Infectivity of feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation

The infectivity of the feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation was examined by the try pan blue dye exclusion method by assaying their penetration into feline fib roblast cells in vitro and by inoculation of the intestinal mucosa of cats. A large population of the parasites showed trypan blue dye exclusion activ ity. When feline fibroblast cells were inoculated with feline enteroepithel ial stage parasites, no intracellular parasites were found 18 h post-inocul ation. Kittens inoculated intraduodenally with 2 x 10(6) feline enteroepith elial stage parasites shed oocysts between 2 and 8 days post-inoculation. T hese results indicate that the isolated feline enteroepithelial stage paras ites display infectivity towards enterocytes of cats and are capable of gam etogenesis. (C) 1999 Elsevier Science B.V. All rights reserved.