After 6-7 days incubation all animals develop fever conjunctivitis, depression, anorexia, diarrhoea, clonic spasms, nasal haemorrhagic discharge, erythematous facial rash. The pathology shows moderate to severe encephalitis with vasculitis. In Cavia porcella , Junin virus produces a fatal disease resembling Argentine Haemorrhagic Fever in man. The animals develop fever on 5-8th day. Death occurs in hypothermic shock on the 11th to 15th day.
Viraemia persists until death.
The virus is located in the principal organs and is excreted with urine and saliva. Pathological findings are macroscopic and microscopic haemorrhagic lesions, in subcutaneous tissues, haemorrhagic lesions in the stomach wall, the small and large intestine, adrenals, lymph nodes, lung, peritoneum and thoracic cavity. Bone marrow shows moderate to massive necrosis. Guinea pigs infected with XJ CL3 strain develop an inapparent infection detectable by the appearance of antibody. The virus is detected in spleen and lymph nodes only.