Prevalence and Clinical Characteristics of Primary Epstein–Barr Virus Infection Among Children Presented with Cervical Lymphadenopathy

Epstein–Barr virus (EBV) is a double-stranded DNA virus, a member of the Herpes viridae family, is a known cause of infectious mononucleosis (IM) in children [1]. The virus usually becomes latent subsequent to the primary infection and more than 90% of adults are known to be seropositive and hence associated EBV malignancies are likely [2]. In low resources settings transmission of EBV generally occurs during infancy and early childhood and virtually all children are infected by the age of three years, resulting in asymptomatic infection resembling many febrile infections that occur during childhood [2]. Cervical lymphadenopathy (CL) is common in children with a range estimate of 38% to 90% of otherwise healthy children [3]. The commonest causes of childhood CL in similar settings as ours are reactive hyperplasia, specific infection, and malignancy [4]. Although it is not a serious disease, IM is known to present with CL [5]. In clinical practice many febrile children can present with IM-like syndrome and hence IM is not sought as a cause in children with lymphadenopathy particularly in low-resources settings as ours [2]. Furthermore, the prevalence of EBV infection among children with CL was not studied before in Sudan.

The aims of this study were to estimate the prevalence of primary EBV infection and to describe clinical characteristics of children presenting with cervical lymphadenopathy at an outpatient clinic of tertiary level Children’s hospital.

This cross-sectional study was conducted among children who presented for the first time with cervical lymph nodes enlargement (lymph node of ≥ 10 millimeters) to the outpatient clinic of Khartoum Children Emergency Hospital (KCEH), Khartoum, Sudan during the period from February 2009 to January 2010. KCEH is the main referral hospital for children in Sudan with the capability of 240 beds and serving approximately five million people, the population of the capital, Khartoum [6].

Since the prevalence of cervical lymphadenopathy among Sudanese children was not known, a pilot study was conducted to determine the sample size. A pilot survey was first conducted among 60 patients attending the outpatient clinic. Twenty of them were selected by simple random sample and were found to have cervical adenopathy. Among those 20, the group aged 1-5 constitute 45% of the sample with sex ration 5/4, and age group 6-10 constitutes 50% with even sex ratio while only 5% was found in the age group 11-15 year. According to the result of this survey and since the age is one of the important determinant factors; a population of 250 patients was assigned following a systemic proportional stratified random sampling. A sample size of 82 patients (52 males & 30 females) was chosen constituting about 30% of the assigned population. A child was included if he/she had single or multiple lymph nodes in the cervical region measuring ≥1 centimeter in both dimensions. Children who were known to have tuberculosis or malignancy were excluded from the study.

A preformed data sheet was designed to record demographic, history and clinical examination data. Five milliliters of venous blood were obtained for estimation of haemoglobin concentration, ESR, total and differential white blood cell count and centrifuged for sera. Sera were then analysed for anti viral capsid antigens (VCA)-IgM Epstein–Barr virus (Ortho Diagnostic Systems) ELISA test. The analysis was performed according to the standards of the manufacturer’s guidelines [7]. The diagnosis of primary EBV infection was based on the presence of IgM antibodies to VCA in the children’s sera [1]. Children who were seropositive and symptomatic were treated by appropriate doses of acetaminophen for pain and fever and encouraged to take adequate fluids and rest and then followed up until resolution of the disease [8]. Seronegative children were subjected for further investigations for other causes of lymphadenopathy and were accordingly managed.

Parents/caregivers of the children were informed about the study and each had signed a written consent. KCEH Development and Ethical Committee had approved this study.

Data were double entered and analysed into SPSS statistical software for windows version 20 (SPSS Inc., Chicago, IL, U.S.A.). Parametric tests were calculated for numerical variables where appropriate and frequency tabulation was done. Fisher Exact test was used to compare the difference between categorical data. Univariate and multivariate regressions were conducted to detect correlation between demographic, clinical and laboratory variables as independent variables and IgM seropositivity of EBV as a dependent outcome. Results were expressed as odds ratio (OR) within 95% CI limit. The level of significance was set at p ≤ 0.05.

Eighty-two children with CLA were included in this study. Primary Epstein-Barr virus infection was serologically diagnosed in 13 (15.9%) children with CLA. The average age of these children was 7.5 (SD±3.3) years. Eight (61.5%) of them were males, while 5 (38.5%) were females with a male to female ratio of 1.6. However, there was no significant gender difference among children of different age groups (p=0.188).

The most frequent symptoms in children with primary IM and lymphadenopathy were fever, loss of appetite, cough and headache.

The most affected group of lymph nodes were the anterior cervical, and the least were the preauricular. Generalized lymphadenopathy was reported in 5 children (38.5%). All patients had mobile lymph nodes and 12 (92.3%) of these children had firm lymph nodes, whereas only one (7.7%) had tender lymphadenopathy. The other frequent physical signs were splenomegaly (30.8%) and pharyngo-tonsillitis (23.1%). These are further illustrated in [Table/Fig-1] . The number of lymph nodes varied from 2-6 nodes, with a mean of 3.5 nodes and their average size was 3.6 cm (range 2-7 cm). Chest examination was normal in all children.

[Table/Fig-2] illustrates the laboratory values of CL patients with primary EBV infection. The mean white blood cell count was 7.43X10⁹/L and three (23%) children had leukocytosis (WBC>10×10⁹/L).

Age was the only significant association with seropositivity of IgM antibody of EBV (OR 0.81, 95% CI 0.67-0.99, p=0.041) [Table/Fig-1,2] . The odds of being seropositive decreased when the child with CL was ≤ 9 years of age (OR 0.18, 95% 0.04-0.78 CI p=0.022). In a multivariate regression model, age retained association with EBV seropositivity (OR 0.15, 95% CI 0.03-0.78, p=0.023) in children with CL [Table/Fig-3] .

This is the first report on the prevalence of EBV infection among children with cervical lymphadenopathy in Sudan, and is an addition to the available literature on prevalence studies of EBV infection in children.

Despite the relatively small sample size, this prevalence (15.9%) was approximately similar to the figure reported by Abdel-Aziz et al., from Egypt [5]. Higher prevalence of up to 40% has been reported from Ugandan patients of different age groups, including adults. The higher rates of concomitant HIV infection in their sample might be a factor of the high prevalence. Furthermore, the majority of children in central Africa is usually asymptomatically infected with or has mild EBV by the age of 3 years [2].

Our study results are significant for evidence of prior EBV infection has been reported in 36.3% of paediatric patients with leukemia in Sudan [9]. Prior EBV infection has also been demonstrated in 37% biopsies of adult Sudanese oral squamous cell carcinoma patients [10].

In this study the mean age of children with primary EBV infection (7.5 years) was higher compared to the more common younger age of preschool children observed by other authors from India and Egypt [5,11].

The most frequent associated symptom in children with cervical lymphadenopathy and primary EBV infection in our study was fever, reported in approximately 70% of patients. Abdel-Aziz et al., have also documented similar rates, however, Gao et al., reported a higher figure (92.3%) from Northern China [5,12]. Though all patients in this study had CL, pharyngitis was seen in less than a third of patients, a lower than reported from Egypt and China but comparable to a study from India [5,11,12].

The anterior cervical group in contradiction to Abdel-Aziz et al., were commonly enlarged in this series, followed by submandibular, posterior groups and then generalized lymphadenopathy [5]. There was no significant variation of the characteristics of the nodes in different studies [5,8,11-14]. Splenomegaly and hepatomegaly were detected among approximately 30% and 8% of patients respectively in this study, while Gao et al., recorded 47.4% for splenomegaly and 58.1% for hepatomegaly among their cohort [12]. Thompson et al., noticed hepatosplenomegaly among 27.1% of their cases while Abel-Aziz et al., reported splenomegaly in 58.3% and hepatomegaly in 25% of their cases [5,15,16].

Leukocytosis was detected in 23% of patients in this study, lower than the 45.8% and 67.5% leukocytosis reported by other authors. Children with varied age groups including infants were recruited our, which may provide an explanation for some these differences.

Age younger than 9 year was the only correlated factor with seropositivity of EBV among all demographic, clinical and laboratory factors. The odds of contracting infection in an earlier age are a well-known trend in developing countries [1,17,18].

This study has several limitations. The relatively small sample limits the generalizability of the results. Detection of IgG antibodies in patients’ sera would have added further information on the nature of primary versus secondary infections. Follow-up complications were not sought in this cohort because of its cross-sectional nature. A larger scale longitudinal survey in this country will provide further information on this topic.

Epstein-Barr virus primary infection is not an uncommon cause of cervical lymphadenopathy among Sudanese children. The commonest presenting symptoms are fever, loss of appetite and cough. The anterior cervical nodes were the most affected and they are characteristically mobile but infrequently tender. Splenomegaly is not an infrequent finding. The odds of EBV-IgM seropositivity decreased with an age ≤ 9 years.

The author would like to acknowledge the efforts of the technicians of the National AIDS program, Khartoum for performing the ELISA test. Much of appreciation goes to Dr. Mohammad Alsammani, associate professor of Obstetrics and Gynecology, University of Bahri, for revising this manuscript.

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