The spreading of viral RNA within Swiss Albino mice orally inoculated with coxsackievirus B4 E2 strain (CVB4 E2) was studied by using RT-PCR and semi-nested-RT-PCR methods. Viral RNA was detected in various organs: pancreas, heart, small intestine, spleen, thymus, and blood at various postinfectious (p.i.) times ranging from 8 hr to 150 days. Our results show that (i) outbred mice can be infected with CVB4 E2 following an oral inoculation, which results in systemic spreading of viral RNA, (ii) CVB4 E2 infection can be associated with a prolonged detection of viral RNA in spleen, thymus and blood, up to 70 days p.i. and further in other organ tissues.