SEROLOGIC AND MOLECULAR DIAGNOSIS OF COLORADO TICK FEVER VIRAL-INFECTIONS

Molecular and serologic methods usable for the biological diagnosis of Coltivirus infection are reported. We designed a multiplex reverse tr anscription-polymerase chain reaction system that allowed the simultan eous and specific amplification of three genomic segments from as litt le as 0.01 plaque-forming units. Another system in the S2 viral segmen t permitted the differential diagnosis of American and European viral isolates. We also discuss some improvements of previous ELISAs, and th e results obtained with paired sera from Colorado tick fever (CTF) vir us-infected individuals. Western blot analysis was developed that allo wed the detection of antibodies to a 38-kD viral protein in all tested sera. It also enabled the detection of anti-CTF virus antibodies in E LISA-negative sera. Specific IgM antibodies against a synthetic viral peptide could be detected in sera at the acute stage of the infection. Together, these results should permit the diagnosis of Coltivirus inf ection at any stage of the pathology.