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

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.