Q fever

A 23-year-old backpacker doing farm work presents with a low-grade fever for 4 days. Q fever is suspected. What is the most appropriate diagnostic method for acute Q fever in Australia?

A 55-year-old farmer presents with a week of fever, severe headache, and myalgia. He reports recent exposure to lambing ewes on his property. Physical examination is unremarkable except for mild hepatomegaly and normal vital signs. Considering the patient's occupation, exposure history, and clinical presentation, what is the most likely diagnosis?

A 55-year-old farmer presents with a week of severe retro-orbital headache, fever, and myalgia. He reports recent exposure to birthing sheep on his property. On examination, he is febrile (39.5°C) and mildly jaundiced. Liver enzymes are elevated (ALT 250 U/L). Chest X-ray is clear. What is the most likely diagnosis?

A farmer successfully treated for acute Q fever presents 6 months later with unexplained weight loss and night sweats. Physical exam reveals a new murmur. What is the most likely diagnosis?

A 45-year-old farmer presents with a 10-day history of fever, severe retro-orbital headache, and myalgia. He denies cough or dyspnoea. Physical examination is unremarkable. What is the most appropriate initial investigation?

A 58-year-old man presents to his general practitioner with a 3-week history of intermittent fever, severe headache, and profound fatigue. He describes the headache as diffuse and often retro-orbital, not relieved by simple analgesia. He also reports generalised muscle aches and occasional night sweats. He denies cough, shortness of breath, or gastrointestinal symptoms. His medical history is unremarkable, and he takes no regular medications. He lives on a rural property in Queensland where he raises sheep and cattle. On examination, he is afebrile at the time of consultation (37.2°C), blood pressure is 130/80 mmHg, pulse is 85 bpm, and respiratory rate is 16 breaths per minute. Physical examination is otherwise unremarkable; specifically, there is no rash, lymphadenopathy, or focal neurological signs. Initial laboratory investigations reveal a white cell count of 7.5 x 10^9/L (neutrophils 65%, lymphocytes 25%), haemoglobin 145 g/L, platelets 250 x 10^9/L. Liver function tests show AST 85 U/L (normal <40), ALT 90 U/L (normal <40), alkaline phosphatase 110 U/L (normal <130), total bilirubin 15 µmol/L (normal <20). C-reactive protein is elevated at 45 mg/L (normal <5). A chest X-ray performed a week prior was reported as normal. Given the clinical presentation and epidemiological context, which of the following is the most appropriate initial diagnostic investigation?

A 58-year-old farmer presents with a 10-day history of fever, severe retro-orbital headache, myalgia, and profound fatigue. He denies cough or sore throat. Examination reveals mild scleral icterus. Liver function tests show elevated transaminases. He works closely with sheep and cattle. What is the most likely diagnosis?