The purpose of this study is to find out if we can predict the progress of acute upper respiratory tract infection to acute bacterial rhinosinusitis in Finnish conscripts by symptoms, clinical, endoscopic or radiological findings, middle meatal swab samples or nitric oxide measurement.

We will recruit conscripts with upper respiratory tract infection (common cold) during a two month period. We will recruit non-allergic conscripts. These conscripts should either have not had history of recurrent ABR or they should have experienced recurrent acute (ABR) bacterial rhinosinusitis at least 3 times during the last two years (diagnosed by a doctor and at least one time with x-ray or sinus puncture). The recruits will keep a record of their symptoms. They will be examined by a doctor soon after the symptoms have started (2-4 days) and when the symptoms have lasted about 7-10 days. Clinical examination, nasal endoscopy and ultrasonographic examination of the maxillary sinuses are made, middle meatal specimen for bacteria and bacteria-pcr are taken, virus-pcr samples are taken from the nostril and nasopharynx, Nitric oxide-measurements from both nasal cavities are recorded. Cone beam CT of the maxillary and ethmoidal sinuses is made during the first examination, 2-4 days later and during the last examination. If the last CT-scan shows any other radiological signs than mild mucosal oedema in either maxillary sinus, maxillar sinus puncture is made and secretion is aspirated for culture and PCR. Biopsy from the mucosa of nasal cavity (middle meatal area) is taken to examine the cilia and possible bacteria biofilm.

Inclusion Criteria:

• Conscript with acute upper respiratory tract infection symptoms (nasal obstruction/decongestion, post nasal drip or nasal secretion) lasted for 2-4 days

Exclusion Criteria:

• Allergy, asthma, nasal polyposis, sinus surgery, autoimmune illness

Finnish conscripts from the prigade of Kainuu who suffer from acute common cold with nasal symptoms. Consecutive sample. Subjects with known allergies, nasal polyps and prior sinus surgery are excluded.