Congenital cytomegalovirus infection and neonatal auditory screening

CMV-induced Hearing Loss

Congenital cytomegalovirus (cCMV) infection is the most common fetal viral infection and contributes to about 25% of childhood hearing loss by the age of 4 years. It is the leading nongenetic cause of sensorineural hearing loss (SNHL). Infants born to seroimmune mothers are not completely protected from SNHL, although the severity of their hearing loss may be milder than that seen in those whose mothers had a primary infection. Both direct cytopathic effects and localized inflammatory responses contribute to the pathogenesis of cytomegalovirus (CMV)-induced hearing loss. Hearing loss may be delayed onset, progressive or fluctuating in nature, and therefore, a significant proportion will be missed by universal newborn hearing screening (NHS) and warrants close monitoring of hearing function at least until 5-6 years of age. A multidisciplinary approach is required for the management of hearing loss. These children may need assistive hearing devices or cochlear implantation depending on the severity of their hearing loss. In addition, early intervention services such as speech or occupational therapy could help better communication, language, and social skill outcomes. Preventive measures to decrease intrauterine CMV transmission that have been evaluated include personal protective measures, passive immunoprophylaxis and valacyclovir treatment during pregnancy in mothers with primary CMV infection. Several vaccine candidates are currently in testing and one candidate vaccine in phase 3 trials. Until a CMV vaccine becomes available, behavioral and educational interventions may be the most effective strategy to prevent maternal CMV infection.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cytomegalovirus-A Risk Factor for Childhood Hearing Loss: A Systematic Review

OBJECTIVE

Permanent hearing loss is an important public health issue in children with consequences for language, social, and academic functioning. Early hearing detection, intervention, and monitoring are important in mitigating the impact of permanent childhood hearing loss. Congenital cytomegalovirus (CMV) infection is a leading cause of hearing loss. The purpose of this review was to synthesize the evidence on the association between CMV infection and permanent childhood hearing loss.

DESIGN

We performed a systematic review and examined scientific literature from the following databases: MEDLINE, Ovid MEDLINE(R) Daily and Ovid MEDLINE(R), Embase, and CINAHL. The primary outcome was permanent bilateral or unilateral hearing loss with congenital onset or onset during childhood (birth to 18 years). The secondary outcome was progressive hearing loss. We included studies reporting data on CMV infection. Randomized controlled trials, quasi-experimental studies, nonrandomized comparative and noncomparative studies, and case series were considered. Data were extracted and the quality of individual studies was assessed with the Qualitative Assessment Tool for Quantitative Studies (McMaster University). The quality and strength of the evidence were graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). A narrative synthesis was completed.

RESULTS

Sixty-five articles were included in the review. Prevalence of hearing loss at birth was over 33% among symptomatic CMV-infected newborns and less than 15% in asymptomatic infections. This difference in prevalence was maintained during childhood with more than 40% prevalence reported for symptomatic and less than 30% for asymptomatic CMV. Late-onset and progressive hearing loss appear to be characteristic of congenital CMV infections. Definitions of hearing loss, degree of loss, and reporting of laterality varied across studies. All degrees and both bilateral and unilateral loss were reported, regardless of symptomatic and asymptomatic status at birth, and no conclusions about the characteristics of hearing loss could be drawn. Various patterns of hearing loss were reported including stable, progressive, and fluctuating, and improvement in hearing (sometimes to normal hearing) was documented. These changes were reported in children with symptomatic/asymptomatic congenital CMV infection, presenting with congenital/early onset/late-onset hearing loss and in children treated and untreated with antiviral medication.

CONCLUSIONS

Symptomatic and asymptomatic congenital CMV infection should be considered a risk factor for hearing loss at birth and during childhood and for progressive hearing loss. Therefore, CMV should be included as a risk factor in screening and surveillance programs and be taken into account in clinical follow-up of children with hearing loss.

Congenital cytomegalovirus infection and the risk of hearing loss in childhood: A PRISMA-compliant meta-analysis

BACKGROUND

Congenital cytomegalovirus (cCMV) infection is the most common cause of childhood hearing loss (HL), although the strength of this association remains limited and inconclusive. Thus, the purpose of this study was to summarize evidence regarding the strength of the relationship between cCMV and childhood HL and to determine whether this relationship differs according to patient characteristics.

METHODS

The PubMed, EmBase, and Cochrane Library databases were searched for studies evaluating the relationship between cCMV and HL from inception to September 2019. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to calculate the investigated outcomes in a random-effects model. Sensitivity, subgroup, and publication bias analyses were also performed.

RESULTS

A total of 15 studies involving 235,026 children met the inclusion criteria and were included in the final analysis. The summary results indicated that cCMV infection was associated with an increased risk of HL (odds ratio [OR]: 8.45; 95% confidence interval [CI]: 3.95-18.10; P < .001), irrespective of whether studies reported sensorineural HL (OR: 5.42; 95% CI: 1.98-14.88; P = .001), or did not evaluate HL types among their patients (OR: 11.04; 95% CI: 3.91-31.16; P < .001). However, in studies conducted in the United States (P < 0.001) and published in or after 2000 (P = 0.026), the study populations included <60% males (P < 0.001). Moreover, studies of high quality (P < .001) demonstrated a significantly greater risk of HL with cCMV infection than that in the corresponding subgroups.

CONCLUSIONS

The study results suggest that cCMV infection increases the risk of HL. Further studies are required to investigate the association of cCMV infection with the risk of specific subtypes of HL.

Role of cochlear synaptopathy in cytomegalovirus infected mice and in children

OBJECTIVES

Determine whether a murine model of cytomegalovirus (CMV) and CMV- infected children show evidence of synaptopathy.

STUDY DESIGN

Murine model of CMV infection and case series.

SUBJECTS AND METHODS

C57 BL/6 mice were inoculated with murine-CMV (mCMV). Auditory function was assessed using Auditory Brainstem Response (ABR) and distortion product otoacoustic emission (DPOAE) testing. Temporal bones from mCMV-infected mice were used for both ribbon synapse and hair cell quantification. Four groups of children (non-CMV normal hearing, non-CMV hearing impaired, CMV normal hearing and CMV hearing impaired) underwent ABRs between 2014 and 2018. The outcomes included raw amplitude, wave I:V amplitude ratio, absolute latency, and interpeak latency.

RESULTS

Mice at 8 weeks post mCMV infection had higher ABR and DPOAE (P < 0.05) thresholds and increased outer hair cell loss compared to uninfected mice and mCMV-infected mice at 4 and 6 weeks post infection, indicating progressive hearing loss. A reduction in the wave I amplitude and synaptic counts were noted earlier at 4 weeks in CMV-infected mice (P < 0.05). The human data indicated that the wave I:V amplitude ratio was lower on average in CMV-infected groups when compared to the uninfected cohorts. The wave I:V amplitude ratio for the click and 4k stimuli were not significantly different between the congenital CMV-infected and uninfected children with normal or with hearing loss.

CONCLUSION

This study suggests mCMV infection results in a synaptopathy before hair cell damage. Additional studies need to be performed to determine whether this effect is also observed in CMV-infected children.

LEVEL OF EVIDENCE

Animal studies and basic science- NA; human studies: level 4.

Cytomegalovirus infection during pregnancy: state of the science

Cytomegalovirus is the most common congenital infection, affecting 0.5-2% of all live births and the main nongenetic cause of congenital sensorineural hearing loss and neurological damage. Congenital cytomegalovirus can follow maternal primary infection or nonprimary infection. Sensorineurological morbidity is confined to the first trimester with up to 40-50% of infected neonates developing sequelae after first-trimester primary infection. Serological testing before 14 weeks is critical to identify primary infection within 3 months around conception but is not informative in women already immune before pregnancy. In Europe and the United States, primary infection in the first trimester are mainly seen in young parous women with a previous child younger than 3 years. Congenital cytomegalovirus should be evoked on prenatal ultrasound when the fetus is small for gestation and shows echogenic bowel, effusions, or any cerebral anomaly. Although the sensitivity of routine ultrasound in predicting neonatal symptoms is around 25%, serial targeted ultrasound and magnetic resonance imaging of known infected fetuses show greater than 95% sensitivity for brain anomalies. Fetal diagnosis is done by amniocentesis from 17 weeks. Prevention consists of both parents avoiding contact with body fluids from infected individuals, especially toddlers, from before conception until 14 weeks. Candidate vaccines failed to provide more than 75% protection for >2 years in preventing cytomegalovirus infection. Medical therapies such as cytomegalovirus hyperimmune globulins aim to reduce the risk of vertical transmission but 2 randomized controlled trials have not found any benefit. Valaciclovir given from the diagnosis of primary infection up to amniocentesis decreased vertical transmission rates from 29.8% to 11.1% in the treatment group in a randomized controlled trial of 90 pregnant women. In a phase II open-label trial, oral valaciclovir (8 g/d) given to pregnant women with a mildly symptomatic fetus was associated with a higher chance of delivering an asymptomatic neonate (82%), compared with an untreated historical cohort (43%). Valganciclovir given to symptomatic neonates is likely to improve hearing and neurological symptoms, the extent of which and the duration of treatment are still debated. In conclusion, congenital cytomegalovirus infection is a public health challenge. In view of recent knowledge on diagnosis and pre- and postnatal management, health care providers should reevaluate screening programs in early pregnancy and at birth.

Contribution of Congenital Cytomegalovirus Infection to Permanent Hearing Loss in a Highly Seropositive Population: The Brazilian Cytomegalovirus Hearing and Maternal Secondary Infection Study

BACKGROUND

The exact contribution of congenital cytomegalovirus infection (cCMVI) to permanent hearing loss (HL) in highly seropositive populations is unknown. We determined the contribution of cCMVI to HL and estimated the effectiveness of newborn hearing screening (HS) in identifying neonates with CMV-related HL.

METHODS

A total of 11 900 neonates born from a population with ≥97% maternal seroprevalence were screened for cCMVI and HL. cCMVI was confirmed by detection of CMV-DNA in saliva and urine at age <3 weeks.

RESULTS

Overall, 68 (0.6%; 95% confidence interval [CI], 0.4-0.7) neonates were identified with cCMVI. Of the 91 (0.8%) newborns who failed the HS, 24 (26.4%) were confirmed with HL, including 7 (29.2%; 95% CI, 17.2-59.3) with cCMVI. Another newborn with cCMVI passed the HS but was confirmed with HL at age 21 days. Of the 62 neonates with cCMVI who underwent a complete hearing evaluation, 8 (12.9%; 95% CI, 6.7-23.4) had HL and most (7/8; 87.5%; 95% CI, 46.6-99.7) were identified by HS. The rate of CMV-related HL was 8 per 11 887 neonates (0.7 per 1000 live births). The prevalence ratio of HL among neonates with cCMVI compared to CMV-uninfected neonates was 89.5 (95% CI, 39.7-202.0). No late-onset cCMVI-related HL was detected during a median follow-up of 36 months.

CONCLUSIONS

cCMVI is an important cause of HL in childhood in all settings. Integrating targeted cCMVI screening among neonates who fail a HS could be a reasonable, cost-effective strategy to identify newborns with early-onset cCMVI-related HL.

The Natural History and Rehabilitative Outcomes of Hearing Loss in Congenital Cytomegalovirus: A Systematic Review

OBJECTIVE

The purpose of this study was to examine the literature regarding the natural history and rehabilitative outcomes of sensorineural hearing loss from congenital cytomegalovirus infections.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

A systematic search was performed in PubMed, PsychINFO, CINAHL, and Web of Science to identify peer-reviewed research. Eligible studies were those containing original peer-reviewed research in English addressing either the natural history or rehabilitative outcomes of sensorineural hearing loss (SNHL) in congenital cytomegalovirus (cCMV).

STUDY APPRAISAL AND SYNTHESIS METHODS

Two investigators independently reviewed all articles and extracted data. Bias was assessed using the Cochrane Collaboration's tool and the Newcastle-Ottawa Assessment Scale.

RESULTS

Thirty-six articles were reviewed. Universal screening identifies 0.2 to 1% of newborns with cCMV infection. SNHL ranged from 8 to 32% of infants and was more prevalent in symptomatic versus asymptomatic cases. Nine to 68% of hearing loss occurs in a late or delayed fashion. In 7 to 71% of cases hearing loss is progressive. Cochlear implantation (CI) is a viable option for patients with cCMV associated hearing loss and leads to improvements in hearing and language. There is limited literature comparing rehabilitation outcomes in cCMV and non-cCMV CI recipients.

CONCLUSION

Late onset and progressive hearing loss is seen in children who develop hearing loss from cCMV. Frequent audiologic follow-up is necessary considering the natural history of cCMV hearing loss. Universal screening should be pursued due to the number of asymptomatic children, at birth, who develop late onset/delayed hearing loss. CI is an effective means of improving speech and language in this population.

The Role of Antioxidants in the Treatment of Congenital CMV-Related Hearing: A Case-Control Study

Objective

Antioxidants have been used as a therapeutic measure for several causes of hearing loss, and this study aims to examine the use of antioxidants in children with congenital cytomegalovirus (cCMV)–related hearing loss.

Study Design

Case-control study.

Setting

Academic pediatric hospital.

Subjects and Methods

A retrospective chart review of pediatric patients with cCMV-related hearing loss treated with and without antioxidants (vitamins A, C, and E and magnesium, known as ACE-Mg) was completed. The primary end point was the mean change in hearing thresholds for the right and left ears after therapy. An evaluation of the mean change in thresholds was evaluated at the following frequencies: 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. A 2-sample t test and multiple linear regression were used to evaluate the data.

Results

A total of 78 children with cCMV-related hearing loss were included in the study, of whom 10 were treated with antioxidants. The average amount of time in which antioxidants were taken was 387 days. When comparing cases and controls, there was no differences in the mean change of hearing thresholds at each frequency for both the right and left ears (P > .05). Length of antioxidant therapy and age at which therapy was initiated had no effect on hearing scores (P > .05).

Conclusions

Oxidative stress plays a role in the pathogenesis of cCMV-related hearing loss. ACE-Mg is a safe adjuvant therapy for the treatment of hearing loss in children; however, this study demonstrates no hearing-related benefit from ACE-Mg antioxidant therapy.

Prospective Cohort Study of Congenital Cytomegalovirus Infection during Pregnancy with Fetal Growth Restriction: Serologic Analysis and Placental Pathology

OBJECTIVE

To investigate prospectively the prevalence of congenital cytomegalovirus (CMV) infection and the pathologic features of the placenta in cases of fetal growth restriction (FGR).

STUDY DESIGN

Forty-eight pregnant women who were diagnosed with FGR during pregnancy were enrolled for 15 months. Maternal CMV serologic tests, pathologic examinations of the placenta, and newborn urinary CMV-DNA polymerase chain reaction tests were performed in all the cases. The clinical characteristics and laboratory findings of the pregnant women and their newborns were collected. Biomarkers for inflammation, angiogenesis, and placental hormones were measured in the maternal serum at FGR diagnosis or in the neonatal urine at birth.

RESULTS

One of the 48 cases with FGR was a congenital CMV infection. CMV antigen was detected in the placenta of 7 cases with FGR. The change rate of the estimated fetal body weight was significantly lower in FGR cases with placental CMV detection. Placental villitis was observed more frequently in FGR cases with placental CMV detection. Human placental lactogen was significantly decreased in FGR cases with placental CMV detection. Increased C-reactive protein and serum amyloid A levels in the maternal serum were observed more frequently in FGR cases with placental CMV detection. Newborn urine β-2 microglobulin levels were significantly higher in FGR cases with placental CMV detection.

CONCLUSIONS

Serologic tests for maternal CMV, the change rate of the estimated fetal body weight, analysis of several biomarkers, and placental pathologic examinations might be helpful in comprehensively predicting the possibility of congenital CMV infection.

Disparities in access to pediatric hearing health care

PURPOSE OF REVIEW

There are significant disparities in care facing children with hearing loss. The objective of this review is to assess the current disparities in pediatric hearing healthcare delivery, describe the barriers of efficient and effective pediatric hearing health care, and explore the innovations to improve pediatric hearing healthcare delivery.

RECENT FINDINGS

Children with hearing loss from certain geographic regions or ethnic background are significantly delayed in diagnosis and treatment. Multiple patient characteristics (presentation of hearing loss), parental factors (insurance status, socioeconomic status, educational status, and travel distance to providers), and provider barriers (specialist shortage and primary care provider challenges) prevent the delivery of timely hearing health care. Advances, such as improved screening programs and the expansion of care through remote services, may help to ameliorate these disparities.

SUMMARY

Timely identification and treatment of pediatric hearing loss is critical to prevent lifelong language complications. Children from vulnerable populations, such as rural residents, face significant disparities in care. Careful assessment of these barriers and implementation of culturally acceptable interventions are paramount to maximize communication outcomes of children with hearing loss.

Evaluation and management of cytomegalovirus-associated congenital hearing loss

PURPOSE OF REVIEW

The current article reviews the current literature related to congenital cytomegalovirus (CMV)-related hearing loss. The discussion will focus on the epidemiology, pathogenesis, and clinical presentation of human CMV infection as it pertains to hearing loss. Current methods of CMV diagnosis with a focus on the evolving trend toward broader neonatal screening protocols will also be explored. Discussion of medical, surgical, and audiologic management of the condition will also be addressed.

RECENT FINDINGS

Much of the current research on this topic is focused on improving detection of CMV through screening programs. Some advances in understanding cochlear pathogenesis have also been made.

SUMMARY

Congenital CMV infection remains an important cause of hearing loss in infants and children. Early detection of CMV infection can broaden treatment options and allow for improved hearing and language outcome for patients with CMV-associated sensorineural hearing loss.

Outcomes From a Hearing-Targeted Cytomegalovirus Screening Program

BACKGROUND AND OBJECTIVES

Cytomegalovirus (CMV) is the most common congenital infection and nongenetic cause of congenital sensorineural hearing loss in the United States. Utah was the first state to pass legislation mandating CMV screening for newborns who fail newborn hearing screening (NBHS). The study objective was to present outcomes of hearing-targeted CMV screening and determine factors predicting CMV screening.

METHODS

We used Utah Department of Health HiTrack and Vital Records databases to examine CMV screening from 509 infants who failed NBHS in the 24 months after implementation of the Utah legislation. Multivariate logistic regression analyses were conducted to identify predictors of compliance with CMV screening and diagnostic hearing evaluation.

RESULTS

Sixty-two percent of infants who never passed hearing screening underwent CMV screening. Fourteen of 234 infants tested within 21 days were CMV positive; 6 (42.9%) had hearing loss. Seventy-seven percent of eligible infants completed a diagnostic hearing evaluation within 90 days of birth. Compliance with CMV screening was associated with sociodemographic factors, time since the law was enacted, and NBHS protocol. Infants born after the legislation showed greater odds of achieving timely diagnostic hearing evaluation than infants born before the law.

CONCLUSIONS

Incorporating CMV screening into an established NBHS program is a viable option for the identification of CMV in infants failing NBHS. The addition of CMV testing can help a NBHS program attain timely audiological diagnostics within 90 days, an important early hearing detection and intervention milestone.

Screening for seemingly healthy newborns with congenital cytomegalovirus infection by quantitative real-time polymerase chain reaction using newborn urine: an observational study

OBJECTIVE

Approximately 8-10% of newborns with asymptomatic congenital cytomegalovirus (cCMV) infection develop sensorineural hearing loss (SNHL). However, the relationship between CMV load, SNHL and central nervous system (CNS) damage in cCMV infection remains unclear. This study aimed to examine the relationship between urinary CMV load, SNHL and CNS damage in newborns with cCMV infection.

STUDY DESIGN

The study included 23 368 newborns from two maternity hospitals in Saitama Prefecture, Japan. Urine screening for cCMV infection (quantitative real-time PCR) and newborn hearing screening (automated auditory brainstem response (AABR) testing) were conducted within 5 days of birth to examine the incidence of cCMV infection and SNHL, respectively. CNS damage was assessed by MRI of cCMV-infected newborns.

RESULTS

The incidence of cCMV infection was 60/23 368 (0.257%; 95% CI 0.192% to 0.322%). The geometric mean urinary CMV DNA copy number in newborns with cCMV was 1.79×10⁶ copies/mL (95% CI 7.97×10⁵ to 4.02×10⁶). AABR testing revealed abnormalities in 171 of the 22 229 (0.769%) newborns whose parents approved hearing screening. Of these 171 newborns, 22 had SNHL (12.9%), and 5 of these 22 were infected with cCMV (22.7%). Newborns with both cCMV and SNHL had a higher urinary CMV DNA copy number than newborns with cCMV without SNHL (p=0.036). MRI revealed CNS damage, including white matter abnormalities, in 83.0% of newborns with cCMV. Moreover, newborns with CNS damage had a significantly greater urinary CMV load than newborns without CNS damage (p=0.013).

CONCLUSIONS

We determined the incidence of cCMV infection and urinary CMV DNA copy number in seemingly healthy newborns from two hospitals in Saitama Prefecture. SNHL and CNS damage were associated with urinary CMV DNA copy number. Quantification of urinary CMV load may effectively predict the incidence of late-onset SNHL and neurodevelopmental disorders.

Pathogenesis of developmental anomalies of the central nervous system induced by congenital cytomegalovirus infection

In humans, the herpes virus family member cytomegalovirus (CMV) is the most prevalent mediator of intrauterine infection-induced congenital defect. Central nervous system (CNS) dysfunction is a distinguishing symptom of CMV infection, and characterized by ventriculoencephalitis and microglial nodular encephalitis. Reports on the initial distribution of CMV particles and its receptors on the blood brain barrier (BBB) are rare. Nevertheless, several factors are suggested to affect CMV etiology. Viral particle size is the primary factor in determining the pattern of CNS infections, followed by the expression of integrin β1 in endothelial cells, pericytes, meninges, choroid plexus, and neural stem progenitor cells (NSPCs), which are the primary targets of CMV infection. After initial infection, CMV disrupts BBB structural integrity to facilitate the spread of viral particles into parenchyma. Then, the initial meningitis and vasculitis eventually reaches NSPC-dense areas such as ventricular zone and subventricular zone, where viral infection inhibits NSPC proliferation and differentiation and results in neuronal cell loss. These cellular events clinically manifest as brain malformations such as a microcephaly. The purpose of this review is to clearly delineate the pathophysiological basis of congenital CNS anomalies caused by CMV.

Surgical manifestations of gastrointestinal cytomegalovirus infection in children: Clinical audit and literature review

INTRODUCTION

Gastrointestinal sequelae of cytomegalovirus are rare, usually associated with significant immune compromise, and carry a high morbidity and mortality. Gastrointestinal disease frequently requires surgical intervention for diagnosis and management.

AIM

The aim of the study is to evaluate the incidence, presentation and management of gastrointestinal cytomegalovirus disease in a pediatric population.

METHOD

Between January 2003 and June 2011, a retrospective folder review was conducted of all symptomatic children with proven CMV disease, presenting to the surgical service. Eligible patients were identified using the surgical, histopathology and serology databases.

RESULTS

Thirty-eight patients (1.8/1000 surgical admissions) were identified with a median presenting age of 5months (range 3days-12years). Esophagitis (n=18) and small bowel disease (n=16) predominated, but CMV was seen throughout the gastrointestinal tract. Risk factors included HIV infection (n=21, 55%) and recent gastrointestinal surgery or infection (n=10, 26%). Characteristic multiple jejunoileal perforations were seen in six patients. Compared to upper GIT disease, intestinal involvement was associated with younger age and doubled mortality. In HIV-infected children, median CD4 (%) was lower in intestinal compared to upper gastrointestinal disease. Morbidities included anastomotic breakdowns (5), anastomotic strictures (3), relook laparotomies (10), resistant esophageal strictures (5) and prolonged parenteral nutrition (5). Anti-CMV drugs were given in 63%. Overall mortality was 32% (12/38) and was associated with lower GIT disease.

CONCLUSION

Invasive CMV gastrointestinal disease in our children was predominantly HIV-associated, or followed a major lower gastrointestinal inflammatory insult in infants younger than 6months. Successful therapy requires a high index of suspicion of active CMV disease to allow early implementation of CMV viral load control and aggressive treatment of the underlying immune impairment. Multiple surgical interventions are often required for both tissue diagnosis and management of acute and chronic complications. CMV-viral-load-tailored anti-CMV therapy is supported by recent literature.

Asymmetric and unilateral hearing loss in children

Asymmetric and unilateral hearing losses in children have traditionally been underappreciated, but health care practitioners are now beginning to understand their effect on development and the underlying pathophysiologic mechanisms. The common wisdom among medical and educational professionals has been that at least one normal-hearing or near-normal-hearing ear was sufficient for typical speech and language development in children. The objective of this review is to illustrate, to the non-otolaryngologist, the consequences of asymmetric and unilateral hearing loss in children on developmental and educational outcomes. Etiology, detection, and management are also discussed. Lastly, implications for further research are considered.

Hearing loss and congenital CMV infection: a systematic review

BACKGROUND AND OBJECTIVE

Hearing loss caused by congenital cytomegalovirus (cCMV) infection was first observed in 1964. Today cCMV is the most common cause of nonhereditary sensorineural hearing loss in childhood. Our objective was to provide an overview of the prevalence of cCMV-related hearing loss, to better define the nature of cCMV-associated hearing loss, and to investigate the importance of cCMV infection in hearing-impaired children.

METHODS

Two reviewers independently used Medline and manual searches of references from eligible studies and review articles to select cohort studies on children with cCMV infection with audiological follow-up and extracted data on population characteristics and hearing outcomes.

RESULTS

Thirty-seven studies were included: 10 population-based natural history studies, 14 longitudinal cohort studies, and 13 retrospective studies. The prevalence of cCMV in developed countries is 0.58% (95% confidence interval, 0.41-0.79). Among these newborns 12.6% (95% confidence interval, 10.2-16.5) will experience hearing loss: 1 out of 3 symptomatic children and 1 out of 10 asymptomatic children. Among symptomatic children, the majority have bilateral loss; among asymptomatic children, unilateral loss predominates. In both groups the hearing loss is mainly severe to profound. Hearing loss can have a delayed onset, and it is unstable, with fluctuations and progression. Among hearing-impaired children, cCMV is the causative agent in 10% to 20%. Despite strict selection criteria, some heterogeneity was found between selected studies.

CONCLUSIONS

This systematic review underscores the importance of cCMV as a cause of sensorineural hearing loss in childhood.

A diagnostic paradigm including cytomegalovirus testing for idiopathic pediatric sensorineural hearing loss

OBJECTIVES/HYPOTHESIS

To determine the feasibility and cost effectiveness of incorporating cytomegalovirus (CMV) testing to determine the etiology of pediatric hearing loss.

STUDY DESIGN

Retrospective study of children presenting with sensorineural hearing loss (SNHL) at one institution from 2008 to 2013.

METHODS

Children aged 3 years or younger who presented to the senior author (A.P.) between May 2008 and September 2013 with confirmed SNHL were evaluated. These children underwent a sequential diagnostic paradigm that incorporated CMV testing if no obvious etiology could be determined from the history or physical examination.

RESULTS

One hundred eleven children with SNHL were evaluated between 2008 and 2013. Eighty-three children underwent CMV testing, imaging, and a genetic evaluation. Those with confirmed or probable CMV-induced SNHL made up 30% of all children tested (n = 25), the largest group identified. CMV screening had the lowest cost compared to genetic testing or imaging for all types of hearing loss, except for those with auditory neuropathy spectrum disorder.

CONCLUSION

We present the first sequential diagnostic paradigm utilizing CMV testing for children presenting with SNHL. The relatively high incidence of CMV-induced SNHL, the low cost for this assay, and the indirect benefits from early diagnosis support the role of early CMV testing for these patients.

LEVEL OF EVIDENCE

4.

Long-distance interferon signaling within the brain blocks virus spread

Serious permanent neurological or psychiatric dysfunction may result from virus infections in the central nervous system (CNS). Olfactory sensory neurons are in direct contact with the external environment, making them susceptible to infection by viruses that can enter the brain via the olfactory nerve. The rarity of full brain viral infections raises the important question of whether unique immune defense mechanisms protect the brain. Here we show that both RNA (vesicular stomatitis virus [VSV]) and DNA (cytomegalovirus [CMV]) virus inoculations of the nasal mucosa leading to olfactory bulb (OB) infection activate long-distance signaling that upregulates antiviral interferon (IFN)-stimulated gene (ISG) expression in uninfected remote regions of the brain. This signaling mechanism is dependent on IFN-α/β receptors deep within the brain, leading to the activation of a distant antiviral state that prevents infection of the caudal brain. In normal mice, VSV replication is limited to the OB, and these animals typically survive the infection. In contrast, mice lacking the IFN-α/β receptor succumbed to the infection, with VSV spreading throughout the brain. Chemical destruction of the olfactory sensory neurons blocked both virus trafficking into the OB and the IFN response in the caudal brain, indicating a direct signaling within the brain after intranasal infection. Most signaling within the brain occurs across the 20-nm synaptic cleft. The unique long-distance IFN signaling described here occurs across many millimeters within the brain and is critical for survival and normal brain function.

IMPORTANCE

The olfactory mucosa can serve as a conduit for a number of viruses to enter the brain. Yet infections in the CNS rarely occur. The mechanism responsible for protecting the brain from viruses that successfully invade the OB, the first site of infection subsequent to infection of the nasal mucosa, remains elusive. Here we demonstrate that the protection is mediated by a long-distance interferon signaling, particularly IFN-β released by infected neurons in the OB. Strikingly, in the absence of neurotropic virus infection, ISGs are induced in the posterior regions of the brain, activating an antiviral state and preventing further virus invasion.

Congenital cytomegalovirus infection: update on management strategies

Congenital cytomegalovirus (CMV) infections are underrecognized as a cause of serious morbidity in newborn infants. The era of therapeutic nihilism regarding these infections has come to an end, however, as useful therapies are now available that may modify the outcome. The infected fetus can be treated in utero, or the newborn infant can be treated when CMV is recognized in the neonatal period. Expanded screening of newborns for congenital CMV infection will make it even more important for clinicians to be aware of current therapeutic options. The most effective option for the treatment of life-threatening or sight-threatening CMV disease at any age is the nucleoside analog ganciclovir. For the newborn with congenital CMV infection, the value of ganciclovir appears to relate to its ability to preserve hearing; other improvements in overall neurodevelopmental status are inferred but remain to be proven. In the pregnant woman with primary CMV infection, the use of CMV-specific immune globulin, though still investigational, is garnering attention and may prove to be a valuable therapy.

Infecciones neonatales (II)☆

Las infecciones neonatales son un problema de salud pública mundial. Su incidencia se aproxima al 1 % de los nacimientos en los países industrializados, pero es más elevada en los países en desarrollo. En 1996, las infecciones aparecidas en el primer mes de vida eran responsables de cinco millones de fallecimientos anuales.

Casi todos los microorganismos patógenos (bacterias, hongos y virus) pueden ser causantes de infecciones en el recién nacido. La epidemiología bacteriana varía según las épocas, los países e incluso las regiones, lo que impide extrapolar las propuestas terapéuticas formuladas a partir de la expenencia de un centro, tanto en lo que se refiere a los protocolos curativos como a los preventivos.

Real-time PCR-based testing of saliva for cytomegalovirus at birth

Evaluation of: Boppana SB, Ross SA, Shimamura M et al. Saliva polymerase-chain-reaction assay for cytomegalovirus screening in newborns. N. Engl. J. Med. 364, 2111-2118 (2011). Cytomegalovirus (CMV) commonly causes congenital infection. As such, CMV is a prominent etiology for nongenetic sensori-neural hearing loss. However, screening examination in the perinatal and early infant period fails to identify most children at risk for CMV-produced hearing loss because of the absence of symptoms early in life. Furthermore, generalized screening for congenital CMV infection has yet to be implemented. Currently, newborns are tested via means of a rapid saliva culture but large-scale automation of this test would be difficult. Fortunately, newer potential replacement tests have been created. An important advance includes testing newborns via means of PCR using liquid or dried saliva samples. In a large-scale, prospective, multi-institutional study both types of salivary samples were compared with the gold standard of saliva culture. Of the 34,989 neonates tested, 0.5% or 177 samples tested positive for CMV. Testing of both liquid and dried saliva were sensitive (>97%) as well as specific (>98%) when measured against CMV culture. PCR testing of dried saliva has the potential benefit of adapting to generalized screening of neonates for congenital CMV infection. The advantages of early detection, intervention for and treatment of cases that are not clinically apparent needs to be carefully evaluated before proposing universal newborn screening for CMV infection as a valuable public health strategy.

Saliva polymerase-chain-reaction assay for cytomegalovirus screening in newborns

BACKGROUND

Congenital cytomegalovirus (CMV) infection is an important cause of hearing loss, and most infants at risk for CMV-associated hearing loss are not identified early in life because of failure to test for the infection. The standard assay for newborn CMV screening is rapid culture performed on saliva specimens obtained at birth, but this assay cannot be automated. Two alternatives--real-time polymerase-chain-reaction (PCR)-based testing of a liquid-saliva or dried-saliva specimen obtained at birth--have been developed.

METHODS

In our prospective, multicenter screening study of newborns, we compared real-time PCR assays of liquid-saliva and dried-saliva specimens with rapid culture of saliva specimens obtained at birth.

RESULTS

A total of 177 of 34,989 infants (0.5%; 95% confidence interval [CI], 0.4 to 0.6) were positive for CMV, according to at least one of the three methods. Of 17,662 newborns screened with the use of the liquid-saliva PCR assay, 17,569 were negative for CMV, and the remaining 85 infants (0.5%; 95% CI, 0.4 to 0.6) had positive results on both culture and PCR assay. The sensitivity and specificity of the liquid-saliva PCR assay were 100% (95% CI, 95.8 to 100) and 99.9% (95% CI, 99.9 to 100), respectively, and the positive and negative predictive values were 91.4% (95% CI, 83.8 to 96.2) and 100% (95% CI, 99.9 to 100), respectively. Of 17,327 newborns screened by means of the dried-saliva PCR assay, 74 were positive for CMV, whereas 76 (0.4%; 95% CI, 0.3 to 0.5) were found to be CMV-positive on rapid culture. Sensitivity and specificity of the dried-saliva PCR assay were 97.4% (95% CI, 90.8 to 99.7) and 99.9% (95% CI, 99.9 to 100), respectively. The positive and negative predictive values were 90.2% (95% CI, 81.7 to 95.7) and 99.9% (95% CI, 99.9 to 100), respectively.

CONCLUSIONS

Real-time PCR assays of both liquid- and dried-saliva specimens showed high sensitivity and specificity for detecting CMV infection and should be considered potential screening tools for CMV in newborns. (Funded by the National Institute on Deafness and Other Communication Disorders.).

Effects of congenital HCMV infection on synaptic plasticity in dentate gyrus (DG) of rat hippocampus

This study was carried out to investigate whether the congenital HCMV infection affect the induction and maintenance of LTP /DP. Rat models of Sprague-Dawley rats congenitally infected by HCMV were made. Field excitatory postsynaptic potentials (EPSPs) were recorded in the hippocampal slices of offspring rats (50-65days) to study alterations of LTP /DP in area dentate gyrus (DG) of the hippocampus after congenital infection. The Ca(2+) and mRNA level of calmodulin (CaM) in the hippocampus neurons of the experiment group (congenital infected by HCMV) and the control group were measured;The input/output (I/O) curves of the EPSP slope PS amplitude in area DG in experiment group were significantly depressed when compared to control group (P<0.05). LTP of the EPSP slope and PS amplitude in area DG of the hippocampus was 137±4% (EPSP) and 225±11% (PS) in control rats and 115±9% (EPSP) and 163±7% (PS) in experiment rats (EPSP: F=25.29,P<0.05;PS: F=74.33 P<0.05, two-way ANOVA with Tukey test); DP of the EPSP slope and PS amplitude was 86±3% (EPSP) and 85±2% (PS) in control rats and 94±5% (EPSP) and 93±4% (PS) in congenitally infected rats (EPSP: F=5.62, P<0.05;PS: F=4.22, P<0.05, two-way ANOVA with Tukey test) . At the same time, intracellular [Ca(2+)] and mRNA level of CaM in the hippocampus neurons of the experiment group were significantly increased than that of in the controls ([Ca(2+)]: P<0.01;CaM mRNA: P<0.01) . The results demonstrate that congenital HCMV infection could reduce the range of synaptic plasticity in the Sprague-Dawley rats, which may trigger the dysfunction of learning and memory through disrupting the calcium balance.

Congenital cytomegalovirus infection in pediatric hearing loss

OBJECTIVES

To compare the prevalence of congenital cytomegalovirus (CMV) infection in Washington State in children with hearing loss (HL) and the general population and to compare the characteristics of HL in children with and without congenital CMV infection.

DESIGN

Matched case-control; case cohort.

SETTING

Regional pediatric hospital, Washington State Department of Health (WSDOH).

PATIENTS

Cases were children 4 years and older with HL born in Washington State. Control individuals matched for demographic characteristics were identified at random through the WSDOH.

MAIN OUTCOME MEASURES

Congenital CMV status determined using quantitative polymerase chain reaction testing on newborn heel stick blood spots archived by the WSDOH. Audiologic data were used to characterize HL.

RESULTS

Congenital CMV testing was performed for 222 matched cases and controls. Congenital CMV infection was detected in 1.4% of controls and in 9.9% of cases (odds ratio, 10.5; 95% confidence interval, 2.6-92.4). An estimated 8.9% of HL in children in Washington can be attributed to CMV infection. After inclusion of an additional 132 children with HL (for a total of 354 cases in the case cohort), we observed that children with congenital CMV had more severe HL (P < .001) and higher proportions of progressive (P = .02) and unilateral (P = .002) HL compared with children without congenital CMV infection. In the 35 children with congenital CMV infection, there was no relationship between neonatal CMV load and severity of HL.

CONCLUSIONS

In Washington State, children with HL had a far higher prevalence of congenital CMV viremia than did the general pediatric population, and CMV infection seems to be responsible for an appreciable fraction of pediatric HL in Washington State.

Murine model for congenital CMV infection and hearing impairment

Background

Congenital cytomegalovirus (CMV) infection is the leading cause of sensorineural hearing loss (SNHL), and SNHL is the most frequent sequela of congenital CMV infection. But the pathogenic mechanism remains unknown, and there is no ideal CMV intrauterine infection animal model to study the mechanisms by which SNHL develops.

Methods

We established the congenital murine cytomegalovirus (MCMV) infection model by directly injecting the virus into the placenta on day 12.5 of gestation. Then, we observed the development and the MCMV congenital infection rate of the fetuses on the day they were born. Furthermore, we detected the auditory functions, the conditions of the MCMV infection, and the histological change of the inner ears of 28-day-old and 70-day-old offspring.

Results

Both the fetal loss rate and the teratism rate of offspring whose placentas were inoculated with MCMV increased, and their body length, head circumference, and weight decreased. The hearing level of offspring both decreased at both 28- and 70-days post birth; the 70-day-old mice developed lower hearing levels than did the 28-day old mice. No significant inflammatory changes in the cochleae of the mice were observed. MCMV DNA signals were mainly detected in the spiral ganglion neurons and the endolymph area, but not in the perilymph area. The number of neurons decreased, and their ultrastructures changed. Moreover, with age, the number of neurons dramatically decreased, and the ultrastructural lesions of neurons became much more severe.

Conclusions

The results suggest that the direct injection of MCMV into the placenta may efficiently cause fetal infection and disturb the intrauterine development of the fetus, and placental inoculation itself has no obvious adverse effects on offspring. The reduction in the number of spiral ganglion neurons and the ultrastructural lesions of the neurons may be the major cause of congenital CMV infection-induced progressive SNHL.

Etiological diagnosis in the hearing impaired newborn: proposal of a flow chart

OBJECTIVE

Most industrialized countries have introduced some form of universal newborn hearing screening program. Both identification and rehabilitation of hearing loss in newborns have evolved to an acceptable standard and the need for a standardized etiological protocol is emerging.

METHODS

Extensive literature search to determine which investigations can help identifying the cause of congenital hearing loss and how to limit extensive testing in these children by taking into account the most prevalent causes.

FINDINGS

A stepwise approach to detect the cause of hearing loss in children with congenital sensorineural hearing loss was developed.

CONCLUSION

In general it is advised to first rule out Cx26/Cx30 and infectious causes (cytomegalovirus and, if indicated, toxoplasmosis and rubella), and to preserve more extensive investigations for those children in whom these causes do not explain the hearing loss.

Human cytomegalovirus reinfection is associated with intrauterine transmission in a highly cytomegalovirus-immune maternal population

OBJECTIVE

To determine contribution of reinfection with new strains of cytomegalovirus in cytomegalovirus seromimmune women to incidence of congenital cytomegalovirus infection.

STUDY DESIGN

In 7848 women studied prospectively for congenital cytomegalovirus infection from a population with near universal cytomegalovirus seroimmunity, sera from 40 mothers of congenitally infected infants and 109 mothers of uninfected newborns were analyzed for strain-specific anticytomegalovirus antibodies.

RESULTS

All women were cytomegalovirus seroimmune at first prenatal visit. Reactivity for 2 cytomegalovirus strains was found in 14 of 40 study mothers and in 17 of 109 control mothers at first prenatal visit (P = .009). Seven of 40 (17.5%) study women and 5 of 109 (4.6%) controls (P = .002) acquired antibodies reactive with new cytomegalovirus strains during pregnancy. Evidence of infection with more than 1 strain of cytomegalovirus before or during current pregnancy occurred in 21 of 40 study mothers and 22 of 109 controls (P < .0001).

CONCLUSION

Maternal reinfection by new strains of cytomegalovirus is a major source of congenital infection in this population.

DECIBEL study: Congenital cytomegalovirus infection in young children with permanent bilateral hearing impairment in the Netherlands

BACKGROUND

A significant number of asymptomatic newborns infected with congenital cytomegalovirus (CMV) will present with permanent childhood hearing impairment (PCHI) during early childhood.

OBJECTIVES

To investigate the role of congenital CMV infection in causing PCHI in the Netherlands, and assess the efficacy of two different hearing screening strategies and the developmental outcome following each strategy.

STUDY DESIGN

We included 192 children with PCHI at the age of 3-5 years, who were offered hearing screening in their first year of life. Dried blood spots from 171 children were available for CMV detection using real-time PCR. The results of eight previously tested samples were also available. Clinical baseline characteristics were collected from medical records and the Child Development Inventory was used to investigate the developmental outcome.

RESULTS

The rate of congenital CMV among the 179 children was 8% (14/179) and 23% (9/39) among children with profound PCHI. Two of eight CMV-positive children with PCHI at the age of 3-5 years had passed the newborn hearing screening (NHS) test. Developmental outcome measures showed a significantly greater delay in language comprehension in children with both PCHI and congenital CMV infection (the largest in symptomatic children) than in the children with PCHI without congenital CMV infection.

CONCLUSIONS

Congenital CMV infection is important in the etiology of PCHI. Universal NHS is not a guarantee of normal hearing and development in childhood for children with congenital CMV infection. This is a problem which might be solved by universal congenital CMV screening.

Treatment of congenital cytomegalovirus infection: implications for future therapeutic strategies

Cytomegalovirus (CMV) infection is the most common cause of congenital infection in the developed world, occurring in approximately 1% of all liveborns. Symptomatic disease occurs in 10% of all congenitally infected infants, resulting in a spectrum of clinical manifestations that include microcephaly, chorioretinitis, hepatosplenomegaly and sensorineural hearing loss, among others. Even those children who are asymptomatic at birth have a risk of hearing loss, with approximately 8% experiencing this sequela. Overall, congenital CMV infection accounts for one-third of all cases of sensorineural hearing loss. The economic burden of disease exceeds $2 billion annually in the USA. Therefore, this infection has been the target for antiviral therapy. Studies performed by the National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group (CASG) have evaluated ganciclovir for the treatment of symptomatic congenital CMV infection with central nervous system involvement. In a randomized, controlled clinical trial of ganciclovir treatment (6 mg/kg iv every 12 h for 6 weeks) brainstem-evoked responses were utilized as the primary endpoint and demonstrated stabilization of hearing both at 6 months and >1 year. Treatment was associated with neutropenia in over 60% of treated patients. Since ganciclovir must be given intravenously, studies with its prodrug, valganciclovir, have been performed to assess pharmacokinetics and pharmacodynamics. Currently, a clinical trial of 6 weeks versus 6 months of valganciclovir is being performed by the CASG. Notably, only intravenous ganciclovir and orally administered valganciclovir have been used to treat congenital CMV infection. Hopefully, other drugs such as maribavir will be available for evaluation in this population.

Rehabilitation and outcome of severe profound deafness in a group of 16 infants affected by congenital cytomegalovirus infection

The aim of the study was to characterize the audiological consequences of congenital cytomegalovirus infection (CMV) and to evaluate the outcome of rehabilitation with hearing aids and/or cochlear implant (CI), associated with an adequate speech-language therapy. A retrospective review of data was made from a total of 16 infants, affected by severe to profound hearing loss from congenital CMV infection, referred to a tertiary audiological center for rehabilitation. Audiological evaluation was performed using behavioral audiometry, auditory brainstem responses (ABR) and/or electrocochleography (ECochG). Of the 16 children (median age at diagnosis of hearing loss: 21.33 +/- 0.7 months) with CMV hearing loss, 14 were affected by profound bilateral hearing loss and received a CI, while 2 were affected by bilateral severe hearing loss and received hearing aids. Cochlear implants can provide useful speech comprehension to patients with CMV-related deafness, even if language development is lower when compared to a group of Connexin (Cx) 26+ cochlear-implanted children (eight subjects), matched for age. Congenital CMV infection still represents a serious clinical condition, as well as an important cause of hearing loss in children. More studies have claimed to identify the pathophysiological mechanisms of damage and thus to ensure a better therapeutic approach. Nonetheless, in cases of CMV-deafened babies, the overall outcome of cochlear implantation is good.

Neuropathogenesis of congenital cytomegalovirus infection: disease mechanisms and prospects for intervention

Congenital cytomegalovirus (CMV) infection is the leading infectious cause of mental retardation and hearing loss in the developed world. In recent years, there has been an improved understanding of the epidemiology, pathogenesis, and long-term disabilities associated with CMV infection. In this review, current concepts regarding the pathogenesis of neurological injury caused by CMV infections acquired by the developing fetus are summarized. The pathogenesis of CMV-induced disabilities is considered in the context of the epidemiology of CMV infection in pregnant women and newborn infants, and the clinical manifestations of brain injury are reviewed. The prospects for intervention, including antiviral therapies and vaccines, are summarized. Priorities for future research are suggested to improve the understanding of this common and disabling illness of infancy.

Trends in hospitalizations for diagnosed congenital cytomegalovirus in infants and children in Australia

Background

Cytomegalovirus (CMV) is responsible for a wide range of diseases in neonates, and has been recognized as a major cause of congenital defects in developed countries for many years. More children suffer serious disabilities caused by congenital CMV than by several better-known childhood maladies. Insight into the epidemiology of congenital CMV disease is needed for the assessment of preventive strategies.

Methods

Using data from the National Hospital Morbidity Database (NHMD) complied by the Australian Institute of Health and Welfare (AIHW), we examined the rates of hospital admissions for children diagnosed with congenital cytomegalovirus (CMV) by year, sex, age group and length of stay.

Results

Over an 8-year period (1993–2001), there were 1314 admissions for the congenital form of CMV disease. Of these admissions, 25% were principally hospitalized because of congenital CMV. The average annual rate of admissions in children aged 0–4, 5–9 and 10–14 years was 9.40, 2.40 and 0.85 per 100,000 Australian population respectively.

Conclusion

Compared with many other congenital illnesses, which are now vaccine preventable, the burden of congenital CMV is comparatively high. A vaccination program would be justifiable should a vaccine become available.

Brain trauma enhances transient cytomegalovirus invasion of the brain only in mice that are immunodeficient

Cytomegalovirus (CMV) is one of the most common viral pathogens leading to neurological dysfunction in individuals with depressed immune systems. How CMV enters the brain remains an open question. The hypothesis that brain injury may enhance the entrance of CMV into the brain was tested. Insertion of a sterile needle into the brain caused a dramatic increase in mouse CMV in the brains of immunodeficient SCID mice inoculated peripherally within an hour of injury and examined 1 week later; peripheral inoculation 48 h after injury and a 1-week survival resulted in only a modest infection at the site of injury. In contrast, uninjured SCID mice, as well as injured immunocompetent control mice, showed little sign of viral infection at the same time intervals. Direct inoculation of the brain resulted in widespread dispersal and enhanced replication of mCMV in SCID brains tested 1 week later but not in parallel control brains. Differential viremia was unlikely to account for the greater viral load in the SCID brain, since increased mCMV in the blood of SCID compared to controls was not detected until a longer interval. These data suggest that brain injury enhances CMV invasion of the brain, but only when the adaptive immune system is compromised, and that the brain's ability to resist viral infection recovers rapidly after injury.

Manifestations of human cytomegalovirus infection: proposed mechanisms of acute and chronic disease

Infections with human cytomegalovirus (HCMV) are a major cause of morbidity and mortality in humans with acquired or developmental deficits in innate and adaptive immunity. In the normal immunocompetent host, symptoms rarely accompany acute infections, although prolonged virus shedding is frequent. Virus persistence is established in all infected individuals and appears to be maintained by both a chronic productive infections as well as latency with restricted viral gene expression. The contributions of the each of these mechanisms to the persistence of this virus in the individual is unknown but frequent virus shedding into the saliva and genitourinary tract likely accounts for the near universal incidence of infection in most populations in the world. The pathogenesis of disease associated with acute HCMV infection is most readily attributable to lytic virus replication and end organ damage either secondary to virus replication and cell death or from host immunological responses that target virus-infected cells. Antiviral agents limit the severity of disease associated with acute HCMV infections, suggesting a requirement for virus replication in clinical syndromes associated with acute infection. End organ disease secondary to unchecked virus replication can be observed in infants infected in utero, allograft recipients receiving potent immunosuppressive agents, and patients with HIV infections that exhibit a loss of adaptive immune function. In contrast, diseases associated with chronic or persistent infections appear in normal individuals and in the allografts of the transplant recipient. The manifestations of these infections appear related to chronic inflammation, but it is unclear if poorly controlled virus replication is necessary for the different phenotypic expressions of disease that are reported in these patients. Although the relationship between HCMV infection and chronic allograft rejection is well known, the mechanisms that account for the role of this virus in graft loss are not well understood. However, the capacity of this virus to persist in the midst of intense inflammation suggests that its persistence could serve as a trigger for the induction of host-vs-graft responses or alternatively host responses to HCMV could contribute to the inflammatory milieu characteristic of chronic allograft rejection.

Clinical aspects of hereditary hearing loss

Hearing loss is an etiologically diverse condition with many disease-related complications and major clinical, social, and quality of life implications. As the rate of acquired hearing loss secondary to environmental causes decreases and improvements in the diagnosis of abnormalities occur, the significance of genetic factors that lead to deafness increases. Advancements in molecular biology have led to improved detection and earlier intervention in patients with hearing loss. Subsequently, earlier implementation of educational services and cochlear implant technology in patients with profound hearing loss now results in superior communication skills and enhanced language development. The aim of this review is to provide a comprehensive framework underlying the causes of hearing impairment and to detail the clinical management for patients with hereditary hearing loss.

Universal hearing screening

OBJECTIVE

To determine the weighted incidence of hearing impairment in a standardized population of at risk and not at risk neonates seeking care at a tertiary level hospital in India.

METHODS

A prospective study of a nonrandomized cohort of 1769 neonates (1490: Not at risk; 279: At risk) from a total of 8192 neonates (6509: Not at risk; 1683: At risk) who sought care at St John's medical College hospital from 1st September 2002 to 31st March 2006 were screened for hearing impairment using transient evoked otoacoustic emissions. Weighting was performed using the expected value of 10 % at risk and 90 % not at risk infants in a typical tertiary care level center in India derived from the National Neonatology and Perinatology database 2002-2003. Z test and 95 % confidence interval was used to determine the external validity of the results. P less than 0.05 was considered as statistically significant. The power of the study is 90 %.

RESULTS

The incidence of hearing impairment in infants screened was 10 per 1769 infants screened (1490: Not at risk; 279: At risk) which is 5.65 per 1000 screened. 279 at risk infants were screened and 3 were detected to have hearing impairment which is an incidence of approximately 10.75 per 1000 screened. Of the 1490 not at risk infants screened 7 had hearing impairment that is 4.70 per 1000 screened. If this was extrapolated to a standardized population consisting of 10 % at risk and 90 % not at risk then the incidence would be 5.60 per 1000 screened with a 95 % confidence interval of 4.13-7.06. This narrow 95 % confidence interval with a p equal to 0.001 indicates that this value may be close to the caseload in a typical tertiary care center.

CONCLUSION

In this study the incidence of hearing impairment is 3 per 279 in at risk infants screened and 7 per 1490 in not at risk infants screened. The weighted incidence in a standardized population of neonates seeking care at tertiary level center in India is 5.60 per 1000 as per this study. This high incidence calls for all pediatricians to consider incorporating a basic hearing screen for all the neonates using cost effective and appropriate technology. Initial screening may be performed using behavioral observation techniques and confirmation by otoacoustic emissions.

Immunological response to cytomegalovirus in congenitally infected neonates

Cytomegalovirus (CMV) is the most common cause of congenital infection worldwide and occurs as a result of transplacental transmission of the virus. The human neonate is highly susceptible to infection due to a combination of immaturity of the immune system and antigenic inexperience. This study uses the in vivo model of congenital CMV to examine both the humoral and cell-mediated immune responses in vertically infected neonates and their mothers. Ten pairs of matched neonates and their mothers were evaluated for specific IgM responses to three immunodominant CMV antigens: pp38 (pUL80a), pp52 (pUL44) and pp150 (pUL32). In contrast to conventional enzyme immunoassay (EIA) testing for CMV-specific IgM, which found five of the mothers and four of the neonates to be positive, Western immunoblotting showed all 10 adults and nine newborns to be positive. Eight mothers and nine newborns had serological evidence of primary infection. All neonates showed a response to pp38, an assembly protein, nine responded to the pp52 immediate early antigen but only four had reactivity to the pp150 tegument associated protein. Of the mothers, eight had pp38 reactivity, 10 showed a response to the pp52 antigen and seven to the pp150 antigen. T cell-mediated immunity was assessed by measuring cytokines using a multiplex microarray assay. Levels of interferon (IFN)-gamma were high in both groups [mean +/- standard error of the mean (s.e.m.): neonates = 657 +/- 238 pg/ml, mothers = 1072 +/- 677 pg/ml, pNS]; however, neonates had significantly higher levels of interleukin (IL)-8 (316 +/- 136 pg/ml versus 48 +/- 28 pg/ml, P < 0.005). Similar levels of IL-2, IL-7, IL-10 and IL-12 were measured in both groups, but levels of IL-1alpha, IL-1beta, IL-4, IL-6 and tumour necrosis factor (TNF)-alpha were either absent or low. In response to CMV, neonates and adults mount a predominant T helper 1 (Th1) response, as evidenced by the presence of IL-2, IL-8, IL-12 and IFN-gamma with concomitant lack of IL-4. These findings suggest that the neonate, when presented with infection in utero, is capable of mounting an individual response; however, the lower IFN-gamma and higher IL-8 levels suggest reduced immune responsiveness when compared to their adult counterparts.

Mutations inGJB2,GJB6, and mitochondrial DNA are rare in African American and Caribbean Hispanic individuals with hearing impairment

Autosomal recessive nonsyndromic sensorineural hearing impairment (ARNSHI) comprises 80% of familial hearing loss cases. Approximately half result from mutations in the connexin 26 (Cx26) gene, GJB2, in Caucasian populations. Heterozygous mutations in GJB2 occasionally co-occur with a deletion of part of GJB6 (connexin 30; Cx30). It is estimated that approximately 1% of deafness is maternally inherited, due to mutations in mitochondrial DNA (mtDNA). Few studies have focused on the frequency of mutations in connexins or mtDNA in African American (AA) and Caribbean Hispanic (CH) admixture populations. In this study, we performed bidirectional sequencing of the GJB2 gene and polymerase chain reaction (PCR) screening for the common GJB6 deletion, as well as PCR/RFLP analysis for three mutations in mtDNA (A1555G, A3243G, A7445G), in 109 predominantly simplex AA and CH individuals. Variations found were a 101T > C (M34T; 1/101 cases), 109G > A (V37I; 1/101), 35delG (mutation; 4/101, (3/4) of non-AA/CH ethnicity), 167delT (mutation; 1/101), 139G > T (mutation; E47X; 1/101 homozygote, consanguineous), -15C > T (1/101), 79G > A (V27I; 9/101), 380G > A (R127H; 4/101; Guyana, India, Pakistan ethnicity), 670A > C (Indeterminate; K224Q; 1/101), 503A > G (novel; K168R; 3/101) and 684C > A (novel; 1/101). All but one of the AA and CH patients had monoallelic variations. There were no hemizygous GJB6 deletions in those with monoallelic GJB2 variations. We also did not identify any patients with the three mutations in mtDNA. Bidirectional sequencing of the GJB2 gene was performed in 187 AA and Hispanic healthy individuals. Our results reveal that GJB2 mutations, GJB6 deletions, and mtDNA mutations may not be significant in these minority admixture populations.

Real-time PCR assay using specimens on filter disks as a template for detection of cytomegalovirus in urine

Since congenital cytomegalovirus (CMV) infection causes late-onset sequelae, the identification of CMV-infected newborns is important. For this purpose, we established a simple real-time PCR assay using a filter disk. Combined with the collection of urine using filter papers placed in the diaper, this assay can make CMV screening more feasible and cost-effective.

Audiological Outcome of Infants with Congenital Cytomegalovirus Infection in a Prospective Study

The aim of this study was to evaluate the audiological outcome of long-term follow-up of infants with asymptomatic congenital cytomegalovirus (CMV) infection as defined by the presence of CMV DNA in neonatal urine. 12599 pregnant women underwent screening for CMV IgG and IgM antibodies between 1996 and 2003. Eighteen infants with congenital CMV infection were identified. These infants underwent the newborn hearing screening test or auditory brainstem response test. Follow-up hearing assessments were performed with the auditory brainstem response and behavioral audiometry. The seropositive rate of CMV IgG antibody among the pregnant women was 75.3%, and the yearly seropositive rate decreased over the study period. One hundred and forty-six pregnant women were positive for IgM antibody, and 18 neonates (12.3%) had congenital CMV infection. Sensorineural hearing loss (SNHL) was detected in 4 (25%) of the 16 infants with asymptomatic infection and 1 (50%) of the 2 infants with symptomatic infection during the first 6 months of life. Two infants who passed the newborn hearing screening had a delayed-onset SNHL in follow-up examinations up to 4 years of age. Two had progressive hearing loss and 2 had improvement of hearing loss. Screening of pregnant women for CMV infection and repeated audiological examinations of infants are necessary because there are infants with delayed-onset SNHL or improved SNHL caused by asymptomatic congenital CMV infection.

Cytomegalovirus induces interferon-stimulated gene expression and is attenuated by interferon in the developing brain

Cytomegalovirus (CMV) is considered the most common infectious agent causing permanent neurological dysfunction in the developing brain. We have previously shown that CMV infects developing brain cells more easily than it infects mature brain cells and that this preference is independent of the host B- and T-cell responses. In the present study, we examined the innate antiviral defenses against mouse (m) and human (h) CMVs in developing and mature brain and brain cells. mCMV infection induced interferon (IFN)-stimulated gene expression by 10- to 100-fold in both glia- and neuron-enriched cultures. Treatment of primary brain cultures with IFN-alpha, -beta, and -gamma or a synthetic RNA, poly(I:C), reduced the number of mCMV-infected cells, both in older cells and in fresh cultures from embryonic mouse brains. When a viral dose that killed almost all unprotected cells was used, IFN-protected cells had a natural appearance, and when they were tested with whole-cell patch clamp recording, they appeared physiologically normal with typical resting membrane potentials and action potentials. mCMV infection increased expression of representative IFN-stimulated genes (IFIT3, OAS, LMP2, TGTP, and USP18) in both neonatal and adult brains to similarly large degrees. The robust upregulation of gene expression in the neonatal brain was associated with a much higher degree of viral replication at this stage of development. In contrast to the case for downstream gene induction, CMV upregulated IFN-alpha/beta expression to a greater degree in the adult brain than in the neonatal brain. Similar to the case with cultured brain cells, IFN treatment of the developing brain in vivo depressed mCMV replication. In parallel work with cultured primary human brain cells, IFN and poly(I:C) treatment reduced hCMV infection and prevented virus-mediated cell death. These results suggest that coupling IFN administration with current treatments may reduce CMV infections in the developing brain.