Epstein-Barr virus reactivation and upper-respiratory illness in elite swimmers.
OBJECTIVE
The aim of this study was to investigate the relationships between latent viral shedding of Epstein-Barr virus (EBV) in saliva, upper-respiratory illness, and mucosal immune suppression in a cohort of highly trained swimmers undertaking intensive training.


METHODS
Saliva was collected before selected training sessions from 14 elite male swimmers during a 30-d period of intensive training. Prior infection with EBV was determined by EBV antibody serology. Salivary IgA concentrations were measured by enzyme linked immunosorbent assay (ELISA), and EBV viral shedding (EBV-DNA) was detected by polymerase chain reaction (PCR). Symptoms of upper-respiratory illness were recorded daily.


RESULTS
Eleven swimmers (79%) were seropositive for prior EBV infection. Seven EBV seropositive swimmers (64%) had EBV-DNA detected during the study period. Upper-respiratory symptoms (URS) were reported in six of seven swimmers in whom EBV-DNA was detected and in three of four swimmers with no EBV-DNA detection. No URS were reported in the EBV seronegative swimmers. There was a statistically significant relationship between EBV serology status and URS (P = 0.027). EBV-DNA was detected in saliva before the appearance of URS. Salivary IgA levels were significantly lower immediately before the URS (P = 0.01) compared with subsequent peak IgA levels and declined to pre-URS levels on average 11 d after the first appearance of URS.


CONCLUSIONS
The time course of appearance of EBV-DNA in relation to URS suggests latent viral EBV shedding may be a contributing factor in the URS. The low levels of salivary IgA detected before the URS indicated transient mucosal immune suppression in the study cohort. The viral shedding may alternatively be a reflection of the altered immune control mechanisms that occur in response to intensive exercise and unrelated to the URS.
Gleeson
Maree
M
Hunter Immunology Unit, Hunter Area Pathology Service, Royal Newcastle Hospital, Newcastle NSW 2300, Australia. mgleeson@mail.newcastle.edu.au
Pyne
David B
DB
Austin
Jason P
JP
Lynn Francis
J
J
Clancy
Robert L
RL
McDonald
Warren A
WA
Fricker
Peter A
PA
D000293:Adolescent; D000328:Adult; D004279:DNA, Viral / Q000032:analysis; D004854:Herpesvirus 4, Human / Q000254:growth & development*; D006801:Humans; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000032:analysis; D012141:Respiratory Tract Infections / Q000276:immunology / Q000821:virology*; D012463:Saliva / Q000821:virology*; D013550:Swimming; D014775:Virus Activation; D017201:Virus Shedding
D004279:DNA, Viral; D007070:Immunoglobulin A