Hosts are typically co-parasitized by multiple species. Parasites can benefit or suffer from the presence of other parasites, which can reduce or increase the overall virulence due to competition or facilitation. Outcomes of new multi-parasite systems are seldom predictable. In 1994 the bacterium Mycoplasma gallisepticum jumped from poultry to songbirds in which it caused an epidemic throughout North America. Songbirds are often parasitized by hard ticks, and can act as reservoirs for tick-borne pathogens. We tested the hypothesis that Mycoplasma infection in house finches influences North America's most important tick vector Ixodes scapularis, by affecting the tick's feeding success, detachment behaviour and survival to the next stage. Most ticks detached during the daylight hours irrespective of the bird's disease status and time since infestation. Birds incrementally invested in anti-tick resistance mechanisms over the course of the experiment; this investment was made earlier in the Mycoplasma-infected birds. At higher tick densities, the feeding success on birds with more severe conjunctivitis was lower than in the uninfected birds. Throughout the experiment we found positive density dependent effects on the tick's feeding success. More diseased hosts suffered more from the tick infestations, as shown by reduced haematocrits. Three Mycoplasma-infected birds died during the weeks following the experiment, although all birds were kept in optimal housing conditions. Mycoplasma made the bird a less accessible and valuable host for ticks, which is an example of ecological interference. Therefore, Mycoplasma has the potential to ultimately reduce transmission outcomes of tick-borne pathogens via songbird hosts.

中文翻译：

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禽疾病暴发期间的寄生虫病：支原体感染雀科和壁虱的实验。

宿主通常被多个物种共同寄生。寄生虫可从其他寄生虫中受益或遭受其他寄生虫的侵害，这些寄生虫可因竞争或促进而降低或增加总体毒力。新的多寄生虫系统的结果很少可以预测。1994年，鸡支原体支原体细菌从家禽跳到了鸣禽，在整个北美引起了流行。鸣禽经常被硬tick虫寄生，可以充当tick虫传播的病原体。我们测试了一种假设，即家雀的支原体感染会影响北美tick的饲养成功，分离行为和到下一阶段的存活，从而影响北美最重要的tick载体I肩I。白天，大多数tick虫都会脱落，无论鸟儿是 侵染以来的疾病状况和时间。在实验过程中，鸟类逐渐增加了抗-虫抗性机制的投入；这项投资是在感染支原体的鸟类中进行的。在较高的tick密度下，患有严重结膜炎的家禽的饲喂成功率低于未感染的家禽。在整个实验过程中，我们发现对tick的饲养成功有正面的密度依赖性影响。如减少的血液危害，更多的患病宿主遭受from虫侵害的机会更多。在实验后的几周内，三只被支原体感染的鸟类死亡，尽管所有鸟类都处于最佳的饲养条件下。支原体使这只鸟成为壁虱的较难获得和有价值的寄主，这是生态干扰的一个例子。因此，