Diagnosis of Swine Toxoplasmosis by Specific PCR Assay and the Isolation of Toxoplasma gondii Strains

Objective To diagnose swine toxoplasmosis by specific PCR assay and to isolate Toxoplasma gondii strain from infected tissues through inoculation in mice. Methods Swine toxoplasmosis was diagosed by microscopy of tissue smear amd specific PCR assay (using the first internal transcribed spacer of ribosomal DNA as genetic marker). The diagnosis was further confrimed and the T. gondii strain was isolated by the inoculation of infected tissues in mice. Results Two cases of swine toxoplasmosis were analyzed. A few T. gondii tachyzoites were observed in case 1 by microscopy, but not in case 2. In both cases, DNA fragment specific for T. gondii was amplified from genomic DNA from infected tissues by specific PCR assay. One strain of T. gondii was isolated from each case through inoculation of infected tissues and serial passages in mice. Conclusion Specific PCR assay is a rapid and accurate method for diagnosing swine toxoplasmosis. Inoculation of infected tissues in mice is an effective method for the isolation of T.gondii strains and to confirm the diagnosis.