The incubation was continued until
the maximum number of tachyzoites was released from both host
cells (for 4 consecutive days). The numbers of extracellular tachyzoites
from 10 fields in each flask were counted. The daily average
number of extracellular tachyzoites per flask was calculated (Lv
et al., 2010), and growth curves of N. caninum tachyzoites in vitro
were drawn.