PCR-RFLP based genotyping of Indian isolates of Toxoplasma gondii.

Toxoplasma gondii is an apicomplexan parasite capable of infecting a wide variety of warm-blooded animals, including birds and humans and is zoonotically important too. Felidae serve its definitive hosts and most infections are inoccous while in various intermediate hosts (e.g. sheep), it is responsible for abortion, still births. Humans which are immune compromised are also susceptible to toxoplasmosis. Most of the epidemiological studies have revealed it to be belonging to three clonal types with exceptions in South Africa having atypical isolates. Current genotyping was carried out at 11 genetic loci (SAG1, 5'-SAG2, 3'-SAG2, alt. SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358 and PK1) using multiplex-nested polymerase chain reaction restriction fragment length polymorphism (Mn-PCR-RFLP). SAG1, alt SAG2, SAG3, BTUB, GRA6, C22-8, C29-2, L358 and PK1 could differentiate our strain/isolates as type I (T. gondii RH) and type III (T. gondii isolates from Chennai and Izatnagar). 5'SAG2 and 3'SAG2 in combination confirmed these as above mentioned genotypes. Further, the T. gondii RH was assigned Toxo DB#10 and local isolates of T. gondii were assigned Toxo DB#2. The present study is the first report on existence of Type III T. gondii lineage from animal population of Indian subcontinent based on PCR-RFLP.