Results of nested PCR. M1—100 bp DNA ladder. M2—1 kb DNA ladder. a Results of nested PCR done to prove the identity of various cell lines and primary kidney cells. Species specific primers were used to amplify the Cyt b gene of mitochondrial DNA. Lane 1 to 10 shows species specific amplicon of BHK-21 (245 bp), VERO (301 bp), MRC-5 (441 bp), Hep-2 (441 bp), MDCK (755 bp), A72 (755 bp), MNA (948 bp), MDBK (1090 bp), Negative control, IBRS-2 (819 bp) cell lines, respectively. Lanes 11–13 shows species specific amplicons of primary Syrian hamster kidney (245 bp), Primary dog kidney (755 bp) and Primary cattle kidney (1090 bp) cells, respectively. b Results of nested PCR done on the primary blood cells. Lanes 1, 3 and 4 show species specific amplicons of monkey (301 bp), cattle (1090 bp) and dog (755 bp) blood cells, respectively. Lane 2 is negative control. c Nested PCR result of the MDCK cell line deliberately contaminated with 1% of BHK-21. Lane 1–4 shows Syrian hamster specific amplicon (245 bp) and Lanes 7–10 shows canine specific amplicon (755 bp) of passages P0, P1, P2 and P3, respectively. Lanes 5 and 6 are negative controls. d Nested PCR result of the Vero cell line deliberately contaminated separately with 1% of MDBK and 1% of MDCK. Lane 1–4 shows monkey specific amplicon (301 bp) and Lane 5–8 shows bovine specific amplicon (1090 bp) of passages P0, P1, P2 and P3, respectively. Lanes 9 to 11 show canine specific amplicon (755 bp) at P0, P1 and P2, respectively. Canine specific amplicon at P3 is missing in lane 12. Lanes 13 to 16 show African green monkey specific (301 bp) amplicon at P0, P1, P2 and P3, respectively. eLanes 1 and 3 show Syrian hamster specific amplicons (245 bp) and Lanes 2 and 4 show bovine specific amplicons (1090 bp) of the primary cattle kidney cells deliberately contaminated with 1 and 5% of BHK-21 cell line. Lanes 5 and 7 show Syrian hamster specific amplicons (245 bp) and lanes 6 and 8 shows bovine specific amplicons (1090 bp) of the BHK-21 cell line deliberately contaminated with 1 and 5% of primary cattle kidney cells