SEROLOGIC AND VIROLOGICAL EVIDENCE OF A PROSPECT HILL-LIKE HANTAVIRUSIN WISCONSIN AND MINNESOTA

The purposes of this study were to determine if hantaviruses were pres ent in the Great Lakes port areas of Wisconsin and Minnesota and if so , to identify which virus and which rodent host species were involved. Rodents were trapped in Duluth, Minnesota, Superior, Green Bay, and M ilwaukee, Wisconsin, all ports of call for international maritime ship ping. A total of 675 wild rodents were captured and tested, including 310 meadow voles (Microtus pennsylvanicus), 173 Norway rats (Rattus no rvegicus), 179 Peromyscus spp., (including white footed mice [P. leuco pus] and deer mice [P. maniculatus gracilis and P. maniculatus bairdii ]), and 13 house mice (Mus musculus). Twenty percent of the rats, 17% of the meadow voles, 8% of the house mice, and 3% of the Peromyscus sp p. had antibody to a hantavirus by immunofluorescent antibody assay (I FA). By the plaque-reduction neutralization test (PRNT), nine of 36 me adow voles, one of 4 P. leucopus, and one of 34 rats had hantavirus an tibody, with the highest titers to Prospect Hill (PH) virus. All of th e PRNT-seropositive individuals were from the twin cities of Superior and Duluth. Hantavirus antigen was detected in lung tissue by IFA in M . pennsylvanicus and Peromyscus spp., but not in rats. Two hantaviruse s, designated SD-1 and SD-2, were isolated from M. pennsylvanicus capt ured in Duluth and found to be very similar to prototype PH virus by c ross-IFA and cross-PRNT Virus isolation attempts were unsuccessful fro m tissues of the Peromyscus spp. and the rats.