Studies on the epidemiology of child infections in the Bari area (south Italy). VII. Epidemiology of Epstein-Barr virus infections

Herpesvirus-Bacteria pathogenic interaction in juvenile (aggressive) periodontitis. A novel etiologic concept of the disease

Localized juvenile (aggressive) periodontitis starts at puberty in otherwise healthy individuals and involves the proximal surfaces of permanent incisors and first molars. The disease destroys a sizeable amount of periodontal bone within a few months despite minimal dental plaque and gingival tissue inflammation. Cytomegalovirus and Epstein-Barr virus, as well as the two main periodontopathic bacteria Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, are linked to juvenile periodontitis. Juvenile periodontitis-affected teeth show cementum hypoplasia. We hypothesize that an active herpesvirus infection, at the time of root formation, hampers cementum formation and, at puberty, herpesvirus reactivation triggers an upgrowth of bacterial pathogens which produce rapid periodontal destruction on teeth with a defective periodontium. A pathogenic interaction between active herpesviruses and bacterial pathogens can potentially explain the etiology and incisor-first molar destructive pattern of juvenile periodontitis. Effective treatment of juvenile periodontitis may target the herpesvirus-bacteria co-infection.

Multiple sclerosis among first- and second-generation immigrants in Denmark: a population-based cohort study

Multiple sclerosis is a disease with a highly variable incidence worldwide. While knowledge about multiple sclerosis risk factors has grown over the years, the aetiology of multiple sclerosis has still not been fully established. We examined multiple sclerosis incidence rates among first-generation immigrants in Denmark, a high-incidence country, and their Danish-born children (second-generation immigrants), to evaluate the importance and timing of exposure to environmental factors in the aetiology of multiple sclerosis. By means of the Danish Civil Registration System we identified 9 121 187 individuals living in Denmark between 1968 and 2015, including 1 176 419 first-generation and 184 282 second-generation immigrants. Study participants were followed for multiple sclerosis in the Danish Multiple Sclerosis Registry from 1968 to 2015. The relative risk (RR) of multiple sclerosis according to immigration status was estimated by means of multiple sclerosis incidence rate ratios obtained in log-linear Poisson regression analysis. Altogether, 16 905 cases of multiple sclerosis were identified in the study cohort, 578 among first-generation and 106 among second-generation immigrants. Multiple sclerosis risk among first-generation immigrants whose parents were born in low, intermediate and high multiple sclerosis risk areas were 21% (RR = 0.21; 95% CI: 0.16-0.28), 43% (RR = 0.43; 95% CI: 0.36-0.50) and 75% (RR = 0.75; 95% CI: 0.67-0.83), respectively, of that among ethnic Danes (test for trend P < 0.0001). First-generation immigrants arriving in Denmark before age 15 years had a multiple sclerosis risk higher than that in their country of birth but lower than that in Denmark, reaching on average 69% of the multiple sclerosis risk among ethnic Danes (RR = 0.69; 95% CI: 0.55-0.87). Multiple sclerosis risk among individuals who came to Denmark at a later age remained closer to that of their country of birth, corresponding to 45% of the multiple sclerosis risk among ethnic Danes (RR = 0.45; 95% CI: 0.41-0.49). Our study supports the idea that environmental factors exerting their role in childhood or adolescence may be of aetiological relevance in multiple sclerosis.

Clinical Utility of Epstein-Barr Virus Viral Load Monitoring and Risk Factors for Posttransplant Lymphoproliferative Disorders After Kidney Transplantation: A Single-Center, 10-Year Observational Cohort Study

Background

Posttransplant lymphoproliferative disease (PTLD) is an important cause of morbidity and mortality in solid organ transplants. Epstein Barr virus (EBV) plays a major role in PTLD development. Guidelines recommend EBV viral load (VL) monitoring in high-risk populations in the first year.

Methods

Retrospective observational study in all adult patients who had at least 1 EBV-VL performed in the postkidney transplant (KT) period from January 2005 to December 2014 at the Policlinico Modena Hospital. We compared patients with negative EBV-DNA to patients with positive EBV-DNA and we described PTLD developed in the study period.

Results

One hundred ninety (36.3%) KT patients of 523 were screened for EBV-DNA with 796 samples. One hundred twenty-eight (67.4%) of 190 tested patients presented at least 1 positive sample for EBV. Older age, the use of sirolimus, everolimus, and steroids were associated with EBV-DNA positivity in the univariate analysis. Nine (1.7%) of 523 patients had PTLD. Incidence rate of PTLD in the KT cohort was 0.19/100 person year follow-up (95% confidence interval, 0.09-0.37). One of 9 patients developed early PTLD and was a high-risk patient. Only this PTLD case was positive for EBV. No PTLD case had an EBV-VL superior to 4000 copies/mL.

Conclusions

Our results suggest that the keystone of PTLD diagnosis is the clinical suspicion. Our study suggests that, in line with guidelines, EBV-VL assays may be avoided in low-risk patients in the absence of a strong clinical PTLD suspicion without increasing patients' risk of developing PTLD. This represents a safe and cost-saving clinical strategy for our center.

Determinants of Ethnic Differences in Cytomegalovirus, Epstein-Barr Virus, and Herpes Simplex Virus Type 1 Seroprevalence in Childhood

OBJECTIVE

To identify whether there are ethnic differences in cytomegalovirus (CMV), Epstein-Barr virus (EBV), and herpes simplex virus type 1 (HSV-1) seroprevalence rates in children at 6 years of age, and when present, to evaluate how these differences can be explained by sociodemographic and environmental factors.

STUDY DESIGN

This study was embedded within a multi-ethnic population-based prospective cohort study. Serum IgG levels against CMV, EBV, and HSV-1 were measured by enzyme-linked immunosorbent assay in 4464 children (median age 6.0 years). Information on demographics and characteristics were assessed by questionnaires. Herpesvirus seroprevalences between Surinamese-Creole, Surinamese-Hindustani, Turkish, Moroccan, Cape Verdean Antillean, and Native Dutch children were compared.

RESULTS

Non-Western ethnicity was an independent risk factor for CMV (aOR, 2.16; 95% CI 1.81-2.57), EBV (1.76; 1.48-2.09), and HSV-1 seropositivity (1.52; 1.39-1.66). Among the ethnic groups, CMV seroprevalences ranged between 29% and 65%, EBV between 43% and 69%, and HSV-1 between 13% and 39%. Low family net household income, low maternal educational level, crowding, and lifestyle factors explained up to 48% of the ethnic differences in HSV-1 seroprevalences, and up to 39% of the ethnic differences in EBV seroprevalences. These factors did not explain ethnic differences in CMV seroprevalences.

CONCLUSIONS

Socioeconomic position and factors related to lifestyle explain only a part of the large ethnic differences in EBV and HSV-1 seroprevalences, whereas they do not explain ethnic differences in CMV seroprevalences in childhood.

Targeting Epstein-Barr virus infection as an intervention against multiple sclerosis

We here review contemporary data on genetic and environmental risk factors, particularly Epstein-Barr virus infection, for multiple sclerosis. There is an important immunogenetic etiological factor for multiple sclerosis. However, a general assumption is that immune defense genes are activated by the environment, basically by infections. We contend that the relationship between infectious mononucleosis and multiple sclerosis cannot be completely explained by genetics and inverse causality. Epstein-Barr infection as indicated by positive serology is an obligatory precondition for multiple sclerosis, which is a stronger attribute than a risk factor only. Data on events in the early pathogenesis of multiple sclerosis are cumulating from bio-banks with presymptomatic specimens, but there is only little information from the critical age when Epstein-Barr infection including infectious mononucleosis is acquired, nor on the detailed immunological consequences of this infection in individuals with and without multiple sclerosis. We discuss how focused bio-banking may elaborate a rationale for the development of treatment or vaccination against Epstein-Barr virus infection. A cohort in which intervention against Epstein-Barr infections was performed should be the object of neurological follow-up.

Seroprevalence of Anti-EBV IgG among Various Age Groups from Khon Kaen Province, Thailand

Epstein-Barr virus (EBV) is an extremely common herpesvirus that may cause asymptomatic infection or various diseases, including infectious mononucleosis, certain lymphoproliferative diseases and several types of neoplasms. Vaccine development is an important strategy to reduce the burden of EBV-associated diseases and the timing of vaccinations should be before primary infection occurs. In the past, more than 90% of Thai children were infected with EBV in early childhood. Now, due to the improved healthcare system in Thailand, we aim to determine current prevalence of EBV infection among people in different age groups. A total of 538 sera were collected from residents of Khon Kaen province in northeastern Thailand for detecting anti-EBV IgG. Sera of infants under 2-years-old were also tested for anti-EBV IgM and EBV-DNA. The prevalence of anti-EBV IgG was 47.1% (95% CI: 23.3-70.8) in infants aged 0-6 months, 34.9% (95% CI: 23.1-46.7) in those aged 6-24 months, 87.9% (95% CI: 79.5-96.3) in children aged 3-5 years and then maintained at above 95% through adulthood. These seropositivity rates among Thai children remain similar to those found in a previous study conducted 20 years ago. Thai children are still exposed to EBV from an early age. Therefore, a prophylactic vaccine should be given within the first two years of life.

Hypothesis: could Epstein-Barr virus play a role in the development of gastroschisis?

BACKGROUND

The strong inverse association between maternal age and risk of gastroschisis in offspring has spurred many investigators to hypothesize that behaviors among younger females are the cause. Examples include cigarette smoking, illicit drugs, genitourinary infections, and sexually transmitted diseases, each of which has been reported to be associated with gastroschisis. Although these exposures are more common in young women, recent studies have shown that cigarette smoking, genitourinary infections, and sexually transmitted diseases are most strongly associated with gastroschisis in older women. There is both anecdotal and published evidence showing that gastroschisis sometimes (but not always) occurs in clusters, raising the possibility that an infectious agent might be involved in its pathogenesis.

RESULTS

One such agent whose epidemiologic characteristics parallel those of gastroschisis is Epstein-Barr virus (EBV). Primary EBV infection in early childhood has been decreasing over time, leaving a greater proportion of adolescents at risk, as reflected by increased rates of infectious mononucleosis over time. During the childbearing years, risk of primary EBV infection decreases dramatically, as does risk of gastroschisis. The stronger risks of gastroschisis associated with cigarette smoking, genitourinary infections, and sexually transmitted diseases in older women might be explained by EBV reactivation resulting from multiple challenges to immune response such as pregnancy, age, toxic exposures, and genitourinary and sexually transmitted infections.

CONCLUSION

EBV and other herpes viruses should be added to the research agenda for gastroschisis.

Prevalence of Epstein-Barr virus in Japan: Trends and future prediction

Epstein-Barr virus (EBV) is the causative agent of infectious mononucleosis and some malignancies including EBV-associated-lymphomas. A large portion of adults all over the world are infected with EBV. In children, however, there are geographic variations. Most of the children in Asia and in other developing countries are infected in their early life, before 1 year of age (>90% of 5-9-year-old children are infected), while the age of primary infection is delayed in Western countries (approx. 50% of 5-9-year-old children are infected). The purpose of the present paper was to investigate the recent time trend of the EBV seropositivity among 5-7-year-old children living in Tokyo and its neighboring prefectures. Indirect immunofluorescein study for IgG antibody to viral capsid antigen was performed on 442 archival sera. Before the early 1990s, >80% of 5-7-year-old children were found to be seropositive, while the positivity rate decreased to 59% (P < 0.001) for the years 1995-1999. These results also showed that the delay in the age of primary infection is continuing and that the rate is estimated to be <50% in 2006. This result suggests that the delay will affect the incidence of EBV-associated disorders in Japan.

Maintenance of serum immunoglobulin G antibodies to Epstein-Barr virus (EBV) nuclear antigen 2 in healthy individuals from different age groups in a Japanese population with a high childhood incidence of asymptomatic primary EBV infection

Immunoglobulin G (IgG) antibodies to Epstein-Barr virus (EBV) nuclear antigens 2 and 1 (EBNA-2 and EBNA-1, respectively) were studied using sera from healthy individuals of a population with a high incidence of asymptomatic primary EBV infections during infancy or childhood in Japan. Two CHO-K1 cell lines expressing EBNA-2 and EBNA-1 were used for anticomplement and indirect immunofluorescence assays. The positivity rate for EBNA-2 IgG rose in the 1- to 2-year age group, increased and remained at a plateau ( approximately 45%) between 3 and 29 years of age (3- to 4-, 5- to 9-, 10- to 14-, and 15- to 29-year age groups), and then reached 98% by age 40 (>/== 40-year age group). Both seropositivity for EBNA-1 and seropositivity for EBNAs in Raji cells (EBNA/Raji) were detected in the 1- to 2-year age group, remained high, and finally reached 100% by age 40. The geometric mean titer (GMT) of EBNA-2 IgG reached a plateau in the 5- to 9- and 10- to 14-year-old groups and remained elevated in the older age groups (15 to 29 and >/== 40 years). The GMT of EBNA-1 IgGs increased to a plateau in the 1- to 2-year-old group and remained unchanged in the older age groups. The GMT of EBNA/Raji IgGs also reached a plateau in the 1- to 2-year-old group, remained level throughout the 3- to 14-year age groups, and decreased in the 15- to 29-year-olds. EBNA-2 IgGs emerged earlier than EBNA-1 IgGs in 8 of 10 patients with infectious mononucleosis, who were between 1 and 27 years old, and declined with time in three of eight cases. These results suggest that EBNA-2 IgG antibodies evoked in young children by asymptomatic primary EBV infections remain elevated throughout life, probably because of reactivation of latent and/or exogenous EBV superinfection.

A role of late Epstein-Barr virus infection in multiple sclerosis

OBJECTIVE

To assess Epstein-Barr virus (EBV) seroconversion in a high multiple sclerosis (MS) prevalence area and to evaluate the recall of diagnosed infectious mononucleosis in MS patients.

METHODS

The study was based on information or blood samples, or both, from schoolchildren, young MS patients and matched controls. EBV serology was performed on 1154 blood samples.

RESULTS

We demonstrate that more than one third of the population in a high MS prevalence area is seronegative to EBV at puberty. This is in contrast to the virtually complete seroconversion to EBV early in life in individuals from areas with a low prevalence of MS. Furthermore, we demonstrate that recall of diagnosed infectious mononucleosis (IM), but not recall of common childhood diseases, is significantly more frequent among MS patients than healthy controls. All MS patients, including patients without prior immunosuppressive treatment, were EBV seropositive.

CONCLUSION

During or after puberty, EBV is transmitted to a major proportion of the population in an MS high-prevalence area. Together with our previous documentation of an association between late infection with EBV and an increased risk of developing MS, these data support a role of EBV infection in MS.

Sero-epidemiological patterns of Epstein-Barr and herpes simplex (HSV-1 and HSV-2) viruses in England and Wales

The aim was to carry out a population-based sero-prevalence survey of Epstein-Barr virus (EBV) across a wide age range in England and Wales and to identify any associations between EBV and herpes simplex virus types one and two (HSV-1 and 2). Sera from an age-stratified sample of 2,893 individuals, submitted for diagnostic purposes to 15 public health laboratories in England and Wales in 1994, were tested for immunoglobulin G (IgG) antibody to EBV. The samples had been tested previously for IgG antibody to HSV-1 and HSV-2. The serological profile of EBV was consistent with an endemic infection with peaks in transmission in those less than 5 years old and in young adults. An age adjusted analysis found a significant association between EBV and HSV-1 seropositivity that is most likely explained by similarities in their mode of transmission. The very low seroprevalence of HSV-2 in this sample complicated the comparisons of EBV and HSV-1 with HSV-2. Any associations were most likely explained by chance. Given the association between EBV and HSV-1, it is likely that recently documented epidemiological changes in HSV-1 also apply to EBV. Continuing surveillance of these herpes viruses is necessary as the predicted changes could have a significant public health impact, especially in the young adult population.