Virulence assessment of a Neospora caninum isolate for inbred C57BL/6 mouse

Neospora caninum (n. caninum) is an apicomplexan parasite and causes abortion and congenital neosporosis in cattle worldwide. in this study, we evaluate the virulence of a n. caninum isolate on mouse strain c57bl/6. six groups of five mice c57bl/6 were intraperitoneally inoculated with 1 × 10^7, 1.5 × 10^7, 2 × 10^7, 3 × 10^7 and 4 × 10^7 tachyzoites and a control inoculum of dmem, respectively. clinical signs and mortality rate were recorded and confirmed by histopathological findings and molecular method. the results of this study indicated that ld50 was 2.5 × l07 tachyzoites of n. caninum per c57bl/6 mouse. this can be used as a lethal challenge model in vaccine development studies.