Microarray technology is a powerful tool to investigate gene expression profiles to study the interactions  between pathogens and associated hosts that cause illness. It can be used to understand the mechanism of virulence, and might also be used to identify a unique host-response signature for pathogen and disease identification purposes. Microarrays have been used to perform DNA sequence analysis of pathogens. In addition to detection and identification of pathogens, microarrays are ideal for characterizing genetic differences between bacteria isolates of the same species to the strain level. Furthermore, the use of microarrays has been gaining importance in the detection of viral agents.