Persistence of attenuated Junin virus strains in guinea pigs infected by IM or IC routes.

Abstract

The XJC13 and XJO attenuated strains of JV, the etiologic agent of Argentine hemorrhagic fever, behave similarly in the guinea-pig model [1], and cause a mild illness with low (11%) mortality when inoculated im and severe disease with high (65070) mortality when administered ic [2]. Surviving animals in both groups showed no sequelae, and virus isolation by conventional methods 20 days postinfection proved negative, although other investigators have detected viral antigen at 35 and 45 days postinfection in guinea pigs infected im with XJC13 [3]. In all cases humoral neutralizing antibodies have been present, and the animals have resisted challenge with the JV-XJ pathogenic strain, thereby showing that protection has been conferred. In the present experiment seven guinea pigs that survived inoculation with an attenuated strain of JV (administered ic in four and im in three) were studied beyond 45 days postinfection. The results showed that even in the presence of circulating neutralizing antibodies, attenuated JV strains persisted for long periods in the organs of all the animals; however, the negative results obtained by conventional techniques showed that the virus was present in very low titers and was detectable