Cytomegalovirus DNA among children attending two day-care centers in Tokyo

High prevalence of asymptomatic CMV shedding in healthy children attending the minnesota state fair

BACKGROUND

Young children in the household are a known risk factor for maternal CMV infection and consequently, congenital infection in infants. However, little is known about viral shedding in pre-school aged children.

OBJECTIVES

To estimate the prevalence of CMV DNA shedding and CMV antibodies among healthy children and their mothers.

STUDY DESIGN

A study of children ages 0 through 5 years was undertaken at the 2019 Minnesota State Fair. Children and their mothers were assessed for CMV shedding by procurement of a saliva swab for CMV PCR testing. An optional finger-stick for capillary blood was used to assess CMV antibodies.

RESULTS

A total of 109 children and 85 mothers were enrolled. The prevalence of CMV saliva shedding among children (mean age 3.1 years, SE=0.16) and their mothers was 12/109 (11.0%) and 1/85 (1.2%), respectively. The prevalence of CMV DNA among children peaked at 3 years of age (26%) while the mean viral load was greatest at one year of age (236,693 IU/mL). CMV IgG antibodies among those who agreed to a finger-stick were detected in 16/35 mothers (45.7%) and 0/7 children (0%). Mothers of children aged 5 years or greater had the highest seroprevalence (61.5%).

CONCLUSIONS

The prevalence of CMV salivary shedding in this unselected sample of young children was approximately 11.0%. The overall maternal seroprevalence in our sample was <50%, suggesting these women are at risk for acquisition of a primary CMV infection in subsequent pregnancies.

Salivary cytomegalovirus excretion in children in daycare centers and home care facilities in Japan

Cytomegalovirus (CMV) is the most common cause of congenital viral infection in developed countries. The incidence of in utero infection is high in pregnant women who are CMV antibody negative. An important infection route is in contact with children who attend daycare centers (DCCs). However, there are few reports on CMV excretion in children at DCCs in Japan. Saliva samples were collected twice during a 6-month interval from children attending one of two DCCs (DCC1 and DCC2 groups) and from those receiving home care (HC group). The samples were used to quantitatively evaluate CMV using real-time polymerase chain reaction and to determine glycoprotein B (gB) genotypes. The percentage of subjects who demonstrated CMV excretion in either the first or second sample collection was higher in the DCC groups than in the HC group, with incidences in the DCC1, DCC2, and HC groups of 53.4% (n = 47 of 88), 23.9% (n = 16 of 67), and 12.7% (n = 7 of 55), respectively. Compared with the DCC2 group, the DDC1 group had a higher incidence of CMV excretion and included more subjects with a high number of viral copies. In both DCC groups, the incidence of CMV excretion was highest in children younger than 3 years of age. In all three groups, the predominant genotypes were gB1 and gB3. Based on the higher incidence of CMV excretion in the DCC groups compared with the HC group, it is considered that CMV infection is acquired mainly in DCCs in children under the age of 3.

Human cytomegalovirus quantification in toddlers saliva from day care centers and emergency unit: a feasibility study

BACKGROUND

Cytomegalovirus (CMV) infection is the most important cause of congenital viral infection in developed countries. In utero transmission occurs at higher rates in seronegative women during primary infection, especially those in contact with young children in day-care centers (DCC). Nevertheless data on variability of CMV excretion among children in French DCCs are lacking, and are important for public health planning.

OBJECTIVES

Our main objective was to assess the feasibility of a salivary sample in DCCs in order to study CMV excretion among toddlers. Our secondary aims were to assess prevalence of CMV excretion in children attending Hospital Emergency Unit (EU) in comparison with various types of DCCs and to validate the analytical chain for collected specimens.

STUDY DESIGN

Excretion of CMV in saliva was quantified using a real-time PCR assay in children aged from 3 months to 6 years old in EU and in DCC, with gB, gH and gN genotypes determined in infected children. Salivary sampling was performed using small sponges placed into a DNA conservation medium. Socio cultural and medical information were collected from attending parents.

RESULTS

A total of 625 children were included, with 256 from six DCCs and 369 from one EU. In DCCs, the acceptability of the procedure was 87.3% (95%CI 78.5-96.2) amongst parents and children, and in the EU, acceptability was higher at 97.6% (95%CI 95.5-98.9). CMV shedding overall prevalence was 21.7% (95%CI 17.6-26.2), with CMV shedding prevalence in DCCs of 51.9% (95%CI 22.8-81.1).

CONCLUSION

We validated the feasibility and acceptability of measuring CMV shedding in the saliva of French toddlers. The discrepancy between CMV infection rates in day care centers and in the general population (as sampled in the EU) indicates the need for a further study to determine risk factors and shedding levels in the DCC population.

Nasal Peptide Vaccination Elicits CD8 Responses and Reduces Viral Burden after Challenge with Virulent Murine Cytomegalovirus

Infection of BALB/c mice with murine cytomegalovirus (MCMV) leads to CD8 cell responses to an immunodominant epitope YPHFMPTNL. We presented this epitope as a nasal peptide vaccine in combination with cholera toxin adjuvant, and evaluated immune responses and protection from MCMV challenge. Vaccination of naive mice generated elevated numbers of peptide-specific interferon-gamma-secreting splenocytes (median 80/million, range 60 to 490), compared to control mice (median 2/million, range -4.5 to 8; P=0.008, Mann-Whitney test). Twelve days after challenge with virulent MCMV, vaccinated mice had a 1.1 log(10) reduction in salivary gland viral titer compared to unvaccinated controls (5.36+/-0.24 vs. 6.42+/-0.12, mean +/-SD log(10) plaque-forming-units; P <0.001, t -test). Mice with chronic MCMV infection had consistent responses to the peptide (183+/-24/million interferon-gamma-secreting splenocytes). Nasal peptide vaccination during chronic infection boosted peptide-specific responses in two of four mice to >900/million interferon-gamma-secreting splenocytes. Nasal peptide vaccination was immunogenic in naïve and MCMV-infected mice, and reduced viral burden in naive mice after virulent MCMV challenge. The nasal route may be useful for peptide presentation by novel human vaccines.

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.

Vaccine-induced control of viral shedding following rhesus cytomegalovirus challenge in rhesus macaques

The use of animal models of human cytomegalovirus (HCMV) infection is critical to refine HCMV vaccine candidates. Previous reports have demonstrated that immunization of rhesus monkeys against rhesus cytomegalovirus (RhCMV) can reduce both local and systemic replication of RhCMV following experimental RhCMV challenge. These studies used prime/boost combinations of DNA expression plasmids alone or DNA priming and boosting with either inactivated virion particles or modified vaccinia virus Ankara (MVA) expressing the same antigens. Viral outcomes included reduced RhCMV replication at the site of subcutaneous inoculation and RhCMV viremia following intravenous inoculation. Since shedding of cytomegalovirus from mucosal surfaces is critical for horizontal transmission of the virus, DNA priming/MVA boosting was evaluated for the ability to reduce oral shedding of RhCMV following subcutaneous challenge. Of six rhesus monkeys vaccinated exclusively against RhCMV glycoprotein B (gB), phosphoprotein 65 (pp65), and immediate-early 1 (IE1), half showed viral loads in saliva that were lower than those of control monkeys by 1 to 3 orders of magnitude. Further, there was a strong association of memory pp65 T cell responses postchallenge in animals exhibiting the greatest reduction in oral shedding. These results highlight the fact that a DNA/MVA vaccination regimen can achieve a notable reduction in a critical parameter of viral replication postchallenge. The recently completed clinical trial of a gB subunit vaccine in which the rate of HCMV infection was reduced by 50% in the individuals receiving the vaccine is consistent with the results of this study suggesting that additional immunogens are likely essential for maximum protection in an outbred human population.

Prevalence and determinants of cytomegalovirus infection in pre-school children

AIM

The aim of this study is to measure the seroprevalence of cytomegalovirus (CMV) infection in 3.5-year-old children, and identify the determinants of seropositivity.

METHODS

A total of 1714 children were enrolled at birth. Approximately half were small for gestational age and half were appropriate for gestational age. Information on the children was collected at birth, 1 year and 3.5 years. At 3.5 years blood was collected and tested for CMV-specific immunoglobulin by an enzyme-linked immunosorbent assay in 530 children.

RESULTS

The weighted seroprevalence of CMV was 32.8% (95% confidence interval (CI) 27.4-38.1%). The seroprevalence of CMV varied markedly by ethnicity (European: 26.5% (95% CI 20.9-32.2%); Maori: 68.0% (44.0-92.0%); Pacific: 74.5% (56.3-92.6%); Indian: 50.0% (20.2-79.8%); Chinese: 47.2% (10.8-83.5%); Other: 21.9% (0.0-52.7%); P < 0.001). Socio-economic factors, number of siblings, day care centres attendance, maternal smoking, breastfeeding and other factors examined were not related to CMV seropositivity.

CONCLUSIONS

The seroprevalence of CMV in New Zealand pre-school children is similar to that reported from other developed countries. The finding of marked ethnic differences is unexplained by socio-economic factors, or other factors that were examined.

Nonhuman primate models of intrauterine cytomegalovirus infection

Congenital human cytomegalovirus (HCMV) infection has long been recognized as a threat to the developing fetus, even though studies have shown that only a subset of congenital infections results in clinical signs of disease. Among the estimated 8000 children who develop sequelae from congenital CMV infection each year in the United States alone, most suffer permanent developmental defects within the central nervous system. Because there is currently no approved vaccine for HCMV, and anti-HCMV drugs are not administered to gravid women with congenital infection because of potential toxicity to the fetus, there is a clear clinical need for effective strategies that minimize infection in the mother, transplacental transmission of the virus, and/or fetal disease. Animal models provide a method to understand the mechanisms of HCMV persistence and pathogenesis, and allow for testing of novel strategies that limit prenatal infection and disease. The rhesus macaque model is especially well suited for these tasks because monkeys and humans share strong developmental, immunological, anatomical, and biochemical similarities due to their close phylogenetic relationship. This nonhuman primate model provides an invaluable system to accelerate the clinical development of promising new therapies for the treatment of human disease. This review addresses salient findings with the macaque model as they relate to HCMV infection and potential avenues of discovery, including studies of intrauterine CMV infection. The complexity of the natural history of HCMV is discussed, along with the ethical and logistical issues associated with studies during pregnancy, the recent contributions of animal research in this field of study, and future prospects for increasing our understanding of immunity against HCMV disease.

Changes in seroprevalence to four herpesviruses over 30 years in Swedish children aged 9–12 years

BACKGROUND

Changing social conditions and life-styles in Sweden may have affected the spread of varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV).

OBJECTIVES

To study possible changes over 30 years in prevalence of antibodies against VZV, HSV, CMV, and EBV in Swedish children, using modern serological methods.

STUDY DESIGN

Serum samples from 819 Swedish children who were 9-12 years old in 1967-1968, in 1977-1978 (two cohorts), and in 1997, respectively, were examined. IgG antibodies against VZV, HSV, and CMV were measured by well validated enzyme-linked immunosorbent assays and against EBV by indirect immunoflourescense.

RESULTS

The seropositivity for VZV for 9-12 years old children was 50% in 1967-1968, 74-82% in 1977-1978, and 98% in 1997. The corresponding figures were 31%, 53%, 50%, and 58% for CMV, 35%, 35%, 32%, and 38% for HSV, and 64% in 1967-1968 and in 1977-1978 (both cohorts), and 62% in 1997 for EBV.

CONCLUSIONS

The seroprevalence for VZV increased significantly from 1967-1968 to 1997, and there was also a significant but smaller increase in the CMV seroprevalence, while seroprevalence to HSV and EBV remained relatively stable.

Inter- and intra-person cytomegalovirus infection in Malawian families

Sequence polymorphisms in the gN and gO genes of cytomegalovirus (CMV) amplified from mouth rinse and urine samples of 19 Malawian patients with Kaposi's sarcoma (KS) and 58 of their first-degree relatives were investigated. CMV-DNA was amplified from 41 people (53%) from either the gN or gO region in at least one sample, from 14 people (18%) in both domains in at least one sample, and from 13 (17%) in either domain in both samples. Twenty-one (51%) were seropositive for human immunodeficiency virus-1 (HIV). Identical gN sequences were recovered from eight families and non-identical sequences in six, while identical gO sequences were found in three families and non-identical sequences in five. Five people, four of whom were children, each carried multitypic gN sequences or gO sequences. The findings are consistent with CMV spread along intra- and extra-household routes, and with multiple intra-host CMV infection.

Analysis of respiratory viral coinfection and cytomegalovirus coisolation in pediatric inpatients

OBJECTIVE

To determine (1) the rates of single infection and coinfection with 7 respiratory viruses in pediatric inpatients undergoing respiratory viral cultures, (2) the rate of cytomegalovirus (CMV) coisolation in these patients and (3) the relationship between these and length of hospital stay.

METHODS

A retrospective analysis of all respiratory viral cultures undertaken at the Royal Children's Hospital, Melbourne, Australia during a 4-year period.

RESULTS

A total of 6706 respiratory virus cultures were identified, of which 3955 were the first nasopharyngeal or nasal specimen taken within 48 hours of admission from inpatients younger than 18 years of age. A virus was isolated in 1444 (36.5%) specimens. Coinfection was found in only 13 (0.9%) of these culture-positive specimens (0.3% of all 3955 specimens). After adjustment for age and seasonal variation in virus isolation, rates of coinfection were lower than would have been predicted for most respiratory viruses, particularly for respiratory syncytial virus (RSV) with influenza A, and RSV with any other virus. CMV was isolated in 174 (4.4%) specimens. Rates of CMV coisolation with respiratory viruses were lower than predicted from independent infection rates, with clearest evidence for the most common virus, RSV. The length of hospital stay varied between different viruses, but there was no evidence of increased length of stay in patients with coinfection (median, 1.9 days) compared with single infection (median, 2.5 days). The length of stay was longer in patients with CMV, especially when coisolated with a respiratory virus (a median of 3.9 days for coisolation compared with a median of 2.5 days for CMV isolation alone).

CONCLUSION

Coinfection with respiratory viruses is rare and in our study occurred less commonly than predicted from the independent virus isolation rates. Coisolation of CMV occurs less commonly than predicted with RSV. CMV coisolation, in contrast to respiratory virus coinfection, is associated with a longer length of stay.