polyparasitism

例句：

1. 1. The parasites that live on the host's blood are called malaria.
   寄生在宿主血液中的寄生虫被称为疟疾。
2. 2. Polyparasitism is a common phenomenon in many ecosystems.
   多寄生现象在许多生态系统中很常见。
3. 3. The parasites can cause significant damage to the host's immune system.
   这些寄生虫可以严重破坏宿主的免疫系统。