Seroepidemiologic study of Epstein-Barr virus infections in a rural community

Case report and literature review: A hiccup patient developed encephalitis and duodenal perforation

Brainstem encephalitis is rare and this study aims to report the clinical course, imaging features, and therapeutic response of hiccup patient with gastric ulcer who developed brainstem encephalitis with Epstein-Barr virus (EBV) detected in cerebrospinal fluid and then subsequently followed by development of duodenal perforation. Data of a gastric ulcer patient who suffered from hiccups, with brainstem encephalitis detected and then subsequently suffered from duodenal perforation were collected retrospectively and analyzed. A literature search was conducted on Epstein-Barr virus associated encephalitis using keywords like "Epstein-Barr virus encephalitis" and "brainstem encephalitis," "hiccup." The etiology of EBV-related brainstem encephalitis in this case report is not clear. However, from the initial hiccup to the presentation of both brainstem encephalitis and duodenal perforation during the course of hospitalizations builds up an uncommon case.

Unstable EBV latency drives inflammation in multiple sclerosis patient derived spontaneous B cells

Epidemiological studies have demonstrated that Epstein-Barr virus (EBV) is a known etiologic risk factor, and perhaps prerequisite, for the development of MS. EBV establishes life-long latent infection in a subpopulation of memory B cells. Although the role of memory B cells in the pathobiology of MS is well established, studies characterizing EBV-associated mechanisms of B cell inflammation and disease pathogenesis in EBV (+) B cells from MS patients are limited. Accordingly, we analyzed spontaneous lymphoblastoid cell lines (SLCLs) from multiple sclerosis patients and healthy controls to study host-virus interactions in B cells, in the context of an individual's endogenous EBV. We identify differences in EBV gene expression and regulation of both viral and cellular genes in SLCLs. Our data suggest that EBV latency is dysregulated in MS SLCLs with increased lytic gene expression observed in MS patient B cells, especially those generated from samples obtained during "active" disease. Moreover, we show increased inflammatory gene expression and cytokine production in MS patient SLCLs and demonstrate that tenofovir alafenamide, an antiviral that targets EBV replication, decreases EBV viral loads, EBV lytic gene expression, and EBV-mediated inflammation in both SLCLs and in a mixed lymphocyte assay. Collectively, these data suggest that dysregulation of EBV latency in MS drives a pro-inflammatory, pathogenic phenotype in memory B cells and that this response can be attenuated by suppressing EBV lytic activation. This study provides further support for the development of antiviral agents that target EBV-infection for use in MS.

Infectious Mononucleosis: diagnosis and clinical interpretation

EBV is the sole causative agent of the acute illness in humans described either as infectious mononucleosis (IM), or glandular fever. IM, when not clinically silent, can present in patients with at least two of the classic triad of symptoms of fever, pharyngitis, and lymphadenopathy. Challenges for the clinician arise when atypical cases present. Early, accurate and informed laboratory test results are vital for diagnosis, appropriate treatment, and management. A key challenge for the practitioner, particularly in cases where the illness can present atypically, is distinguishing bacterial tonsillitis infections from early acute IM. The ability to draw on timely, clear, and insightful laboratory results to distinguish viral from bacterial infection is vital. Correct and prompt diagnosis of IM can help prevent the unnecessary administration of antibiotics and mitigate the need for other expensive exploratory tests in cases of IM that present with splenomegaly, lymphadenopathy, or suspect haematological conditions. Good communication between the requesting clinician and those carrying out the investigative process, and between the different laboratory departments involved, is good practice and would ultimately benefit the patient. This communication will comprehensively review the aetiology, clinical presentation, and laboratory findings in IM with a view to promoting further research and so derive a standard diagnostic algorithm of the condition.

High pretreatment plasma Epstein-Barr virus (EBV) DNA level is a poor prognostic marker in HIV-associated, EBV-negative diffuse large B-cell lymphoma in Malawi

Plasma Epstein-Barr virus (EBV) DNA measurement has established prognostic utility in EBV-driven lymphomas, where it serves as a circulating tumor DNA marker. The value of plasma EBV measurement may be amplified in sub-Saharan Africa (SSA), where advanced imaging and molecular technologies for risk stratification are not typically available. However, its utility in diffuse large B-cell lymphoma (DLBCL) is less certain, given that only a subset of DLBCLs are EBV-positive. To explore this possibility, we measured plasma EBV DNA at diagnosis in a cohort of patients with DLBCL in Malawi. High plasma EBV DNA at diagnosis (≥3.0 log10 copies/mL) was associated with decreased overall survival (OS) (P = .048). When stratified by HIV status, the prognostic utility of baseline plasma EBV DNA level was restricted to HIV-positive patients. Unexpectedly, most HIV-positive patients with high plasma EBV DNA at diagnosis had EBV-negative lymphomas, as confirmed by multiple methods. Even in these HIV-positive patients with EBV-negative DLBCL, high plasma EBV DNA remained associated with shorter OS (P = .014). These results suggest that EBV reactivation in nontumor cells is a poor prognostic finding even in HIV-positive patients with convincingly EBV-negative DLBCL, extending the potential utility of EBV measurement as a valuable and implementable prognostic marker in SSA.

Hypothesis: Multiple sclerosis is caused by three-hits, strictly in order, in genetically susceptible persons

Multiple Sclerosis is a chronic, progressive and debilitating neurological disease which, despite extensive study for over 100 years, remains of enigmatic aetiology. Drawn from the epidemiological evidence, there exists a consensus that there are environmental (possibly infectious) factors that contribute to disease pathogenesis that have not yet been fully elucidated. Here we propose a three-tiered hypothesis: 1) a clinic-epidemiological model of multiple sclerosis as a rare late complication of two sequential infections (with the temporal sequence of infections being important); 2) a proposal that the first event is helminthic infection with Enterobius Vermicularis, and the second is Epstein Barr Virus infection; and 3) a proposal for a testable biological mechanism, involving T-Cell exhaustion for Epstein-Barr Virus protein LMP2A. We believe that this model satisfies some of the as-yet unexplained features of multiple sclerosis epidemiology, is consistent with the clinical and neuropathological features of the disease and is potentially testable by experiment. This model may be generalizable to other autoimmune diseases.

The role of the early social environment on Epstein Barr virus infection: a prospective observational design using the Millennium Cohort Study

Epstein-Barr virus (EBV) is a highly prevalent herpesvirus linked to infectious mononucleosis and several malignancies. This paper aims to study the association between children's early life social environment at 9 months and EBV infection at 3 years of age.

METHODS

We used data on children included in the UK Millennium Cohort Study. We described the social environment using area-level and material factors as well as socioeconomic position (SEP) at 9 months. EBV was measured at 3 years of age (n = 12 457).

RESULTS

Lower rates of EBV infection were observed in children living in towns and rural areas compared with those living in cities. Lower SEP and overcrowding in the household increased the odds of being infected. Children whose parents were social tenants were more likely to be infected than homeowners. In the overall model, the strength of the association between material factors and EBV infection weakened.

CONCLUSIONS

We showed that early life material deprivation was associated with a higher risk of EBV infection among 3-year-olds. Children living in more deprived social conditions may be more likely to become EBV carriers at an earlier age.

Frequency of Epstein - Barr Virus in Patients Presenting with Acute Febrile Illness in Kenya

Background

Most acute febrile illnesses (AFI) are usually not associated with a specific diagnosis because of limitations of available diagnostics. This study reports on the frequency of EBV viremia and viral load in children and adults presenting with febrile illness in hospitals in Kenya.

Methodology/Principal Findings

A pathogen surveillance study was conducted on patients presenting with AFI (N = 796) at outpatient departments in 8 hospitals located in diverse regions of Kenya. Enrollment criterion to the study was fever without a readily diagnosable infection. All the patients had AFI not attributable to the common causes of fever in Kenyan hospitals, such as malaria or rickettsiae, leptospira, brucella and salmonella and they were hence categorized as having AFI of unknown etiology. EBV was detected in blood using quantitative TaqMan-based qPCR targeting a highly conserved BALF5 gene. The overall frequency of EBV viremia in this population was 29.2%, with significantly higher proportion in younger children of <5years (33.8%, p = 0.039) compared to patients aged ≥5 years (26.3% for 5–15 years or 18.8% for >15 years). With respect to geographical localities, the frequency of EBV viremia was higher in the Lake Victoria region (36.4%), compared to Kisii highland (24.6%), Coastal region (22.2%) and Semi-Arid region (25%). Furthermore, patients from the malaria endemic coastal region and the Lake Victoria region presented with significantly higher viremia than individuals from other regions of Kenya.

Conclusions/Significance

This study provides profiles of EBV in patients with AFI from diverse eco-regions of Kenya. Of significant interest is the high frequency of EBV viremia in younger children. The observed high frequencies of EBV viremia and elevated viral loads in residents of high malaria transmission areas are probably related to malaria induced immune activation and resultant expansion of EBV infected B-cells.

Coprevalence of Epstein-Barr Virus, Cytomegalovirus, and Herpes Simplex Virus Type-1 Antibodies Among United States Children and Factors Associated With Their Acquisition

BACKGROUND

Epstein-Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus type-1 (HSV-1) infections are common worldwide, but age-specific prevalence of primary infection varies by race or ethnicity and geographical location. Comparing demographic groups could identify factors influencing the rate of acquisition, age-specific antibody prevalence is relevant for determining when to administer prophylactic vaccines, and coprevalence suggests similar risk factors.

METHODS

Stored sera collected from the cross-sectional National Health and Nutrition Examination Surveys 2003-2004 cycle were tested for EBV, CMV, and HSV-1 antibody. Demographic information was obtained through self-reported questionnaires. Statistical analysis included logistic regression and multivariate analysis adjusting for the multistage cluster design.

RESULTS

Overall, 36% of children had antibody against 2 or more of the viruses. Coprevalence with EBV, CMV, and HSV-1 was higher in females, in non-Hispanic blacks, and Mexican Americans, compared with non-Hispanic whites, and in those without health insurance. Antibody prevalence was associated with (1) lower household income and education and (2) greater crowding. Nearly all children with CMV antibody or HSV-1 antibody had been infected with EBV.

CONCLUSIONS

There was a disproportionately high prevalence of EBV, CMV, and HSV-1 antibody among Mexican Americans and non-Hispanic blacks, groups with a lower poverty income ratio, and those with less household education. They might benefit from receiving prophylactic herpes vaccines when fairly young. The presence of EBV, CMV, or HSV-1 antibody increases the odds of having antibody against one of the other viruses and is a ripe area for future research.

The incidence of epstein-barr virus primary infection among suspected patients referred to namazi hospital of shiraz, iran

Background:

Many children become infected with Epstein-Barr virus (EBV) during their childhood. Since the clinical profile of EBV primary infection is challenging, it is important to use the best diagnostic clinical means. Detection of IgM against viral capsid antigen (VCA) by ELISA has been shown to be a reliable method.

Objectives:

This study was conducted to demonstrate the incidence of EBV primary infection, among suspected patients referred to Namazi hospital, Shiraz, Iran.

Patients and Methods:

The sample included 346 patients with an age range of 0 to 20 years (6.31 ± 4.66: 10.97 years). A volume of 5 mL of blood was collected from each case. The patients were divided to four age groups. The sera were tested for the presence of VCA-IgM by commercially available Anti-EBV-VCA ELISA kit.

Results:

The results indicated that 104 (30.0%) of the patients were EBV VCA IgM positive, with no significant difference in the incidence of EBV primary infection between males and females. However, the incidence of infection was significantly different between age group I (0 - 5 years) and III (11 - 15 years), and also between age group I (0 - 5 years) and IV (16 - 20 years) (P < 0.05).

Conclusions:

Considering the results, accurate and on time diagnosis of EBV primary infection in both children and adolescents will help prevent unnecessary hospitalization, medication and incorrect medical decisions. In addition, this will decrease further treatment costs and related medical procedures.

Early virological and immunological events in asymptomatic Epstein-Barr virus infection in African children

Epstein-Barr virus (EBV) infection often occurs in early childhood and is asymptomatic. However, if delayed until adolescence, primary infection may manifest as acute infectious mononucleosis (AIM), a febrile illness characterised by global CD8+ T-cell lymphocytosis, much of it reflecting a huge expansion of activated EBV-specific CD8+ T-cells. While the events of AIM have been intensely studied, little is known about how these relate to asymptomatic primary infection. Here Gambian children (14-18 months old, an age at which many acquire the virus) were followed for the ensuing six months, monitoring circulating EBV loads, antibody status against virus capsid antigen (VCA) and both total and virus-specific CD8+ T-cell numbers. Many children were IgG anti-VCA-positive and, though no longer IgM-positive, still retained high virus loads comparable to AIM patients and had detectable EBV-specific T-cells, some still expressing activation markers. Virus loads and the frequency/activation status of specific T-cells decreased over time, consistent with resolution of a relatively recent primary infection. Six children with similarly high EBV loads were IgM anti-VCA-positive, indicating very recent infection. In three of these donors with HLA types allowing MHC-tetramer analysis, highly activated EBV-specific T-cells were detectable in the blood with one individual epitope response reaching 15% of all CD8+ T-cells. That response was culled and the cells lost activation markers over time, just as seen in AIM. However, unlike AIM, these events occurred without marked expansion of total CD8+ numbers. Thus asymptomatic EBV infection in children elicits a virus-specific CD8+ T-cell response that can control the infection without over-expansion; conversely, in AIM it appears the CD8 over-expansion, rather than virus load per se, is the cause of disease symptoms.

A large-scale seroprevalence of Epstein-Barr virus in Taiwan

Background

Epstein-Barr virus (EBV) causes a variety of clinical manifestations from asymptomatic infection to acute infectious mononucleosis in human. Moreover, the EBV infection is associated with malignancies. The large-scale EBV seroepidemiology across all age groups has been lacking in Taiwan.

Methods

A total of 1411 serum samples were tested to examine the seroprevalence of EBV in 2007. The samples were collected during an island-wide seroepidemiological survey of vaccine preventable diseases in Taiwan. The enzyme-linked immunosorbent assay was performed to detect anti-EBV viral capsid IgG in sera. Demographic and personal health data were obtained by questionnaires.

Results

The overall weighted seropositive rate of EBV was 88.5% (95% CI, 86.7%–90.1%). The seropositive rate of EBV reached 52.8% (95% CI, 44.0%–61.6%) in children aged 2 years, rapidly rose to 88.7% (95% CI, 79.0%–95.1%) in those aged 5–7 years and 93.0% (95%CI, 83.0%-98.1%) for those aged 14–16 years. Age and higher educational level were associated with the increased EBV seropositive rate.

Conclusion

In Taiwan, people had the EBV infection early in life. Children under 7 years should be the primary target popution of public health measures in the future.

Infectious Mononucleosis

Infectious mononucleosis is a clinical entity characterized by sore throat, cervical lymph node enlargement, fatigue, and fever most often seen in adolescents and young adults and lasting several weeks. It can be caused by a number of pathogens, but this chapter only discusses infectious mononucleosis due to primary Epstein-Barr virus (EBV) infection. EBV is a γ-herpesvirus that infects at least 90% of the population worldwide. The virus is spread by intimate oral contact among teenagers and young adults. How preadolescents acquire the virus is not known. A typical clinical picture with a positive heterophile test is usually sufficient to make the diagnosis, but heterophile antibodies are not specific and do not develop in some patients. EBV-specific antibody profiles are the best choice for staging EBV infection. In addition to causing acute illness, there can also be long-term consequences as the result of acquisition of the virus. Several EBV-related illnesses occur including certain cancers and autoimmune diseases, as well as complications of primary immunodeficiency in persons with the certain genetic mutations. A major obstacle to understanding these sequelae has been the lack of an efficient animal model for EBV infection, although progress in primate and mouse models has recently been made. Key future challenges are to develop protective vaccines and effective treatment regimens.

Correlates of illness severity in infectious mononucleosis

Infectious mononucleosis is caused by Epstein-Barr virus and can lead to complications, including hepatitis and hematological abnormalities, in a subset of patients. The authors of this article assessed measures of illness severity as well as viral load at presentation and six weeks later among a cohort of individuals <25 years of age for the purpose of informing the management of patients with infectious mononucleosis.

INTRODUCTION:

Understanding the spectrum and frequencies of Epstein-Barr virus (EBV) complications and markers of illness severity in immunocompetent patients with primary EBV infection will inform management of patients with EBV-related illnesses.

OBJECTIVES:

To determine the clinical and laboratory correlates of illness severity among infants, children and youth with infectious mononucleosis (IM).

METHODS:

Study subjects with confirmed IM were prospectively enrolled. Illness severity was assessed at baseline and at six weeks using a scoring tool. Peripheral blood viral loads served as a measure of viral burden.

RESULTS:

Among 32 children and young adults with IM, the median age was 16 years (range two to 24 years). The predominant clinical findings were lymphadenopathy (23 of 32 [72%]), pharyngitis (16 of 32 [50%]), fever (nine of 32 [28%]) and splenomegaly (six of 32 [19%]). With respect to symptoms or signs that persisted to at least six weeks after illness onset, the predominant complaint was lymphadenopathy in 35% of subjects available for reassessment. Deranged liver function tests were present at presentation in up to 44% of subjects. Patients with the highest viral loads at presentation had significantly higher illness severity scores associated with fatigue (P=0.02). Other than the scores associated with fatigue, viral load values were not significantly correlated with the illness severity scores at baseline and at six weeks.

CONCLUSION:

In IM, viral loads are not necessarily correlated with illness severity, with the exception of fatigue. EBV-related hepatitis is common in IM, confirming the status of this virus as a relatively common cause of transient hepatitis in children and youth. This entity is not necessarily a marker of disease severity.

Clinical and virologic manifestations of primary Epstein-Barr virus (EBV) infection in Kenyan infants born to HIV-infected women

BACKGROUND

Human immunodeficiency virus (HIV) infection is a risk factor for Epstein-Barr virus (EBV)-associated lymphomas. Characterizing primary infection may elucidate risk factors for malignancy.

METHODS

To describe clinical and virologic manifestations of primary EBV infection among infants born to HIV-infected women, specimens were utilized from a cohort study conducted in Nairobi, Kenya. HIV and EBV viral loads were measured serially in plasma. EBV serology was performed on EBV DNA-negative infants. Monthly clinical examinations were performed by pediatricians.

RESULTS

The probability of EBV infection by 1 year of age was .78 (95% CI, .67-.88) in HIV-infected and .49 (95% CI, .35-.65) in HIV-uninfected infants (P < .0001). At 2 years, probability of EBV infection was .96 (95% CI, .89-.99) in HIV-infected infants. Peak EBV loads were higher in HIV-infected versus HIV-uninfected infants (median 2.6 vs 2.1 log10 copies/mL; P < .0001). The majority of HIV-infected infants had detectable EBV DNA for >3 months (79%). Primary EBV infection was associated with cough, fever, otitis media, pneumonia, hepatomegaly, splenomegaly, and hospitalization in HIV-infected infants; conjunctivitis and rhinorrhea in HIV-uninfected infants.

CONCLUSIONS

EBV infection occurs early in infants born to HIV-infected women. HIV infection was associated with more frequent and higher quantity EBV DNA detection.

Gastric cancer incidence among Hispanics in California: patterns by time, nativity, and neighborhood characteristics

BACKGROUND

Better understanding about gastric cancer incidence patterns among Hispanics by birthplace, socioeconomic status (SES), and acculturation can improve preventive strategies and disease models.

METHODS

Incidence rates, rate ratios, and estimated annual percent change (EAPC) in rates of anatomic and histologic subtype-specific gastric cancer were calculated by age, sex, and nativity among Hispanics using California Cancer Registry data from 1988 through 2004. Incidence rates in 1998 to 2002 were compared by neighborhood SES and Hispanic enclave status according to 2000 US Census data.

RESULTS

Incidence rates of diffuse gastric cancer increased from 1988 through 2004 among foreign-born Hispanic men (EAPC: 3.5%, 95% CI: 1.5%-5.5%) and U.S.-born Hispanic women (EAPC: 3.0%, 95% CI: 0.7%-5.3%). During the same time period, incidence rates of intestinal gastric cancer declined significantly and both cardia and noncardia gastric cancer were steady or declined among foreign-born and U.S.-born Hispanic men and women. Noncardia and both intestinal and diffuse gastric cancer were more common in foreign-born than U.S.-born Hispanic men and women, and in those from lower SES, higher enclave neighborhoods. By contrast, among younger and middle-aged Hispanic men, cardia tumors were more common in the U.S.-born than the foreign-born, and in higher SES, lower enclave neighborhoods.

CONCLUSIONS

Varying gastric cancer risk factors among Hispanic subgroups and increasing rates of diffuse gastric cancer in foreign-born Hispanic men and U.S.-born Hispanic women merit further investigation to identify separate disease etiologies.

IMPACT

Age, sex, birthplace, SES, and acculturation modify gastric cancer incidence in Hispanics and should be considered when examining disease risk and prevention.

Epstein-Barr virus infection and central nervous system involvement after orthoptic liver transplant

Epstein-Barr virus (EBV) infection presenting as encephalitis in seronegative adults in the context of solid organ transplantation is rarely reported. EBV seroconversion illnesses in the adult population after organ transplantation are quite uncommon. This report describes a case of encephalitis due to EBV infection after liver transplantation in an adult patient. The patient was seronegative for EBV pretransplant. She showed persistent viral replication indicated by high levels of EBV DNA in the serum, which raised concerns for future development of post-transplant lymphoproliferative disorder. The report discusses the management of such patients, awareness of EBV infection and earlier diagnosis by use of EBV PCR in adult immunocompromised individuals where infection may cause particular problems.

Progress and problems in understanding and managing primary Epstein-Barr virus infections

Epstein-Barr virus (EBV) is a gammaherpesvirus that infects a large fraction of the human population. Primary infection is often asymptomatic but results in lifelong infection, which is kept in check by the host immune system. In some cases, primary infection can result in infectious mononucleosis. Furthermore, when host-virus balance is not achieved, the virus can drive potentially lethal lymphoproliferation and lymphomagenesis. In this review, we describe the biology of EBV and the host immune response. We review the diagnosis of EBV infection and discuss the characteristics and pathogenesis of infectious mononucleosis. These topics are approached in the context of developing therapeutic and preventative strategies.

Parental educational attainment as an indicator of socioeconomic status and risk of childhood cancers

Background:

Little has been reported on socioeconomic (SES) patterns of risk for most forms of childhood cancer.

Methods:

Population-based case–control data from epidemiological studies of childhood cancer conducted in five US states were pooled and associations of maternal, paternal and household educational attainment with childhood cancers were analysed. Odds ratios (ORs) and 95% confidence intervals were estimated using logistic regression, controlling for confounders.

Results:

Although there was no association with parental education for the majority of cancers evaluated, there was an indication of a positive association with lower education for Hodgkin's and Burkitt's lymphoma and Wilm's tumour, with the ORs ranging from 1.5 to >3.0 times that of more educated parents. A possible protective effect was seen for lower parental education and astrocytoma and hepatoblastoma, with ORs reduced by 30 to 40%.

Conclusions:

These study results should be viewed as exploratory because of the broad nature of the SES assessment, but they give some indication that childhood cancer studies might benefit from a more thorough assessment of SES.

Changing patterns in the frequency of Hodgkin lymphoma subtypes and Epstein-Barr virus association in Taiwan

Epstein-Barr virus (EBV) infection is a risk factor for Hodgkin lymphoma (HL). To test whether the frequency of HL subtypes and their association with EBV has shifted with rising socioeconomic status in Taiwan, we compared the pathological features and EBV status, detected by in situ hybridization, of HL diagnosed between 1996 and 2007 (99 cases) and 1982 and 1995 (74 cases). The male-to-female ratio was 121:52 (2.3:1) and the mean age at presentation was 41.5 years. The overall EBV positivity rate was 50% (86/173 cases). Comparing the distribution of HL cases diagnosed at two different time periods, we found an increased frequency of the nodular sclerosis (NS) subtype (53 vs 68%, P = 0.045), a decreased frequency of the mixed cellularity subtype (35 vs 13%, P < 0.001), a reduced male-to-female ratio (2.9:1 compared to 1.4:1) and mean age (42.4 vs 36.6 years) in the NS subtype, and a significant decrease in EBV positivity rates among the NS and lymphocyte-depletion subtypes (61 vs 39%, P = 0.03). These data indicate shifts in the frequency of histological subtype and EBV association for HL in Taiwan over the last decade, with a trend closer to that seen in Western countries and Japan.

Prevalence of Epstein-Barr virus antibodies in healthy children and adolescents in Vitória, State of Espírito Santo, Brazil

The prevalence and age distribution of Epstein-Barr virus infection varies in different populations and there is little information about the epidemiology of this infection in Brazil. We studied the prevalence of EBV antibodies in a sample of 283 children and adolescents between 1 and 21 years old. The sample was taken from two neighborhoods in Vitória (capital city of Espirito Santo, Brazil). The São Pedro (SP) neighborhood represented an area with lower socioeconomic status and the Praias (P) neighborhood represented an area with higher SES. Anti-VCA (Virus Capsid Antigen) antibodies were detected by ELISA and anti-EBNA (Epstein-Barr Nuclear Antigen) antibodies were detected by an anti-complement immunofluorescence method, both using commercial kits. The results showed an overall prevalence rates of anti-VCA and anti-EBNA of 71% and 54% respectively. The prevalence for both anti-EBV antibodies was higher and probably the infection occurred earlier in the SP neighborhood. Among the various socioeconomic factors studied only low family income and maternal education level were significantly correlated with a higher frequency of positive serology for anti-VCA. These results demonstrate that there is a high prevalence of EBV antibodies in children and adolescents living in Vitória, that occurs more frequently at a younger age in children from families with low socioeconomic status. In addition, the results demonstrate an intermediate age distribution pattern between those reported in developed and underdeveloped countries.

Diagnosis of Epstein-Barr virus-associated diseases

Epstein-Barr virus (EBV) is a common DNA virus distributed worldwide. Usually the initial infection involves the upper respiratory tract without any problems and almost the entire population more than 25 years old test positive for anti-EBV antibodies. However, EBV often causes not only acute lytic infection but also chronic active infection with B cells and even T cells. In addition the EBV genome has been detected in tumors of hematopoietic or epithelial cell origin such as Burkitt's lymphomas, Hodgkin's disease, NK/T cell lymphomas, nasopharyngeal carcinomas (NPCs) and gastric adenocarcinomas. It is clearly important to make a correct diagnosis for EBV associated diseases and monitor the EBV load in individual patients for an appropriate therapy. In this paper recent advances in serological, immunological and molecular approaches for detection of EBV associated disease are described.

Epstein-barr virus-associated malignancies: epidemiologic patterns and etiologic implications

Epstein-Barr virus (EBV), a ubiquitous B-lymphotrophic herpesvirus, has been found in the tumor cells of a heterogeneous group of malignancies (Burkitt's lymphoma, lymphomas associated with immunosuppression, other non-Hodgkin's lymphomas, Hodgkin's disease, nasopharyngeal carcinoma, gastric adenocarcinoma, lymphoepithelioma-like carcinomas, and immunodeficiency-related leiomyosarcoma). As the epidemiologic characteristics of these cancers have not been considered together, this review seeks to relate their incidence patterns and risk factors to EBV biology and virus-host interaction in an attempt to help elucidate factors involved in EBV-related carcinogenesis. We include a brief review of EBV virology and primary infection to provide a biologic context for considering the epidemiology, summarize the most salient epidemiologic features of each malignancy, synthesize epidemiologic data by risk factor to uncover commonalities and informative contrasts across the diseases, and propose hypotheses regarding etiologic mechanisms, based on the possible effect of the risk factors at various stages in the viral life cycle.

Population density and childhood leukaemia: results of the EUROCLUS Study

The EUROCLUS study assembled incidence data for 13,551 cases of childhood leukaemia (CL) diagnosed between 1980 and 1989 in 17 countries (or regions of countries). These were referenced by location at diagnosis to small census areas of which there were 25,723 in the study area. Population counts, surface area and, hence, population density were available for all these small areas. Previous analyses have shown limited extra-Poisson variation (EPV) of case counts within small areas; this is most pronounced in areas of intermediate population density (150-499 persons/km2). In this study, the data set was examined in more detail for evidence that variations in incidence and EPV of CL are associated with population density. Incidence showed a curvilinear association with population density and was highest in areas which were somewhat more densely populated (500-750 persons/km2), where the incidence rate ratio relative to areas having > or = 1000 persons/km2 was 1.16 (95% confidence interval 1.07-1.26) and the P value for quadratic trend across eight strata of population density was 0.02. Incidence in these areas is uniformly elevated and showed no evidence of heterogeneity (i.e. EPV). Statistically significant evidence of EPV was evident amongst some of the areas previously classified as intermediate density areas (specifically, those with a density of 250-499 persons/km2, P < 0.001 for CL). These results were interpreted in terms of the current aetiological hypotheses for CL which propose that exposure to localised epidemics of one or more common infectious agent may contribute to the development of leukaemia. They suggest that such epidemics arise regularly in moderately densely populated areas and also sporadically in areas which are somewhat less densely populated. Although other interpretations are possible, these results may assist in the identification of characteristics which infectious agents must possess if direct or indirect causes of CL.

Epidemiology of Epstein-Barr virus infection in pre-adolescent children: application of a new salivary method in Edinburgh, Scotland

STUDY OBJECTIVE

To describe the epidemiology of Epstein-Barr virus (EBV) among primary school children by testing saliva with a new EBV capsid antigen "G" antibody capture radioimmunoassay (GACRIA).

DESIGN

A population based sample of 7 year old schoolchildren were followed up at age 11.

SETTING

30 randomly chosen primary schools in Edinburgh, Scotland.

PARTICIPANTS

552 schoolchildren.

MEASUREMENTS

Data on risk factors for infection were collected by questionnaire at ages 7 and 11. Saliva samples collected at age 11 were examined by GACRIA for evidence of previous infection with EBV. For 102 subjects, a second salivary specimen collected approximately one month after the first sample was available for testing as a measure of the repeatability of the method.

MAIN RESULTS

Unequivocal results were found in 91% of samples and the repeatability of the test was good (kappa = 0.71). Fifty six per cent of children had antibodies to EBV. In a logistic regression analysis, independent risk factors for infection were sharing a room (odds ratio 1.78, 1.14, 2.79), head of household's social class IV/V compared with I (odds ratio 2.87, 1.08, 7.34), and schools serving predominantly rented housing estates (odds ratio 2.3, 1.09, 4.84).

CONCLUSION

This study is the first application of EBV viral capsid GACRIA to salivary samples. The method was successfully used to describe the epidemiology of EBV. In this study, characteristics of the home seemed to be more important than those of the school in determining the likelihood of infection with EBV.

What every pediatrician should know about infectious mononucleosis in adolescents

Infectious mononucleosis (IM) is one of the most common diseases occurring during adolescence. Appreciation of IM's varied clinical presentations, its differential diagnosis, and the difficulties involved in making the laboratory diagnosis will enable clinicians to treat teenagers more effectively in their office practices.

Direct detection of Epstein-Barr viral antigen in nasopharyngeal swabs from patients with infectious mononucleosis

OBJECTIVE

To determine whether direct immunologic detection of Epstein-Barr virus (EBV) early antigen diffuse component (EA-D) from nasopharyngeal swabs is a feasible approach to the development of a rapid diagnostic test for infectious mononucleosis (IM).

METHODS

Nasopharyngeal swabs from 20 patients presenting with a presumptive diagnosis of IM (having the classic triad of symptoms-acute pharyngitis, fever, and lymphadenopathy) and 5 controls were assayed for EA-D. EBV serologic testing and a heterophil antibody titer (HAT) test also were performed. EA-D was assayed by polyacrylamide gel electrophoresis and subsequent transfer to a nylon membrane, followed by immunoblotting with a monoclonal antibody.

RESULTS

EA-D was detected in 17 of 20 patients (85%) with presumptive diagnoses of IM and in 1 of 5 normal subjects and was highly significant in predicting IM (p < 0.01). There was no significant difference in numbers of positive and negative results using either EA-D assay or HAT test in patients with IM (p < 0.35). Pharyngeal exudate in the 17 pharyngitis patients with this variable documented was significantly correlated with positive EA-D (p < 0.01), but not with the HAT test (p < 1.00).

CONCLUSIONS

Immunologic detection of EBV-derived antigens from nasopharyngeal swabs is a potential early diagnostic tool for clinically suspected IM. Sensitivity and specificity in pediatric and adult populations, patients with other viral etiologies, and patients with streptoccocal pharyngitis should be determined in subsequent investigations.

Seroepidemiological study of Epstein-Barr virus infection in Bangladesh

A seroepidemiological study was carried out on 502 sera to determine the prevalence of EBV infection in a group of Bangladeshi people (age range: 15 days-90 years). All sera were tested for IgG antibody to the EBV viral capsid antigen (VCA) by a commercially available enzyme linked immunosorbent assay (ELISA) and the negative sera were checked subsequently by indirect immunofluorescence (IF) methods. The prevalence of EBV infection in the study group was 81.27%. 42.37% of infants had antibodies to EBV by the age of 1 year. A significant rise in the percentage of seropositives between 0-1- and 1-2-year-old children was demonstrated, indicating a high rate of primary infection at these ages. The prevalence of IgG antibody to VCA was 87.93% in the 2-10 years age group and was sustained at over 85% thereafter. Higher ELISA values were more common both in the 0-2- and > 25-year age groups, the latter being statistically significant (P < 0.025). Similar higher values were also observed in females as compared to males (P = 0.05). Eighteen out of 109 negative sera and two equivocal sera by ELISA were found to be positive by indirect IF, indicating a negative predictive value of 82% for ELISA. The concordance between the two methods was 97% with ELISA proving to be less sensitive than indirect IF. It is concluded that the prevalence of EBV infection in Bangladeshi population is similar to that observed in other developing countries and that ELISA can be used for seroepidemiological surveys; however, the sera negative by ELISA should be checked routinely by indirect IF.

The chronically fatigued patient

This article illustrates that the diagnostic evaluation as well as the management of the patient presenting with chronic fatigue can be done in an orderly manner. If a medical illness is the cause of the patient's fatigue, this is usually evident on initial presentation. A thorough history and complete physical examination, in conjunction with some screening laboratory tests, can rule out most medical causes of fatigue, and any remaining cases declare themselves over the next several visits. If a medical cause is not evident, a further "fishing expedition" is fruitless. Psychiatric illness, such as depression or generalized anxiety disorder, accounts for another significant proportion of cases of chronic fatigue. As with medical illness, psychiatric illness should be suspected based on history and is not a diagnosis of exclusion. Some patients presenting with chronic fatigue have a history and symptom pattern consistent with the diagnosis of CFS. The cause of this syndrome is controversial and is still unknown. The clinician, however, can offer the patient care in an environment that is respectful of their physical and psychological discomfort and can provide significant symptomatic improvement to the patient. Lastly, some patients with fatigue do not fit any diagnostic category, including CFS. As with many other common complaints, such as headaches or abdominal pain, although a diagnosis may not be given to the patient, the clinician can do a lot to reassure the patient and assist the patient in living with his or her symptoms. As Solberg eloquently wrote: "[E]valuation of the fatigued patient requires all of a physician's best attributes--a broad view of disease, psychosocial sensitivity, and a good ongoing relationship with the patient."

Clinical immunology and infectious diseases

Without the application of immunology, understanding of the pathogenesis and pathophysiology of infectious diseases would be severely retarded. The development new vaccines for the prevention of infectious diseases has been based on new immunologic findings. Immunodiagnostic modalities have provided for the growth of diagnostic techniques for infectious diseases. Clinical immunology also has laid the groundwork for immunotherapies using the old intravenous immunoglobulin preparations and the new monoclonal antibodies, cytokines, and interferons.

Sex difference in the serostatus of adults to the Epstein-Barr virus

A total of 1047 adults, aged between 18 and 90 years, including blood donors and surgical patients of the Medical University of Lübeck in Germany, were screened for IgG antibodies to the Epstein-Barr Virus, either by standard indirect immunofluorescence or by a novel enzyme-linked immunosorbent assay (Enzygnost Anti-EBV/IgG, Behring, Marburg, Germany). There was a significant sex difference in the serostatus to the Epstein-Barr virus in adults. Male adults were more likely than females (p < 1%) to be EBV-seronegative. The same trend was seen in both a group of 713 blood donors and 334 surgical patients and when different test methods were used. However, this sex difference was not shown in the sera of 86 pediatric patients of the Medical University of Lübeck tested by indirect immunofluorescence for IgG antibodies to the Epstein-Barr virus. Furthermore, titers of IgG antibodies to Epstein-Barr virus specific antigens of female adults, obtained by the enzyme-linked immunosorbent assay (Enzygnost Anti-EBV/IgG), had significantly higher median values than male adults (p < 5%).

A case of fatal infectious mononucleosis presenting with fulminant hepatic failure associated with an extensive CD8-positive lymphocyte infiltration in the liver

We describe a fatal case of infectious mononucleosis presenting with fulminant hepatic failure associated with extensive CD8-positive lymphocyte infiltration and diffuse karyorrhexis in the liver. Immunohistochemical analysis of mononuclear cells showed that Leu-2a (CD8)-positive lymphocytes were heavily distributed in the portal areas and the sinusoidal spaces, but Leu-3a (CD4)-, Leu-14 (CD22)-, or My 4 (CD14)-positive cells were undetectable in sections of the liver. Southern blot hybridization studies disclosed the presence of Epstein-Barr virus DNA fragments in the liver tissue. The unusual pathologic and immunologic responses observed in this case could not simply be explained by severe Epstein-Barr virus infection. Some superimposed factors should be considered.

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

Serological patterns against Epstein-Barr virus (EBV) specific antigens were determined in 3732 healthy babies and children aged 0-10 years living in the Bari area (South Italy). IgG antibodies against EBV capsid antigen (VCA) were found in 2713 subjects (72.7%). Seropositivity rates, high in the first semester of life (83.8%), declined between 6 and 12 months (65.6%) and even further between 1 and 2 years (43.8%). After 2 years the frequency of positive children rose progressively reaching steady levels between 5 and 7 years (80.2%) and between 8 and 10 years (81.9%). IgA antibodies against VCA, IgG anti-early viral antigen (EA) and IgG against virus-associated nuclear antigens (EBNA) were found in 17.9%, 15.9% and 25.7% of the subjects tested, respectively. IgM anti-VCA were found only in 35 (0.9%) children, but 818 (21.9%) exhibited antibody patterns suggestive of a recent infection: IgG anti-VCA > or = 1:160 alone or in association with IgA anti-VCA or IgG anti-EA or both. These results suggest that in this area the primary infection by EBV occur early in life, with immunity to EBV acquired primarily after 4 years.

Viruses, clusters and clustering of childhood leukaemia: a new perspective?

Clusters of childhood leukaemia have, during a lengthy and controversial history, focussed attention on two alternative putative aetiological agents: infections and localised environmental pollution. In the United Kingdom emphasis is currently placed on the latter because of reports of localised clusters in the vicinity of two nuclear reprocessing plants. Now the most recent studies of spatial clustering in the United Kingdom also support the hypothesis that a substantial population of cases of childhood acute lymphoblastic leukaemia (ALL) arise as a rare host response to certain patterns of exposure to common infectious agents--the aberrant response model. Relevant aspects of the epidemiology of ALL are reviewed from this perspective and the hypothesis shown to be capable of unifying reported associations with different types of risk factor. It is probable that specific agent(s) are involved though none have been identified and these may share many epidemiological characteristics of herpes viruses. The possible relevance of these results to associations with prenatal parental occupational exposures to dusts and ionising radiation is explored.

Epstein-Barr virus as a cause of autoimmune disease and other medical morbidity in patients with affective disorders

We hypothesize that psychiatric patients suffering from the major affective disorders (depression and manic-depressive illness) may commonly also suffer from a chronic active infection with the Epstein-Barr virus. This infection would be a consequence of the immune dysfunction known to be associated with these disorders of mood. According to this hypothesis, the increased medical morbidity and mortality reported in these psychiatric patients would be attributable in part to diseases in which Epstein-Barr virus is implicated or suspected as a cause.

Elevated Toxoplasma IgG antibody in patients tested for infectious mononucleosis in an urban emergency department

There are many infectious causes of fatigue, sore throat, and fever, including mononucleosis and toxoplasmosis. Toxoplasma antibody testing is rarely performed in most emergency departments; as a result, toxoplasmosis is diagnosed infrequently. We obtained Toxoplasma IgG IFA titers on ED patients who had mononucleosis testing performed to determine the frequency of toxoplasmosis in this population. Two hundred sixty patients were included in our study. Eleven (4.2%) had a positive mononucleosis test, and 14 (5.4%) had a positive Toxoplasma titer. In the detection of toxoplasmosis, Toxoplasma IgG titers of 1:1,024 or greater have been shown to be a sensitive means of detecting infection in the first six months. Further testing with IgM titers is needed to establish a positive diagnosis when necessary. We found more patients with elevated Toxoplasma IgG titers than with positive heterophil antibody titers in an ED population tested for mononucleosis over a two-year period. We conclude that toxoplasmosis may be as common as mononucleosis in our ED and that clinicians should consider this pathogen when working up patients with appropriate symptoms.

Rheumatoid arthritis, juvenile arthritis, iridocyclitis and the Epstein-Barr virus

In order to examine the relation of Epstein-Barry virus (EBV) infection to chronic arthritis in children antibodies to EB virus capsid antigen (EBVCA) and rheumatoid arthritis nuclear antigen (RANA) were analysed in sera from 133 patients classified as juvenile rheumatoid arthritis (JRA) or pauciarticular, polyarticular, or systemic juvenile chronic arthritis. Except for an increased frequency in the systemic subgroup, the prevalence of antibodies to EBVCA and titres of anti-RANA antibodies was similar in patients and controls. These data do not support an aetiological role for EBV in chronic arthritis in children, including JRA, and suggest that the mechanisms which may account for the higher titres of anti-RANA antibodies in adult RA do not occur in children.

Humoral immune response in infectious mononucleosis. Late emergence of anti-EA(R) and the effects of corticosteroid therapy

The antibody response to Epstein-Barr virus (EBV) antigens in patients with infectious mononucleosis (IM) was studied to assess antibody appearance to the restricted (R) component of the early antigen (EA) complex and to determine the effect of corticosteroids on all aspects of the humoral immune response. Sixty college students with heterophil-positive clinical IM, confirmed by EBV-specific serology, were followed for a period of 4-26 weeks, Half received prednisone for six days, and the remainder received no corticosteroid therapy. Regardless of therapy, 48% of the patients developed anti-EA(R) antibodies. The response to other antigens was similar in both groups with the exception that antibodies to the EB-associated nuclear antigen (EBNA) developed later during convalescence and at lower titers in the corticosteroid-treated group. We conclude that 1) anti-EA(R) antibodies develop with considerable frequency following IM and are not a marker, as previously proposed, of unusually severe disease, and 2) corticosteroid therapy may retard the formation of anti-EBNA antibodies but it does not otherwise influence the humoral immune response to EBV.

Humoral immune response to Epstein-Barr virus antigens and immunoglobulin allotypes in African Burkitt lymphoma patients

We examined whether any immunoglobulin allotype was associated with an elevated risk of Burkitt's lymphoma because of the association between Burkitt's lymphoma and abnormalities of the immunoglobulin-bearing chromosomes. The distribution of Gm and Km phenotypes among 56 Burkitt lymphoma cases and 25 age-matched controls was unremarkable. Burkitt's lymphoma has also been associated with the Epstein-Barr virus, and we therefore sought a relationship between immunoglobulin allotypes and antibody response to the component antigens of the Epstein-Barr virus, VCA, EA-D, EA-R and EBNA. No immunoglobulin phenotype was associated with higher antibody titers against any antigen, but there appeared to be an interactive effect in which persons homozygous at both Gm and Km loci had elevated titers against several of the component antigens of the Epstein-Barr virus. This is the first report of an interactive effect between immunoglobulin allotypes and viruses. Antibody titers against antigens of the Epstein-Barr virus were higher in cases than in controls, as expected. However, female cases had significantly higher titers than male cases, a finding similar to that previously reported in healthy persons.

The capsid antigen of Epstein-Barr virus in nasopharyngeal carcinomas: comparison of serum antibody titre, cellular antigen content and histopathology

In a retrospective study of 21 patients with nasopharyngeal malignancies (lymphoepithelial carcinomas, both undifferentiated and dedifferentiated serological and immunohistological methods were used to examine the significance of the IgG- and IgM-antibody against the capsid antigen of Epstein-Barr virus for early detection and follow-up, and the findings compared with those from a control group. Furthermore, the IgA-antibody is taken into account and presented with examples from the literature. Other possible forms of therapy (combined radio- and polychemotherapy) are also discussed.

Immature B cells in fetal development and immunodeficiency: studies of IgM, IgG, IgA and IgD production in vitro using Epstein-Barr virus activation

Epstein-Barr virus has been used as a B cell mitogen to explore the parallels between the B cells found in patients with hypogammaglobulinemia and the immature B cells in fetal tissues. Peripheral blood lymphocytes from 29 cases of late onset hypogammaglobulinemia (common variable immunodeficiency) and from 10 cases of X-linked hypogammaglobulinemia were depleted of T lymphocytes and stimulated with virus in vitro. Immunoglobulin production was measured over a 4-week culture period using inhibition radioimmunoassays for IgM, IgG, IgA and IgD. The results were compared with those seen with fetal liver cells, cord blood lymphocytes and adult lymphocytes. Virus-stimulated cells from fetal sources produced small amounts of IgG and IgA relative to IgM, the ratio of IgM to IgG in the second week being in all cases greater than 10. Similar patterns were seen in 25/29 cases of late onset hypogammaglobulinemia, and in the eight cases of X-linked hypogammaglobulinemia that responded in vitro. In contrast, the ratio of IgM to IgG was always less than 8 in cultures of normal adult peripheral blood or bone marrow lymphocytes, and also in cultures from four cases of hypogammaglobulinemia known independently to have abnormal circulating suppressor cells. Eight cases of selective IgA deficiency showed reduced IgA production; six of these showed a normal ratio of IgM to IgG production. Thus, the B lymphocytes which circulate in many patients with hypogammaglobulinemia are functionally immature.

EB virus-specific IgA in serum of patients with infectious mononucleosis and of healthy people of different ages

The following sera were tested for EB virus-specific IgA: serial sera from 61 cases of infectious mononucleosis (IM) and from 195 EBV IgG positive healthy students; single sera from each of 1469 persons of different ages, 63 cases of untreated Hodgkin's disease, and 22 neonates. EBV specific IgA was found in the sera from 88% of cases of IM, from 18.5% of EBV IgG positive healthy students, and in 13.5% of repeat samples from the same students three years later. The incidence of EBV IgA varied from 5 to 30% at different ages in single sera from EBV IgG positive persons aged 2 to 70 years. The higher percentages occurred in the age groups where recent sero-conversion rates were high. Fifteen percent of sera from cases of Hodgkin's disease were positive for EBV IgA, an incidence similar to that for healthy adults in the age group 25-45 years. None of the EBV IgG positive sera from neonates gave a positive reaction for EBV IGA.

Infectious mononucleosis and Epstein-Barr virus. 2. Clinical picture, diagnosis, management

The diagnosis of infectious mononucleosis is confirmed by hematologic, biochemical, and serologic data. An absolute increase in peripheral mononuclear cells to at least 4,500/cu mm is an essential feature. The serologic hallmark of the disease is the presence of heterophile antibody. The age of the patient may affect the clinical presentation and laboratory findings. Therapy is largely supportive, with steroids being used only in the presence of certain severe complications.