Question category: Respiratory
A 42 year old gentleman who is a welder presents to his GP with a flu like illness. He has just returned from a 2 week holiday to work. He did not travel abroad. He presented with fever, chills, myalgia, headache, nausea and fatigue. He remembers during the day having a sweet flavour taste in his mouth. Within 24 hours his symptoms have settled. Which of the following is the most likely diagnosis?