A 62-yr-old nonsmoking male, a former medical doctor, met and fell in love with a female whom he met occasionally in his apartment or hotels. Besides seasonal rhinoconjunctivitis the patient was healthy until ∼4 months after the first meeting with the female when he experienced fever, flu-like symptoms, fatigue and polyuria with a latency of some hours after each meeting. The same symptoms, but much more severe, together with shortness of breath on exertion occurred after the couple had met in the bungalow where the female lives. She had bought the bungalow 6 months earlier following her divorce. She had moved clothes and furniture from her marital home to the bungalow. The patient suffered further recurrence of the symptoms after spending a night in the bungalow. A chest radiograph, which was normal 4 yrs earlier, showed an area of increased opacity in the right lower lobe and discrete ill defined nodular opacities with ground-glass appearance in both lungs (fig. 1a⇓). Medication containing clarithromycine appeared to improve symptoms, but the patient sought medical advice from a pneumologist. A mild restrictive ventilation pattern with a total lung capacity (TLC) of 87% predicted was measured. The single-breath diffusing capacity of the lung for carbon monoxide (DL,CO) was reduced to 49% pred.