Pathogenesis of simian varicella virus.

Simian varicella virus (SVV) is closely related to varicella-zoster virus (VZV) and induces a natural varicella-like disease in nonhuman primates. Therefore, simian varicella is a useful model to investigate varicella pathogenesis and to evaluate antiviral therapies. In this report, we review recent studies on SVV pathogenesis and latency. Experimental infection of African green monkeys is followed by a 7-10 day incubation period during which a viremia disseminates the virus throughout the body. Clinical disease is characterized by fever and vesicular skin rash. Pneumonia and hepatitis may occur during more severe infections. Examination of acutely infected tissues reveals histopathology including necrosis and hemorrhage in the skin, lung, liver, and spleen. In contrast, the neural ganglia exhibit minimal histopathology. SVV DNA, immediate early, early, and late gene transcripts, and viral antigens are detected in the tissues of acutely infected monkeys. Host immune responses are induced which resolve the acute infection within 21 days. During or after acute infection, SVV establishes latent infection in the ganglia of surviving monkeys. The virus may reactivate later in life to cause secondary disease and viral transmission to susceptible monkeys. Copyright 2003 Wiley-Liss, Inc.