Pathology of Experimental Machupo Virus Infection, Chicava Strain, in Cynomolgus Macaques (Macaca fascicularis) by Intramuscular and Aerosol Exposure:

Machupo virus, the causative agent of Bolivian hemorrhagic fever (BHF), is a highly lethal viral hemorrhagic fever of which little is known and for which no Food and Drug Administration–approved vaccines or therapeutics are available. This study evaluated the cynomolgus macaque as an animal model using the Machupo virus, Chicava strain, via intramuscular and aerosol challenge. The incubation period was 6 to 10 days with initial signs of depression, anorexia, diarrhea, mild fever, and a petechial skin rash. These were often followed by neurologic signs and death within an average of 18 days. Complete blood counts revealed leukopenia as well as marked thrombocytopenia. Serum chemistry values identified a decrease in total protein, marked increases in alanine aminotransferase and aspartate aminotransferase, and moderate increases in alkaline phosphatase. Gross pathology findings included a macular rash extending across the axillary and inguinal regions beginning at approximately 10 days postexposure as well ...