CD4 and infection: HAdV shedding from the lower GI tract may occur in healthy adults [3], [4], [5], but is more common in children (where it may represent a primary infection) [6], [7], [8], [9], immunocompromised individuals [2], and persons with HIV infection, particularly those with symptomatic infection and low CD4 counts [3], [10], [11], [12].