ABSTRACT
Polymerase chain reaction amplification assays have been described for two members of the Rickettsiae: Rickettsia typhi, the etiological agent of murine typhus and Rickettsia rickettsii and Rickettsia conorii, the etiological agents of Rocky Mountain spotted fever and boutonneuse fever, respectively. Both assays already display sufficient sensitivity and specificity to be regarded as supplementary to candidates for routine early diagnosis of respective pathogens in a clinical setting. Dengue Virus (DV) causes the most important mosquito-borne viral infection of humans, affecting millions of people annually in tropical countries. Aedes mosquitos are the common vectors of DV. In spot hybridization assays with RNA extracted from cells infected with one of 14 different flaviviruses or Semliki Forest virus, DV was detectable by DV-specific photobiotin-labeled probes. Restriction endonuclease analysis and deoxyribonucleic acid hybridization characterized Borrelia Burgdorferi from different isolates in North America and Europe and demonstrated genotypic heterogeneity within this genus and species.
