A series of 10-fold dilutions of the plasmid DNA starting from 2.88 × 107to 2.88 × 100 copies/l were prepared to construct standard curve. A linear regression relationship between the plas-mid dilutions and the threshold cycle (Ct) values was observed with a coefficient of determination (R2) of 0.9947 and a slope of−3.0763. The lower detection limit achieved was 2.88 copies/ l with corresponding Ct value of 35.93 (Fig. 2). The lower detection limit based on tissue culture infectivity titre was 0.0001 TCID50/m l with a corresponding Ct value of 31.9 (data not shown).