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

EBV viral load in AFI patients across different geographical regions.

<p>Mann-Whitney test showed that viral load were significantly higher in Lake Victoria basin vs. Kisii highland (p = 0.003), Coastal region vs. Kisii highland (p = 0.005), and Coastal region vs. semi arid (p = 0.024).</p

EBV viral load in different age groups.

<p>EBV viral load in patients with AFI were determined by quantitative real time PCR as described in the methods section. The geometric mean viral load were significantly different between the <5 year vs. 5–15 year age categories.</p

Frequency of EBV viremia among different age categories.

<p>Frequency of EBV was highest among children under 5 years, and was significantly different between <5 years vs. 5–15 years (p = 0.039) and between <5 years and >15 years (p = 0.002) age categories.</p

Distribution of EBV infection in AFI patients from four geographical regions.

<p>The frequency of EBV was highest in patients from Lake Victoria region compared to other sites, with the difference being significant between Lake Victoria basin and Kisii highland (p = 0.001) (*) and between Lake Victoria and coastal region (p = 0.045) (**).</p

Map of Kenya showing the locations of various surveillance hospitals.

<p>Lake Victoria basin: Kisumu District Hospital, New Nyanza Provincial Hospital and Alupe District Hospital. Kisii highland: Kisii District Hospital. Semi-arid: Marigat District Hospital on floor of the Rift Valley. Arid north eastern Kenya: Garissa District Hospital and Iftin sub-District Hospital. Coast of Indian Ocean: Malindi District Hospital. The map was generated in house using the ArcView^®10.0 application (Environmental Systems Research Institute, Redlands, CA, USA). Elevation base data was downloaded from the world resources institute website (<a href="http://www.wri.org/" target="_blank">http://www.wri.org/</a>).</p

Demographic and clinical findings of the patients in this study.

<p>Demographic and clinical findings of the patients in this study.</p