Hemostatic derangement produced by Rift Valley fever virus in rhesus monkeys

Area of Science:

• Veterinary Medicine
• Infectious Diseases
• Pathology

Background:

• Rift Valley fever (RVF) is a significant zoonotic disease in sub-Saharan Africa.
• Severe human cases can lead to fatal hemorrhage.
• The Zagazig Hospital strain of RVF virus was used for experimental inoculation.

Purpose of the Study:

• To investigate the clinical and pathological effects of RVF virus in rhesus monkeys.
• To determine if rhesus monkeys can serve as a model for human RVF, particularly hemorrhagic complications.
• To examine hemostatic and hepatic abnormalities associated with RVF infection.

Main Methods:

• Rhesus monkeys were inoculated with the Zagazig Hospital strain of RVF virus.
• Clinical signs, hemostatic function (coagulation tests), viremia, and serum hepatic enzymes were monitored.
• Necropsy and histopathological examination were performed on severely affected animals.

Main Results:

• 10 out of 17 monkeys exhibited clinical signs of hemostatic impairment and coagulation abnormalities, including disseminated intravascular coagulation (DIC).
• The remaining 7 monkeys showed only transient fever, with abnormalities correlating to viremia and elevated hepatic enzymes.
• Autopsy revealed hepatic necrosis in severely ill monkeys.

Conclusions:

• Rhesus monkeys inoculated with RVF virus can develop a clinical picture resembling human RVF, including hemorrhagic complications.
• The study demonstrates significant hemostatic impairment and DIC in a subset of infected monkeys.
• Hepatic necrosis is a key pathological finding in severe cases, supporting the rhesus monkey as a relevant model for RVF research.