DETERMINANTS OF ROTAVIRUS HOST-RANGE RESTRICTION - A HETEROLOGOUS BOVINE NSP1 GENE DOES NOT AFFECT REPLICATION KINETICS IN THE PIG

The genetic basis of rotavirus host range restriction (host species sp ecificity) is unknown but the NSP1 (fifth) gene has been implicated in some studies. We studied the replication kinetics in vivo of a NSP1 g ene monoreassortant, E11, to assess the influence of a heterologous NS P1 gene on the ability to replicate in pigs, The monoreassortant posse ssed 10 genes from the porcine parent rotavirus SW20/21, which replica ted productively in pigs, and the NSP1 gene from the bovine rotavirus UK which produced an abortive infection in pigs. Groups of up to four pigs;were inoculated orally with 10(5) to 10(6) TCID50 of the monoreas sortant, the porcine parent rotavirus, or the bovine parent rotavirus or were sham inoculated. The monoreassortant replicated productively i n pigs with replication kinetics almost identical to the porcine paren t rotavirus. During a 9-day observation period after inoculation, the number of days with virus in the faeces, the onset and duration of vir us excretion, and peak titres in faeces were similar for the monoreass ortant and the parent porcine rotavirus. The genetic composition of th e viruses excreted in the faeces was confirmed as that of the inocula by PAGE. Thus possession of a heterologous NSP1 gene from a bovine rot avirus which failed to replicate in pigs did not produce an abortive i nfection or affect the replication kinetics in vivo. The genetic basis of host range restriction between porcine and bovine rotaviruses rema ins to be established. (C) 1998 Academic Press.