Vázquez D P, Canale D, Gürtler R E
Laboratorio de Ecología General, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Buenos Aires, Argentina.
Mem Inst Oswaldo Cruz. 1999 May-Jun;94(3):413-9. doi: 10.1590/s0074-02761999000300024.
We tested experimentally the effects of the presence of non-susceptible hosts on the infection with Trypanosoma cruzi of the vector Triatoma infestans. The experiment consisted in two treatments: with chickens, including two chickens (non-susceptible hosts) and two infected guinea pigs (susceptible hosts), and without chickens, including only two infected guinea pigs. The hosts were held unrestrained in individual metal cages inside a closed tulle chamber. A total of 200 uninfected T. infestans third instar nymphs were liberated in each replica, collected on day 14, and examined for infection and blood meal sources on day 32-36. The additional presence of chickens relative to infected guinea pigs: (a) significantly modified the spatial distribution of bugs; (b) increased significantly the likelihoods of having a detectable blood meal on any host and molting to the next instar; (c) did not affect the bugs' probability of death by predation; and (d) decreased significantly the overall percentage of T. infestans infected with T. cruzi. The bugs collected from inside or close to the guinea pigs' cages showed a higher infection rate (71-88%) than those collected from the chickens' cages (22-32%). Mixed blood meals on chickens and guinea pigs were detected in 12-21% of bugs. Although the presence of chickens would decrease the overall percentage of infected bugs in short term experiments, the high rate of host change of T. infestans would make this difference fade out if longer exposure times had been provided.
我们通过实验测试了非易感宿主的存在对媒介昆虫骚扰锥蝽感染克氏锥虫的影响。实验包括两种处理方式：一种有鸡，包括两只鸡（非易感宿主）和两只感染的豚鼠（易感宿主）；另一种没有鸡，仅包括两只感染的豚鼠。宿主被无限制地饲养在封闭纱网室内的单个金属笼中。每个重复样本中释放了总共200只未感染的骚扰锥蝽三龄若虫，在第14天收集，并在第32 - 36天检查感染情况和血餐来源。相对于感染的豚鼠，鸡的额外存在：(a) 显著改变了虫子的空间分布；(b) 显著增加了在任何宿主上有可检测到的血餐并蜕皮到下一龄期的可能性；(c) 不影响虫子被捕食死亡的概率；(d) 显著降低了感染克氏锥虫的骚扰锥蝽的总体百分比。从豚鼠笼子内部或附近收集的虫子显示出比从鸡笼中收集的虫子更高的感染率（71 - 88%），而从鸡笼中收集的虫子感染率为（22 - 32%）。在12 - 21%的虫子中检测到鸡和豚鼠的混合血餐。虽然在短期实验中鸡的存在会降低感染虫子的总体百分比，但如果提供更长的暴露时间，骚扰锥蝽较高的宿主更换率会使这种差异逐渐消失。
