 and January 1999 when they underwent a cytomegalovirus serologic study using the ELISA method. A case note was kept on each patient with the following data: age of patient at admission, serologic result for cytomegalovirus, history of maternal infection, prematurity, fetal distress, birth weight, ponderal gain, choluria and fecal acholia. The final anatomic diagnosis of cholestasis was based on the results of an abdominal ultrasonography, a liver biopsy and its evolution. The patients were then divided into two groups: group I - intrahepatic cholestasis and group II - extrahepatic cholestasis. Each of these groups were then divided into two subgroups: subgroup A - positive serology (IgM) for cytomegalovirus and subgroup B - negative serology (IgM) for cytomegalovirus.

RESULTS

The frequency of positive serology (IgM) for cytomegalovirus was 29.4% in children with intrahepatic cholestasis and 28.5% in children with extrahepatic cholestasis. In comparison with group IIB, group IIA presented a higher rate of maternal infection history. The patients in group IIA demonstrated a delayed access to the service in comparison with group IA. The groups did not demonstrate any significant differences regarding the onset age of jaundice, choluria and fecal acholia, birth weight and ponderal gain.

CONCLUSIONS

The positive (IgM) seroprevalence for cytomegalovirus in children with intrahepatic cholestasis and extrahepatic cholestasis is high. The history of maternal infection was more common in extrahepatic cholestasis patients with positive serology for cytomegalovirus. There was a delay in the referral of these patients which resulted in a late diagnosis and surgical treatment.

Detection of congenital cytomegalovirus infection in Chinese newborn infants using polymerase chain reaction

Polymerase chain reaction (PCR) amplification was used to detect cytomegalovirus (CMV) in 1000 urine specimens from Chinese newborns for defining the incidence of congenital CMV infection in the Chinese population. The major immediate-early and the late antigen genes of CMV were amplified and detected by gel electrophoresis. There were 18 congenitally infected infants found when tests were performed with one or both primer pairs. Comparing with tissue culture, PCR of both primer sets provided a sensitivity of 94%, a specificity of 100% and a predictive value of positive result of 100%.

Fetal and neonatal thrombocytopenia

Thrombocytopenia is defined as platelet count less than 150,000 plat/mm3. Etiologic factors involved include immunological (NAIT and ITP), fetal infectious disease, chromosomal and nonchromosomal, and miscellaneous causes. While the understanding of fetal thrombocytopenia is driven by reason to do fetal blood sampling, discovery of neonatal thrombocytopenia is driven by blood counts performed because of the risk of infections. The most serious consequence of thrombocytopenia in the fetus/neonate is intracranial hemorrhage which can occur in utero as early as 18 weeks gestation. The key factor in perinatal prevention of intracranial hemorrhage is early diagnosis and treatment, possibly in utero. Cordocentesis under direct ultrasound guidance and platelet transfusions have played a major role in the management of fetal/neonatal thrombocytopenia. Ongoing studies and high resolution ultrasound will continue to explore and hopefully clarify fetal and neonatal thrombocytopenia and facilitate recognition of primary and secondary thrombocytopenias.

Human cytomegalovirus (HCMV) immediate-early enhancer/promoter specificity during embryogenesis defines target tissues of congenital HCMV infection

Congenital human cytomegalovirus (HCMV) infection is a common cause of deafness and neurological disabilities. Many aspects of this prenatal infection, including which cell types are infected and how infection proceeds, are poorly understood. Transcription of HCMV immediate-early (IE) genes is required for expression of all other HCMV genes and is dependent on host cell transcription factors. Cell type-specific differences in levels of IE transcription are believed to underlie differences in infection permissivity. However, DNA transfection experiments have paradoxically suggested that the HCMV major IE enhancer/promoter is a broadly active transcriptional element with little cell type specificity. In contrast, we show here that expression of a lacZ gene driven by the HCMV major IE enhancer/promoter -524 to +13 segment is restricted in transgenic mouse embryos to sites that correlate with known sites of congenital HCMV infection in human fetuses. This finding suggests that the IE enhancer/promoter is a major determinant of HCMV infection sites in humans and that transcription factors responsible for its regulation are cell type-specifically conserved between humans and mice. The lacZ expression patterns of these transgenic embryos yield insight into congenital HCMV pathogenesis by providing a spatiotemporal map of the sets of vascular, neural, and epithelial cells that are likely targets of infection. These transgenic mice may constitute a useful model system for investigating IE enhancer/promoter regulation in vivo and for identifying factors that modulate active and latent HCMV infections in humans.

Problems with serum IgM as a screening test for congenital infection

The purpose of this study was to determine the usefulness of the total serum IgM level as a screening test for congenital infection in asymptomatic or mildly symptomatic infants. A retrospective medical record review was performed on 168 infants in whom the serum IgM was measured as a screen for congenital infection. The indications for testing, the yield of testing, and the adequacy of follow-up of abnormal values were examined. Only one infant was diagnosed with a congenital infection which was not specifically suspected prior to screening; this was a case of congenital cytomegalovirus (CMV). Inappropriate screening was frequently performed in infants in whom indications for specific evaluation were present. Appropriate follow-up testing was performed in only 30% (seven of 23) of the infants with elevated serum IgM who received their pediatric care at our institution. Because of the low yield (< 1%) and lack of follow-up shown in this study, as well as poor sensitivity, serum IgM was not a useful screening test for congenital infection in our institution.

Screening for congenital cytomegalovirus infection among preterm infants born before the 34th gestational week in Finland

83 infants born before 34 weeks of gestation between 1989 and 1990 and cared for at a neonatal intensive care unit in Kuopio, Finland, were screened for congenital cytomegalovirus (CMV) infection, defined as a positive culture from the sample of urine taken on the first day after birth. Four infants were infected and excreted CMV in the urine. The overall incidence of CMV excretors was 4.8%. The incidence was 1/13 infants born before 28 weeks' gestation and 3/70 infants born between 28 and 34 weeks of gestation. The 4 CMV excretors were followed up for 12-25 months. Two children had normal psychomotor and mental development but exhibited decreasing head growth during follow-up. The other 2 developed severe psychomotor retardation, retinopathy of prematurity, chorioretinitis, and microcephaly. The long-term morbidity was associated not only with congenital CMV infection but to prematurity as well. The incidence of congenital CMV excretors in this preterm population seemed to be higher than reported previously among unselected live-born infants. Early diagnosis of congenital CMV infection would seem to be important in view of forthcoming new therapeutic regimes in the near future.

Viral infections in the dental setting: potential effects on pregnant HCWs

Occupational exposure of pregnant health care workers to infectious diseases may cause a variety of effects. This article reviews potential effects of viral infections in pregnant health care workers by pathogens transmittable in a dental setting.

Viral infections during pregnancy: a guide for the emergency physician

Emergency physicians are frequently called on to treat or advise pregnant patients. When faced with a pregnant patient who has clinical evidence of or exposure to a viral illness, the emergency physician must be aware of the potential maternal and fetal risks posed by various viral agents. This review provides current, accurate information and guidance for the pregnant patient.

Prevalence of CMV antibodies among women of childbearing age in different social environments in southern Israel

The prevalence rate of IgG antibodies to cytomegalovirus (CMV) was determined in a sample of 567 women of childbearing age in the southern part of Israel by the immunoperoxidase assay to membrane antigen (IPAMA) technique. Urban Jewish women of Afro-Asian origin showed significantly higher rates of seropositivity than urban Jewish women of European-American origin (80% vs 65%, respectively, P less than 0.001), closely resembling the level of CMV seropositivity found in Afro-Asian and European-American countries in the same age and sex population groups. The Bedouin women showed slightly lower rates of CMV seropositivity (75%) than Jewish women of Afro-Asian origin. Particularly high rates of CMV seropositivity were detected in women who live in a kibbutz environment: 96% in women of Afro-Asian origin and 80% in women of Euro-American origin. Multiple discriminant analysis also singles out the kibbutz environment as a major contributor to the variance between the groups tested (P less than 0.003).

Occupational hazards in hospitals: risk of infection

In this review of the risk of infection to hospital staff, attention is drawn to the continuing risk presented by hepatitis B and pulmonary tuberculosis, which are more common than diseases such as typhoid fever, brucellosis, histoplasmosis, whooping cough, infectious gastroenteritis, measles, and parotiditis. Other items considered include the susceptibility of female hospital staff to rubella and the importance of their undergoing screening and vaccination; the risks currently presented by epidemic keratoconjunctivitis and by herpes viruses (herpes simplex, varicella zoster, and cytomegalovirus); and the risk of contracting the new infectious diseases (Legionnaires' disease, Marburg disease, Lassa fever, and the acquired immune deficiency syndrome).

Confirmation of human cytomegalovirus by reverse passive hemagglutination with monoclonal antibodies reactive to the major glycosylated peptide (GP-66)

Sheep erythrocytes coated with three monoclonal antibodies, each reactive to a different epitope of the 66-kilodalton cytomegalovirus (CMV) matrix protein, were used in a reverse passive hemagglutination test with CMV-infected cell lysate to identify and confirm the CMV. The test is specific only for CMV, since 5 laboratory strains of CMV (AD169, Davis, Espilat, C-87, and Towne) and 10 clinical isolates reacted well, but uninfected MRC-5 cell lysate, lysates of herpes simplex virus types 1 and 2, varicella-zoster virus, and adenoviruses did not react. The reactive CMV lysate was confirmed by the pretreatment of CMV lysate with the three monoclonal antibodies followed by the addition of antibody-coated erythrocytes. The reverse passive hemagglutination test and the confirmatory blocking test are performed at the same time, requiring 2 h to complete. Since V-bottom microtiter 96-well plates and a 25-microliter pipette can be used to perform the test, it is ideal for CMV confirmation, especially when the equipment to read the fluorescent-antibody test or enzyme-linked immunosorbent assay is not available.

Congenital cytomegalovirus infection: predisposing maternal factors

In a prospective study of cytomegalovirus (CMV) infection in pregnancy 69 congenitally infected infants were identified. The age, race, marital status, social class, and parity of the mothers of congenital CMV infants were compared with those of the screened population of women with non-infected infants. These factors were all individually strongly associated with the prevalence of congenital CMV. However, once age, marital status, and race were accounted for, neither social class nor parity had any additional effect. The overall congenital CMV rate was 3 per 1000 livebirths, ranging from 25/1000 for single black women under 20 to 1.6/1000 in married or cohabitating white women over 25.

An early marker of fetal infection after primary cytomegalovirus infection in pregnancy

Fourteen patients with primary cytomegalovirus infection diagnosed by serological screening at antenatal attendances were examined for their responses in the lymphocyte transformation test against cytomegalovirus. Tests were done during pregnancy, shortly after the diagnosis of primary infection. Eight women showed positive lymphocyte transformation responses and gave birth to uninfected babies. Six showed negative responses and four of the babies were born congenitally infected. Cellular immunity therefore plays a part in preventing intrauterine transmission of cytomegalovirus, and its depression after primary infection in the mother during pregnancy may be used as an early marker of fetal infection.

Congenital cytomegalovirus infection

Clinical details of 50 infants with congenital cytomegalovirus infection identified in a prospective study are reported. The mean birthweight, gestational age, and head circumference of children with congenital cytomegalovirus infection were not significantly different from those of controls. Three (6%) had symptoms at birth--two neurological and one pneumonitis. In the first four months of life transient hepatosplenomegaly occurred in two infected children and six suffered interstitial pneumonitis. Three congenitally infected children have major neurological handicaps including spastic quadriplegia, microcephaly, and psychomotor delay, and five (10%), including the one with quadriplegia, have sensorineural deafness which is bilateral in three (6%). Estimates based on these findings suggest that the impact of congenital cytomegalovirus infection is comparable to that of congenital rubella in the era before vaccination. Of the 42 children where the nature of maternal infection was classifiable, congenital infection followed primary maternal infection in 32 (76%) and recurrent infection in 10 (24%). Neurological defects followed exposure to primary maternal infection in all three trimesters of pregnancy and also recurrent maternal infection.

A prospective study of maternal cytomegalovirus infection and its effect on the fetus

In order to define the effects of maternal cytomegalovirus infection in pregnancy and to identify risk factors associated with delivery of a cytomegalovirus-infected infant, a cohort of 1089 adolescents were prospectively evaluated during pregnancy. One hundred twenty-four subjects (11.4%) manifested cytomegaloviruria during pregnancy. Primary cytomegalovirus infection, defined virologically and serologically, occurred in three subjects. Infants of 119 cytomegalovirus-excreting mothers were cultured at birth, with detection of 12 congenital infections (10%), including one infant delivered of a mother with a third-trimester primary infection. A high titer of urinary virus or a fourfold or greater increase in antibody during the third trimester was significantly associated with delivery of a congenitally infected infant. All maternal and infant infections were asymptomatic. None of the congenitally infected infants manifested adverse effects during the first year of life. Our data demonstrate that pregnant women with cytomegaloviruria are at increased risk of being delivered of congenitally infected infants, particularly if active infection occurs late in pregnancy. If the maternal infection represents reactivation, overall probability of a poor fetal outcome is low.

Congenital and postnatally acquired cytomegalovirus infections: long-term follow-up

To determine long-term outcome of children with inapparent congenital cytomegalovirus infection, an assessment of congenitally infected children observed since birth was undertaken. Children with early postnatal acquisition of CMV infection were also evaluated. Cognitive, behavioral, neurologic, audiometric, and speech and language evaluations were performed in 48 patients, including 17 congenitally infected children, 10 children with postnatal infection, and 21 uninfected control subjects. Mean IQ of the three groups of children did not differ significantly. Behavioral, neurologic, speech and language examinations similarly failed to distinguish differences among the three groups. Audiologic abnormalities were present in four congenitally infected children, including one child with a severe unilateral sensorineural loss; in none of the children was hearing loss functionally significant. No hearing abnormalities were detected in postnatally infected children. Although inapparent CMV infection can result in audiologic sequelae, the continued lack of cognitive, behavioral, and neurologic sequelae in these school-age children reemphasizes the need to focus attention on prevention of primary maternal CMV infection to avoid the potentially devastating effects of intrauterine CMV infection.

Congenital cytomegalovirus infection and disease in Sweden and the relative importance of primary and secondary maternal infections. Preliminary findings from a prospective study

In a prospective Swedish study started in 1977 and still in progress 10 328 newborn infants in an urban district were investigated for cytomegalovirus (CMV) excretion in the urine by the virus isolation test. Congenital infection was found in 50 cases (0.5%). Of 47 infected infants with known clinical status at birth 9 (19%) had hepatomegaly, splenomegaly, jaundice and/or petechiae. The symptoms were moderate or mild. Of the infants followed up, 2 (25%) of 8 neonatally symptomatic ones and 3 (9%) of 35 asymptomatic ones developed neurologic sequelae. Altogether 5 (12%) of 43 had permanent neurologic symptoms corresponding to 0.06% in the general population. The children ranged in age from 6 months to 4 yr at the last examination. 21 mothers of the 47 infants with known status at birth had a confirmed or presumed primary infection, 15 a confirmed or presumed secondary infection and 11 an undetermined type of infection. Of the 5 infants with neurologic sequelae, 1 with a grave psychomotor retardation and deafness was born to a mother with a primary infection in the 1st trimester; 1 infant with a moderate retardation and 3 deaf infants were all exposed to confirmed or presumed secondary maternal infections. Prospective serological studies of maternal sera in early pregnancy would have suspected only the gravely retarded infant to be at risk.

Factors associated with primary cytomegalovirus infection during pregnancy

We compared a group of 40 susceptible pregnant women who acquired CMV during gestation with a group of 86 women of similar race and socioeconomic background who remained seronegative to define factors associated with the risk of CMV infection during pregnancy. A logistic regression model using a stepwise procedure showed that a positive statistically significant correlation occurred with the age of the mother, the father's high-intensity contact with young children, and children living at home. A negative correlation occurred with mother's high-risk intensity contact with children outside the home. This study underlines the possibility that pregnant women may acquire CMV infection introduced into the household by their young children and husbands, a phenomenon that is reminiscent of rubella infection.

The consequences of primary cytomegalovirus infection in pregnancy

Altogether 54 children exposed prenatally to maternal cytomegalovirus (CMV) infection were followed up in a prospective study. Nine had congenital infection with CMV and 37 escaped congenital infection; in 8 congenital CMV could not be confirmed. The birthweight of children with congenital CMV was significantly lower than that of both controls and those who escaped congenital infection. Intrauterine infection was not clinically suspected in any of the children with congenital CMV, although two had head circumferences less than the third centile. Subsequently one child with congenital CMV developed marked psychomotor retardation, and one, in whom congenital CMV was not confirmed, showed mild developmental delay. Speech and language ability was significantly impaired in children with congenital CMV compared with controls and those who escaped congenital infection, suggesting that subtle damage may have occurred. The incidence of intrauterine transmission of CMV after exposure to infection in the first trimester was 20% and in the third trimester 40%, but no congenital infections resulted from exposure in the second trimester. The severity of congenital infection was not related to the time of exposure in utero. Our findings suggest that the risk to an individual fetus from maternal infection in early gestation is so low that termination of pregnancy cannot be recommended; screening of women for primary CMV infection in pregnancy seems therefore to have limited value.

A prospective study of congenital cytomegalovirus infection in Japan

A prospective study on congenital cytomegalovirus (CMV) infection was carried out in Sapporo, Japan. Only 77 (6.2%) of 1233 pregnant women were seronegative in the first trimester. In such a highly immune population, 11 (0.5%) of 2070 newborn infants were found to have congenital CMV infection. None of them showed any clinical abnormalities during the period of observation (3-24 months), except for a cyst of septum pellucidum in one case. The incidence of congenital CMV infection in the first pregnancies was 1.1% (9/816) and in subsequent pregnancies 0.2% (2/1254). The difference was statistically significant. Three mothers of infants with congenital CMV infection were already seropositive in the first trimester. 26/30 (86.7%) infants, born to mothers with active CMV infection during pregnancy, had started to excrete CMV with urine before the age of 12 months. In contrast, none of the 4 infants born to seronegative mothers excreted CMV.

Production and characterization of monoclonal antibodies specific for a glycosylated polypeptide of human cytomegalovirus

Nine hybrid cell lines producing antibodies specific for cytomegalovirus (CMV) antigen were obtained after fusion of P3/X63-Ag8 myeloma cells with spleen cells from BALB/c mice immunized with CMV complement-fixing antigen. By the immunoblot technique, five of nine antibodies (4D11, 7B4, 7D2, 8E3, and 8E10) were identified as being reactive to a CMV glycosylated polypeptide with molecular weight of 66,000 (GP66). Four other antibodies (1B8, 8E9, 4D2, and 7E2) appeared to be reactive with CMV antigen(s) only if the antigen was not denatured by sodium dodecyl sulfate. These remain unassigned until further studies are done. With the enzyme-linked immunosorbent assay (ELISA), competitive bindings were performed with a constant amount of horseradish peroxidase-conjugated antibody and various concentrations of unconjugated homologous and heterologous antibodies on CMV antigen-coated ELISA wells, and the antigenic determinant specific for each antibody was determined. The nine antibodies could be classified into six different groups, each group reacting with a different epitope or a different region with two or more antigenic determinants which are so close to each other that they cause binding inhibition. They are groups A (4D11), B (7B4, 8E10), C (7D2), D (4D2, 7E2, 8E9), E (8E3), and F (1B8). The extent of competition among antibodies within each group was the same. By using the two antibodies that reacted with different epitopes on GP66, a double-antibody sandwich ELISA method was developed. The method was sensitive enough to detect as little as 50% of the antigen present in one infected cell or 0.000245 U of CMV complement-fixing antigen per test well. Other strains of CMV (David, Kerr, Espilat, C-87, and five clinical isolates) gave positive results, whereas herpes simplex virus types 1 and 2, varicella-zoster virus and Epstein-Barr virus nuclear antigen preparations did not. By the indirect immunofluorescence assay, antibodies 4D11 and 8E3 were able to detect GP66 in the nucleus of CMV-infected F-5000 human embryonic fibroblasts as early as 2 h postinfection and were superior in this respect to the remaining seven antibodies tested. By the double-antibody sandwich ELISA, the presence of GP66 in CMV-infected cells was detected as early as 2 h postinfection.

Cytomegalovirus infection in pregnancy: preliminary findings from a prospective study

8278 (56%) of 14 789 pregnant women who were screened for cytomegalovirus (CMV) antibodies at their first antenatal visit were seropositive. 42 (3 per 1000) infants screened were congenitally infected. 3 (7%) have serious handicaps, 14 (33%) have minor or transient problems, and 25 (60%) have so far had no problems. In 26 of the 42 mothers with infected infants CMV antibodies were present in the first antenatal blood sample. 28 (67%) of the infected infants were born to mothers who had experienced a primary infection in pregnancy and 7 (17%) to mothers who had experienced recurrent infection. In the remaining 7 (17%) it was not possible to determine the type of maternal infection. One handicapped infant was born after a probable recurrent CMV infection during pregnancy. These preliminary findings suggest that routine screening of pregnant women to detect evidence of primary CMV infection is not helpful.

Cytomegalovirus infection. Overview and new developments

Cytomegalovirus (CMV) is a ubiquitous agent that causes infection in all age-groups. Fortunately, the infection is usually asymptomatic, and thus it goes unnoticed. It can, however, have serious sequelae in affected neonates. One of the most significant new developments in our understanding of CMV is its possible role in acquired immune deficiency syndrome, a syndrome that has an extremely high mortality rate. CMV is also closely related to Epstein-Barr and herpes simplex viruses, both of which have known oncogenic potential. Drs Bhumbra and Nankervis discuss the disease potential of CMV and research being done on prevention of CMV infection.

Inhibition of human cytomegalovirus by trifluorothymidine

The antiviral activity of trifluorothymidine (TFT) singly and in combination with other antiviral agents against human cytomegalovirus (HCMV) was evaluated by using an infectious center plaque reduction assay. The 50% inhibitory dose of TFT against six different patient HCMV strains was 0.57 (+/- 0.24, standard deviation) microM and ranged from 0.32 to 0.97 microM. The 50% inhibitory dose for the laboratory-adapted HCMV strain, AD-169, was 2.1 microM. When TFT (0.17 microM) was combined with human fibroblast interferon (25 U/ml), the combination was additive against all four HCMV isolates evaluated. Synergism was observed when TFT (0.17 microM) was combined with phosphonoformic acid (25 microM) for all strains studied or with acyclovir (20 microM) for three of the four clinical HCMV strains tested. Each of the three antiviral agents, when combined with TFT, exhibited additive effects against strain AD-169. TFT at concentrations of 0.5, 1.7, and 3.5 microM had an increasing inhibitory effect on uninfected human embryonic lung fibroblast (HEL) cell growth over 72 h, with 16% growth inhibition at 3.5 microM after 3 days. There was no increased toxicity to growing HEL cells when the paired antiviral agent combinations were evaluated. These findings suggest that TFT may be useful singly or in combination with other antiviral agents in treating HCMV infections.

Effects of acyclovir combined with other antiviral agents on human cytomegalovirus

At present, there is no effective therapy for human cytomegalovirus (CMV) infections. Although acyclovir inhibits in vitro clinical isolates of CMV, preliminary human trials suggest that acyclovir may not be successful as a single antiviral agent in treating CMV infections. The antiCMV activity of acyclovir in combination with human fibroblast interferon (IFN-beta), phosphonoformic acid (PFA), or trifluorothymidine (TFT) was therefore evaluated. When acyclovir (20 microM) was combined with IFN-beta (25 U/ml), additive antiviral effects were observed for the four clinical CMV isolates studied and the laboratory adapted strain, AD-169. The combination of acyclovir (20 microM) with PFA (25 microM) was synergistic for all four clinical isolates studied, but additive for the AD-169 strain. Similarly, the combination of acyclovir (20 microM) and TFT (0.17 microM) was synergistic for three of four clinical isolates, and additive for one clinical strain and the AD-169 virus. These findings suggest that acyclovir combined with other antiviral agents may be useful in the treatment of CMV disease.

Congenital cytomegalovirus infection: The relative importance of primary and recurrent maternal infection

We studied the incidence of primary and recurrent cytomegalovirus infection in 3712 pregnant women--2698 of middle to high income and 1014 of low income--to determine whether there were differences in the effects on the fetus. In the higher-income group, 1203 women (45 per cent) did not have antibodies to cytomegalovirus and were therefore susceptible to primary infection, as compared with 179 women (18 per cent) of low income. Congenital infection occurred more often (1.6 vs. 0.6 per cent) in infants in the low-income group. In this group it was associated with recurrent maternal infection more often (in 82 per cent) than with primary maternal infection, whereas in the upper-income group, it was associated with primary maternal infection in half the cases. Altogether, there were 32 cases of congenital cytomegalovirus infection - 16 in each group. Whereas primary maternal infection resulted in fetal infection in only half the cases, it was more likely to ge associated with clinically apparent disease than was recurrent infection. When these cases were combined with 28 cases of congenital infection retrospectively identified at other prenatal clinics, five of 33 infected infants born after primary maternal infection had clinically apparent disease, as compared with none of 27 born after recurrent maternal infection. We conclude that congenital cytomegalovirus infection resulting from primary maternal infection is more likely to be serious than that resulting from recurrent infection, and is more likely to occur in upper socioeconomic groups.

The presumptive diagnosis of primary cytomegalovirus infection in early pregnancy by means of a radioimmunoassay for specific-IgM antibodies

During a 30 month investigation 3633 women were studied when the booked for antenatal care. Complement fixing antibodies against cytomegalovirus (CMV) were detected in 2078 (57 per cent) of the women and these sera were further tested for the presence of specific IgM antibodies by means of a solid-phase radioimmunoassay. Since specific IgM antibodies have previously been shown to persist for up to four months after primary CMV infection, their presence in a booking serum sample (mean gestation 15 weeks) was taken as presumptive evidence of a first trimester primary CMV infection. From theoretical considerations, 11.6 positive CMV-IgM reactions were predicted in these women and 11 were observed. A highly significant (p less than 0.001) excess of fetal death was seen in the infected women since three pregnancies ended in missed abortion (15 weeks), intrauterine death (29 weeks) and spontaneous abortion (24 weeks) whilst the remaining 8 women gave birth to apparently normal babies. Cord sera were available from 5 of the surviving babies and only one contained specific IgM antibodies, showing that transplacental spread of the maternal infections had not occurred in 4 of the 5 survivors.