A: Fertile hydatid cyst, black arrow points at positive parasite cells inside the protoscolex. B: Infertile hydatid cyst without host cell infiltration, black arrow points at positive parasite cells along the germinal layer. C: Infertile hydatid cyst with host cell infiltration, red arrows points at host cells nucleus, which are negative to Echinococcus granulosus aldolase antibody detection. D Fertile hydatid cyst, red arrow points at positive macrophage while Echinococcus granulosus cells are negative E: Infertile hydatid cysts without host cell infiltration, red arrows points at positive macrophages while black arrow points at negative germinal layer cells. F: Infertile hydatid cyst with host cell infiltration, red arrow points at positive macrophages within both the germinal layer and the adventitial layer. Size bar: A, B, C, D, E: 50 μm. F: 100 μm.