Use of Molecular Diagnostics for Infectious Equine Pathogens

The focus of rapid diagnosis of infectious disease of horses in the last decade has shifted from the conventional laboratory techniques of antigen detection, microscopy and culture to molecular diagnosis of infectious agents. Equine practitioners must be able to interpret the use, limitations and results of molecular diagnostic techniques as they are increasingly integrated into routine microbiology laboratory protocols. Polymerase chain reaction is the best known and most successfully implemented diagnostic molecular technology to date. It can detect slow-growing, difficult-to-cultivate or uncultivable microorganisms and can be used in situations in which clinical microbiology diagnostic procedures are inadequate, time-consuming, difficult, expensive or hazardous to laboratory staff. Inherent technical limitations of PCR are present, but they are reduced in laboratories that use standardized protocols, conduct rigid validation protocols and adhere to appropriate quality control procedures. Improvements in PCR, especially probe-based quantitative PCR (qPCR), have broadened its diagnostic capabilities in clinical infectious diseases to complement and even surpass traditional methods in some situations. Automation of all components of PCR is now possible, which will decrease the risk of generating false positive results due to contamination. The diagnostic PCR applications most relevant for equine practice are presented below along with their advantages and potential pitfalls.  […]