Pathogenesis of a North American hantavirus, Black Creek Canal virus, in experimentally infected Sigmodon hispidus

Abstract

This report describes the first detailed analysis of the replication, persistence, and excretion of a North American hantavirus in its natural rodent reservoir. Black Creek Canal virus was isolated from Sigmodon hispidus (cotton rat) shortly after the identification of a hantavirus pulmonary syndrome (HPS) case occurring in southern Florida. Six-week-old male cotton rats were inoculated subcutaneously with 1,000 tissue culture infectious doses. Viral complementary RNA (vcRNA) was quantified as a means of determining the site(s) of viral activity (transcription and replication). In the first few weeks post inoculation (pi), vcRNA was detectable in every tissue examined except blood. The quantities of vcRNA decreased over time, and by five months pi it could be detected only in the brain. In addition to using a quantitative polymerase chain reaction (QPCR) as a means of measuring viral replication/transcription, attempts were made to reisolate virus from all tissue samples taken. Virus could be isolated from every solid tissue examined, and the titers appeared to decrease over time, similar to the QPCR results. However, in contrast to the QPCR results, infectious virus was still routinely detectable at low levels in adrenal gland, liver, kidney, and testicle 150 days pi. Although results of testing for vcRNA in the blood were uniformly negative, infectious virus was detected at one week pi, reached highest titers at two weeks, and decreased dramatically by three weeks. After three weeks pi, infectious virus could only be detected sporadically in blood. Virus was isolated from urine collected during the first 70 days pi and throughout the entire study period in feces and wet bedding. These data indicate that the viral infection can be separated into an acute phase associated with high virus titers, and a chronic or persistent phase associated with lower virus titers and continued shedding of virus in excreta.