Even the body's aches make you more sensitive,  连身体疼痛也会使你变得更敏感，

　　drawing attention to infected cuts that might be worsening, or even causing your condition. 让你注意到有个感染的伤口可能加重，或造成了你目前的状况。

　　In addition to physical symptoms, sickness can also make you irritable, sad, and confused. 除了身体症状外，生病也会令你感到烦躁、忧伤以及思想混乱。

　　That's because cytokines and prostaglandin can reach even higher structures in your brain,  那是因为细胞因子和前列腺素能到达脑部更高层的组织，

　　disrupting the activity of neurotransmitters, like glutamate, endorphins, serotonin, and dopamine. 干扰神经传导物质的运作，例如：谷氨酸 (glutamate)、内啡肽 (endorphin)、血清素 (serotonin)及多巴胺 (dopamine)。

　　This affects areas like the limbic system, which oversees emotions, and your cerebral cortex, which is involved in reasoning. 这会影响一些区域，如监督情绪的边缘系统（Limbic System）及参与推理的大脑皮质。

　　So it's actually the body's own immune response that causes much of the discomfort you feel every time you get ill. 所以事实上是身体自己的免疫系统导致每次感冒时的诸多不舒服。

　　Unfortunately, it doesn't always work perfectly. 不幸的是，免疫系统并不总是运作完美。

　　Most notably, millions of people worldwide suffer from autoimmune diseases,  最值得一提的是，全球有数百万人罹患自体免疫性疾病，

　　in which the immune system treats normal bodily cues as threats, so the body attacks itself. 也就是免疫系统将正常身体信号视为威胁，因而攻击自己的身体。

　　But for the majority of the human race, 但对大部份的人类而言，

　　millions of years of evolution have fine-tuned the immune system so that it works for, rather than against us. 数百万年来的演化已将免疫系统精细调整以便为人类效力，而非对抗。

　　The symptoms of our illnesses are annoying, but collectively, they signify an ancient process  生病的症状虽很恼人，但总体而论，它们象征着一种久远的过程，

　　that will continue barricading our bodies against the outside world for centuries to come. 在未来的世纪将继续保卫我们的身体，对抗外在的世界。