Two hundred young adults with common colds were studied during a 10-month period. Virus culture, antigen detection, PCR, and serology with paired samples were used to identify the infection. Viral etiology was established for 138 of the 200 patients (69%). Rhinoviruses were detected in 105 patients, coronavirus OC43 or 229E infection was detected in 17, influenza A or B virus was detected in 12, and single infections with parainfluenza virus, respiratory syncytial virus, adenovirus, and enterovirus were found in 14 patients. Evidence for bacterial infection was found in seven patients. Four patients had a rise in antibodies against Chlamydia pneumoniae, one had a rise in antibodies against Haemophilus influenzae, one had a rise in antibodies against Streptococcus pneumoniae, and one had immunoglobulin M antibodies against Mycoplasma pneumoniae. The results show that although approximately 50% of episodes of the common cold were caused by rhinoviruses, the etiology can vary depending on the epidemiological situation with regard to circulating viruses. Bacterial infections were rare, supporting the concept that the common cold is almost exclusively a viral disease.

A waterborne epidemic took place in a Finnish municipality in April 1994. Some 1500-3000 people, i.e. 25-50% of the population, had symptomatic acute gastroenteritis. Laboratory findings confirmed adenovirus, a Norwalk-like agent, small round viruses (SRV), and group A and C rotaviruses as causative agents, Norwalk virus being the main cause of the outbreak. The epidemic was most probably associated with contaminated drinking water. The groundwater well, situated in the embankment of a river, was contaminated by polluted river water during the spring flood. A back flow from the river to the well had occurred via a forgotten drainage pipe.

Four-layer antispecies radioimmunoassay (RIA) and enzyme immunoassay (EIA) procedures were developed for the detection of respiratory syncytial virus (RSV), parainfluenza type 2 virus, and adenovirus antigens in nasopharyngeal specimens from children hospitalized for acute respiratory disease. Polystyrene beads (RIA) or flat-bottomed polystyrene microtiter plates (EIA) were used as the solid phases, guinea pig anti-virus immunoglobulin were used as the captive antibodies, rabbit anti-virus immunoglobulin were used as the secondary antibodies, and '25I-labeled sheep anti-rabbit (RIA) or horseradish peroxidase-labeled

Viral sinusitis frequently occurs in the early days of the common cold, but it is a self-limited illness. The sinuses should not be imaged in patients with the common cold if the signs and symptoms of illness gradually become less severe and no specific signs suggestive of bacterial sinusitis occur.

Because 19 patients were infected with the Chlamydia species strain TWAR and M. pneumoniae, and 24 patients were infected with beta-hemolytic streptococci, the diagnostic procedures and therapies for adult patients with pharyngitis need to be reconsidered. The results of our study also confirm earlier suggestions that the Chlamydia species strain TWAR alone is a causative agent for pharyngitis in adults.