When hay fever first occurs it is often mistaken for a summer cold.

花粉病刚发作时，常会被误认为是热伤风。

《柯林斯英汉双解大词典》

Cold symptoms such as stuffy nose, runny nose and scratchy throat typically develop gradually, and adults and teens often do not get a fever.

感冒症状，如鼻塞、流鼻涕和喉咙发痒，通常是逐渐出现的，成年人和青少年通常不发烧。

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Symptoms include fever and muscle aches, often with other gastrointestinal symptoms.

病症包括发烧和肌肉疼痛，常伴有其他肠胃病的症状。

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Often children get cabin fever if they cannot go outside to play.

VOA: special.2010.03.28

Diagnosis is difficult, because early symptoms of fever, muscle aches and fatigue often are confused with the flu.

CNN: STORY HIGHLIGHTS

Once a person contracts the flu virus, he or she is contagious approximately 12 to 24 hours before the peak onset of symptoms, and is often contagious up to 24 hours after resolution of fever.

CNN: How the holidays spread the flu

While not dangerous, and often symptomless in more healthy patients, in the elderly, weak or immuno-suppressed, MRSA can cause fever and pneumonia.

BBC: NEWS | Health | Hospital infections: Case studies