Exposure of Toxocara canis eggs to Purpureocillium lilacinum as a biocontrol strategy: an experimental model evaluation

Abstract Purpureocillium lilacinum is a nematophagous fungus used in biological control against some parasites, including Toxocara canis. This study researched the infectivity of embryonated T. canis eggs after exposure to the fungus P. lilacinum. T. canis eggs were exposed to P. lilacinum for 15 or 30 days and subsequently administered to Swiss mice (n=20). Control group consisted of mice who received T. canis embryonated eggs without fungal exposure. Forty-eight hours after infection, heart, lung, and liver from animals of each group were collected to assess larval recovery. The organs of mice that received embryonated eggs exposed to the fungus showed a lower average larval recovery (P<0.05) suggesting that exposure of T. canis eggs to P. lilacinum was able to reduce experimental infection. Under the evaluated conditions, the interaction time between the fungus and the parasite eggs was not a significant factor in larvae recovery. P. lilacinum may be considered a promising T. canis biological control agent. However, further studies are needed to determine a protocol for the use of this fungus as a biological control agent.

摘要：淡紫紫孢菌（Purpureocillium lilacinum）是一类食线虫真菌，可用于多种寄生虫的生物防治，其中包括犬弓首蛔虫（Toxocara canis）。本研究探讨了经淡紫紫孢菌处理后的犬弓首蛔虫已胚胎化虫卵的感染活性。实验中将犬弓首蛔虫已胚胎化虫卵与淡紫紫孢菌共培养15天或30天，随后接种至瑞士小鼠（每组n=20）。对照组小鼠则接种未经真菌处理的犬弓首蛔虫已胚胎化虫卵。感染48小时后，采集各组小鼠的心脏、肺脏与肝脏，以评估幼虫回收量。结果显示，接种真菌处理组虫卵的小鼠，其平均幼虫回收量显著低于对照组（P<0.05），提示犬弓首蛔虫虫卵经淡紫紫孢菌处理后可降低实验性感染风险。在本研究评估的条件下，真菌与寄生虫卵的相互作用时长对幼虫回收量无显著影响。淡紫紫孢菌有望成为犬弓首蛔虫的潜在生物防治制剂，但仍需开展进一步研究以确立该真菌作为生物防治制剂的应用规范。