Restriction Fragment Length Polymorphism-based Genotyping of Toxoplasma gondii From Autopsy-Proven Cases of Acquired Immunodeficiency Syndrome-associated Cerebral Toxoplasmosis

Ann Indian Acad Neurol. Oct-Dec 2018;21(4):250-255. doi: 10.4103/aian.AIAN_358_17.


Context: Published data on genetic characterization of Toxoplasma gondii (T.gondii) from clinical cases of toxoplasmosis from India is lacking.

Aims: The present study was aimed at identifying genetic types of T. gondii in fatal cases of cerebral toxoplasmosis (CT) associated with HIV, from India.

Settings and design: Archived tissues of CT were obtained postmortem from 25 acquired immunodeficiency syndrome patients between 2000 and 2014.

Subjects and methods: Direct amplification of eight different loci, namely, SAG1, 5'-3'SAG2, Alt. SAG2, SAG3, BTUB, GRA6, C22-8, and L358 followed by restriction fragment length polymorphism was used to genotype the parasite.

Results: The canonical Types I, II, or III were not found in our study. More than 96% of the cases harbored atypical genotypes-likely recombinants of the canonical types; one case closely corresponded to Type II genotype.

Conclusions: Thus, a majority of T. gondii causing CT in South India belonged to a noncanonical lineage. These nonarchetypal genotypes differed from the conventional Types I, II, and III and caused devastating severity in patients with CT in the background of HIV. These results are a step further to deciphering the population genetics of this important zoonotic parasitic infection in Indian patients, information that has thus far been lacking.

Keywords: Cerebral toxoplasmosis; HIV/Acquired Immunodeficiency Syndrome patients; Toxoplasma gondii; multilocus polymerase chain reaction-restriction fragment length polymorphism genotyping.