Specific criteria for the primers and amplicon selection for the SYBR Green based PCR array were: 1) the same range of annealing temperature (T) -57-60uC -for all primers, 2) high G/C content for primers, allowing higher specificity of annealing, and 3) an amplicon size in the range of 100-200 b.p. in order to have a high PCR amplification efficiency and to sufficiently distinguish the products from primer dimers based on melting T peak (Tm). All primers were checked for potential dimer formation using ''Primer Express'' software (version 3.0, Applied Biosystems). After design, all primers were again checked using the National Center for Biotechnology Information (NCBI) Basic Local Alignment Search Tool (BLAST) (http://blast.ncbi.nlm.nih.gov/Blast.cgi) to avoid any cross-reactivity with other species. Newly designed and previously published primer sets adapted for the final version of the real-time PCR array are listed in Table 1 . In addition, primers specific for the human beta-globin gene were included in the array as an internal control for the quality of DNA/RNA preparation as well as for estimation of viral copy number per host cell if needed (the last row of Table 1 ).