Serologic Evidence of Jamestown Canyon Anc Keystone Virus Infection in Vertebrates T - ' Te of the Delmarva Peninsula

Serological data accumulated during the past decade indicated that a variety of feral and domestic animals of the Delaware-Maryland-Virginia (DelMarVa) Peninsula were infected with Jamestown Canyon (JC) and/or Keystone (KEY) viruses (Bunyaviridae, California serogroup). Neutralizing (N) antibody to JC virus was most prevalent in white-tailed deer, sika deer, cottontail rabbits and horses. KEY virus N antibody was detected most frequently in gray squirrels and domestic goats. N antibody indicative of past infection by one or both viruses also was found in raccoons, horses and humans. JC and/or KEY virus N antibodies were not demonstrable in sera of several other species of small mammals and reptiles. Investigations were extended to evaluate the role of domestic goats as an amplifying host of JC and KEY viruses and to assess their potential as sentinels of virus transmission. Goats maintained in the Pocomoke Cypress Swamp during the summer season of 1978, acquired N antibodies to JC and KEY viruses. Following experimental inoculation with either JC or KEY virus, all goats developed N antibody despite the absence of a demonstrable viremia in most animals. Goats proved to be effective as sentinels for monitoring the transmission of JC and KEY viruses; however, the exceptionally low titers or absence of viremia following inoculation with these viruses would seem to preclude a potential virus-amplifying role for this species. Although findings implicated primarily gray squirrels and white-tailed deer as possible amplifying hosts of KEY and JC virus, respectively, further investigations will be required to clarify their role, particularly since both viruses may be maintained entirely by transovarial transmission. Keystone (KEY) and Jamestown Canyon (JC) implicated a variety of small mammal(s) as potenviruses (Bunyaviridae, California serogroup) octial amplifying hosts of KEY virus, while serocur in scattered enzootic foci on the Delawaresurveys suggest white-tailed deer to be the preMaryland-Virginia (DelMarVa) Peninsula.1 5 dominant host for JC virus." The relative Transovarial transmission of KEY virus has been involvement of other feral animals, as well as the demonstrated in Aedes atlanticus," and field-colpossible role of domestic animals, has not been lected Aedes canadensis have yielded isolates of resolved. Transmission of these viruses to verteJC virus.I Studies conducted on the ecology of brates and the potential for subsequent virus amthese viruses on the DelMarVa Peninsula have plification become important parameters in understanding the ecology and epidemiology of Accepted 3 March 1982. viruses that are presumably transovarially maintained.' This study addresses the latter parame* In conducting the research described in this report, ters in regard to virus ecology, and assesses the the investigators adhered to the "Guide for the Care and practical use of domestic goats as sentinels to deUse of Laboratory Animals," as promulgated by the tect transmission of KEY and JC viruses. Committee on Care and Use of Laboratory Animals of the Institute of Laboratory Animal Resources, National >& Research Council. The facilities are fully accredited by MATERIALS AND METHODS the American Association for Accreditation of Labora_ tory Animal Care. Serum collections 5 The views of the authors do not purport to reflect the positions of the Department of the Army or the DepartHuman serum specimens were obtained from ment of Defense. s LA.J Address correspondence to: Dr. D. M. Watts, U.S. serum storage files maintained at the Walter Reed Army Medical Research Institute of Infectious Diseases, Army Institute of Research. Specimens tested were ! Fort Detrick, Frederick, Maryland 21701. from persons previously ass"iated with field in-