Journal of Veterinary Parasitology

Toxoplasmosis caused by Toxoplasma gondii is a fatal disease in immunocompromised individuals. Currently diagnosis of the disease is based on detection of specific antibodies and/or application of scanning techniques. A SYBR Green chemistry based quantitative real-time polymerase chain reaction (PCR) assay was laboratory standardized for early detection of the infective agent. The test was standardized for amplification of a 193 bp fragment targeting the B1 gene, the sequence of which is conserved and highly repetitive in T. gondii genome. The sensitivity of the assay was determined using ten-fold serial dilutions of template DNA in 25 μl of reaction mixture which revealed the amplification limit of 0.015ng of template DNA. Further, the amplification profile also revealed the relationship between the threshold cycle and the quantity of template DNA used i.e. increase in quantity of template DNA resulting in an early threshold cycle (Ct value).The real-time quantitative PCR assay standardized is highly sensitive, simple to perform and suitable for rapid screening of toxoplasmosis in intermediate hosts and useful for molecular epidemiological study of T. gondii.