Molecular pathology and diagnosis of infectious diseases.

The authors have reviewed and described molecular methods for the detection of etiologic agents or genetic sequences involved in the pathogenesis of various diseases. Molecular probes are now available for the rapid diagnosis of diseases caused by a large number of viruses, bacteria, fungi, spirochetes, rickettsia, and other infectious agents. Since nucleic acid probes can distinguish minute differences indicative of genetic mutations or alternations, specific probes also can be developed even for those diseases with unknown causative agents or etiologies. Further, using these techniques, specific drug-resistant and pathogenic strains associated with epidemics in widely separated areas of a country or a town have been identified. Thus, the sensitivity and specificity of molecular detection methods using both radioactive and nonradioactive probes are at a point that clinical specimens can be tested for rapid diagnosis and identification of etiologic agent(s) that may be responsible for the pathogenesis of a wide variety of diseases.