SVV causes a highly contagious, life-threatening disease in nonhuman primates. This natural disease of Old World monkeys is characterized by fever, vesicular skin rash, and often disseminated disease, including hepatitis and pneumonia. Once initiated, the disease may rapidly spread throughout a primate colony to susceptible monkeys. Several major simian varicella epizootics have occurred sporadically in primate facilities over the past three decades. These epizootics in captive nonhuman populations have involved high morbidity and sometimes high mortality, resulting in lost research resources and valuable research data. Appropriate antiviral therapy to control epizootics is possible if the disease is quickly diagnosed. Unfortunately, diagnostic methods for the rapid diagnosis of simian varicella are not currently available. The overall goal of this application is to develop rapid and specific diagnostic assays which will be useful for the control of SVV epizootics in primate facilities. Immunohistochemical assays will be designed to detect specific SVV antigens in accessible tissues in SVV-infected monkeys. Assays utilizing the polymerase chain reaction (PCR) will be developed to detect SVV nucleic acid in tissues of infected monkeys. In addition, an enzyme-linked immunoassay (ELISA) will be developed to detect antibodies to SVV antigens in sera derived from infected monkeys in order to evaluate exposure to SVV and susceptibility to simian varicella. This assay will be used to conduct an epidemiological survey of simian varicella at the TRPRC.