Dynamics of persistent oral cytomegalovirus shedding during primary infection in Ugandan infants.

Abstract:

Cytomegalovirus (CMV) infection occurs frequently in young children, who are then a major source of transmission. Oral CMV shedding by 14 infants with primary infection was comprehensively characterized using quantitative PCR weekly for >9 months. Three phases of oral shedding were identified: expansion, transition, and clearance. Viral expansion occurred over a median of 7 weeks, with a median doubling time of 3 days. During the transition phase, expansion slowed over a median of 6 weeks before reaching peak viral load. Clearance was slow (22-day median half-life) and shedding did not resolve during observation for any infant. Mathematical modeling demonstrated that prolonged oral CMV expansion is explained by a low within-host reproduction number (median 1.63) and a delayed immune response that only decreases the infected cell half-life by 44%. Thus, the prolonged oral CMV shedding observed during primary infection can be explained by slow viral expansion and inefficient immunologic control.