每日一题_2022.11.22

A previously healthy 41-year-old man misses several days of work as a result of a viral illness with symptoms including fever, headache, and fatigue. He also experiences a nonproductive cough and a sore throat. By the third day, his symptoms begin to subside and he is able to return to work. The next week, however, he experiences a rapid relapse. His cough returns, but now it is a productive cough with mucopurulent sputum. He also begins to experience pleuritic chest pain. On visiting a physician, x-ray of the chest is ordered and is shown in the image. Which of the following describes the structure of the viral genome that most likely caused his initial illness?

一名既往健康的41岁男性因病毒性疾病而错过数天的工作，症状包括发热、头痛和疲乏。他还出现干咳和咽喉痛。到第三天，他的症状开始消退，他能够恢复工作。然而，下周，他的病情迅速复发。患者咳嗽复发，但现在是咳痰伴粘液脓痰。他还开始出现胸膜炎性胸痛。就诊时，预约胸部 x 线检查，并在图像中显示。以下哪一项描述了最有可能导致他初始疾病的病毒基因组结构？

(A)  Enveloped, double-stranded DNA

(B)  Enveloped, nonsegmented, single-stranded RNA

(C)  Enveloped, segmented, single-stranded RNA

(D)  Non-enveloped, nonsegmented, double- stranded RNA

(E)  Non-enveloped, nonsegmented, single- stranded RNA

答案解析：

从历史上看，这名男子最初似乎出现了非特异性的病毒症状，但没有足够的信息来确定他患有哪种病毒。然而，很明显的是，他的初始症状与他复发时所表现的不同。X 线片显示他患有大叶性肺炎（右肺下叶），可由任何数量的细菌引起。因此，必须提出的问题是，“在一个健康的个体中，哪种病毒性疾病易导致随后的细菌性肺炎？”典型的答案是流感。流感病毒是一种有包膜的单链 RNA 病毒，具有分节段基因组，允许编码血凝素和神经氨酸酶蛋白的基因重配，导致抗原转移的命名。流感的并发症包括病毒性肺炎（由于疾病扩散到下呼吸道）和细菌性肺炎。后者被认为主要是由于流感损害了上呼吸道上皮，损害了其保持下呼吸道无菌的能力。肺炎链球菌、金黄色葡萄球菌和流感嗜血杆菌是继发于流感的细菌性肺炎中最常见的微生物。胸部 x 线检查显示右下叶实变以及肺炎旁积液，高度怀疑细菌性肺炎。

正确答案：C