Children with multiple viral respiratory infections are older than those with single viruses.

Aim: To study the clinical impact of multiple viral respiratory infections compared to single infections.

Methods: Demographic data from 37 multiple infection periods in children <5 years of age were compared to data from 193 episodes with single infections. Clinical data derived from patient records of the multiple infection episodes were further compared to data from 93 matched control episodes with single infections.

Etiology of community-acquired pneumonia: increased microbiological yield with new diagnostic methods.

Background: The microbial etiology of community-acquired pneumonia (CAP) is still not well characterized. During the past few years, polymerase chain reaction (PCR)-based methods have been developed for many pathogens causing respiratory tract infections. The aim of this study was to determine the etiology of CAP among adults-especially the occurrence of mixed infections among patients with CAP-by implementing a new diagnostic PCR platform combined with conventional methods.

Merkel cell polyomavirus in respiratory tract secretions.

Merkel cell polyomavirus (MCPyV), associated with Merkel cell carcinoma, was detected in 27 of 635 nasopharyngeal aspirate samples by real-time PCR. MCPyV was more commonly found in adults than in children. Presence in the upper respiratory tract may be a general property of human PyVs.

Development and implementation of a molecular diagnostic platform for daily rapid detection of 15 respiratory viruses.

Acute respiratory tract infections are caused by a large number of viruses. Diagnostic methods have until recently been available only for a limited number of these viruses. With the objective to achieve sensitive assays for all respiratory viruses, a rational workflow in the laboratory, and a short turn-around time, a real-time PCR diagnostic platform for daily rapid detection of 15 respiratory viruses was developed.

A single-tube, real-time PCR assay for detection of the two newly characterized human KI and WU polyomaviruses.

Background: Three new human polyomaviruses have been recently described, and investigating their in vivo biology and pathogenicity will require sensitive and rational detection assays.

Objectives: To develop and evaluate a sensitive and rational assay for detection of the newly identified KI and WU polyomaviruses.

Study Design: A single-tube, dual-probe, real-time PCR assay for simultaneous detection and discrimination of KI and WU polyomaviruses was developed.

High diagnostic yield by CSF-PCR for entero- and herpes simplex viruses and TBEV serology in adults with acute aseptic meningitis in Stockholm.

Acute aseptic meningitis (AAM) affects 10-20/100,000 inhabitants per years in Sweden. Up to the beginning of the 1980s the diagnoses were made by virus isolation and/or determination of viral antibodies in serum. The development of PCR for detection of viruses in CSF samples has increased the sensitivity and diagnostic efficiency considerably.

Norovirus strains belonging to the GII.4 genotype dominate as a cause of nosocomial outbreaks of viral gastroenteritis in Sweden 1997--2005. Arrival of new variants is associated with large nation-wide epidemics.

Background: In recent years an increase of the incidence of nosocomial outbreaks caused by noroviruses has been observed throughout Sweden, with high peaks noted in the winter seasons 2002/2003 and 2004/2005, respectively.

Objectives: To phylogenetically characterize norovirus strains causing nosocomial outbreaks from 1997 to 2005 and estimate the impact of norovirus-like disease on the Swedish health care system during the peak season 2002/2003 when a new variant of norovirus occurred.

Study Design: Stool samples from 115 randomly selected nosocomial outbreaks occurring during 1997--2005 throughout Sweden were studied by RT-PCR and sequencing.

Molecular epidemiology and genetic variability of respiratory syncytial virus (RSV) in Stockholm, 2002-2003.

The epidemiology and genetic variability of circulating respiratory syncytial virus (RSV) strains in Stockholm during the season 2002-2003 were studied in consecutive RSV isolates derived from respiratory samples and diagnosed in the laboratory. Two hundred thirty-four viruses were sequenced. The samples were mainly from children under 1 year old (79%).

High occurrence of a new variant of Chlamydia trachomatis escaping diagnostic tests among STI clinic patients in Stockholm, Sweden.

Background: In 2006, a genetic variant of Chlamydia trachomatis not detectable with the most commonly used diagnostic tests was identified. Initial reports suggested that as many as 10% to 13% of all chlamydia cases would have remained undiagnosed. The aim of the study was to find the occurrence and clinical findings of this genetic variant among a high-risk population in Stockholm, Sweden.

Increased detection rate in diagnosis of herpes simplex virus type 2 meningitis by real-time PCR using cerebrospinal fluid samples.

Efficient and sensitive diagnostic methods are needed in the management of virus infections in the central nervous system. There is a demand for an evaluation of the sensitivity of PCR methods for early diagnosis of meningitis due to herpes simplex type 2 (HSV-2) and varicella-zoster virus (VZV). The objective of this study was to evaluate real-time PCR in the detection of HSV-2 and VZV DNA from cerebrospinal fluid (CSF) for etiological diagnoses in clinically well-characterized cases of primary and recurrent aseptic meningitis.

Cloning of a human parvovirus by molecular screening of respiratory tract samples.

The identification of new virus species is a key issue for the study of infectious disease but is technically very difficult. We developed a system for large-scale molecular virus screening of clinical samples based on host DNA depletion, random PCR amplification, large-scale sequencing, and bioinformatics. The technology was applied to pooled human respiratory tract samples.

Identification of viral agents associated with diarrhea in young children during a winter season in Beijing, China.

Background: Viral diarrhea remains a major cause of childhood morbidity and mortality worldwide. Although rotavirus was extensively studied in China, few comprehensive studies of all viral agents related to diarrhea in children have been conducted.

Objectives: Our study was performed to investigate the role of enteric viruses in acute diarrhea in our country and to evaluate methods that could be used in routine diagnostics.

Molecular epidemiology of norovirus infections in Stockholm, Sweden, during the years 2000 to 2003: association of the GGIIb genetic cluster with infection in children.

The incidence of norovirus-associated gastroenteritis and the molecular epidemiology of norovirus strains were studied during three seasons (2000-2001, 2001-2002, and 2002-2003) among patients of all ages, mainly from the Stockholm region in Sweden. A total of 3,252 fecal samples were analyzed by reverse transcription-PCR. The incidences of norovirus infection among adults were 23, 26, and 30% during the three seasons studied and 18, 11, and 15% among children 0 to 15 years of age.