一种寄生虫，能够改变您的睡眠方式，引起混乱和人格变化，最终导致昏迷和死亡的能力，听起来像是电影中的东西，但是锥虫是可以做到这一点的寄生虫。在撒哈拉以南非洲的部分地区，睡眠疾病或Human African Trypanosomiasis，，，，is a disease that is caused when an infected tsetse fly bites a human and injects trypanosomes as it takes a blood meal.
尽管人类案件是目前处于创纪录的低due to intensive control and surveillance programmes, epidemics in the past have had灾难性的死亡人数在受影响的社区中。根据寄生虫物种，患者可以在极端神经系统症状赋予该疾病的名称并导致死亡的极端神经系统症状之前几个月或几年。一些锥虫感染动物（非洲锥虫病）的某些物种，导致浪费和死亡，包括牛和马在内。这种疾病也被称为长纳（Nagana），对受影响地区的社会经济发展产生了广泛的影响，包括限制食品供应（肉类，牛奶）以及在情节培养或运输和刺激性方面使用动物。
The history of African Trypanosomiasis
It was in the late 1800s that the parasite was first identified by Sergeant Major MajorDavid Bruce，实验开始了解动物和人类的疾病。这是一个幸运的人奴隶贸易的副产品that much interest was generated at this time from the presence of illness in Africans transported to Western countries.
While it had been known that some trypanosomes do infiltrate other tissues and lymph nodes, it was understood that the parasites are adapted to survive and multiply within the blood system for transmission to the insect vector.
但是，早在1895年，Bruce observed一种动物可以transmit the disease despite having no detectable parasites in the blood, stating “In what part of the organism these parasites exist during their absence from the blood is a curious point”. This has been a curious point for researchers ever since, although it seemed probable that these patients likely had trypanosomes circulating at such low numbers that they couldn’t be seen under the microscope.
锥虫藏在哪里？
Over 100 years later, at least a part of this mystery is understood – a combination of three papers published in the last year have shed new light on the mysterious life cycle in the host. These developments have revealed that parasites have the ability to adapt and survive under the skin and within fat tissues.
Last yeara team of researchers led by Anette Macleod reported that, in mouse infections, populations of parasites can be found under the skin, and can be transmitted to a biting tsetse even in the absence of parasites in the blood. A second paper，，，，by Guy Caljon and colleagues，使用荧光标记的寄生虫，表明寄生虫通过采收咬合沉积在皮肤中，并能够在真皮中繁殖。同样，这项研究表明，可以通过进食采采蝇来摄入皮肤居民。
最后，一篇论文由Sandra Trindade和Filipa Rijo-Ferriera合着的人物描述了他们的团队如何研究脂肪（脂肪）组织，鉴定了对这种环境具有特定适应的寄生虫种群，包括在血液寄生虫中未发现的一种代谢（另请参见参见以前的错误博客）。尚不确定这些寄生虫是否可以传输，命名为脂肪组织形式（ATF），并且可以单独具有诸如免疫反应的保护，更合适的生长环境或储层，以使血液重新流op绕作为免疫反应清除寄生虫。
All three papers here have used an animal model ofTrypanosoma brucei brucei
感染的小鼠虽然密切模仿了人类感染，但它是一种不自然的宿主 - 寄生虫组合。将需要进一步的工作来验证自然感染中的这些发现。麦克劳德（MacLeod）组审查了从独立筛查计划中收集的历史皮肤样本，并在少数患者中发现了类似锥虫的生物，尽管他们无法确认它们是引起睡眠疾病的绝对物种。
现在需要进一步的工作来了解我们当前的药物治疗如何影响不在血液中的寄生虫 - 锥虫是否能够在皮肤或脂肪组织中“隐藏”？我们仍然可以仅根据血液检查准确地诊断患者和动物被感染吗？哪些比例的宿主被感染但没有可检测到的血寄生虫？这些宿主如何有助于该领域的传输？
As so often, new discoveries seem to raise as many questions as they answer but perhaps these findings go some way to answering David Bruce’s musings from a century ago.
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