Molecular epidemiology of primary human cytomegalovirus infection in pregnant women and their families

Thirty years of CMV seroprevalence-a longitudinal analysis in a German university hospital

Human cytomegalovirus (CMV) is a significant cause of morbidity and mortality in patient groups at risk. We have previously shown that the anti-CMV IgG seroprevalence in an urban region of Germany has changed over the last decades. Overall, a decline from 63.7 to 57.25% had been observed between 1988–1997 and 1998–2008 (p < 0,001). Here, we continuously follow the trends to the most recent decade 2009 to 2018. In a retrospective analysis, we determined the seroprevalence of CMV IgG antibodies in our patient cohort, stratified by gender and selected groups at risk (e.g., patients with HIV infection; women of childbearing age). The overall prevalence of anti-CMV IgG non-significantly declined further from 57.25% in 1998–2008 to 56.48% in 2009–2018 (p = 0.881). Looking at gender differences, overall CMV seroprevalence in males declined to 52.82% (from 55.54% in 1998–2008; p = 0.0254), while it non-significantly increased in females to 59.80%. The high seroprevalence in patients with a known HIV infection further increased from 87.46% in 1998–2008 to 92.93% in the current period (p = 0.9999). In women of childbearing age, no significant changes over the last three decades could be observed. The CMV seroprevalence in oncological patients was determined to be 60.64%. Overall, the former significant decline of CMV seroprevalence between the decades 1988–1997 and 1998–2008 in this urban region of Germany slowed down to a non-significant decrease of 0.77% (1998–2008 vs. 2009–2018). This might be an indicator that CMV seroprevalence has reached a plateau.

The MRI spectrum of congenital cytomegalovirus infection

Human cytomegalovirus (CMV) is an ubiquitous pathogen, with a high worldwide seroprevalence. When acquired in the prenatal period, congenital CMV (cCMV) is a major cause of neurodevelopmental sequelae and hearing loss. cCMV remains an underdiagnosed condition, with no systematic screening implemented in pregnancy or in the postnatal period. Therefore, imaging takes a prominent role in prenatal diagnosis of cCMV. With the prospect of new viable therapies, accurate and timely diagnosis becomes paramount, as well as identification of fetuses at risk for neurodevelopmental sequelae. Fetal magnetic resonance imaging (MRI) provides a complementary method to ultrasound (US) in fetal brain and body imaging. Anterior temporal lobe lesions are the most specific finding, and MRI is superior to US in their detection. Other findings such as ventriculomegaly, cortical malformations and calcifications, as well as hepatosplenomegaly, liver signal changes and abnormal effusions are unspecific. However, when seen in combination these should raise the suspicion of fetal infection, highlighting the need for a full fetal assessment. Still, some fetuses deemed normal on prenatal imaging are symptomatic at birth or develop delayed cCMV-associated symptoms, leaving room for improvement of diagnostic tools. Advanced MR sequences may help in this field and in determining prognosis, but further studies are needed.

Congenital Cytomegalovirus Infection

Background: Congenital cytomegalovirus (cCMV) is the leading cause of nongenetic congenital hearing loss in much of the world and a leading cause of neurodevelopmental disabilities. Infected babies can be born to women who are seropositive and seronegative prior to pregnancy, and the incidence is approximately 0.6%-0.7% in the United States. Symptoms vary from mild to severe, and hearing loss can be delayed in onset and progressive. Methods: We reviewed the literature to summarize the epidemiology, clinical manifestations, diagnosis, treatment, and future directions of cCMV. Results: The best way to diagnose the infection is with polymerase chain reaction of urine or saliva within 3 weeks after birth, followed by a repeat confirmatory test if positive. Moderately to severely symptomatic neonates should be treated for 6 months with valganciclovir, and some practitioners also choose to treat infants who have isolated hearing loss only. Treatment is not recommended for asymptomatic infants. All infected infants should be screened for hearing loss and neurodevelopmental sequelae. Universal and targeted screening may be cost effective. Currently, no vaccine is commercially available, although multiple candidates are under study. Conclusion: Congenitally acquired cytomegalovirus is found in all communities around the world with a disease burden that is greater than many other well-known diseases. Advances are being made in prevention and treatment; however, improved awareness of the disease among clinicians and patients is needed.

High Seroprevalence of CMV Among Women of Childbearing Age Implicates High Burden of Congenital Cytomegalovirus Infection in Poland

Cytomegaloviruses are common worldwide, with variable frequency of infections. The infection in pregnancy may lead to pregnancy loss or serious sequelae for the child. To understand the risk posed by CMV in Poland we conducted cross-sectional study on women aged 15-49 basing on existing serum bank. Age dependent incidence, the rates of congenital infection and sequelae were modelled from sero-prevalence, literature and demographic data. The overall anti-CMV IgG prevalence was 81.9% increasing from 74.3% in <30 years old to 94.3% in subjects 45+ years old. The lowest incidence was estimated at the age of 15 and the highest at the age 34 (3.8 and 8.95 respectively/100 women/year). The estimated rate of cCMV varies from 22.4 to 37.2 per 1000 live birth depending on the assumptions made. The proportion of cases due to secondary infection ranged from 34.8% to 49.9% accordingly.

Sociodemographic factors associated with IgG and IgM seroprevalence for human cytomegalovirus infection in adult populations of Pakistan: a seroprevalence survey

Background

The seroprevalence of human cytomegalovirus (HCMV) infection ranges from 30 to 90 % in developed countries. Reliable estimates of HCMV seroprevalence are not available for Pakistan. This study determined the seroprevalence and sociodemographic factors associated with HCMV infection in adult populations of Karachi, Pakistan.

Methods

A seroprevalence survey was conducted on 1000 adults, including residents of two semi-urban communities, and visitors to a government and a private hospital. Questionnaire-based interviews were conducted. Sera were analysed for HCMV-specific IgG and IgM. Chi-square or Fisher’s exact test was used for comparing sociodemographic variables against seropositivity of HCMV-IgG or IgM. Multiple logistic regression modeling was performed for IgG seroprevalence and adjusted odds ratios were computed.

Results

The seroprevalence of HCMV-IgG and IgM was 93.2 and 4.3 % respectively. 95.3 % of individuals who were IgM seropositive were also seropositive for IgG. Around 6 % (15/250) of women of childbearing age remained uninfected and were therefore susceptible to primary infection. HCMV-IgG seroprevalence was associated with being female (p = 0.001), increasing age (p = 0.002) and crowding index (p = 0.003) and also with lower levels of both education (p < 0.001) and income (p = 0.008). Seroprevalence also differed significantly by marital status (p = 0.008) and sampling location (p < 0.001). A logistic regression model for HCMV-IgG seroprevalence showed associations with being female (OR = 1.89; 95 % CI: 1.10–3.25), increasing age (OR = 3.95; 95 % CI: 1.79–8.71) and decreasing income (OR = 0.72; 95 % CI: 0.54–0.96). A strong association was observed between increased seroprevalence of HCMV-IgM and decreasing household size (p = 0.008).

Conclusions

Seroprevalence of HCMV is very high in Pakistan, although 6 % of women of childbearing age remain at risk of primary infection. The IgM seropositivity observed in some individuals living in small household size (1–3 individuals) with persistent HCMV infection could have resulted from a recurrent HCMV infection. Future longitudinal research in pregnant women and neonates is required to study the trends in HCMV seroprevalence over time in Pakistan for the development of a potential HCMV prevention and vaccination programme.

Prevention of Primary Cytomegalovirus Infection in Pregnancy

Background

Cytomegalovirus (CMV) is the leading infectious agent causing congenital sensorineural hearing loss and psychomotor retardation. CMV vaccine is currently unavailable and treatment options in pregnancy are limited. Susceptible pregnant women caring for children are at high risk for primary infection. CMV educational and hygienic measures have the potential to prevent primary maternal infection.

Methods

A mixed interventional and observational controlled study was conducted to investigate the effectiveness of hygiene information among pregnant women at risk for primary CMV infection for personal/occupational reasons. In the intervention arm, CMV-seronegative women, identified at the time of maternal serum screening for fetal aneuploidy at 11–12 weeks of gestation, were given hygiene information and prospectively tested for CMV until delivery. The comparison arm consisted of women enrolled at delivery who were neither tested for nor informed about CMV during pregnancy, and who had a serum sample stored at the screening for fetal aneuploidy. By design, groups were homogeneous for age, parity, education, and exposure to at least one risk factor. The primary outcome was CMV seroconversion. Acceptance of hygiene recommendations was a secondary objective and was measured by a self-report.

Findings

Four out of 331 (1.2%) women seroconverted in the intervention group compared to 24/315 (7.6%) in the comparison group (delta = 6.4%; 95% CI 3.2–9.6; P < 0.001). There were 3 newborns with congenital infection in the intervention group and 8 in the comparison group (1 with cerebral ultrasound abnormalities at birth). Ninety-three percent of women felt hygiene recommendations were worth suggesting to all pregnant women at risk for infection.

Interpretation

This controlled study provides evidence that an intervention based on the identification and hygiene counseling of CMV-seronegative pregnant women significantly prevents maternal infection. While waiting for CMV vaccine to become available, the intervention described may represent a responsible and acceptable primary prevention strategy to reduce congenital CMV.

•

The rate of CMV seroconversion was 4/331 (1.2%) in the intervention group vs 24/315 (7.6%) in the comparison group

•

This study shows that hygiene information of CMV-seronegative pregnant women significantly prevents maternal infection.

•

93% participants in the study found hygiene recommendations worth suggesting to all pregnant women.

Cytomegalovirus is the leading infectious agent causing congenital sensorineural hearing loss and psychomotor retardation. Contacts with young children have been identified as the main source of virus transmission to mothers. While waiting for a CMV vaccine to become available, this study documents that an intervention based on the identification and hygiene counseling of pregnant women susceptible to be infected by CMV for the first time during pregnancy, significantly prevents maternal infection.

Strain Variation and Disease Severity in Congenital Cytomegalovirus Infection: In Search of a Viral Marker

The wide spectrum of congenital cytomegalovirus (CMV) disease and known differences in the biology and in vitro growth of CMV strains continue to drive studies in search for specific viral genetic determinants that may predict severity of congenital CMV disease. Several CMV genes have been studied in detail in congenitally infected children, but the complexity of the viral genome and differences in the definition of symptomatic disease versus asymptomatic CMV infection continue to raise questions related to what constitutes a pathogenic CMV strain.

The DRY box and C-terminal domain of the human cytomegalovirus US27 gene product play a role in promoting cell growth and survival

Human cytomegalovirus (HCMV) is a widespread pathogen that can lay dormant in healthy individuals and establish lifelong latent infection. This successful co-existence is facilitated by a number of viral gene products that manipulate host cellular functions and immune responses. Among these immunomodulatory genes are four G-protein coupled receptors (GPCRs) encoded by HCMV, designated US27, US28, UL33, and UL78. Studies have shown the US28 gene product to be a functional chemokine receptor that signals both constitutively and in a ligand-dependent manner, resulting in a wide range of cellular effects. In previous work, we have found that US27 expression results in at least two biological effects: enhanced CXCR4 signaling and increased in cellular proliferation in HEK293 cells. Here, we examined the involvement of two protein domains, the DRY box and the C-terminal intracellular domain (CTD) of US27, in mediating both cell proliferation and survival. While both domains were required for a proliferative effect, loss of either domain only moderately impacted cell survival, suggesting that US27 may interact with cell survival pathways through protein regions other than the DRY box and CTD. Quantitative RT-PCR arrays were used to profile changes in cellular gene expression in the HEK293-US27 cell line, and down-regulation of cell cycle regulators CDKN1A/p21/CIP1 (cyclin dependent kinase inhibitor 1A) and SESN (Sestrin2 or Hi95) was observed. These results indicate that increased cell proliferation due to US27 may be linked to suppression of negative growth regulators, and that these interactions require the DRY box and CTD.

Cross-sectional study of cytomegalovirus shedding and immunological markers among seropositive children and their mothers

Background

Congenital cytomegalovirus (CMV) is the leading infectious cause of birth defects in the United States. To better understand factors that may influence CMV transmission risk, we compared viral and immunological factors in healthy children and their mothers.

Methods

We screened for CMV IgG antibodies in a convenience sample of 161 children aged 0-47 months from the Atlanta, Georgia metropolitan area, along with 32 mothers of children who screened CMV-seropositive. We assessed CMV shedding via PCR using saliva collected with oral swabs (children and mothers) and urine collected from diapers using filter paper inserts (children only).

Results

CMV IgG was present in 31% (50/161) of the children. Half (25/50) of seropositive children were shedding in at least one fluid. The proportion of seropositive children who shed in saliva was 100% (8/8) among the 4-12 month-olds, 64% (9/14) among 13-24 month-olds, and 40% (6/15) among 25-47 month-olds (P for trend = 0.003). Seropositive mothers had a lower proportion of saliva shedding (21% [6/29]) than children (P < 0.001). Among children who were shedding CMV, viral loads in saliva were significantly higher in younger children (P <0.001); on average, the saliva viral load of infants (i.e., <12 months) was approximately 300 times that of two year-olds (i.e., 24-35 months). Median CMV viral loads were similar in children's saliva and urine but were 10-50 times higher (P < 0.001) than the median viral load of the mothers' saliva. However, very high viral loads (> one million copies/mL) were only found in children's saliva (31% of those shedding); children's urine and mothers' saliva specimens all had fewer than 100,000 copies/mL. Low IgG avidity, a marker of primary infection, was associated with younger age (p = 0.03), higher viral loads in saliva (p = 0.02), and lower antibody titers (p = 0.005).

Conclusions

Young CMV seropositive children, especially those less than one year-old may present high-risk CMV exposures to pregnant women, especially via saliva, though further research is needed to see if this finding can be generalized across racial or other demographic strata.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0568-2) contains supplementary material, which is available to authorized users.

Genotype distribution, viral load and clinical characteristics of infants with postnatal or congenital cytomegalovirus infection

Background

Congenital cytomegalovirus infection is a leading cause of long-term sequelae. Cytomegalovirus is also frequently transmitted to preterm infants postnatally, but these infections are mostly asymptomatic. A correlation between cytomegalovirus genotypes and clinical manifestations has been reported previously in infants with congenital infection, but not in preterm infants with postnatal infection.

Objectives

The main objective of this study was to investigate cytomegalovirus genotype distribution in postnatal and congenital cytomegalovirus infection and its association with disease severity.

Methods

Infants admitted to the neonatal intensive care unit of the University Medical Center Utrecht, The Netherlands between 2003–2010 and diagnosed with postnatal or congenital cytomegalovirus infection were included. Classification of cytomegalovirus isolates in genotypes was performed upon amplification and sequencing of the cytomegalovirus UL55 (gB) and UL144 genes. Clinical data, cerebral abnormalities, neurodevelopmental outcome and viral load were studied in relation to genotype distribution.

Results

Genotyping results were obtained from 58 preterm infants with postnatal cytomegalovirus infection and 13 infants with congenital cytomegalovirus infection. Postnatal disease was mild in all preterm infants and all had favourable outcome. Infants with congenital infection were significantly more severely affected than infants with postnatal infection. Seventy-seven percent of these infants were symptomatic at birth, 2/13 died and 3/13 developed long-term sequelae (median follow-up 6 (range 2–8) years). The distribution of cytomegalovirus genotypes was comparable for postnatal and congenital infection. UL55 genotype 1 and UL144 genotype 3 were predominant genotypes in both groups.

Conclusions

Distribution of UL55 and UL144 genotypes was similar in asymptomatic postnatal and severe congenital CMV infection suggesting that other factors rather than cytomegalovirus UL55 and UL144 genotype are responsible for the development of severe disease.

Human cytomegalovirus intrahost evolution-a new avenue for understanding and controlling herpesvirus infections

Human cytomegalovirus (HCMV) is exquisitely adapted to the human host, and much research has focused on its evolution over long timescales spanning millennia. Here, we review recent data exploring the evolution of the virus on much shorter timescales, on the order of days or months. We describe the intrahost genetic diversity of the virus isolated from humans, and how this diversity contributes to HCMV spatiotemporal evolution. We propose mechanisms to explain the high levels of intrahost diversity and discuss how this new information may shed light on HCMV infection and pathogenesis.

The human cytomegalovirus US27 gene product enhances cell proliferation and alters cellular gene expression

Human cytomegalovirus (HCMV) is a prevalent pathogen worldwide. Although generally harmless in healthy individuals, HCMV can pose a serious threat to immune compromised individuals and developing fetuses in utero. HCMV encodes four genes predicted to give rise to G protein-coupled receptors (GPCRs): US27, US28, UL33, and UL78. The US28 gene product is a functional chemokine receptor that enhances cell growth in some cell types but induces apoptosis in others. In contrast, the US27 gene product has not been demonstrated to signal either constitutively or in a ligand-induced manner. In this study, US27 was expressed in transfected cells, and both cell proliferation and DNA synthesis were significantly increased compared to control cells. PCR array analysis revealed that expression of US27 led to changes in a limited number of cellular genes, but genes that were up-regulated included the pro-survival factor Bcl-x, AP-1 transcription factor components jun and fos, and the IL-6 family cytokine oncostatin M. These results demonstrate that US27 can impact host cell physiology and may shed light on the function of this orphan viral GPCR.

Congenital cytomegalovirus infection: new prospects for prevention and therapy

Cytomegalovirus is the commonest congenital viral infection in the developed world, with an overall prevalence of approximately 0.6%. Approximately 10% of congenitally infected infants have signs and symptoms of disease at birth, and these symptomatic infants have a substantial risk of subsequent neurologic sequelae. These include sensorineural hearing loss, mental retardation, microcephaly, development delay, seizure disorders, and cerebral palsy. Antiviral therapy for children with symptomatic congenital cytomegalovirus infection is effective at reducing the risk of long-term disabilities and should be offered to families with affected newborns. An effective preconceptual vaccine against CMV could protect against long-term neurologic sequelae and other disabilities.

The US27 gene product of human cytomegalovirus enhances signaling of host chemokine receptor CXCR4

Human cytomegalovirus (HCMV) is a member of the Herpesviridae family that manipulates host immune responses and establishes life-long latent infection, in part through mimicry of cytokines, chemokines, and chemokine receptors. The HCMV US27 gene product is a putative chemokine receptor with no known ligands. We generated a stable US27 cell line to screen for chemokine ligands but unexpectedly found that US27 potentiated the activity of an endogenous human chemokine receptor, CXCR4. Cells expressing both US27 and CXCR4 exhibited greater calcium mobilization and enhanced chemotaxis in response to CXCL12/SDF-1α than controls. Quantitative RT-PCR revealed a significant increase in CXCR4 expression when US27 was present, and elevated CXCR4 receptor levels were detected via flow cytometry, western blot, and immunofluorescence microscopy. Potentiation of CXCR4 signaling by US27 could represent a novel strategy by which HCMV targets virus-infected cells to the bone marrow in order to expand the reservoir of latently infected cells.

Restoration of viral epithelial tropism improves immunogenicity in rabbits and rhesus macaques for a whole virion vaccine of human cytomegalovirus

Maternal immunity to human cytomegalovirus (HCMV) prior to conception is ~70% protective against congenital transmission and in utero infection of HCMV. Both functional antibodies capable of neutralizing virus and effective T-cells are believed to be important for the protection. Previous HCMV vaccines have rarely been shown able to induce neutralizing antibody titers comparable to those seen in naturally infected HCMV seropositive subjects. Recent studies link a glycoprotein H (gH) complex to receptor-mediated viral entry of endothelial/epithelial cells and leukocytes. This pentameric gH complex, composed of five proteins (gH, gL, UL128, UL130 and UL131 proteins), is notably missing in all HCMV vaccine previously evaluated in clinic. Here we showed that a HCMV virus, with restored expression of the pentameric gH complex, can induce 10-fold higher neutralizing antibody titers than an attenuated AD169 virus or a recombinant glycoprotein B vaccine in multiple animal species in which viral replication is not expected. Encouragingly, the peak neutralizing titers post vaccination in rabbits and monkeys were within 2-4-fold of the levels determined in HCMV seropositive subjects. Functional antibodies by vaccination could further be improved when formulated with a novel adjuvant, and the titers of the antiviral antibodies were sustained in rabbits for over a year after vaccination. These results indicate that the pentameric gH complex is associated with greatly improved functional antibodies following vaccination, and support a vaccine concept based on a nonreplicating whole HCMV with the pentameric gH-associated epithelial tropism restored.

[Seroprevalence of antibodies against infectious pathogens relevant to pregnancy among healthcare workers]

Healthcare workers (HCWs) are exposed to infectious diseases throughout the course of their work. The concerns of pregnant HCWs are considerable because certain otherwise mild infections may affect fetal development. We studied 424 pregnant HCWs at the University Hospital Frankfurt between March 2007 and July 2011. Serological tests were carried out for varicella zoster virus (VZV), measles, mumps, rubella (MMR), cytomegalovirus (CMV) and parvovirus B19. Our overall seroprevalence data with regard to VZV, MMR, CMV and parvovirus B 19 corresponded to the general population. However, physicians demonstrated lower seroprevalence towards the two non-vaccine-preventable diseases (CMV: 37.5% [KI 27.4-48.5]; parvovirus B19: 69.3% [KI 58.6-78.7]) compared with nurses (CMV: 53.4% [KI 46.1-60.6], parvovirus B19: 75.1% [68.4-81.1]). It was striking that, only one in five of the study population showed IgG antibodies against all of the six pregnant-relevant viral diseases tested, of the physicians as few as one in six. A routine exclusion from the workplace due to non-immunity would mean that it would not be possible to employ the majority of pregnant staff in healthcare and childcare.

Role of human cytomegalovirus genotype polymorphisms in AIDS patients with cytomegalovirus retinitis

Although several host factors have been identified to influence the course of HCMV infection, it still remains unclear why in AIDS patients without highly active antiretroviral therapy human cytomegalovirus (HCMV) retinitis is one of the most common opportunistic infections, whereas in other immunosuppressed individuals it has a low incidence. It was suggested that HCMV glycoprotein B strains may be suitable as marker for virulence and HCMV retinitis. Moreover, UL144 ORF, a member of the TNF-α receptor superfamily, may play a crucial role in innate defences and adaptive immune response of HCMV infection. Furthermore, sequence analyses of HCMV genes UL128, UL130, and UL131A as major determinants of virus entry and replication in epithelial and other cell types were performed. To evaluate the association of sequence variability of depicted viral genes with HCMV retinitis and in vitro growth properties in retinal pigment epithelial cells (RPE) and human foreskin fibroblasts (HFF), we compared 14 HCMV isolates obtained from vitreous fluid and urine of AIDS patients with clinically proven HCMV retinitis. Isolates were analyzed by PCR cycle sequencing and phylogenetic analysis. In addition, sequences of HCMV strains AF1, U8, U11, VR1814, and its cell culture adapted derivates were included. Sequence analysis of gB yielded three genetic subtypes (gB type 1 (5 isolates), gB type 2 (12 isolates), and gB type 3 (5 Isolates)), whereas sequence analysis of UL144 showed a greater diversity (7 isolates type 1A, 2 isolates type 1C, 7 isolates type 2, and 3 isolates type 3). In contrast, the UL128, UL130, and UL131A genes of all low-passage isolates were highly conserved and showed no preferential clustering. Moreover, in HFF and RPE cells, all of our HCMV isolates replicated efficiently independently of their genetic subtype. In conclusion, beside a possible link between the gB subtype 2 and HCMV retinitis, our study found no direct evidence for a connection between UL144/UL128/UL130/UL131A genotypes and the incidence of HCMV retinitis in AIDS patients.

Awareness of and behaviors related to child-to-mother transmission of cytomegalovirus

OBJECTIVE

Congenital cytomegalovirus (CMV) infection is a common cause of hearing loss and intellectual disability. We assessed CMV knowledge and the frequency of women's behaviors that may enable CMV transmission to inform strategies for communicating prevention messages to women.

METHODS

We analyzed survey responses from 4184 participants (2181 women, 2003 men) in the 2010 HealthStyles survey, a national mail survey designed to be similar to the United States population.

RESULTS

Only 7% of men and 13% of women had heard of congenital CMV. Women with children under age 19 (n=918) practiced the following risk behaviors at least once per week while their youngest child was still in diapers: kissing on the lips (69%), sharing utensils (42%), sharing cups (37%), and sharing food (62%). Women practiced protective, hand cleansing behaviors most of the time or always after: changing a dirty diaper (95%), changing a wet diaper (85%), or wiping the child's nose (65%), but less commonly after handling the child's toys (26%).

CONCLUSIONS

Few women are aware of CMV and most regularly practice behaviors that may place them at risk when interacting with young children. Women should be informed of practices that can reduce their risk of CMV infection during pregnancy.

Review of cytomegalovirus shedding in bodily fluids and relevance to congenital cytomegalovirus infection

Congenital cytomegalovirus (CMV) infections are a leading cause of sensorineural hearing loss (SNHL) and neurological impairment. Congenital transmission of CMV can occur with maternal primary infection, reactivation, or reinfection during pregnancy. We reviewed studies of CMV shedding in bodily fluids (defined as CMV detected by culture or CMV DNA detected by polymerase chain reaction). Following diagnosis at birth, children with congenital CMV infection exhibited the highest prevalences of CMV shedding (median = 80%, number of sample population prevalences [N] = 6) and duration of shedding, with a steep decline by age five. Healthy children attending day care shed more frequently (median = 23%, N = 24) than healthy children not attending day care (median = 12%, N = 11). Peak shedding prevalences in children occurred at 1-2 years of age, confirming that young children are the key transmission risk for pregnant women. CMV shedding among children was more prevalent in urine specimens than in oral secretions (median prevalence difference = 11.5%, N = 12). Adults with risk factors such as STD clinic attendance had higher shedding prevalences (median = 22%, N = 20) than adults without risk factors (median = 7%, N = 44). In adults with risk factors, CMV was shed more frequently in urine; in adults without risk factors genital shedding was most common. The prevalence of CMV shedding in nine sample populations of pregnant women increased with advancing gestation. In seven sample populations of children with congenital CMV infection, higher viral load at birth was consistently associated with an elevated risk of SNHL. Higher CMV viral load at birth also consistently correlated with the presence of symptoms of congenital CMV at birth. Published 2011. This article is a US Government work and is in the public domain in the USA.

Role of prenatal diagnosis and counseling in the management of 735 pregnancies complicated by primary human cytomegalovirus infection: a 20-year experience

BACKGROUND

The burden of congenital human cytomegalovirus (HCMV) infection is well recognized. However, screening for maternal infection remains controversial in view of diagnostic challenges, counseling difficulties, and absence of medical treatment.

OBJECTIVE

To assess the role of prenatal diagnosis and counseling in the management of pregnancy complicated by primary HCMV infection.

STUDY DESIGN

Retrospective study aimed at investigating diagnostic features, options, and pregnancy outcome in 735 women with primary HCMV infection over a period of 20 years (1990-2009).

RESULTS

Overall, 25.6% women were found to be seronegative before the actual pregnancy. However, none were informed about HCMV infection and potential prevention strategies. Diagnosis of primary HCMV infection was achieved by seroconversion in 44.4% cases and by different combinations of virus-specific IgM, low IgG avidity, and DNAemia in 43.9% cases. Non-specific symptoms and/or haematological/biochemical alterations were recalled by 73.5% women. The onset of infection could be established, and counseling adjusted accordingly in >90% cases. The overall rate of vertical transmission was 37.1%, ranging from 5.6% for preconceptional infections to 64.1% for third trimester infections. Amniocentesis was chosen by 43.1% women, whereas pregnancy termination was requested by 15.6%.

CONCLUSIONS

Reference virology centers and ad hoc trained and experienced physicians are required for accurate diagnosis of primary infection in pregnancy and ensuing counseling. Prenatal diagnosis has a central role in the management of pregnancies complicated by primary HCMV infection. HCMV-seronegative women should receive adequate information.

Detection of a single identical cytomegalovirus (CMV) strain in recently seroconverted young women

Background

Infection with multiple CMV strains is common in immunocompromised hosts, but its occurrence in normal hosts has not been well-studied.

Methods

We analyzed CMV strains longitudinally in women who acquired CMV while enrolled in a CMV glycoprotein B (gB) vaccine trial. Sequencing of four variable genes was performed in samples collected from seroconversion and up to 34 months thereafter.

Results

199 cultured isolates from 53 women and 65 original fluids from a subset of 19 women were sequenced. 51 women were infected with one strain each without evidence for genetic drift; only two women shed multiple strains. Genetic variability among strains increased with the number of sequenced genetic loci. Nevertheless, 13 of 53 women proved to be infected with an identical CMV strain based on sequencing at all four variable genes. CMV vaccine did not alter the degree of genetic diversity amongst strains.

Conclusions

Primary CMV infection in healthy women nearly always involves shedding of one strain that remains stable over time. Immunization with CMVgB-1 vaccine strain is not selective against specific strains. Although 75% of women harbored their unique strain, or a strain shared with only one other woman, 25% shared a single common strain, suggesting that this predominant strain with a particular combination of genetic loci is advantageous in this large urban area.

Congenital cytomegalovirus (CMV) epidemiology and awareness

This commentary highlights and discusses the implications of a number of recent studies that refine epidemiologic knowledge of CMV infection and assess awareness of congenital CMV among clinicians and the public. These studies highlight that: (1) congenital CMV results in a disease burden that is substantial and severe; (2) a high proportion of United States women of reproductive age are susceptible to CMV infection; (3) the majority of congenital CMV infections in the United States result from recurrent infections among pregnant women; (4) CMV seroprevalence and seroincidence are much higher among racial/ethnic minorities and persons of lower socioeconomic status (SES); (5) household transmission of CMV appears to be an important transmission route in the United States; (6) sexual transmission of CMV appears to be an important transmission route in some population sub-groups in the United States; (7) women have limited awareness and knowledge about congenital CMV; (8) most obstetrician/gynecologists do not counsel women about prevention of congenital CMV; (9) most women view CMV prevention messages positively.