Measuring sporadic gastrointestinal illness associated with drinking water - an overview of methodologies.

There is an increasing awareness that drinking water contributes to sporadic gastrointestinal illness (GI) in high income countries of the northern hemisphere. A literature search was conducted in order to review: (1) methods used for investigating the effects of public drinking water on GI; (2) evidence of possible dose-response relationship between sporadic GI and drinking water consumption; and (3) association between sporadic GI and factors affecting drinking water quality. Seventy-four articles were selected, key findings and information gaps were identified.

Genetic diversity among food-borne and waterborne norovirus strains causing outbreaks in Sweden.

A total of 101 food-borne and waterborne outbreaks that were caused by norovirus and that resulted in more than 4,100 cases of illness were reported to the Swedish Institute for Infectious Disease Control from January 2002 to December 2006. Sequence and epidemiological data for isolates from 73 outbreaks were analyzed. In contrast to health care-related outbreaks, no clear seasonality could be observed.

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.

Improved contact tracing of Chlamydia trachomatis in a Swedish county--is genotyping worthwhile?

The vast majority of genital Chlamydia trachomatis infections are non-symptomatic or mildly symptomatic. Efficient contact tracing and screening programmes are the most effective means to reveal these infections. We conducted a prospective study on the effects of contact tracing performed by specially trained midwives in a centralized municipality-based organization during one year.

Characterization of ompA genotypes by sequence analysis of DNA from all detected cases of Chlamydia trachomatis infections during 1 year of contact tracing in a Swedish County.

In this study we aimed to characterize the ompA gene by sequencing DNA from all detected cases of Chlamydia trachomatis infection in a Swedish county during 2001, in order to improve the efficiency of contact tracing. Approximately 990 bp of the ompA gene was amplified, and sequence analysis was achieved in 678 (94%) of 725 C. trachomatis-positive cases in this unselected population.