Cytomegalovirus infection among migrant children

Prevalence, Magnitude, and Genotype Distribution of Urinary Cytomegalovirus (CMV) Shedding Among CMV-Seropositive Children and Adolescents in the United States

Background

There are limited nationally representative data on correlates of cytomegalovirus (CMV) shedding among children and adolescents. In addition, the genotype distribution of CMV infections has not been well characterized among general populations in the United States.

Methods

This study characterized urinary CMV shedding among CMV immunoglobulin G-positive 6- to 19-year-olds in the US household population using data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). Multivariable Poisson regression was used to estimate adjusted prevalence ratios (aPR) and corresponding 95% confidence intervals (CIs). Analyses were weighted and multiple imputation was performed to handle missing data (with the exception of CMV genotypes).

Results

Prevalence of urinary CMV shedding was significantly lower among 9- to 11-year-olds (20.6%; aPR = 0.61; 95% CI, 0.44-0.83) and 12- to 19-year-olds (7.0%; aPR = 0.21; 95% CI, 0.14-0.30) compared with 6- to 8-year-olds (34.4%). Among CMV shedders, the youngest age group also had the highest urinary CMV viral loads. The prevalence of urinary CMV shedding among obese individuals was significantly lower compared with lean individuals (aPR = 0.68; 95% CI, 0.47-0.99). Among CMV shedders, glycoprotein B (gB)1 (51%) was the most prevalent gB variant, followed by gB2 (29%), gB3 (21%), and gB4 (13%); glycoprotein H (gH)2 (60%) was more prevalent than gH1 (48%). Multiple (≥2) gB (14%) and multiple gH (7%) infections were detected among CMV shedders.

Conclusions

This study underscores the importance of young children even above the age of 5 years as a potential source of CMV transmission. The detection of multiple CMV strains among CMV shedders may have implications for the transmission of viral diversity as well as vaccine development.

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.

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.

Congenital Cytomegalovirus and Deafness

Although the incidence of medical and neurological problems resulting from congenital cytomegalovirus (CMV) infection is relatively low, the widespread and indiscriminate nature of this infection and the severity of these conditions when they do occur are such that it warrants the close attention of medical specialists, audiologists, and educators. The identification of congenital CMV is especially difficult because of its largely nonsymptomatic character, and because conditions associated with it, including hearing impairment, can be either progressive in nature or occur only later in life. Data reviewed in this study resemble those reported for children with impaired hearing from the 1964-65 maternal rubella epidemic: hearing loss in the severe to profound range, often accompanied by serious additional disabilities, especially mental retardation and cerebral palsy. Depressed achievement test results of children with CMV-induced hearing loss are further indications of the serious nature of this disease.The presence of any symptoms of CMV infection in infants or of risk factors associated with it-e.g., purplish skin rash, severe asphyxia, jaundice, low birth weight, swollen lymph glands, and other mononucleosis-like symptoms-signals the need for immediate testing, including audiological evaluation, and, if results are positive, the initiation of early medical and educational intervention.

Seroprevalence of antibodies to human herpesviruses in England and Hong Kong

The age-related prevalence of antibodies to herpesviruses was compared in England and Hong Kong. Altogether 327 sera from England and 266 sera from Hong Kong were tested for antibodies to herpes simplex virus (HSV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpesvirus 6 (HHV-6). Herpesvirus infections were common in both countries but generally were acquired earlier and were more prevalent in Hong Kong. Over 90% of children in Hong Kong were infected with VZV, EBV, and HHV-6 by 8 years of age. HSV and CMV were the least prevalent childhood infections in both countries, although, 30-40% of babies in Hong Kong became infected during the first year of life. CMV infections were rare throughout childhood in the English cohort. Overcrowding and early attendance at kindergarten may aid more efficient and earlier transmission of herpesvirus in Hong Kong. The high prevalence of CMV in particular may have implications for the management of young pregnant women and organ transplant recipients in Hong Kong.

Changing seroepidemiological patterns of cytomegalovirus infection in children in Taiwan from 1984 to 1989

The prevalence of cytomegalovirus (CMV) antibody was studied in 966 children in 1984 and 927 children in 1989. The overall prevalence rate of CMV antibody was 59% for children in 1984 and 46% for children in 1989 (P less than 0.05). In both study years, the prevalence rate of CMV antibody was about 70% in infants under 6 months of age, declined to a trough between the ages of 6 and 12 months, and then increased to 40-50% between 1 and 4 years of age. The rate of CMV antibody for children above 4 years in 1984 increased steadily with age and reached 82% by 12 years. In contrast, the prevalence rate in 1989 remained at the level of 40-50% from age 4 to 10 years. It was followed by a sharp increase after 10 years of age and reached 84% at 12 years old. The seropositive rate in each of the 5-, 6-, 8-, 9-, and 10-year-old groups was higher in 1984 than that in 1989. These observations indicated that the prevalence rate of CMV antibody is decreasing in children. This change may be related to various socioeconomic factors, especially the less crowded family conditions in recent years.

Prevalence of cytomegalovirus antibodies in Brazilian and Japanese populations in the north-east of Brazil

The serological status to cytomegalovirus (CMV) was examined for 616 Brazilians and 399 Japanese immigrants living in the North-East of Brazil. The sera were screened for IgG antibodies to CMV by enzyme-linked immunosorbent assay (ELISA). The overall prevalence of CMV antibodies was higher in the Japanese population (83.7%) than in the Brazilian population (69.8%). The seropositivity was analyzed by factors of age, sex, ethnic background, and socioeconomic status. Mother-baby contact seems to be a factor of significance in the seroepidemiology of CMV infection.

Comparative seroepidemiology of cytomegalovirus infection in the Canadian Arctic and an urban center

We conducted a seroepidemiologic study of cytomegalovirus (CMV) infection among 9,928 Inuit (Eskimo), Dene (Indian) and non-native inhabitants of the Northwest Territories (NWT) of Canada between April 1983 and March 1985. 4,184 inhabitants of Edmonton, a large predominantly white urban center served as controls. Sera were screened for antibody to CMV by enzyme-linked immunosorbent assay (ELISA). The prevalence rates of CMV antibody increased with age in all ethnic groups. By the age of two years 69.2 percent of Dene, 63.5 percent of Inuit, 33.3 percent of non-native and 22.9 percent of Edmonton children had CMV antibody. Over the age of five years Inuit children had higher rates of CMV antibody than Dene children (P less than .05) reflecting differences in infant adoption, breastfeeding practices and patterns of child care in the two native groups. By the age of 15 to 19 years 81.1 percent of Dene and 88.5 percent of Inuit women had CMV antibody compared to 48.8 percent of non-native and 50.9 percent of Edmonton women (P less than .05). Native children had higher prevalence rates than non-native children living in the NWT (P less than .05). Compared to similarly aged Edmonton residents, non-native children in the NWT 2 to 4 years and 5 to 9 years of age had a higher prevalence of CMV antibody (P less than .05). We observed a higher prevalence rate of CMV antibody among non-native children (10-14 years) and young women (15-19 years) living in predominantly native communities compared to those living in predominantly non-native communities in the NWT (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquisition of cytomegalovirus infection from birth to 10 years: a longitudinal serologic study

We performed serial serologic tests for cytomegalovirus (CMV) antibody in 177 children born to low- and middle-income families in Houston from 1975 to 1983. Mean duration of participation in the study was 4.8 years (range 1 to 9.6 years). Most rapid acquisition of antibody occurred during the first and second years of life, 13.6% and 12%, respectively; thereafter, annual acquisition varied from 1.5% to 4.6%, up to 10 years. Overall, 59 (33%) of the group were known to seroconvert by age 10 years. This was a minimal figure because of loss to follow-up. Analysis by the Kaplan-Meier method indicated that the probability of remaining seronegative was 65% at age 6 years, and 58% at age 8 years. Variables positively related to seroconversion by multivariate analysis were order of birth, seroconversion in a family member, and breast-feeding. During the first year of life, acquisition of CMV antibody was related to the seroimmune status of the mother. The variables of socioeconomic status, race, age of the mother, and attendance in a day care center did not appear to be related to seroconversion in these children.

The importance of primary cytomegalovirus infection in childhood cancer

Sixty-eight paediatric patients with malignant tumours or leukaemia were followed for signs of infection with human cytomegalovirus (HCMV) over 1 year. HCMV was isolated from 24 out of 68 patients at some point during the observation period; from urine in 14, from both urine and throat in 9 patients, and from throat alone in 1 patient. Previous antibody analysis indicated the presence of HCMV antibodies in 10 of the 24 virus-shedding patients, while 7 patients were seronegative and 7 undefined. Thus the incidence of reactivation appears to be higher than that of primary infection in these immunocompromised patients. The mean duration of virus shedding was 4.2 months in the primary infection group, 1.7 months in the reactivation group and 1.1 months in the undefined group. No difference in the incidence of HCMV-associated illness was observed between patients with leukaemia and those with malignant tumours. Clinical symptoms associated with HCMV infection (pneumonia (2), fever (6) and hepatitis (1)) were observed in all patients with primary infections and in only five patients with reactivated infection.

Cross-sectional seroepidemiologic study of the prevalence of cytomegalovirus and herpes simplex virus infection in a Canadian Inuit (Eskimo) community

The prevalence of antibody to cytomegalovirus (CMV) and herpes simplex virus (HSV) was determined, using enzyme-linked immunosorbent assay techniques, in a cross-sectional serologic survey of an isolated northern Canadian Inuit (Eskimo) community. The population studied included 155 Inuit and 11 Caucasian residents. By 6 years of age, 80% of the Inuit population were seropositive for CMV and 100% for herpes simplex virus. While only 7/63 Inuit greater than 20 years were seronegative for CMV, 5/11 Caucasian residents were seronegative (p = 0.01). For the Inuit population, no association between seropositivity for CMV and seropositivity for hepatitis A or hepatitis B was observed. This prevalence survey shows a serologic profile for infection with CMV and HSV in this northern Inuit community with an early age of acquisition and high prevalence of infection characteristic of socioeconomically deprived populations throughout the world, and is distinct from that observed in many other North American populations.

Cytomegalovirus (CMV) antibody in male homosexuals: a source for CMV immune globulin

Male homosexuals have been found to have an extraordinarily high prevalence, and high titers, of antibodies to cytomegalovirus (CMV), as determined by complement-fixation and passive hemagglutination tests. These findings support other data suggesting that CMV may be sexually transmitted. The high titers of CMV antibody found in this population suggest that the homosexual population may be a valuable source of plasma for preparations of CMV immune globulins. CMV immune globulins may be useful in passive immunoprophylaxis or immunotherapy in immunosuppressed patients.

Prevalence of antibodies to human cytomegalovirus in urban, kibbutz, and Bedouin children in southern Israel

Prevalence of antibody to human cytomegalovirus (CMV) was determined in a sample of 860 healthy children aged 1-13 years in Beer Sheva, in the Negev region of Israel. Three groups of children were tested: (1) urban Jewish children of low, middle, and high socioeconomic levels; (2) 8 rural communes (kibbutz) in which children live in close contact with each other from the 6th week of life under good hygienic conditions and a high standard of living; (3) Bedouin, seminomadic Arabs living in relatively poor hygienic conditions in the desert. Kibbutz children showed a significantly higher rate of CMV seropositivity by the second year of life than urban Jewish and Bedouin children (76% versus 44% and 54% respectively) with a gradual increase to 94% in the 10-13-year age group. Among children living in urban populations a significantly higher prevalence of CMV seropositivity was associated with crowding, but not with other socioeconomic indicators (place of residence, country of origin, or education level of parents). A marked rise of CMV seropositivity with age was found in urban Jewish children in the 2-5-year age group during which time they attend nurseries (44% to 67%) and in the Bedouin children in the 6-9-year age group (59% to 86%) when they first attend school. The data suggest that close contact is of major importance in CMV infection in childhood. The clinical implications of early acquisition and high prevalence of CMV antibodies in the kibbutz setting are discussed.

Congenital and acquired cytomegalovirus infections. Virological and clinical studies on a Swedish infant population

The study included two clinical materials. First, the frequency of cytomegalovirus and its clinical significance were studied among 661 Swedish children under one year of age admitted to a paediatric hospital. Before the age of one week 4/326 (1%) children excreted virus. At one month the frequency had risen to 6/52 (12%) and after this age the frequency was constant around 20--25%. Sixty per cent of infants born to immigrants were infected after one month of age. One of the four congenitally infected children had symptoms at birth followed by neurological sequelae. The majority of the infections acquired at birth or in early infancy seemed to be subclinical and without sequelae. Second, a retrospective investigation of 18 695 children born during a six-year period was performed. Two cases of virologically confirmed congenital cytomegalic inclusion disease was found. Regarding seven microcephalic patients in the retrospective study congenital CMV-infection could be excluded in four cases. In the remaining three cases the data did not permit any conclusions regarding the etiology.

Prevalence of cytomegalovirus in France

Between October 1968 and February 1970, 30 strains of cytomegalovirus were isolated from the urine of children admitted to hospitals in Lyon. Three groups of children up to the age of 14 years have been investigated.The first group consisted of 304 newborns and infants up to the age of 1 year; cytomegalovirus was grown from five of these (1.6%). Among these five children, two had cerebral disorders. None of them had ever shown any sign of typical CMV infection.The second group comprised 102 children between the ages of 1 and 14 years, from a special service for neurological and mental diseases. Cytomegalovirus was grown from 19 (18.6%).The third group was 27 children also between 1 and 14 years of age, admitted to hospital for miscellaneous diseases excluding cerebral disorders; cytomegalovirus was grown from six (22.2%).It appears that cytomegalovirus has a very low incidence in neonatal disease. The virus spreads at a higher rate in children 1-14 years old. No difference has so far been shown in the excretion rates of two groups of children, one with cerebral disorders and one with other diseases, but the number of children in the last group is too small to allow definite conclusions to be drawn.