Echinococcus Infection and Metacestode Fertility in Yaks and Sheep - Four Provincial-Level Administrative Divisions, Northwestern China, 2023.

What is already known about this topic?: Echinococcosis is a parasitic zoonosis caused by the larval stage of cestode species belonging to the genus Echinococcus, which is highly prevalent in northwestern China. Echinococcus spp. includes numerous species/genotypes that have different infectivity and parasitism patterns in livestock hosts, potentially affecting the transmission dynamics of the parasite.

What is added by this report?: In four PLADs of China, the prevalence of Echinococcus was 16.5% in yaks and 9.41% in sheep. The predominant species/genotype was E. granulosus s.s. (G1/G3), which mainly infected sheep liver and yak lung. However, fertile cysts were more frequent in sheep than in yaks.

What are the implications for public health practice?: Understanding the livestock infection rate, prevalent species/genotypes, and cyst fertility is essential for elucidating the mechanisms of Echinococcus transmission and pathogenesis. This knowledge lays the foundation for developing accurate prevention and control strategies.