Population-based seroprevalence of Puumala hantavirus in Finland: smoking as a risk factor.

Puumala hantavirus (PUUV) causes hemorrhagic fever with renal syndrome in humans, that is an endemic disease in Finland. We estimated the seroprevalence of PUUV in Finland and explored risk factors and disease associations by using unique survey data with health register linkage. A total of 2000 sera from a nationwide health survey from 2011, representative of the adult population, were screened for PUUV IgG by immunofluorescence assay. We performed statistical analysis adjusting for stratified cluster design and taking into account sampling weights. In total, 254 sera among 2000 tested were PUUV-IgG-positive resulting in a weighted seroprevalence of 12.5%, (95% CI 10.9-14.4), mirroring known age and regional variation in reported incidence. No associations between PUUV-seropositivity and chronic diseases including cardiovascular (including hypertension), pulmonary, kidney disease and cancer were observed. Smoking was significantly associated with seropositivity (adjusted OR 1.54; 95% CI 1.16-2.04). In addition, significant dose-response relations were found for the number of cigarettes smoked daily (OR 1.14; 95% CI 1.12-1.28). The results are important for disease burden assessment and guide intervention strategies, highlighting also the role of smoking prevention.

An outbreak of Norovirus infections associated with recreational lake water in Western Finland, 2014.

In July 2014, an outbreak of gastroenteritis occurred among visitors to lakes in Tampere, Finland. We conducted a retrospective cohort study using an internet-based survey, solicited by public announcement, to identify source of infection and to implement control measures. Of 1453 persons enrolled in the study, 244 met the case definition (attack rate, 17%). In the pooled univariate analysis, risk factors for gastroenteritis included getting water in the mouth while swimming (Risk ratio (RR) 3.32; 95% Confidence interval (CI), 2.36-4.68) and playing on the wet sand at the beach (RR 1.90; 95% CI 1.50-2.41). In a multivariable analysis (logistic regression), the source of the infection was likely at two lakes (lake A Odds ratio (OR) 1.66; 95% CI 1.15-2.39 and lake B, OR 2.35; 95% CI 1.49-3.72). Norovirus (NoV) was found in 19 stool samples. All water samples from implicated beaches had acceptable values of fecal indicator bacteria and were negative for NoV. The likely source of the outbreak was lake-water contaminated with NoV at two popular lakes. Closure of swimming beaches, advice on hygienic precautions and rapid outbreak alerts were efficient in controlling the outbreak. Results suggest a need for new indicators of water quality and development of evidence-based recommendations regarding timing of safe reopen of recreational water venues associated with outbreaks.

Clostridium difficile infections in Finland, 2008-2015: trends, diagnostics and ribotypes.

We evaluated Clostridium difficile (CD) diagnostics in Finnish clinical microbiology laboratories during 2006-2011, with an update in 2015, in relation to CD surveillance data of the National Infectious Disease Register (NIDR) and ribotyping data from the national reference laboratory during the years 2008-2015. In 2011, diagnostic activity varied regionally more than three-fold and the positivity rate ranged between 7 and 21%. Nucleic acid amplification testing (NAAT) was implemented in the regions with high activity and NAAT users tested 30% more patients and found 15% more cases per population than those not using it. Culture was performed in 79% of laboratories, primary toxin testing by enzyme immunoassay (EIA) in 83% and by NAAT in 17%. In 2014, 12/19 laboratories used NAAT as the primary detection method and four as the secondary method, and ten cultured. Increasing usage of NAAT was not systematically related to various trends detected regionally in annual CD rates. Polymerase chain reaction (PCR) ribotyping of 1771 CD isolates (4.1% of CD cases) identified 146 distinct profiles, of which 37% were binary toxin positive. The most common ribotype was 027, but its proportion decreased, while 078 slightly increased. Transition from culture to NAAT in CD infection (CDI) diagnostics did not cause a significant increase in the observed CDI incidence. Major differences between diagnostic activity, methods and strategies in different regions have persisted over the years, which should be considered when comparing the regional epidemiology of CDI.

Regional differences in long-term cycles and seasonality of Puumala virus infections, Finland, 1995-2014.

Puumala hantavirus (PUUV) causes haemorrhagic fever with renal syndrome in humans, an endemic disease in Finland. We aimed to study recent trends in PUUV infections in Finland, to evaluate whether there are regional differences in seasonality and long-term cycles and whether the patterns have changed over time. We analysed serologically confirmed acute PUUV infections reported to the National Infectious Disease Register from 1 April 1995 to 31 March 2014. A total of 30 942 cases of PUUV infections were identified during the study period. The average annual incidence was 31 cases/100 000 person-years with the highest in Eastern Finland and the lowest in Southwestern Finland. Throughout Finland there was not an increasing trend in incidence but changes in incidence, seasonality and long-term cycles differed regionally. Long-term cycles supported by high Bayesian posterior probabilities (73-100%) differed between the south and the north, shifting from 3 to 4 years, respectively. Temporal changes in seasonality were most prominent in Southwestern Finland. The pattern of human PUUV infection epidemiology probably primarily reflects the spatio-temporal interaction between bank-vole population dynamics and climate.

Tuberculosis in immigrants in Finland, 1995-2013.

Increasing immigration from high tuberculosis (TB) incidence countries is a challenge for surveillance and control in Finland. Here, we describe the epidemiology of TB in immigrants by using national surveillance data. During 1995-2013, 7030 (84·7%) native and 1199 (14·4%) immigrant cases were identified. The proportion of immigrant cases increased from 5·8% in 1995 to 32·1% in 2013, consistent with increasing immigrant population (2·1-5·6%) and decreasing incidence of TB in the native population (from 12·1 to 3·5/100 000). TB cases in immigrants were significantly younger, more often female, and had extrapulmonary TB more often than native cases (P < 0·01 for all comparisons); multidrug resistance was also more common in immigrants than natives (P < 0·01). Immigrant cases were born in 82 different countries; most commonly in Somalia and the former Soviet Union/Russia. During 2008-2013, 433 Mycobacterium tuberculosis isolates from immigrants were submitted for spoligotyping; 10 different clades were identified. Clades were similar to those found in the case's country of birth. Screening immigrants from high-incidence countries and raising awareness of common characteristics and symptoms of TB is important to ensure early diagnosis and to prevent transmission.

Epidemiology and emm types of invasive group A streptococcal infections in Finland, 2008-2013.

Invasive Streptococcus pyogenes (group A streptococcus, GAS) infections are a major global cause of morbidity and mortality. We analysed the surveillance data on invasive GAS and the microbiological characteristics of corresponding isolates to assess the incidence and emm type distribution of invasive GAS infections in Finland. Cases defined as patients with isolations of blood and cerebrospinal fluid S. pyogenes are mandatorily notified to the National Infectious Disease Registry and sent to the national reference laboratory for emm typing. Antimicrobial data were collected through the network including all clinical microbiology laboratories. Pulsed-field gel electrophoresis (PFGE) analysis was performed to assess clonality. In total, 1165 cases of invasive GAS were reported in Finland during 2008-2013; the median age was 52 years (range, 0-100) and 54% were male. The overall day 7 case fatality rate was 5.1% (59 cases). The average annual incidence was 3.6 cases per 100,000 population. A total of 1122 invasive GAS isolates (96%) were analysed by emm typing; 72 different emm types were identified, of which emm28 (297 isolates, 26%), emm89 (193 isolates, 12%) and emm1 (132 isolates, 12%) were the most common types. During 2008-2013, an increase of erythromycin resistance (1.9% to 8.7%) and clindamycin (0.9% to 9.2%) was observed. This resistance increase was in parallel with the introduction of a novel clone emm33 into Finland. The overall incidence of invasive GAS infections remained stable over the study period in Finland. We identified clonal spread of macrolide-resistant invasive emm33 GAS type, highlighting the importance of molecular surveillance.

Coincidental detection of the first outbreak of carbapenemase-producing Klebsiella pneumoniae colonisation in a primary care hospital, Finland, 2013.

In Finland, occurrence of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP) has previously been sporadic and related to travel. We describe the first outbreak of colonisation with KPC-KP strain ST512; it affected nine patients in a 137-bed primary care hospital. The index case was detected by chance when a non-prescribed urine culture was taken from an asymptomatic patient with suprapubic urinary catheter in June 2013. Thereafter, all patients on the 38-bed ward were screened until two screening rounds were negative and extensive control measures were performed. Eight additional KPC-KP-carriers were found, and the highest prevalence of carriers on the ward was nine of 38. All other patients hospitalised on the outbreak ward between 1 May and 10 June and 101 former roommates of KPC-KP carriers since January had negative screening results. Two screening rounds on the hospital's other wards were negative. No link to travel abroad was detected. Compared with non-carriers, but without statistical significance, KPC-KP carriers were older (83 vs 76 years) and had more often received antimicrobial treatment within the three months before screening (9/9 vs 90/133). No clinical infections occurred during the six-month follow-up. Early detection, prompt control measures and repetitive screening were crucial in controlling the outbreak.

A pilot validation in 10 European Union Member States of a point prevalence survey of healthcare-associated infections and antimicrobial use in acute hospitals in Europe, 2011.

We present a pilot validation study performed on 10 European Union (EU) Member States, of a point prevalence survey (PPS) of healthcare-associated infections (HAIs) and antimicrobial use in Europe in 2011 involving 29 EU/European Economic Area (EEA) countries and Croatia. A total of 20 acute hospitals and 1,950 patient records were included in the pilot study, which consisted of validation and inter-rater reliability (IRR) testing using an in-hospital observation approach. In the validation, a sensitivity of 83% (95% confidence interval (CI): 79­87%) and a specificity of 98% (95% CI: 98­99%) were found for HAIs. The level of agreement between the primary PPS and validation results were very good for HAIs overall (Cohen's κappa (κ):0.81) and across all the types of HAIs (range: 0.83 for bloodstream infections to 1.00 for lower respiratory tract infections). Antimicrobial use had a sensitivity of 94% (95% CI: 93­95%) and specificity of 97% (95% CI: 96­98%) with a very good level of agreement (κ:0.91). Agreement on other demographic items ranged from moderate to very good (κ: 0.57­0.95): age (κ:0.95), sex (κ: 0.93), specialty of physician (κ: 0.87) and McCabe score (κ: 0.57). IRR showed a very good level of agreement (κ: 0.92) for both the presence of HAIs and antimicrobial use. This pilot study suggested valid and reliable reporting of HAIs and antimicrobial use in the PPS dataset. The lower level of sensitivity with respect to reporting of HAIs reinforces the importance of training data collectors and including validation studies as part of a PPS in order for the burden of HAIs to be better estimated.

Estimating the burden of A(H1N1)pdm09 influenza in Finland during two seasons.

In Finland, the pandemic influenza virus A(H1N1)pdm09 was the dominant influenza strain during the pandemic season in 2009/2010 and presented alongside other influenza types during the 2010/2011 season. The true number of infected individuals is unknown, as surveillance missed a large portion of mild infections. We applied Bayesian evidence synthesis, combining available data from the national infectious disease registry with an ascertainment model and prior information on A(H1N1)pdm09 influenza and the surveillance system, to estimate the total incidence and hospitalization rate of A(H1N1)pdm09 infection. The estimated numbers of A(H1N1)pdm09 infections in Finland were 211 000 (4% of the population) in the 2009/2010 pandemic season and 53 000 (1% of the population) during the 2010/2011 season. Altogether, 1·1% of infected individuals were hospitalized. Only 1 infection per 25 was ascertained.

Antimicrobial prescribing in nursing homes in Finland: results of three point prevalence surveys.

PURPOSE: The purpose of this study was to analyse the Finnish European Surveillance of Antimicrobial Consumption (ESAC) nursing home (NH) point prevalence surveys' (PPSs) data in detail, i.e. to evaluate the variability in the prevalence of antimicrobial prescription between NHs and its relationship to resident characteristics. METHODS: All residents present in NHs for ≥ 24 h and receiving systemic antimicrobials on the day of the survey were included. Data on antimicrobials and their indications (prophylaxis or treatment, type of infection) were collected. RESULTS: Three PPSs were performed: eight NHs participated in April and November 2009 and nine in May-September 2010. In total, there were 5,691 eligible residents (range by survey, 1,706-2,320; range by NH, 60-688), 716 (12.6 %; range by NH, 3.2-33.3 %) of which received at least one antimicrobial and 40 residents received two. The most common indication was prophylaxis (487/5,691, 8.6 %), mainly for urinary tract infection (UTI) (460/487, 94.5 %). Of the residents, 269/5,691 (4.7 %, range by NH, 1.5-6.0 %) were on antimicrobial treatment. UTI (119/269; 44.2 %) was the most common indication for treatment. Methenamine (306/756, 40.5 %) was the most commonly used antimicrobial, followed by trimethoprim (13.6 %) and pivmecillinam (11.0 %). In the eight NHs participating in all three surveys, the prevalence of residents receiving antimicrobials decreased from 16.6 to 9.7 %. CONCLUSIONS: Antimicrobial use was common in NHs in Finland and most were used for UTI prophylaxis and treatment. The usage, however, varied among NHs and tended to decrease during the surveys. NHs may benefit from antimicrobial stewardship interventions focused on UTI.

What really happened with pneumonia mortality in Finland in 2000-2008?: a cohort study.

This cohort study examines trends in pneumonia mortality in Finland and the effects of a WHO recommendation restricting the registering of pneumonia as the underlying cause of death (COD) for several chronic diseases. All cases having pneumonia in any COD fields in 2000-2008 were extracted from the COD statistics. We examined trends in underlying-cause pneumonia mortality where pneumonia was also the immediate COD. Results are presented as age-specific and age-standardized rates. In the study period 2000-2008, there were 90 626 deaths with pneumonia in COD fields, while the underlying-cause pneumonia mortality rate decreased from 32 to 6/100 000 person-years. Immediate-cause pneumonia was less often chosen as underlying-cause towards 2008 suggesting an effect from changing coding practices. Changes in coding practices need to be considered when comparing different countries or time periods in pneumonia mortality.

Influenza-associated hospitalisations in Finland from 1996 to 2010: unexpected age-specific burden during the influenza A(H1N1)pdm09 pandemic from 2009 to 2010.

To assess the burden of influenza on the Finnish healthcare system, we analysed hospitalisations during 1996-2010 using the International Classification of Diseases codes potentially related to influenza and its complications from the national hospital discharge registry. To compare the influenza A(H1N1)pdm09 pandemic with previous influenza seasons in 1996-2009, we calculated hospitalisation rates by age- and diagnostic groups. We built a negative binomial regression model based on times series analysis to assess the impact of the pandemic. Influenza-associated hospitalisation rates were higher during the pandemic compared to pre-pandemic influenza seasons for 5-24 year-olds (incidence rate ratio (IRR): 1.52, 95% confidence interval (CI): 1.44-1.60) and 25-64 year-olds (IRR: 1.33, 95% CI: 1.29-1.36), but did not differ for persons aged ≥ 65 years (IRR: 0.98, 95% CI: 0.97-1.00). Hospitalisation rates exceeded the upper limit of the prediction line by 177% in 5-24 year-olds, 66% in 0-4 year-olds and 57% in 25-64 year-olds. During the influenza season of 2003/04, all age groups had higher-than-expected hospitalisation rates, whereas other seasonal peaks were only notable among persons aged ≥ 65 years. These age-specific differences in the hospital burden underscore the importance of the continuous surveillance of hospitalisations in order to evaluate immunisation priorities for seasonal influenza and pandemic preparedness including use of antiviral medication.

Travellers returning with measles from Thailand to Finland, April 2012: infection control measures.

Countries with no autochthonous measles run the risk of the virus being imported by travellers and transmitted to unprotected citizens. In April 2012, two travellers from Finland and one from Estonia were diagnosed with measles after returning from Phuket, Thailand. They were contagious on their return flights and subsequently exposed several individuals, prompting extensive infection control measures. Two secondary cases were detected: one child who had received one vaccine dose and another who was fully vaccinated.

Increased incidence of Mycoplasma pneumoniae infection in Finland, 2010-2011.

The number of cases of Mycoplasma pneumoniae infection detected by laboratory-based surveillance increased in Finland in late 2010. During 2011, the number of cases was four times higher than during the previous epidemic in 2005. The 2011 epidemic affected mostly school-age children. The increased number of cases was probably not due to changes in laboratory procedures, but public interest may have had an effect, since the number of Google queries followed closely the epidemic curve.

Two cases of food-borne botulism in Finland caused by conserved olives, October 2011.

In October 2011 in Finland, two persons fell ill with symptoms compatible with botulism after having eaten conserved olives stuffed with almonds. One of these two died. Clostridium botulinum type B and its neurotoxin were detected in the implicated olives by PCR and mouse bioassay, respectively. The olives were traced back to an Italian manufacturer and withdrawn from the market. The public and other European countries were informed through media and Europe-wide notifications.

Epidemiology, outcome and emm types of invasive group A streptococcal infections in Finland.

In 2006, Finnish nationwide surveillance showed an increase of invasive group A streptococcal (iGAS) disease and clinicians were alarmed by severe disease manifestations, prompting the investigation of recent trends and outcome for iGAS. A case of iGAS was defined as Streptococcus pyogenes isolated from blood or cerebrospinal fluid. Cases during 1998-2007 and isolates during 2004-2007 were included. Case-patients' 7-day outcome was available for 2004-2007. Isolates were emm typed. A total of 1,318 cases of iGAS were identified. The average annual incidence was 2.5/100,000 population. The rate was higher in males than females in persons aged 45-64 years, but lower in persons aged 25-34 years. The annual incidence was highest in 2007 (3.9/100,000). Occasional peaks occurred during midwinter and midsummer. The most common emm types were 28 (21%), 1 (16%), 84 (10%), 75 (7%) and 89 (6%). During 2004-2007, emm1 replaced emm28 as the most predominant type. The overall case fatality was 8%. Cases with emm1 were associated with high case fatality (14% vs. 8% in other types; p < 0.02); that of emm28 infections was 2% (p < 0.01). Changes in emm type prevalence influenced incidence and case fatality. Differences in age- and sex-specific incidence and seasonal patterns suggest variations in predisposing factors and underlying conditions.

Methicillin-resistant Staphylococcus aureus (MRSA) in Europe: which infection control measures are taken?

BACKGROUND: The prevalence of hospital-acquired Methicillin-resistant Staphylococcus aureus (MRSA) infections shows a huge variety across Europe. Some countries reported a reduction in MRSA frequency, while in others countries increasing MRSA rates have been observed. To reduce the spread of MRSA in the healthcare setting, a sufficient MRSA management is essential. In order to reflect the MRSA management across Europe, MRSA prevention policies were surveyed in ten countries. MATERIALS AND METHODS: The survey was performed by questionnaires in European intensive care units (ICUs) and surgical departments (SDs) in 2004. Questionnaires asked for availability of bedside alcohol hand-disinfection, isolation precautions, decolonization and screening methods. The study was embedded in the Hospital in Europe Link for Infection Control through Surveillance (HELICS) Project, a European collaboration of national surveillance networks. HELICS was initiated in order to harmonize the national surveillance activities in the individual countries. Therefore, HELICS participants developed surveillance modules for nosocomial infections in ICUs and for surgical site infections (SSI). The coordination of this surveillance has now been transferred to the European Centre for Disease Prevention and Control (ECDC). RESULTS: A total of 526 ICUs and 223 SDs from ten countries sent data on organisational characteristics and policies, demonstrating wide variations in care. Substantial variation existed in availability of bedside alcohol hand-disinfection, which was much higher in participating ICUs rather than in SDs (86 vs. 59%). Surveillance cultures of contact patients were obtained in approximately three-fourths of all SDs (72%) and ICUs (75%). Countries with decreasing MRSA proportions showed especially strict implementation of various prevention measures. CONCLUSION: The data obtained regarding MRSA prevention measures should stimulate infection control professionals to pursue further initiatives. Particularly, the vigorous MRSA management in countries with decreasing MRSA proportions should encourage hospitals to implement preventive measures in order to reduce the spread of MRSA.

Disease burden of Puumala virus infections, 1995-2008.

Puumala virus (PUUV) causes mild haemorrhagic fever with renal syndrome, a rodent-borne zoonosis. To evaluate the disease burden of PUUV infections in Finland, we analysed data reported by laboratories to the National Infectious Disease Registry during 1995-2008 and compared these with data from other national registries (death, 1998-2007; hospital discharge, 1996-2007; occupational diseases, 1995-2006). A total of 22,681 cases were reported (average annual incidence 31/100,000 population); 85% were in persons aged 20-64 years and 62% were males. There was an increasing trend in incidence, and the rates varied widely by season and region. We observed 13 deaths attributable to PUUV infection (case-fatality proportion 0.08%). Of all cases, 9599 (52%) were hospitalized. Only 590 cases (3%) were registered as occupational disease, of which most were related to farming and forestry. The wide seasonal and geographical variation is probably related to rodent density and human behaviour.

Epidemiological analysis of mosquito-borne Pogosta disease in Finland, 2009.

Pogosta disease is a viral disease caused by a mosquito-borne alphavirus, Sindbis virus (SINV), and large human outbreaks of SINV infection have emerged in Finland every seven years. After a major outbreak in 2002 an epidemic was expected to take place in 2009. Data from the National Infectious Disease Registry showed a small outbreak in humans in 2009 with a total of 105 reported cases but the seven-year cycle did not recur as anticipated.

Outbreak of 2009 pandemic influenza A(H1N1) in a Finnish garrison--a serological survey.

In September 2009, an outbreak of 2009 pandemic influenza A(H1N1) took place in a Finnish garrison. In November 2009, we performed a serological survey among 984 recruits undergoing their military service at the garrison and related the results to self-reported upper respiratory tract infection (URTI) with or without fever. Of 346 volunteers who donated a blood sample, 169 (49%) had pandemic influenza A(H1N1) virus-specific antibodies. Of those, 84 (50%) reported no recent history of URTI, suggesting that a major part of those infected with pandemic influenza A(H1N1) virus may be asymptomatic.