v1=x1 is a rotavirus of species/breed/defining property v2 capable of infecting [at] v3.
x2 may be abu (A), by (B), cy (C),dy (D) or ebu (E). Rotavirus A, the most common, causes more than 90% of infections in humans. See also vidru, norvokovidru and remjinkytoldu'evidru.