GENOTYPE AND VIRULENCE CORRELATION WITHIN MEXICAN STOCKS OF TRYPANOSOMA-CRUZI ISOLATED FROM PATIENTS

Five Trypanosoma cruzi stocks were isolated from infected patients in the central state of Jalisco, Mexico. Parasites were isolated by direc t inoculation of infected blood into BALB/c mice. The five stocks of T . cruzi were analyzed for in vitro growth, and for virulence and paras itic load in vivo. Furthermore, a genetic analysis based on restrictio n fragment length polymorphism associated with a repetitive element fr om the rRNA gene spacer was performed. No differences in in vitro grow th or in parasitic load in vivo were found among the stocks. While thr ee stocks showed low virulence for mice, the other two stocks killed 8 0 and 100% of the infected mice. In addition, Southern blot of total D NA hybridized with a repetitive element from the rRNA gene spacer show ed two clearly distinct patterns that correlated with the observed abi lity of the stocks to kill infected mice. Our results show a correlati on among the ability to kill BALB/c mice, the genetic pattern and clin ical symptoms produced by the different stocks in the infected patient s. (C) 1998 Elsevier Science B.V. All rights reserved.