Campylobacteriosis in the Nordic countries from 2000 to 2015: Trends in time and space.

Aims: This study aimed to describe the demographic and geographic patterns of campylobacteriosis in Denmark, Finland, Norway and Sweden during 2000-2015. Methods: All Campylobacter infections notified to national authorities in the four countries during the study period were included. Background data for each notification consisted of patient age, sex, geographical location, presumed origin of infection and date of sample taken or date of sample received in the laboratory. These data were analysed in order to investigate annual trends, age group and sex patterns, as well as variations in the geographical and seasonal distribution of infections. Results: During the study period, a total of 164,001 Campylobacter infections, excluding travel-related cases, were registered, representing a mean annual incidence of 42.3 cases/100,000 population (ranging from 28.5 in Norway to 60.4 in Denmark). The incidence increased significantly from 2004 onwards in all countries, apart from Denmark. Males had higher infection rates in general. The highest incidences were observed in 0-4 year olds and those aged 20-29 years, apart from in Finland where there was no peak of infections in children aged 0-4 years. Seasonality of disease was distinct in all four countries, showing peaks of infection between July and August. In Sweden and Norway, incidences of campylobacteriosis were significantly higher in municipalities with high degrees of coastline or inland water. Conclusions: Campylobacter in the Nordic countries mostly follows known patterns with respect to demography and seasonality. Our study demonstrates new insights concerning geographical patterns of disease, highlighting possible future vulnerable population groups and locations.

Linked seasonal outbreaks of Salmonella Typhimurium among passerine birds, domestic cats and humans, Sweden, 2009 to 2016.

In 2016, an outbreak of Salmonella Typhimurium (STm) with multilocus variable-number tandem repeat analysis (MLVA) profiles historically associated with passerine birds (2-[11-15]-[3-4]-NA-212) occurred among passerines, cats and humans in Sweden. Our retrospective observational study investigated the outbreak and revisited historical data from 2009-16 to identify seasonality, phylogeography and other characteristics of this STm variant. Outbreak isolates were analysed by whole-genome single nucleotide polymorphism (SNP) typing. The number of notified cases of passerine-associated STm among passerines, cats and humans per month and county, and their MLVA profiles, were compared to birdwatchers' counts of passerines. Seasonal trend decomposition and correlation analysis was performed. Outbreak isolates did not cluster by host on SNP level. Passerine-associated STm was seasonal for birds, cats and humans, with a peak in March. Cases and counts of passerines at bird feeders varied between years. The incidence of passerine-associated STm infections in humans was higher in the boreal north compared with the southern and capital regions, consistent with passerine population densities. Seasonal mass migration of passerines appears to cause STm outbreaks among cats certain years in Sweden, most likely via predation on weakened birds. Outbreaks among humans can follow, presumably caused by contact with cats or environmental contamination.

Association between heavy precipitation events and waterborne outbreaks in four Nordic countries, 1992-2012.

We conducted a matched case-control study to examine the association between heavy precipitation events and waterborne outbreaks (WBOs) by linking epidemiological registries and meteorological data between 1992 and 2012 in four Nordic countries. Heavy precipitation events were defined by above average (exceedance) daily rainfall during the preceding weeks using local references. We performed conditional logistic regression using the four previous years as the controls. Among WBOs with known onset date (n = 89), exceedance rainfall on two or more days was associated with occurrence of outbreak, OR = 3.06 (95% CI 1.38-6.78), compared to zero exceedance days. Stratified analyses revealed a significant association with single household water supplies, ground water as source and for outbreaks occurring during spring and summer. These findings were reproduced in analyses including all WBOs with known outbreak month (n = 186). The vulnerability of single households to WBOs associated with heavy precipitation events should be communicated to homeowners and implemented into future policy planning to reduce the risk of waterborne illness.

Campylobacter infections expected to increase due to climate change in Northern Europe.

Global climate change is predicted to alter precipitation and temperature patterns across the world, affecting a range of infectious diseases and particularly foodborne infections such as Campylobacter. In this study, we used national surveillance data to analyse the relationship between climate and campylobacteriosis in Denmark, Finland, Norway and Sweden and estimate the impact of climate changes on future disease patterns. We show that Campylobacter incidences are linked to increases in temperature and especially precipitation in the week before illness, suggesting a non-food transmission route. These four countries may experience a doubling of Campylobacter cases by the end of the 2080s, corresponding to around 6,000 excess cases per year caused only by climate changes. Considering the strong worldwide burden of campylobacteriosis, it is important to assess local and regional impacts of climate change in order to initiate timely public health management and adaptation strategies.

Household-based prevalence of helminths and parasitic protozoa in rural KwaZulu-Natal, South Africa, assessed from faecal vault sampling.

This study was undertaken to examine the family-based prevalence of environmentally persistent parasites in two rural communities of KwaZulu-Natal, South Africa. Samples were collected from 120 urine-diversion family toilets and screened for selected protozoa and helminths with immunomagnetic separation and the ammonium bicarbonate (AMBIC) protocol respectively. The parasites found were Ascaris lumbricoides (59%), Giardia intestinalis (54%), Trichuris trichiura (48%), Cryptosporidium spp. (21%) and Taenia spp. (18%). Only 14% of the household toilets were negative for these pathogens. The occurrence of A. lumbricoides and T. trichiura was lower (P<0.001) in the area with better hygiene behaviour, whereas G. intestinalis was more common (P<0.05) in families with at least one child aged five years or less and in families with more than four persons. Quantification of the parasites per gram was done for each sample and this provided realistic risk assessment data for the reuse of material from urine-diversion toilets. The high occurrence of parasites found in the two communities, in spite of sanitation and hygiene interventions in the areas, suggests an endemicity that will not be reduced without de-worming campaigns. Finally, the study showed that sampling directly from the deposited faecal material may be useful for parasitic prevalence estimations.