Self-sampling for analysis of respiratory viruses in a large-scale epidemiological study in Sweden.

Viral diagnosis of respiratory tract infections has so far required sampling by health professionals,hampering large-scale epidemiological studies of virus-specific disease outcomes. As part of a population-based, prospective study of work-related risk factors for transmission of viral infections (SWEDE-I), we developed a scheme for self-sampling with nasal swabs. Random selection from the gainfully employed population of a medium-sized town in central Sweden resulted in a study cohort of 2,237 men and women aged 25 to 63 years. From September 2011 through May 2012, the cohort reported all instances of respiratory tract infection or gastroenteritis and participants concomitantly sent self-sampled nasal swabs for analysis using regular mail. Diagnosis of 14 viruses was performed. A total of 1,843 samples were received. The week-wise average delay between disease on set and arrival of the specimens at the laboratory varied between four and six days, and the corresponding median delay was between 3.5 and six days. In line with previous community-based studies, picorna- and coronaviruses dominated in specimens obtained from the self-sampling scheme. The results of self-sampling were contrasted to those from contemporaneous routine clinical sampling, on the same age group, in the adjacent Stockholm county. Although higher proportions of positive samples for respiratory syncytial virus and influenza were observed in the clinical sampling scheme, estimations of seasonality for influenza A and picornaviruses derived from both schemes were similar. Our findings show that nasal self-sampling is feasible in large-scale surveillance of respiratory infections and opens new prospects for population based,virologically verified research on virus spread,burden of disease, and effects of environmental factors or interventions.

[Lung roentgen can be eliminated following uncomplicated pneumonia]. / Lungröntgen kan avskaffas efter okomplicerad pneumoni.

An overwhelming majority of the pulmonary X-rays carried out on patients five to six weeks after recovery from pneumonia reveal no changes. A retrospective study of a five year material shows that pulmonary X-ray after uncomplicated pneumonia is unnecessary if the patient is clinically recovered on his/her next visit to the doctor. This conclusion is independent of the result of possible SR examination.

Diagnosis of whooping cough--a comparison of culture, immunofluorescence and serology with ELISA.

Three methods for diagnosis of whooping cough--culture, immunofluorescence (IF) technique on nasopharyngeal secretion and serology with ELISA--were compared. 52 patients with symptoms of upper respiratory tract infection, which could not exclude pertussis as a differential diagnosis, were investigated. Pertussis infection was confirmed in 30 patients. Of these 16 (53%) were found by culture, 19 (63%) by IF and 28 (93%) by serology. It is concluded that IF analysis of nasopharyngeal secretion is a valuable tool for rapid diagnosis of whooping cough with a sensitivity similar to that of culture. Serodiagnosis with ELISA added a significant number of positive patients in which culture and IF were negative.