Protection against a pathogenic strain of Junin virus by mucosal infection with an attenuated strain

In order to determine the degree of mucosal infectivity of the attenuated XJCl3 strain of Junin virus, guinea pigs were orally or nasally inoculated. Infectivity was 85% for the oral and 100% for the nasal route, as detected by death or serum antibody development. The presence of serum antibodies was closely associated with resistance to challenge with the XJ pathogenic strain, which killed 100% of controls when inoculated by the parenteral or nasal route. However, mortality rates after mucosal infection were low, depending on the dose. Guinea pigs which survived nasal inoculation developed serum neutralizing antibodies, and were fully resistant to challenge with the XJ pathogenic strain.