Since its hosts include almost all vertebrate species, and the genotype and phenotype variate greatly, problems of the host specificity and zoonotic transmission have not been solved thoroughly.

• 由于该虫宿主包括几乎所有脊椎动物,虫种的基因型和表现型变异较大,因而其宿主特异性及人畜共患传播问题尚未完全解决。