Hemostatic derangement produced by Rift Valley fever virus in rhesus monkeys

Rift Valley fever (RVF) is an important cause of disease in animals and humans in sub-Saharan Africa. In a small percentage of human cases, the disease is complicated by hemorrhage, which often is associated with a fatal outcome. Inoculation of rhesus monkeys with the Zagazig Hospital strain of RVF virus produced a clinical picture similar to illness in humans. Ten of 17 monkeys developed clinical evidence of hemostatic impairment. When coagulation tests were performed, this group of monkeys had significant abnormalities, including evidence for disseminated intravascular coagulation. These abnormalities were much less pronounced in the remaining seven monkeys-whose only sign of illness was transient fever-and, in general, they paralleled the level of viremia and the degree of elevation in levels of serum hepatic enzymes. Autopsy of the three monkeys with severe disease revealed hepatic necrosis.