Infectious mononucleosis: new concepts in clinical presentation, epidemiology, and host response

PURPOSE OF REVIEW

Infectious mononucleosis (IM) is an infectious disease that presents clinically in only a small percentage of individuals despite almost universal infection with the causative agent. Here, we review the latest concepts in the clinical presentation, epidemiology, and host response of this disease.

RECENT FINDINGS

Several recently published papers/reviews describe IM as a condition caused by one of several etiologic agents including, cytomegalovirus (HHV-5), Roseola virus (HHV-6) and Toxoplasmosis amongst others; this review focuses on IM as solely caused by the human herpes virus 4 (HHV-4). Since the initial discovery of the virus in the 1960s and its subsequent discovery as the primary etiologic agent for IM it has been associated with several human cancers and autoimmune disorders. Recent published findings show a correlation between HHV-4 and the autoimmune disorder, multiple sclerosis (MS), suggesting earlier IM could possibly act as a causative factor. Considering the important links being made with IM to so many cancers and autoimmune disorders it is surprising that a standard investigative procedure has yet to be determined for this disease. A standard approach to the investigation of IM would ensure more cases are diagnosed, particularly atypical cases, this would benefit epidemiological studies, and more immediately help practitioners distinguish viral from bacterial throat infections, enabling them to treat accordingly.

SUMMARY

The understanding of the latest concepts in clinical presentation, epidemiology and host response to IM would benefit greatly from the introduction of a standard procedure for its investigation and diagnosis.

Modifiable risk factors for multiple sclerosis have consistent directions of effect across diverse ethnic backgrounds: a nested case-control study in an English population-based cohort

BACKGROUND

Multiple sclerosis is a leading cause of non-traumatic neurological disability among young adults worldwide. Prior studies have identified modifiable risk factors for multiple sclerosis in cohorts of White ethnicity, such as infectious mononucleosis, smoking, and obesity during adolescence/early adulthood. It is unknown whether modifiable exposures for multiple sclerosis have a consistent impact on risk across ethnic groups.

AIM

To determine whether modifiable risk factors for multiple sclerosis have similar effects across diverse ethnic backgrounds.

METHODS

We conducted a nested case-control study using data from the UK Clinical Practice Research Datalink. Multiple sclerosis cases diagnosed from 2001 until 2022 were identified from electronic healthcare records and matched to unaffected controls based on year of birth. We used stratified logistic regression models and formal statistical interaction tests to determine whether the effect of modifiable risk factors for multiple sclerosis differed by ethnicity.

RESULTS

We included 9662 multiple sclerosis cases and 118,914 age-matched controls. The cohort was ethnically diverse (MS: 277 South Asian [2.9%], 251 Black [2.6%]; Controls: 5043 South Asian [5.7%], 4019 Black [4.5%]). The age at MS diagnosis was earlier in the Black (40.5 [SD 10.9]) and Asian (37.2 [SD 10.0]) groups compared with White cohort (46.1 [SD 12.2]). There was a female predominance in all ethnic groups; however, the relative proportion of males was higher in the South Asian population (proportion of women 60.3% vs 71% [White] and 75.7% [Black]). Established modifiable risk factors for multiple sclerosis-smoking, obesity, infectious mononucleosis, low vitamin D, and head injury-were consistently associated with multiple sclerosis in the Black and South Asian cohorts. The magnitude and direction of these effects were broadly similar across all ethnic groups examined. There was no evidence of statistical interaction between ethnicity and any tested exposure, and no evidence to suggest that differences in area-level deprivation modifies these risk factor-disease associations. These findings were robust to a range of sensitivity analyses.

CONCLUSIONS AND RELEVANCE

Established modifiable risk factors for multiple sclerosis are applicable across diverse ethnic backgrounds. Efforts to reduce the population incidence of multiple sclerosis by tackling these risk factors need to be inclusive of people from diverse ethnicities.

Infectious mononucleosis is associated with an increased incidence of multiple sclerosis: Results from a cohort study of 32,116 outpatients in Germany

Background

The pathogenesis of multiple sclerosis (MS) has not yet been fully uncovered. There is increasing evidence that Epstein-Barr-Virus (EBV) infection, which affects over 90% of people during life and causes infectious mononucleosis, leads to an increased incidence of MS, and thus may play a crucial role in the pathophysiology of the disease.

Methods

Using the Disease Analyzer database (IQVIA) featuring diagnoses as well as basic medical and demographic data of outpatients from general practices in Germany, we identified a total of 16,058 patients with infectious mononucleosis that were matched to a cohort of equal size without infectious mononucleosis based on patients’ age, sex, index year and yearly consultation frequency. Incidence of MS was compared within a 10-year follow-up period.

Results

Within 10 years from the index date, the incidence of MS was 22.6 cases per 100,000 person-years among patient with infectious mononucleosis but only 11.9 cases per 100,000 person-years among individuals without infectious mononucleosis. In regression analysis, infectious mononucleosis was significantly associated with the incidence of MS (HR: 1.86, 95% CI: 1.09-3.16). Subgroup analysis revealed the strongest association between infectious mononucleosis and MS in the age group between 14 and 20 years (HR: 3.52, 95% CI: 1.00-12.37) as well as a stronger association in men compared to women.

Conclusion

Infectious mononucleosis is associated with an increased incidence of MS especially in younger individuals. Our data support the growing evidence of a decisive involvement of EBV in the currently unknown pathophysiology of MS and should trigger further research efforts to better understand and potentially prevent cases of this disabling disease in future.

Epstein-Barr virus infection status among first year undergraduate university students

OBJECTIVE

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis, which disproportionately affects university students. This population has the potential to benefit from a prophylactic EBV vaccine trial. Our objectives were to determine EBV infection status and associated demographic/lifestyle factors among first year undergraduate university students at the beginning and end of first year.

METHODS

EBV infection status was assessed by testing for circulating IgG class antibodies against EBV viral capsid antigen.

RESULTS

Of 198 starting students; 56.1% were positive for EBV antibodies with a higher rate in women (64.8%) than male (41.1%); p = 0.002. A history of deep kissing was associated with a higher rate of EBV antibody positivity. On follow-up 8 months later at the end of freshman year, 22.4% had acquired EBV antibodies for a primary infection incidence of 33.6/100 person years.

CONCLUSION

These findings indicate that our first year undergraduate population contains sufficient EBV-naïve subjects for a prophylactic vaccine trial.

Risks for Developing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in College Students Following Infectious Mononucleosis: A Prospective Cohort Study

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) involves severe fatigue, unrefreshing sleep, and cognitive impairment, leading to functional difficulties; prior studies have not evaluated risk factors with behavioral and immune data collected before developing ME/CFS. Up to 5% of university students develop infectious mononucleosis (IM) annually, and 9-12% meet criteria for ME/CFS 6 months later. We sought to determine predictors of ME/CFS.

METHODS

We enrolled college students at the start of the school year (time 1), identified those who developed IM (time 2), and followed them for 6 months (time 3), identifying 3 groups: those who developed ME/CFS, severe ME/CFS (meeting >1 set of criteria), and who were asymptomatic. We conducted 8 behavioral and psychological surveys and analyzed cytokines at 3 time points.

RESULTS

238 of the 4501 students (5.3%) developed IM; 6 months later, 55 of the 238 (23%) met criteria for ME/CFS and 157 (66%) were asymptomatic. 67 of the 157 asymptomatic students served as controls. Students with severe ME/CFS were compared with students who were asymptomatic at 3 time points. The former group was not different from the latter group at time 1 (prior to developing IM) in stress, coping, anxiety, or depression but were different in several behavioral measures and had significantly lower levels of IL-6 and IL-13. At time 2 (when they developed IM), the 2 ME/CFS groups tended to have more autonomic complaints and behavioral symptoms while the severe-ME/CFS group had higher levels of IL-12 and lower levels of IL-13 than the recovered group.

CONCLUSIONS

At baseline, those who developed ME/CFS had more physical symptoms and immune irregularities, but not more psychological symptoms, than those who recovered.

Association of Infectious Mononucleosis in Childhood and Adolescence With Risk for a Subsequent Multiple Sclerosis Diagnosis Among Siblings

IMPORTANCE

Epstein-Barr virus and its acute manifestation, infectious mononucleosis (IM), are associated with an increased risk of multiple sclerosis (MS). Whether this association is confounded by susceptibility to infection is still debated.

OBJECTIVE

To assess whether hospital-diagnosed IM during childhood, adolescence, or young adulthood is associated with subsequent MS diagnosis independent of shared familial factors.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used the Swedish Total Population Register to identify individuals born in Sweden from January 1, 1958, to December 31, 1994. Participants aged 20 years were followed up from January 1, 1978, to December 31, 2018, with a median follow-up of 15.38 (IQR, 8.68-23.55; range, 0.01-40.96) years. Data were analyzed from October 2020 to July 2021.

EXPOSURE

Hospital-diagnosed IM before 25 years of age.

MAIN OUTCOMES AND MEASURES

Diagnoses of MS from 20 years of age were identified. Risk of an MS diagnosis associated with IM in childhood (birth to 10 years of age), adolescence (11-19 years of age), and early adulthood (20-24 years of age [time-dependent variable]) were estimated using conventional and stratified (to address familial environmental or genetic confounding) Cox proportional hazards regression.

RESULTS

Of the 2 492 980 individuals (1 312 119 men [52.63%] and 1 180 861 women [47.37%]) included, 5867 (0.24%) had an MS diagnosis from 20 years of age (median age, 31.50 [IQR, 26.78-37.54] years). Infectious mononucleosis in childhood (hazard ratio [HR], 1.98; 95% CI, 1.21-3.23) and adolescence (HR, 3.00; 95% CI, 2.48-3.63) was associated with an increased risk of an MS diagnosis that remained significant after controlling for shared familial factors in stratified Cox proportional hazards regression (HRs, 2.87 [95% CI, 1.44-5.74] and 3.19 [95% CI, 2.29-4.46], respectively). Infectious mononucleosis in early adulthood was also associated with risk of a subsequent MS diagnosis (HR, 1.89; 95% CI, 1.18-3.05), but this risk was attenuated and was not significant after controlling for shared familial factors (HR, 1.51; 95% CI, 0.82-2.76).

CONCLUSIONS AND RELEVANCE

These findings suggest that IM in childhood and particularly adolescence is a risk factor associated with a diagnosis of MS, independent of shared familial factors.

Clinical characteristics and sick leave associated with infectious mononucleosis in a real-world setting in Germany

BACKGROUND

Infectious mononucleosis (IM), mainly caused by the Epstein-Barr virus, can result in prolonged symptoms. The objective of this study was to look at the length of sick leave, diagnosis of IM, treatment and comorbidities in a real-world setting in Germany.

METHODS

This retrospective, cross-sectional study used electronic medical record data from office-based practices in Germany and included patients with an initial confirmed diagnosis of IM between the 1 January 1 2016 and December 31 2018. Patients of working age (18-65 years) with statutory health insurance were included in order to look at the working population who would need a sick note for their employers in case of illness.

RESULTS

Epstein-Barr virus was the most common cause of IM in this population of 1,596 patients with an average age of 32 years. The majority of patients were women in all cohorts (~60%). Although CFS, myocarditis and thrombocytopenia were not recorded frequently around the index date, the occurrence did increase during the follow-up period. Around half of patients received antibiotics. About 62% of all patients were on sick leave for an average of 20 calendar days around the time of their IM diagnosis. Only 1% were still on sick leave after 6 months.

CONCLUSIONS

A small percentage of patients remained on continuous sick leave after 6 months, suggesting that the long-term effect of IM on the ability to work was minor in our cohort. However, patients could still be experiencing symptoms that influence their quality of life.

Systematic review and meta-analysis of the association between Epstein-Barr virus, multiple sclerosis and other risk factors

BACKGROUND

Epstein-Barr virus (EBV) infection is thought to play a central role in the development of multiple sclerosis (MS). If causal, it represents a target for interventions to reduce MS risk.

OBJECTIVE

To examine the evidence for interaction between EBV and other risk factors, and explore mechanisms via which EBV infection may influence MS risk.

METHODS

Pubmed was searched using the terms 'multiple sclerosis' AND 'Epstein Barr virus', 'multiple sclerosis' AND EBV, 'clinically isolated syndrome' AND 'Epstein Barr virus' and 'clinically isolated syndrome' AND EBV. All abstracts were reviewed for possible inclusion.

RESULTS

A total of 262 full-text papers were reviewed. There was evidence of interaction on the additive scale between anti-EBV antibody titre and HLA genotype (attributable proportion due to interaction (AP) = 0.48, p < 1 × 10-4). Previous infectious mononucleosis (IM) was associated with increased odds ratio (OR) of MS in HLA-DRB1*1501 positive but not HLA-DRB1*1501 negative persons. Smoking was associated with a greater risk of MS in those with high anti-EBV antibodies (OR = 2.76) but not low anti-EBV antibodies (OR = 1.16). No interaction between EBV and risk factors was found on a multiplicative scale.

CONCLUSION

EBV appears to interact with at least some established MS risk factors. The mechanism via which EBV influences MS risk remains unknown.

Epidemiology of Epstein-Barr virus infection and infectious mononucleosis in the United Kingdom

BACKGROUND

Epstein-Barr Virus (EBV) is a ubiquitous gamma-herpesvirus with which ~ 95% of the healthy population is infected. EBV infection has been implicated in a range of haematological malignancies and autoimmune diseases. Delayed primary EBV infection increases the risk of subsequent complications. Contemporaneous seroepidemiological data is needed to establish best approaches for successful vaccination strategies in the future.

METHODS

We conducted a sero-epidemiological survey using serum samples from 2325 individuals between 0 and 25 years old to assess prevalence of detectable anti-EBV antibodies. Second, we conducted a retrospective review of Hospital Episode Statistics to examine changes in Infectious Mononucleosis (IM) incidence over time. We then conducted a large case-control study of 6306 prevalent IM cases and 1,009,971 unmatched controls extracted from an East London GP database to determine exposures associated with IM.

RESULTS

1982/2325 individuals (85.3%) were EBV seropositive. EBV seropositivity increased more rapidly in females than males during adolescence (age 10-15). Between 2002 and 2013, the incidence of IM (derived from hospital admissions data) increased. Exposures associated with an increased risk of IM were lower BMI, White ethnicity, and not smoking.

CONCLUSIONS

We report that overall EBV seroprevalence in the UK appears to have increased, and that a sharp increase in EBV seropositivity is seen in adolescent females, but not males. The incidence of IM requiring hospitalisation is increasing. Exposures associated with prevalent IM in a diverse population include white ethnicity, lower BMI, and never-smoking, and these exposures interact with each other. Lastly, we provide pilot evidence suggesting that antibody responses to vaccine and commonly encountered pathogens do not appear to be diminished among EBV-seronegative individuals. Our findings could help to inform vaccine study designs in efforts to prevent IM and late complications of EBV infection, such as Multiple Sclerosis.

Childhood infections, vaccinations, and tonsillectomy and risk of first clinical diagnosis of CNS demyelination in the Ausimmune Study

BACKGROUND

The association between childhood vaccinations and infections and risk of multiple sclerosis is unclear; few studies have considered age at vaccination/infection.

OBJECTIVE

To explore age-related associations between childhood vaccinations, infection and tonsillectomy and risk of a first clinical diagnosis of CNS demyelination.

METHODS

Data on case (n = 275, 76.6% female; mean age 38.6 years) and age- and sex-matched control (n = 529) participants in an incident population-based case-control study included self-reported age at time of childhood vaccinations, infections, and tonsillectomy. Conditional logistic regression models were used to calculate adjusted odds ratios (AOR) and 95% confidence intervals (CI).

RESULTS

Poliomyelitis vaccination prior to school-age was associated with increased risk of a first clinical diagnosis of CNS demyelination (AOR = 2.60, 95%CI 1.02-6.68), based on a very small unvaccinated reference group. Late (11-15 years) rubella vaccination (compared to none) was associated with lower odds of being a case (AOR = 0.47, 95%CI 0.27-0.83). Past infectious mononucleosis at 11-15 years (AOR = 2.84, 95%CI 1.0-7.57) and 16-20 years (AOR = 1.92, 95%CI 1.12-3.27) or tonsillectomy in adolescence (11-15 years: AOR = 2.45, 95%CI 1.12-5.35), including after adjustment for IM, were associated with increased risk of a first clinical diagnosis of CNS demyelination.

CONCLUSIONS

Age at vaccination, infection or tonsillectomy may alter the risk of subsequent CNS demyelination. Failing to account for age effects may explain inconsistencies in past findings.

[Viral hepatitis B, C and infectious mononucleosis: epidemiological similarities and differences.]

INTRODUCTION

The presence of etiologically unencrypted diagnoses in the structure of viral hepatitis determines the relevance of searching for other pathogens involved in liver pathology formation. The role of Epstein-Barr virus in the development of hepatitis was described in the scientific literature, but official statistics do not allow to assess its contribution to liver damage along with hepatitis B and C viruses. The purpose - to identify common and distinctive epidemiological features of viral hepatitis B (HB), C (HC) and infectious mononucleosis (IM).

MATERIAL AND METHODS

A retrospective epidemiological analysis of these nosologies incidence was carried out according to official statistics in 2009-2018 in the Russian Federation.

RESULTS AND DISCUSSION

The multidirectional trends in the long-term dynamics of the incidence of IM, acute and chronic HB and HC and the presence of strong direct correlation between the acute and chronic HB and HC incidence were established. Distinctive features include disparity in epidemic process intensity in different age groups (prevalence of morbidity in children aged 1-2 and 3-6 years with IM and persons older than 18 years - with viral hepatitis). It is common for IM and HB and HC to involve the majority of urban population in the epidemic process, as well as children under the age of 1 year. The described differences are due to the action of transmission mechanisms specific to each infection.

CONCLUSION

The results obtained in this study may serve as a basis for further study of the interaction of EpsteinBarr virus with hepatitis B and C viruses.

Primary Epstein-Barr virus infection with and without infectious mononucleosis

Background

Infectious mononucleosis (IM) is a common adverse presentation of primary infection with Epstein-Barr virus (EBV) in adolescence and later, but is rarely recognized in early childhood where primary EBV infection commonly occurs. It is not known what triggers IM, and also not why IM risk upon primary EBV infection (IM attack rate) seemingly varies between children and adolescents. IM symptoms may be severe and persist for a long time. IM also markedly elevates the risk of Hodgkin lymphoma and multiple sclerosis for unknown reasons. The way IM occurrence depends on age and sex is incompletely described and hard to interpret etiologically, because it depends on three quantities that are not readily observable: the prevalence of EBV-naϊve persons, the hazard rate of seroconverting and the attack rate, i.e. the fraction of primary EBV infections that is accompanied by IM. We therefore aimed to provide these quantities indirectly, to obtain epidemiologically interpretable measures of the dynamics of IM occurrence to provide etiological clues.

Methods and findings

We used joint modeling of EBV prevalence and IM occurrence data to provide detailed sex- and age-specific EBV infection rates and IM attack rates and derivatives thereof for a target population of all Danes age 0–29 years in 2006–2011. We demonstrate for the first time that IM attack rates increase dramatically rather precisely in conjunction to typical ages of puberty onset. The shape of the seroconversion hazard rate for children and teenagers confirmed a priori expectations and underlined the importance of what happens at age 0–2 years. The cumulative risk of IM before age 30 years was 13.3% for males and 22.4% for females. IM is likely to become more common through delaying EBV infection in years to come.

Conclusions

The change in attack rate at typical ages of puberty onset suggests that the immunologic response to EBV drastically changes over a relatively short age-span. We speculate that these changes are an integrated part of normal sexual maturation. Our findings may inform further etiologic research into EBV-related diseases and vaccine design. Our methodology is applicable to the epidemiological study of any infectious agent that establishes a persistent infection in the host and the sequelae thereof.

Low rate of co-infection in complicated infectious mononucleosis

INTRODUCTION

It remains unclarified if bacterial co-infection is common in patients with infectious mononucleosis (IM) and acute tonsillitis and/or peritonsillar abscess (PTA). Recent studies suggest that Fusobacterium necrophorum is a prevalent pathogen in acute tonsillitis and PTA. We hypothesised that this anaerobe may play a significant role for the aggravated infection and the development of PTA among teenagers and young adults with IM.

METHODS

All patients with IM and clinical findings of acute tonsillitis or PTA admitted to our department in the 2001-2015 period were included in the study.

RESULTS

In total, 257 patients with IM and acute tonsillitis (n = 220) or PTA (n = 37) were included. Positive bacterial cultures were obtained in 28% of patients with AT and in 50% with PTA. The most prevalent bacterial findings were Group C/G streptococci (14%) among patients with acute tonsillitis and Staphylococcus aureus (22%) in patients with PTA. F. necrophorum was recovered in 9% and 2% of patients with acute tonsillitis and PTA, respectively.

CONCLUSIONS

We were unable to substantiate a prevalent role for F. necrophorum in patients with IM and acute tonsillitis/PTA. S. aureus may play a role in PTA development in patients IM. The majority of our findings did not support the use of antibiotics in patients with IM, even in this selected group of patients with severe symptoms and a high risk of PTA.

FUNDING

This work was funded by the Lundbeck Foundation (Grant number R185-2014-2482).

TRIAL REGISTRATION

The Danish Data protection Agency approved the project.

Infectious mononucleosis, active component, U.S. Armed Forces, 2002-2018

Infectious mononucleosis (IM) is an acute infectious illness characterized by swollen lymph nodes, fever, pharyngitis, fatigue, and head and body aches. This report describes the incidence rates, trends, and demographic correlates of IM among active component service members during 2002-2018. During the surveillance period, there were 23,780 incident cases of IM, resulting in an overall incidence rate of 104.2 cases per 100,000 person-years (p-yrs). The incidence of IM diagnoses was highest among the youngest age groups and decreased with increasing age. The rate of incident IM diagnoses was markedly higher among non-Hispanic white service members (123.4 per 100,000 p-yrs) compared to those in other race/ethnicity groups. The incidence of IM diagnoses among recruits (364.9 per 100,000 p-yrs) was 3.4 times that among other enlisted personnel (106.0 per 100,000 p-yrs) and 5.6 times that among officers (64.7 per 100,000 p-yrs). The incidence of IM diagnoses remained relatively stable during the surveillance period, at about 100 per 100,000 p-yrs. IM is not considered to be a serious illness; however, it can seriously impact availability for duty during the acute phase.

Increasing Epstein-Barr virus infection in Chinese children: A single institutional based retrospective study

The Epstein-Barr virus (EBV) is a common virus in humans and the most common causative agent of Infectious Mononucleosis. EBV primary infection has recently risen in some countries and children below 2 years of age are highly susceptible. The clinical manifestations in children with EB virus infection involve multiple systems, causing severe illness, meaning attention should be paid during diagnosis and treatment. Objective:  This single institution based retrospective study was carried out with the aim of estimating the overall prevalence of EBV infection and identifying high-risk age group among children.  Methods: This study include total 253 patients under 15 years of age found to be  positive for EBV DNA by serum PCR who were admitted to the Pediatrics Department of Renmin Hospital,(Shiyan, China) during a 4-year period from 2014 to 2017. Patients were divided into three groups; 0-<4years, 4-<6years and 6-<15years. We then calculated the percentage and prevalence of EBV DNA-positive cases. Results: The yearly EBV prevalence rate was 4.99 per 1000 admissions in 2014, 6.97 per 1000 admissions in 2015, 10.42 per 1000 admissions in 2016, and 12.16 per 1000 admissions in 2017. Out of 253 EBV-positive cases, those under 4 years had the highest rate of EBV infection (74.7%). The rate drops to 11.06% in the 4-6 years group, and was 14.22% in the 6-15 years group. Those between 6 months and 1 year are those at the highest risk.  Conclusion: The rate of hospital admission of children due to EBV infection is increasing day by day. Children under 4 years of age are highly susceptible to infection and children of age between 6 months and 1 year are the high-risk group for EBV infection.

Risk of infectious mononucleosis among agonistic swimmers: a cross-sectional study

BACKGROUND

The risk of infectious mononucleosis among athletes is quite debated. Some personal observations seem to suggest an increase risk of mononucleosis among athletes, because they attend always close settings with an high probability of respiratory pathogens transmission; overtraining has been also proposed as risk factor.

STUDY DESIGN

Cross-sectional study in a group of swimmers (aged 11-14 years) of the University Sport Centre of Bari.

METHODS

40 swimmers were interviewed by healthcare personnel at the end of training courses; demographic characteristics, personal habits, information about sport training and diagnosis of mononucleosis were analysed.

RESULTS

The life-time incidence of mononucleosis was around 40%; multivariate analysis showed the association between mononucleosis and use of bottles of other persons (aOR=8.2; 95% CI=1.4-49.2; z=2.32; p=0.021) and average duration of training session was longer among subjects who reported mononucleosis than in subjects who did not indicate this disease.

CONCLUSIONS

Future multi-centric studies are needed to better define the epidemiology of the mononucleosis in sport settings and to formulate appropriate recommendations to prevent the spreading of this disease.

Population attributable fractions and joint effects of key risk factors for multiple sclerosis

AIM

We examined the combined effect of having multiple key risk factors and the interactions between the key risk factors of multiple sclerosis (MS).

METHODS

We performed an incident case-control study including cases with a first clinical diagnosis of central nervous system demyelination (FCD) and population-based controls.

RESULTS

Compared to those without any risk factors, those with one, two, three, and four or five risk factors had increased odds of being an FCD case of 2.12 (95% confidence interval (CI), 1.11-4.03), 4.31 (95% CI, 2.24-8.31), 7.96 (95% CI, 3.84-16.49), and 21.24 (95% CI, 5.48-82.40), respectively. Only HLA-DR15 and history of infectious mononucleosis interacted significantly on the additive scale (Synergy index, 3.78; p = 0.03). The five key risk factors jointly accounted for 63.8% (95% CI, 43.9-91.4) of FCD onset. High anti-EBNA IgG was another important contributor.

CONCLUSIONS

A high proportion of FCD onset can be explained by the currently known risk factors, with HLA-DR15, ever smoking and low cumulative sun exposure explaining most. We identified a significant interaction between HLA-DR15 and history of IM in predicting an FCD of CNS demyelination, which together with previous observations suggests that this is a true interaction.

Level of education and multiple sclerosis risk after adjustment for known risk factors: The EnvIMS study

BACKGROUND

Several recent studies have found a higher risk of multiple sclerosis (MS) among people with a low level of education. This has been suggested to reflect an effect of smoking and lower vitamin D status in the social class associated with lower levels of education.

OBJECTIVE

The objective of this paper is to investigate the association between level of education and MS risk adjusting for the known risk factors smoking, infectious mononucleosis, indicators of vitamin D levels and body size.

METHODS

Within the case-control study on Environmental Factors In MS (EnvIMS), 953 MS patients and 1717 healthy controls from Norway reported educational level and history of exposure to putative environmental risk factors.

RESULTS

Higher level of education were associated with decreased MS risk (p trend = 0.001) with an OR of 0.53 (95% CI 0.41-0.68) when comparing those with the highest and lowest level of education. This association was only moderately reduced after adjusting for known risk factors (OR 0.61, 95% CI 0.44-0.83). The estimates remained similar when cases with disease onset before age 28 were excluded.

CONCLUSION

These findings suggest that factors related to lower socioeconomic status other than established risk factors are associated with MS risk.

Longitudinal follow-up of employment status in patients with chronic fatigue syndrome after mononucleosis

OBJECTIVE

To examine the effect of early clinical and demographic factors on occupational outcome, return to work or awarded permanent disability pension in young patients with chronic fatigue syndrome (CFS).

DESIGN

Longitudinal cohort study.

INTERVENTION

A written self-management programme including a description of active coping strategies for daily life was provided.

SETTING, PARTICIPANTS

Patients with CFS after mononucleosis were evaluated at Department of Neurology, Haukeland University Hospital during 1996-2006 (contact 1). In 2009 self-report questionnaires were sent to all patients (contact 2).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary measure was employment status at contact 2. Secondary measures included clinical symptoms, and Fatigue Severity Scale (FSS) scores on both contacts, and Work and Social Adjustment Scale (WSAS) at contact 2.

RESULTS

Of 111 patients at contact 1, 92 (83%) patients returned the questionnaire at contact 2. Mean disease duration at contact 1 was 4.7 years and at contact 2 11.4 years. At contact 1, 9 (10%) were part-time or full-time employed. At contact 2, 49 (55%) were part-time or full-time employed. Logical regression analysis showed that FSS≥5 at contact 2 was associated with depression, arthralgia and long disease duration (all at contact 1).

CONCLUSIONS

About half of younger patients with CFS with long-term incapacity for work experienced marked improvement including full-time or part-time employment showing better outcomes than expected. Risk factors for transition to permanent disability were depression, arthralgia and disease duration.

Recent advances in the understanding of infectious mononucleosis: are prospects improved for treatment or control?

Symptomatic primary Epstein-Barr virus infection is known more commonly as infectious mononucleosis, an illness known for afflicting adolescents and younger adults as a febrile illness accompanied by pharyngitis and lymphadenopathy. Historically believed to be generally benign, infectious mononucleosis has been linked more recently to increased risks of developing Hodgkin's lymphoma and multiple sclerosis. Advances in the understanding of host immune responses to Epstein-Barr virus have begun to elucidate the reasons why younger children typically experience subclinical infection whereas older individuals develop infectious mononucleosis. This review will highlight recent advances in the understanding of primary Epstein-Barr virus infection, and whether prospective treatments or vaccine strategies may affect native infection and its sequelae.

Infectious mononucleosis and risk of breast cancer in a prospective study of women

PURPOSE

The association between infectious mononucleosis (IM) and risk of breast cancer is unclear; no prospective studies have examined this relationship. We examined self-reported history and age at IM in relation to risk of invasive breast cancer.

METHODS

Self-reported history and age at IM were examined in relation to risk of invasive breast cancer in a large cohort of women, the Nurses' Health Study II (81,807 women followed from 1989 to 2007). Through questionnaires, women were asked whether they ever had IM and if so, at what age. During follow-up, 2,349 cases of invasive breast cancer were documented. Cox proportional hazards regression was used to estimate relative risks (RR) and 95 % confidence intervals (CI) for the association of IM with breast cancer.

RESULTS

The multivariable-adjusted RR for history of IM and risk of invasive breast cancer was 1.00 (95 % CI: 0.90-1.11). Similar null results were obtained when estrogen receptor/progesterone receptor positive and negative tumors were considered separately. There were no clear patterns of association between age at IM and risk of breast cancer: compared to women with no history of IM, those who were ≤15 years old when they had IM were at lower risk (RR: 0.77; 95 % CI: 0.60, 0.97), but there was no association for women who had IM at ages 16-19, 20-24, or 30+. However, an increased RR (1.45; 95 % CI: 1.02-2.04) was observed for women who had IM at ages 25-29.

CONCLUSION

Results of this large prospective study do not support a clear association between history of clinical IM and risk of invasive breast cancer.

Maternal and perinatal factors associated with hospitalised infectious mononucleosis in children, adolescents and young adults: record linkage study

BACKGROUND

There is current interest in the role of perinatal factors in the aetiology of diseases that occur later in life. Infectious mononucleosis (IM) can follow late primary infection with Epstein-Barr virus (EBV), and has been shown to increase the risk of multiple sclerosis and Hodgkin's disease. Little is known about maternal or perinatal factors associated with IM or its sequelae.

METHODS

We investigated perinatal risk factors for hospitalised IM using a prospective record-linkage study in a population in the south of England. The dataset used, the Oxford record linkage study (ORLS), includes abstracts of birth registrations, maternities and in-patient hospital records, including day case care, for all subjects in a defined geographical area. From these sources, we identified cases of hospitalised IM up to the age of 30 years in people for whom the ORLS had a maternity record; and we compared perinatal factors in their pregnancy with those in the pregnancy of children who had no hospital record of IM.

RESULTS

Our data showed a significant association between hospitalised IM and lower social class (p = 0.02), a higher risk of hospitalised IM in children of married rather than single mothers (p < 0.001), and, of marginal statistical significance, an association with singleton birth (p = 0.06). The ratio of observed to expected cases of hospitalised IM in each season was 0.95 in winter, 1.02 in spring, 1.02 in summer and 1.00 in autumn. The chi-square test for seasonality, with a value of 0.8, was not significant.Other factors studied, including low birth weight, short gestational age, maternal smoking, late age at motherhood, did not increase the risk of subsequent hospitalised IM.

CONCLUSIONS

Because of the increasing tendency of women to postpone childbearing, it is useful to know that older age at motherhood is not associated with an increased risk of hospitalised IM in their children. We have no explanation for the finding that children of married women had a higher risk of IM than those of single mothers. Though highly significant, it may nonetheless be a chance finding. We found no evidence that such perinatal factors as birth weight and gestational age, or season of birth, were associated with the risk of hospitalised IM.

Epstein-Barr virus, cytomegalovirus, and infectious mononucleosis

Infectious mononucleosis (IM) is a clinical syndrome that is common in adolescents and young adults and is characterized by fever, lymphadenopathy, pharyngitis, and fatigue. IM is most commonly associated with Epstein-Barr virus (EBV) infection in which case laboratory findings include a lymphocytosis with an elevated number of atypical lymphocytes seen on peripheral smear and a heterophile or EBV-specific antibody response. Approximately 10% of those with IM will not be acutely infected with EBV. Many of these individuals will have their symptoms attributed to cytomegalovirus (CMV) infection. This chapter reviews the history, diagnosis, clinical management, and potential complications of both EBV- and CMV-associated IM in adolescents and young adults.

[Multiple sclerosis and Epstein-Barr virus : new developments and perspectives]

Data from studies of twins and migrants with multiple sclerosis (MS) imply environmental factors in the development of MS. In this respect, increasing evidence indicates that Epstein-Barr virus (EBV) plays a unique role as an infectious risk factor for MS. A nearly 100% seroprevalence of antibodies to EBV in patients with MS, elevated EBV antibody titers years before clinical onset of the disease, and an increased risk for MS after symptomatic primary EBV infection (infectious mononucleosis) suggest an association of MS with a previous infection with EBV. However, the precise mechanisms through which EBV may contribute to MS are still unclear. Currently discussed potential mechanisms are outlined. The notion of a persisting (possibly immunological) change caused during the acute phase of primary EBV infection and subsequently leading to permanently elevated MS risk appears compatible with several aspects of the association found between MS and EBV.

[Clinical risk factors for Epstein-Barr virus-associated hemophagocytic syndrome in children with infectious mononucleosis]

OBJECTIVE

To compare the clinical features of infectious mononucleosis (IM) and Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (EBV-AHS) and identify the clinical risk factors in IM patients complicated with EBV-AHS.

METHOD

A retrospective study was carried out to analyze the clinical and laboratory data of 414 IM and 16 EBV-AHS children from January, 2000 to April, 2006. Then Logistic regression was used to identify the risk factors for progression to EBV-ASH.

RESULTS

(1) The incidence of EBV-AHS among the IM children was 3.72% (16/430). There were significant differences between EBV-ASH and IM children in duration of fever (20 days vs. 7 days, P < 0.001), the peaks of fever (40.0 degrees C vs. 39.0 degrees C, P < 0.001), the degree of hepatomegaly (3.5 cm vs 2.0 cm below costal arch, P < 0.05) and splenomegaly (2.75 cm vs. 1.0 cm below costal arch, P < 0.05), while the incidence of isthmitis in EBV-AHS patients was markedly lower than that of IM patients (37.5% vs. 91.1%, P < 0.01). (2) Pancytopenia was often observed in EBV-AHS patients and significant differences between two groups were found in median of leukocytes (3.1 x 10(9)/L vs. 12.8 x 10(9)/L, P < 0.001), median of neutrophils (0.53 x 10(9)/L vs. 3.17 x 10(9)/L, P < 0.001), mean of hemoglobin (80 g/L vs. 120 g/L, P < 0.001) and median of platelet (27.5 x 10(9)/L vs. 183 x 10(9)/L, P < 0.001). (3) Hepatic derangement evidenced by elevated serum enzymes, hyperbilirubinemia and hypoalbuminemia in EBV-ASH children was much more severe than that in IM children, especially LDH level (2128.5 U/L vs. 445 U/L, P < 0.001) and AST level (489 U/L vs. 59 U/L, P < 0.001). (4) The clinical risk factors for IM patients progressing to EBV-ASH were lasting fever >/= 10 days (OR = 8.097, P = 0.008), LDH > 1000 U/L (OR = 7.998, P = 0.033), hypo-albuminemia (albumine < 35 g/L, OR = 7.838, P = 0.038), neutrophils < 1.5 x 10(9)/L (OR = 7.587, P = 0.022) and Plt < 100 x 10(9)/L (OR = 7.190, P = 0.027). The mortality of EBV-AHS in the patients was 50.0% (8/16).

CONCLUSION

Most of IM children clinically manifest self-limited process, but about 3.72% of whom may progress to fatal EBV-ASH. The clinical risk factors for EBV-AHS are lasting fever > 10 days, LDH > 1000 U/L, hypoalbuminemia, neutropenia and Plt < 100 x 10(9)/L. EBV-ASH is an extremely dangerous state with high mortality. Repeated bone marrow examinations are helpful for diagnosis in time.

Screening for glandular fever in patients with Quinsy: is it necessary?

Quinsy (peritonsillar abscess) is a common emergency seen in otolaryngology practice. These patients are often screened for glandular fever in addition to routine haematological tests. In our unit, we have screened 66 patients with quinsy for glandular fever over a period of 12 months. All these patients were screened for glandular fever by rapid immunoassay. Only one out of 66 patients was tested positive for glandular fever. Due to the extremely low incidence of glandular fever in quinsy patients, we do not see any relevance in screening for glandular fever in quinsy patients. Hence we recommend that routine screening for glandular fever in quinsy patients is an unnecessary invasive investigation for the patients and not cost effective for the hospital.

Clinical manifestations and quantitative analysis of virus load in Taiwanese children with Epstein-Barr virus-associated infectious mononucleosis

BACKGROUND AND PURPOSE

To delineate the clinical manifestations in different age groups and to define the viral load in patients with Epstein-Barr virus-associated infectious mononucleosis (EBV-associated IM).

METHODS

We reviewed data on 69 children with EBV-associated IM from November 2001 to October 2005. Clinical features were evaluated among four age groups: <3 years, 3 to 5 years, 6 to 9 years and 10 to 18 years. EBV viral load was measured by quantitative real-time polymerase chain reaction (PCR) in 13 patients with 15 specimens.

RESULTS

Majority of the children were younger than 7 years of age (76.8%) and the male-to-female ratio was 1.6:1. The symptoms and signs included fever (91.3%), tonsillopharyngitis (88.4%), lymphadenopathy (78.3%) and hepatitis (75.4%). The younger age group had higher monocyte count, lower occurrence of hepatitis, and lower glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels than the older age group. The median (range) EBV viral load of peripheral blood mononuclear cells (PBMCs) and plasma in IM patients was 738 (0-7455) copies/mug DNA and 51 (0-957) copies/mL plasma, respectively. The PBMC detection rate was high in the early (within 10 days after onset) and late phase (>10 days after onset) [90-100%]. The plasma detection rate in the early phase (66.7%) was higher than that in the late phase (40%).

CONCLUSIONS

The younger age group of EBV-associated IM patients had higher monocyte count, lower occurrence of hepatitis, and lower GOT and GPT levels than the older age group. The PBMC detection rate was almost equally high in both the early and late phases, while the plasma detection rate was higher in the early phase. Quantitative real-time PCR of EBV DNA is useful for diagnosing and monitoring EBV-associated IM, especially in younger children.

Infectious mononucleosis, childhood social environment, and risk of Hodgkin lymphoma

Infectious mononucleosis (IM) has been associated with an increased risk of Hodgkin lymphoma (HL), implicating a role for Epstein-Barr virus (EBV) in HL development. Although essential to the understanding of the association, it has remained uncertain if the relationship is restricted to the EBV-positive subset of HL. We collected information on mononucleosis history and childhood socioenvironmental characteristics in a population-based study of 586 patients with classic HL and 3,187 controls in Denmark and Sweden. Tumor EBV status was established for 499 cases by immunohistochemistry and in situ hybridization techniques. Odds ratios (OR) for the relationship between HL risk and mononucleosis and other risk factors were estimated by logistic regression for HL in younger (18-44 years) and older (45-74 years) adults, overall and by tumor EBV status. All analyses were adjusted for country-specific measures of maternal education and mononucleosis history. IM was associated with an increased risk of EBV-positive [OR, 3.23; 95% confidence interval (95% CI) 1.89-5.55] but not EBV-negative HL (OR, 1.35; 95% CI, 0.86-2.14). Risk of EBV-positive HL varied with time since IM and was particularly pronounced in younger adults (OR, 3.96; 95% CI, 2.19-7.18). IM-associated lymphomas occurred with a median of 2.9 years (1.8-4.9 years) after infection. The EBV specificity of the IM association was corroborated by a case-case comparison of IM history between younger adult EBV-positive and EBV-negative HL patients (OR(IM EBV+ HL versus EBV- HL), 2.68; 95% CI, 1.40-5.12). We found further evidence that IM is associated only with EBV-positive HL. This finding is compatible with the notion that EBV-positive and EBV-negative HL may have different etiologies.

Multiple sclerosis after infectious mononucleosis

BACKGROUND

Infectious mononucleosis caused by the Epstein-Barr virus has been associated with increased risk of multiple sclerosis. However, little is known about the characteristics of this association.

OBJECTIVE

To assess the significance of sex, age at and time since infectious mononucleosis, and attained age to the risk of developing multiple sclerosis after infectious mononucleosis.

DESIGN

Cohort study using persons tested serologically for infectious mononucleosis at Statens Serum Institut, the Danish Civil Registration System, the Danish National Hospital Discharge Register, and the Danish Multiple Sclerosis Registry.

SETTING

Statens Serum Institut.

PATIENTS

A cohort of 25 234 Danish patients with mononucleosis was followed up for the occurrence of multiple sclerosis beginning on April 1, 1968, or January 1 of the year after the diagnosis of mononucleosis or after a negative Paul-Bunnell test result, respectively, whichever came later and ending on the date of multiple sclerosis diagnosis, death, emigration, or December 31, 1996, whichever came first.

MAIN OUTCOME MEASURE

The ratio of observed to expected multiple sclerosis cases in the cohort (standardized incidence ratio).

RESULTS

A total of 104 cases of multiple sclerosis were observed during 556,703 person-years of follow-up, corresponding to a standardized incidence ratio of 2.27 (95% confidence interval, 1.87-2.75). The risk of multiple sclerosis was persistently increased for more than 30 years after infectious mononucleosis and uniformly distributed across all investigated strata of sex and age. The relative risk of multiple sclerosis did not vary by presumed severity of infectious mononucleosis.

CONCLUSIONS

The risk of multiple sclerosis is increased in persons with prior infectious mononucleosis, regardless of sex, age, and time since infectious mononucleosis or severity of infection. The risk of multiple sclerosis may be increased soon after infectious mononucleosis and persists for at least 30 years after the infection.

Evidence of shared Epstein-Barr viral isolates between sexual partners, and low level EBV in genital secretions

Epstein-Barr virus is present in the saliva of most persistently infected individuals and is generally thought to be spread by close oral contact. However, there are now several reports of EBV in genital secretions, suggesting the possibility of sexual transmission between adults. The present study was undertaken to investigate the risk of sexual transmission of EBV. PCR analysis was used to examined the degree to which a group (n = 11) of patients with infectious mononucleosis (IM) shared the same viral isolates as their sexual partners, and compare this to the extent of isolate sharing among a different group (n = 18) of IM patients and their non-sexual contacts. There was significantly more sharing of EBV isolates among the IM/sexual-contact pairs than among the IM/non-sexual-contact pairs (P = 0.0012). Female cervical (n = 84), male urethral (n = 55), and semen (n = 30) samples from asymptomatic, unselected volunteers were analyzed for the presence of EBV DNA, revealing 7%, 5%, and 3% to be EBV positive, respectively. Fractionation of cervical and urethral samples into cellular and supernatant fluid components showed EBV to be mainly cell-associated. Quantitation of EBV in these samples gave levels of below 10 EBV genomes per microg of DNA. Overall the findings support the possibility that EBV could on occasions be transmitted sexually, however, the low levels detected in genital secretions compared to saliva suggest that this is not a major transmission route. The finding of small quantities of cell-associated virus suggests a latent infection; thus EBV is probably in the B lymphocyte rather than in the epithelial cell component of the secretions.

Increasing incidence of severe Epstein-Barr virus-related infectious mononucleosis: surveillance study

Older patients are more susceptible to severe Epstein-Barr virus (EBV)-related infectious mononucleosis (IM). This condition may increase in industrialized countries where primary EBV infection occurs later in life. Between 1990 and 2004, 38 patients were admitted to our department with EBV-related IM. Two patients died. The annual incidence increased significantly (r = 0.623; P = 0.013).

Infectious mononucleosis and risk for multiple sclerosis: a meta-analysis

OBJECTIVE

To characterize the association between infectious mononucleosis (IM), a frequent clinical manifestation of primary Epstein-Barr virus infection after childhood, and the risk for multiple sclerosis (MS).

METHODS

We conducted a systematic review and meta-analysis of case-control and cohort studies of IM and MS.

RESULTS

The combined relative risk of MS after IM from 14 studies was 2.3 (95% confidence interval, 1.7-3.0; p < 10(-8)). Potential sources of heterogeneity (ie, study design, MS definition, and latitude) barely influenced our results.

INTERPRETATION

We conclude that Epstein-Barr virus infection manifesting as IM in adolescents and young adults is a risk factor for MS.

Risk and predictors of fatigue after infectious mononucleosis in a large primary-care cohort

BACKGROUND

Fatigue has been found to complicate infectious mononucleosis (IM) when patients are directly asked about it. We do not know whether such fatigue is clinically significant, nor whether IM is a specific risk for fatigue (or whether it can follow other common infections). Various risk markers for post-infectious fatigue have been identified, but findings are inconsistent.

AIM

To determine the risk of clinically reported fatigue (compared with depression) after IM (compared with both influenza and tonsillitis) in patients attending primary care, and to examine risk markers for post-IM fatigue.

DESIGN

Comparison of matched primary-care cohorts.

METHODS

We identified 1438 adult patients with a positive heterophil antibody test for IM from the UK General Practice Research Database. These patients were individually matched on age, sex and practice to two comparison groups; one with a clinical diagnosis of influenza and the other of tonsillitis.

RESULTS

The odds ratios (ORs) (95%CI) for reported fatigue after IM vs. influenza and tonsillitis were 4.4 (2.9-6.9) and 6.6 (4.2-10.4), respectively. Risk markers for post-IM fatigue included female sex and premorbid mood disorder. By comparison, the ORs for depression after IM vs. influenza and tonsillitis were 1.6 (0.9-2.6) and 2.3 (1.4-3.9), respectively.

DISCUSSION

IM is a specific and significant risk for clinically reported fatigue, which is both separate from, and more common than, depression. Female sex and premorbid mood disorder are risk markers for fatigue. These can be used both to target prevention strategies and to explore aetiological mechanisms.

Epstein-Barr virus is associated with all histological subtypes of Hodgkin lymphoma in Vietnamese children with special emphasis on the entity of lymphocyte predominance subtype

Early acquisition of Epstein-Barr virus (EBV) infection is prevalent in developing countries. We studied infectious mononucleosis (IM) and the subtypes of Hodgkin lymphoma (HL) with the status of EBV infection in Vietnamese children. Among the 46 cases of HL, the male-to-female ratio was 38:8, and the mean age at presentation was 6.6 years. Similar to the subtype distribution in developed countries, cases were classified as nodular sclerosis (NSHL) subtype in 56.5% (n = 26), mixed cellularity (MCHL) in 23.9% (n = 11), lymphocyte-rich classic (LRCHL) in 8.7% (n = 4), lymphocyte depletion (LDHL) subtype in 4.4% (n = 2), and nodular lymphocyte predominance (NLPHL) subtype in 6.5% (n = 3). However, in situ hybridization for EBV-encoded RNA revealed that the tumor cells were positive in 93.2% (41/44) of cases, including all 3 cases of nodular lymphocyte predominance HL. Expression of CD20 on Reed-Sternberg cells could be demonstrated in 17% (7/42) of classic HL. The high incidence of EBV in these cases of HL was correlated with an earlier mean age of presentation of primary EBV infection (ie, IM), at 5.3 years, in this patient population, compared with an average of 15 to 19 years reported in developed countries. This study demonstrates that in an area with an earlier mean age of onset of EBV infection, nearly all cases of pediatric HL, including all histological patterns, may be related to EBV infection. The association of NLPHL with EBV is unusual, and the literature is reviewed and discussed.

Multiple sclerosis after infectious mononucleosis: record linkage study

OBJECTIVE

To ascertain if infectious mononucleosis is a risk factor for the development of multiple sclerosis (MS); and, if it is, whether its effect is close to or remote in time from the onset of MS.

DESIGN

Analysis of database of linked abstracts of records of hospital admission and death.

SETTING

Health region in central southern England.

MAIN OUTCOME MEASURE

Ratio of rate of MS in a cohort of people admitted to hospital with infectious mononucleosis to the rate in a comparison cohort.

RESULTS

Considering all time intervals from admission with infection to admission with MS, there was a non-significant increase of risk of MS in the infectious mononucleosis cohort (rate ratio 2.17, 95% confidence intervals 0.79 to 4.77). At the interval of 10 years or more, there was a significant increase in risk of MS (rate ratio 4.01, 1.48 to 8.93). The mean time from infectious mononucleosis to first admission with MS was 14 years.

CONCLUSION

This study adds support to the evidence that Epstein-Barr virus, the cause of infectious mononucleosis, is associated with MS. Its role is probably as an initiator of the disease process of MS, or as a contributor to its early development, rather than as an activator of latent, existing disease.

[The influence of mononucleosis infection on atopic disease development in children]

The aim of the study was to determine whether infectious mononucleosis may trigger atopic symptoms or modulate their clinical course. Data from literature point out to such a relationship and attribute it to the influence of EBV on lymphocytes B and IL-4,IL-5,IL-10 and vIL-10 secretion stimulation. The authors examined 30 children who had suffered from symptomatic infectious mononucleosis 2-4 years previously, evaluating symptoms of allergic diseases and performing skin prick tests with selected inhalant and food allergens. The symptoms of atopic disease were found in 57 % in the mononucleosis group, a significantly higher percentage (p<0.0001) than in general population of children in Lódź (16%). The frequency of positive skin prick tests with common allergens was also significantly higher (60% vs 27%, respectively).

Infectious mononucleosis: return to play

Infectious mononucleosis most commonly affects adolescents and young adults with a febrile illness accompanied by pharyngitis,lymph node enlargement, and transient fatigue. The diagnosis is usually confirmed with demonstration of heterophile antibodies. Typical signs and symptoms are reviewed, along with pitfalls in diagnosis and management. The rare complication of splenic rupture serves to focus recommendations for returning athletes to strenuous physical activities. Because careful prospective studies of infectious mononucleosis in athletes are lacking, review of available literature suggests that clinicians may recommend a return to all sports in those without spleen enlargement 4 weeks after the onset of illness.

Human herpesvirus 8-related childhood mononucleosis: a series of three cases

Human herpesvirus 8 has been implicated in the pathogenesis of a limited subset of lymphoproliferative disorders in adults, but its role in children is unclear. A prospective evaluation of children with atypical lymphocytosis residing in the Hualien area, where the incidence of adult Kaposi sarcoma is high, revealed 3 cases caused by human herpesvirus 8.

[Infectious mononucleosis]

Infectious mononucleosis (IM) is the manifestation of primary infection with Epstein-Barr virus (EBV). EBV persisting after infection for a life-time infects > 90% of the adult population. Primary infection mostly asymptomatic in young children manifests in teenagers and young adults in about 50% as IM with fever, sore throat, generalized lymphadenopathy, frequently hepatosplenomegaly and blood lymphocytosis with the characteristic atypical lymphocytes. Clinical presentation, typical lymphocytosis and heterophile antibodies are diagnostic. Atypical cases may need to be confirmed by specific serology. IM is a self-limiting lymphoproliferation regressing within 2-3 weeks. Complications are rare and may involve many different organs. Severe cases are very uncommon, except in patients with inborn or acquired immunodeficiency carrying a substantially higher risk for severe courses, pogredient lymphoproliferation and lymphoma.

[Peritonsillar abscess associated with infectious mononucleosis: retrospective study of three cases]

Three cases with infectious mononuculeosis associated with peritonsillar abscess were reviewed. The initial diagnoses in these three cases were tonsillitis or peritonsillitis. However, infectious mononucleosis was suspected because of an elevation in aminotransferases and was later confirmed by elevations in the titers of antibodies for Epstein-Barr virus. Peritonsillar abscesses developed and surgical drainage was performed in all three cases. The present study suggests a higher incidence of peritonsillar abscess in patients with infectious mononucleosis than previously expected.

Candidosis of the pharyngeal mucosa in patients with infectious mononucleosis

The aim of our study was to assess the frequency rate of Candida yeast-like fungi in isolations from nasal and pharyngeal mucosa in patients diagnosed with IM who had undergone an antibiotic therapy. The study was performed in 51 patients aged 17-33. The diagnosis of IM was made on the basis of clinical symptoms, haematological, biochemical and serologic examination results. The material constituted of nasal and pharyngeal swabs. The identification of Candida species was done according to the routine microbiological diagnostics. Our results show that among the Candida genus, C. albicans was the only pathogenic species isolated from patients with IM. It was observed only in pharyngeal swabs in 27.4% of the patients.

Heterophile antibody positive infectious mononucleosis

OBJECTIVE

The present study has been carried out to analyse the trend of heterophile antibody positive infectious mononucleosis cases.

METHODS

A total of 1741 cases of clinically suspected infectious mononucleosis from various age groups were investigated during the period January, 1986 to December, 2000 and were analysed for infectious mononucleosis (IM) specific heterophile antibody by Paul-Bunnel-Davidsohn (PBD) test. Forty seven heterophile antibody negative samples were also tested simultaneously for the presence of the IgG antibody to viral capsid antigen (VCA) and Epstein Barr nuclear antigen (EBNA) to detect the exposure to Epstein Barr Virus (EBV) infection.

RESULTS

The overall percentage of EBV specific heterophile (Paul-Bunnel) antibody positivity was found to be 11.1% (194/1741). The average Paul-Bunnel antibody positivity between 1986 to 1990 was 20.5% which declined drastically to 5.7% during 1991-2000. Males comprised of 55.2% of the serologically proven IM cases. Of the 47 heterophile antibody negative cases, 38 (80.9%) and 33 (70.2%) were found to be positive for anti-VCA IgG and anti-EBNA IgG antibodies respectively. Paul Bunnel antibody positivity was found to be higher in >14 year age group patients than those below 14 years.

CONCLUSION

These findings suggest that the EBV infection still continues to be endemic in this part of the country, however, a declining trend in IM cases was observed during the last decade.