Ultrastructure characteristics of Besnoitia darlingi tachyzoites brumpt, 1913 [protozoa: sarcocystidae] of the Michigan strain MIBD1

ABSTRACT

Tachyzoites of Besnoitia darlingi Brumpt, 1913 were redescribed based on new materials isolated from Virginia opossums [Dideiphis virginiana, Kerr] from Michigan, USA. Tachyzoites of the MIBD1 strain were propagated in bovine turbinate cell culture for more than two years. A comparison with previously described tachyzoites of the B. darlingi OP1 strain from Mississippi, USA revealed some morphological differences despite the remarkable genetic homogeneity between the two B. darlingi strains. MIBD1 tachyzoites were distinguished from OP1 tachyzoites by having more rhoptries, and fewer and haphazardly distributed micronemes at the conoidal end. This morphological heterogeneity between tachyzoites of the two strains suggests the role of geographical isolation in the Michigan strain. New morphological features of B. darlingi tachyzoites were described