Potential scenarios for the progression of a COVID-19 epidemic in the European Union and the European Economic Area, March 2020.

Two months after the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the possibility of established and widespread community transmission in the European Union and European Economic Area (EU/EEA) is becoming more likely. We provide scenarios for use in preparedness for a possible widespread epidemic. The EU/EEA is moving towards the 'limited sustained transmission' phase. We propose actions to prepare for potential mitigation phases and coordinate efforts to protect the health of citizens.

Low rate of pneumococci non-susceptible to penicillin in healthy Swedish toddlers.

BACKGROUND: Infection caused by Streptococcus pneumoniae is the leading cause of mortality in children worldwide. The aim of this study was to determine if a noted increase in non-susceptibility to penicillin among pneumococcal clinical isolates from young children reflected a similar increase in healthy children. METHODS: During 2004-2005, before the conjugate pneumococcal vaccine was introduced in Sweden, 663 healthy children (13-24 months of age) attending 17 child health centres in Gothenburg, Sweden, were cultured for bacteria in the nasopharynx. Social factors were identified through a parental questionnaire. Pneumococcal serotypes and antibiotic resistance rates were determined. Antibiotic resistance was also monitored in 162 simultaneously obtained nasopharyngeal pneumococci isolated from clinical samples. RESULTS: The healthy children frequently carried pneumococci (45%), Moraxella catarrhalis (54%), and Haemophilus influenzae (22%). The carriage rates for all these pathogens were higher in children attending day care centres compared to children staying at home (p < 0.001). The dominating pneumococcal serotypes were 6B, 19F, 23F, and 6A. Non-susceptibility to penicillin was low (4.0%) and only exceeded by that to trimethoprim-sulfamethoxazole (9.8%). Both rates were higher in the clinical isolates (9.3% and 16.7%, respectively; p < 0.05). No relationships to geographic area, day care attendance, recent antibiotic use, or travel abroad were shown for any specific serotype or for the presence of penicillin-non-susceptible pneumococci in the healthy children. CONCLUSIONS: Pneumococcal resistance rates in the healthy child population were low and did not reflect the higher rates noted at the laboratory in clinical samples obtained before and during the study.

Enhancing the role of health communication in the prevention of infectious diseases.

Despite the recognized importance of health communication for disease prevention, a gap in knowledge was becoming apparent as regards the extent and nature of its use at the European level to support prevention and control of infectious diseases. To address this gap, the European Centre for Disease Prevention and Control (ECDC) commissioned in 2009 a consortium of universities to undertake a 3-year research project called "Translating Health Communications." The outcomes of this project comprise 2 major areas: (a) primary information gathering to provide insights into how health communication activities are currently being used for communicable disease prevention in the European Union and European Economic Area and (b) synthesis of knowledge on the evidence of use and application of health communication approaches. The overview of main findings of the project presented in this article highlights the many challenges that remain and the various areas of opportunity in order to raise the profile of health communication in the prevention of infectious diseases in the European context.

Imported methicillin-resistant Staphylococcus aureus, Sweden.

Countries such as Sweden that have a low prevalence of methicillin-resistant Staphylococcus aureus (MRSA) offer the opportunity to discern and study transmission of imported cases of MRSA. We analyzed 444 imported cases of MRSA acquisition reported in Sweden during 2000-2003. Risk for MRSA in returning travelers ranged from 0.1 (95% confidence interval [CI] 0.01-0.4) per 1 million travelers to Nordic countries to 59.4 (95% CI 44.5-79.3) per 1 million travelers to North Africa and the Middle East. Most imported cases (246, 55%) were healthcare acquired, but regions with the highest risk for MRSA in travelers showed a correlation with community acquisition (r = 0.81, p = 0.001). Characteristic differences in MRSA strains acquired were dependent on the region from which they originated and whether they were community or healthcare acquired. Knowledge of differences in transmission of MRSA may improve control measures against imported cases.

Hepatocellular carcinoma in individuals with HBV infection or HBV-HCV co-infection in a low endemic country.

OBJECTIVE: The aim of this nationwide cohort study was to assess the risk for hepatocellular carcinoma (HCC) in patients with chronic hepatitis B virus (HBV) infection or HBV and hepatitis C virus (HCV) co-infection in Sweden, a low endemic country. MATERIAL AND METHODS: A total of 12,080 patients with HBV and 3238 patients with HBV-HCV co-infection were notified to the Swedish institute for Infectious Disease Control between 1990 and 2004. After excluding 1850 patients with acute HBV and 584 patients infected in adult life, we analyzed the cohort of 9646 subjects with chronic HBV infection. In the co-infection cohort, 1697 patients were analyzed after excluding 1541 cases with acute HBV. The Swedish national cancer registry was used for follow-up. The HCC incidence rate in the cohorts was compared with the HCC incidence rate in the general population and the standardized incidence ratio (SIR) was calculated for different strata according to estimated infection period. RESULTS: HCC was found in 45 patients in the HBV cohort. In the stratum of 40-49 years of infection we found a SIR of 47 and in stratum 50-59 years the SIR was 54. In the co-infected cohort 10 HCCs were found. The SIR in the stratum 20-29 years of infection was 34 and the SIR in the stratum 30 years and over was 91. CONCLUSIONS: This national cohort study of HBV infected and HBV-HCV co-infected subjects in a low endemic country confirms a highly increased risk of liver cancer compared to the general population.

Serologic analysis of returned travelers with fever, Sweden.

We studied 1,432 febrile travelers from Sweden who had returned from malaria-endemic areas during March 2005-March 2008. In 383 patients, paired serum samples were blindly analyzed for influenza and 7 other agents. For 21% of 115 patients with fever of unknown origin, serologic analysis showed that influenza was the major cause.

Hepatocellular carcinoma and other primary liver cancers in hepatitis C patients in Sweden - a low endemic country.

The aim of this study was to assess the risk of hepatocellular carcinoma (HCC) and other primary liver cancers (PLC) in the nationwide cohort of hepatitis C virus (HCV) infected patients in Sweden. The basis was the total HCV-cohort notified in 1990-2004, after excluding 3238 people also reported with hepatitis B, the study cohort consisted of 36 126 people contributing an observation time of 246 105 person-years. The most common route of transmission was intravenous drug use (57%). The national Cancer Registry was used for follow-up, and 354 developed PLC (mainly HCC), of whom 234 were eligible for statistical analysis. The PLC incidence in the HCV cohort was compared with the incidence in the general population, and a standardized incidence ratio (SIR) was calculated for six different strata according to estimated duration of infection. The highest relative risk, SIR: 46 (95% CI: 36-56) was found in the stratum 25-30 years with HCV infection and SIR: 40 (95% CI: 31-51) in the stratum 30-35 years with infection. In the entire community-based HCV cohort in Sweden we found a highly increased risk of liver cancer compared to the general population. The highest relative risk was among people who had been infected for more than 25 years.

Cause of death in individuals with chronic HBV and/or HCV infection, a nationwide community-based register study.

Studies on chronic viral hepatitis and mortality have often been made on selected populations or in high-endemic countries. The aim of this study was to investigate the causes of death and the mortality rates in the nationwide cohorts of people chronically infected with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) in Sweden, a low-endemic country. All notifications on chronic HBV infection and HCV infection 1990-2003 were linked to the Cause of Death Register. A total of 9517 people with chronic HBV infection, 34 235 people with HCV infection and 1601 with chronic HBV-HCV co-infection were included, and the mean observation times were 6.4, 6.3 and 7.9 years, respectively. The mortality in the cohorts was compared with age- and gender-specific mortality in the general population and standardized mortality ratios (SMR) were calculated. All-cause mortality was significantly increased, SMR 2.3 (HBV), 5.8 (HCV) and 8.5 (HBV-HCV), with a great excess liver-related mortality in all cohorts, SMR 21.7, 35.5 and 46.2, respectively. In HCV and HBV-HCV infected there was an increased mortality due to drug-related psychiatric diagnoses (SMR: 20.7 and 27.6) and external causes (SMR: 12.4 and 11.4), predominantly at younger age. To conclude, this study demonstrated an increased all-cause mortality, with a great excess mortality from liver disease, in all cohorts. In people with HCV infection the highest excess mortality in younger ages was from drug-related and external reasons.

The epidemiology of hepatitis C virus infection in Sweden.

In Sweden, infection with hepatitis C virus (HCV) has been a notifiable disease since 1990, when diagnostic methods became available. Blood donor screening indicated that about 0.5% of the Swedish population (9 millions) had been HCV infected. Here we present the Swedish hepatitis C epidemic based on data from all the HCV notifications 1990-2006. During this time about 42,000 individuals (70% men) were diagnosed and reported as HCV infected. The majority (80%) were born in 1950 or later, with a high percentage (60%) born in the 1950s and 1960s. Younger people, 15-24 years old at notification, were reported on the same level each year. The main reported routes of HCV transmission were intravenous drug use in 65%, blood transfusions/products in 6%, and sexual in 2%, though unknown or not stated in 26%. Approximately 6,000 of all notified individuals have died during the study period. To conclude, the Swedish HCV epidemic is highly related to the increase of intravenous drug use in the late 1960s and 1970s, with a high proportion of people now chronically infected for more than 25 years, resulting in an increase of severe liver complications in form of cirrhosis and hepatocellular carcinoma. Furthermore the unchanged number of notifications of newly infected younger people indicates an ongoing HCV epidemic.

A meta-analysis on the effects of antibiotic treatment on duration of symptoms caused by infection with Campylobacter species.

Eleven randomized, controlled trials of antibiotic treatment versus placebo in patients with Campylobacter species infection were pooled in a meta-analysis. Antibiotic treatment shortened the duration of intestinal symptoms by 1.32 days (95% confidence interval, 0.64-1.99; P<.0001). Because of problems with drug resistance, a restrictive attitude towards the administration of antibiotics in uncomplicated cases is advised.

Is exposure to sick or dead poultry associated with flulike illness?: a population-based study from a rural area in Vietnam with outbreaks of highly pathogenic avian influenza.

BACKGROUND: The verified human cases of highly pathogenic avian influenza in Vietnam may represent only a selection of the most severely ill patients. The study objective was to analyze the association between flulike illness, defined as cough and fever, and exposure to sick or dead poultry. METHODS: A population-based study was performed from April 1 to June 30, 2004, in FilaBavi, a rural Vietnamese demographic surveillance site with confirmed outbreaks of highly pathogenic avian influenza among poultry. We included 45 478 randomly selected (cluster sampling) inhabitants. Household representatives were asked screening questions about exposure to poultry and flulike illness during the preceding months; individuals with a history of disease and/or exposure were interviewed in person. RESULTS: A total of 8149 individuals (17.9%) reported flulike illness, 38,373 persons (84.4%) lived in households keeping poultry, and 11,755 (25.9%) resided in households reporting sick or dead poultry. A dose-response relationship between poultry exposure and flulike illness was noted: poultry in the household (odds ratio, 1.04; 95% confidence interval, 0.96-1.12), sick or dead poultry in the household but with no direct contact (odds ratio, 1.14; 95% confidence interval, 1.06-1.23), and direct contact with sick poultry (odds ratio, 1.73; 95% confidence interval, 1.58-1.89). The flulike illness attributed to direct contact with sick or dead poultry was estimated to be 650 to 750 cases. CONCLUSIONS: Our epidemiological data are consistent with transmission of mild, highly pathogenic avian influenza to humans and suggest that transmission could be more common than anticipated, though close contact seems required. Further microbiological studies are needed to validate these findings.

Modeling pneumococcal resistance to penicillin in southern Sweden using artificial neural networks.

In recent decades, penicillin-resistant pneumococci (PRP) have emerged and spread rapidly between and within countries over the world. In this study we developed an iterative artificial neural network (ANN) model to describe and predict the spread of PRP in space and time as a function of antibiotic consumption and a number of different confounders. Retrospective data from 1997 to 2000 on an international epidemic PRP clone (serotype 9V) and antibiotic consumption data from Southern Sweden were used to train the ANN models and data from 2001 to 2003 for evaluation of the model predictions. Five different ANN models were trained, each with independent topology optimization for alternative sets of input variables to find the most descriptive model. The model containing all variables was the only one performing better than the reference linear models, as assessed by the correlation between predictions and observations. The inability to identify a smaller subset of most predictive parameters may reflect either diffuse causal mechanisms or just the absence of critical experimental indicators from the dataset. The iterative ANN model identified is useful to predict future data. The sensitivity analysis of the model suggests that past incidence has a small effect on the number of PRP cases.

Penicillin-resistant pneumococci in Sweden 1997-2003: increased multiresistance despite stable prevalence and decreased antibiotic use.

Antimicrobial resistance patterns and capsular groups of penicillin-resistant Streptococcus pneumoniae (PRP; MIC penicillin G > or = 0.5 mg/ml) in Sweden between 1997 and 2003 were described, and trends in resistance and antibiotic sales during the same period were compared. The most common serogroups were in descending order 9, 19, 14, 23, and 6. Despite a low and stable annual PRP rate (proportion of PRP out of all pneumococci) of around 2% during the study period, the proportion of PRP resistant to other antibiotics increased. Of all tested PRP isolates, 82% were also resistant to trimethoprim/sulfamethoxazole, 32% had additional resistance to tetracycline, and 26% to erythromycin. Antibiotic sales figures for all studied antibiotic subgroups decreased during the same period. Little correlation was found between antibiotic sales and PRP resistance rates, indicating that there are still other poorly defined factors contributing to the reported resistance levels in the population. However, although PRP strains in Sweden are becoming more commonly resistant to antibiotics other than beta-lactams, the low and further reduced antibiotic sales still might have delayed the development and rapid spread of PRP in the population.

Occurrence of invasive pneumococcal disease and number of excess cases due to influenza.

BACKGROUND: Influenza is characterized by seasonal outbreaks, often with a high rate of morbidity and mortality. It is also known to be a cause of significant amount secondary bacterial infections. Streptococcus pneumoniae is the main pathogen causing secondary bacterial pneumonia after influenza and subsequently, influenza could participate in acquiring Invasive Pneumococcal Disease (IPD). METHODS: In this study, we aim to investigate the relation between influenza and IPD by estimating the yearly excess of IPD cases due to influenza. For this purpose, we use influenza periods as an indicator for influenza activity as a risk factor in subsequent analysis. The statistical modeling has been made in two modes. First, we constructed two negative binomial regression models. For each model, we estimated the contribution of influenza in the models, and calculated number of excess number of IPD cases. Also, for each model, we investigated several lag time periods between influenza and IPD. Secondly, we constructed an "influenza free" baseline, and calculated differences in IPD data (observed cases) and baseline (expected cases), in order to estimate a yearly additional number of IPD cases due to influenza. Both modes were calculated using zero to four weeks lag time. RESULTS: The analysis shows a yearly increase of 72-118 IPD cases due to influenza, which corresponds to 6-10% per year or 12-20% per influenza season. Also, a lag time of one to three weeks appears to be of significant importance in the relation between IPD and influenza. CONCLUSION: This epidemiological study confirms the association between influenza and IPD. Furthermore, negative binomial regression models can be used to calculate number of excess cases of IPD, related to influenza.

Epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Sweden 2000-2003, increasing incidence and regional differences.

BACKGROUND: The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) has gradually become more frequent in most countries of the world. Sweden has remained one of few exceptions to the high occurrence of MRSA in many other countries. During the late 1990s, Sweden experienced a large health-care associated outbreak which with resolute efforts was overcome. Subsequently, MRSA was made a notifiable diagnosis in Sweden in 2000. METHODS: From the start of being a notifiable disease in January 2000, the Swedish Institute for Infectious Disease Control (SMI) initiated an active surveillance of MRSA. RESULTS: The number of reported MRSA-cases in Sweden increased from 325 cases in 2000 to 544 in 2003, corresponding to an overall increase in incidence from 3.7 to 6.1 per 100,000 inhabitants. Twenty five per cent of the cases were infected abroad. The domestic cases were predominantly found through cultures taken on clinical indication and the cases infected abroad through screening. There were considerable regional differences in MRSA-incidence and age-distribution of cases. CONCLUSION: The MRSA incidence in Sweden increased over the years 2000-2003. Sweden now poises on the rim of the same development that was seen in the United Kingdom some ten years ago. A quarter of the cases were infected abroad, reflecting that international transmission is now increasingly important in a low-endemic setting. To remain in this favourable situation, stepped up measures will be needed, to identify imported cases, to control domestic outbreaks and to prevent transmission within the health-care sector.

The comparative burden of salmonellosis in the European Union member states, associated and candidate countries.

BACKGROUND: Salmonella is an infectious agents causing numerous cases of illness each year, and thereby having significant economic impact. Using returning Swedish travellers we estimated the burden of salmonellosis in different European countries. METHODS: From the Swedish database on notifiable communicable diseases 15,864 cases with travel-associated salmonellosis acquired in Europe from 1997-2003 were retrieved. These cases were compared to a dataset from the same years on 14,171 randomly selected Swedish residents, with a history of recent overnight travel in Europe. Distribution of salmonellosis in returning travellers and the distribution of Salmonella Enteritidis was analysed for different member states in the European Union, associated and candidate countries. The risk of being notified with a salmonella infection after return from each European country/region was calculated, and compared with official reporting data rom these countries. Using Norway as reference country, we could 1) construct comparable incidence estimates and 2) calculate the "under-reporting" in each country compared to Norway. RESULTS: The highest burden of salmonellosis was estimated for Bulgaria (2741/100,000), followed by Turkey with 2344/100,000 and Malta with 2141/100,000. S. Enteritidis is the dominating serotype, 66.9 % of all cases and phage type 4 accounts for 37.5 % of the S. Enteritidis cases. CONCLUSION: Using returning tourists as a sentinel population can provide a useful base for comparison of disease burdens in different countries/regions. Focusing prevention of salmonellosis to prevention of egg and poultry associated S. Enteritidis infection will have a major impact from a public health perspective and will significantly lower the burden of disease in most European countries.

Imported giardiasis: impact of international travel, immigration, and adoption.

From the Swedish national database, regarding notified Giardia cases, we could for the period 1997-2003 identify 3,697 cases of travel-associated giardiasis, 4,151 cases in newly arrived immigrants and refugees, and 455 cases in internationally adopted children. These were compared with data sets on the number of international travelers, immigrants/refugees, and adopted children. The overall risk of being notified with giardiasis in returning travelers was 5.3 of 100,000, with the highest incidences in travelers from the Indian Subcontinent (628 of 100,000), East Africa (358 of 100,000), and West Africa (169 of 100,000). A large proportion of the travel-related cases were seen in persons with family roots in the country of infection-a risk group deserving special attention. The overall risk in immigrants and refugees was 1,180/100,000 with the highest risk in persons from Afghanistan (3,800 of 100,000) and Iraq (2,990 of 100,000). The incidence was highest among internationally adopted children (8,110 of 100,000), with geographical risks not entirely correlating to those in travelers and immigrants.

Could flies explain the elusive epidemiology of campylobacteriosis?

BACKGROUND: Unlike salmonellosis with well-known routes of transmission, the epidemiology of campylobacteriosis is still largely unclear. Known risk factors such as ingestion of contaminated food and water, direct contact with infected animals and outdoor swimming could at most only explain half the recorded cases. DISCUSSION: We put forward the hypothesis that flies play a more important role in the transmission of the bacteria, than has previously been recognized. Factors supporting this hypothesis are: 1) the low infective dose of Campylobacter; 2) the ability of flies to function as mechanical vectors; 3) a ubiquitous presence of the bacteria in the environment; 4) a seasonality of the disease with summer peaks in temperate regions and a more evenly distribution over the year in the tropics; 5) an age pattern for campylobacteriosis in western travellers to the tropics suggesting other routes of transmission than food or water; and finally 6) very few family clusters. SUMMARY: All the evidence in favour of the fly hypothesis is circumstantial and there may be alternative explanations to each of the findings supporting the hypothesis. However, in the absence of alternative explanations that could give better clues to the evasive epidemiology of Campylobacter infection, we believe it would be unwise to rule out flies as important mechanical vectors also of this disease.

Mortality following Campylobacter infection: a registry-based linkage study.

BACKGROUND: Campylobacteriosis is one of the most commonly identified causes of bacterial diarrheal disease and a common cause of gastroenteritis in travellers from developed nations. Despite the widespread occurrence, there is little information on Campylobacter mortality. METHODS: Mortality among a cohort of Campylobacter cases were compared with the general population 0-1, 1-3, 3-12 and more than 12 month after the onset of the illness. The cases were sub-grouped according to if they had been infected domestically or abroad. RESULTS: The standardized mortality ratio for cases infected domestically was 2.9 (95% CI: 1.9-4.0) within the first month following the illness. The risk then gradually diminished and approached 1.0 after one year or more have passed since the illness. This initial excess risk was not attributable to any particular age group (such as the oldest). In contrast, for those infected abroad, a lower standardized mortality ratio 0.3 (95% CI: 0.04-0.8) was shown for the first month after diagnosis compared to what would be expected in the general population. CONCLUSION: Infection with Campylobacter is associated with an increased short-term risk of death among those who were infected domestically. On the contrary, for those infected abroad a lower than expected risk of death was evident. We suggest that the explanation behind this is a "healthy traveler effect" among imported cases, and effects of a more frail than average population among domestic cases.

Risk of travel-associated typhoid and paratyphoid fevers in various regions.

BACKGROUND: Although enteric fever (typhoid and paratyphoid fevers) is a major global public health problem, comparable data on the risks of contracting travel-associated enteric fever in various regions of the world are scarce. METHODS: From the Swedish database on notifiable communicable diseases, we retrieved all case records from 1997 to 2003 on typhoid and paratyphoid fevers. The data set was compared with data on travel patterns obtained from a comprehensive travel database with information from interviews with more than 16,000 Swedish residents with recent overnight travel outside Sweden. RESULTS: The overall risk of being notified with enteric fever after travel was 0.42 in 100,000 travelers. The highest risk for typhoid fever was seen in travelers from India and neighboring countries (41.7 in 100,000), the Middle East (5.91 in 100,000), and Central Africa (3.33 in 100,000), whereas the risk was comparatively low in East Asia (0.24 in 100,000). Almost the same risk areas stood out for paratyphoid fever: India and neighbors (37.5 in 100,000), the Middle East (3.64 in 100,000), and East Africa (3.33 in 100,000). The epidemiology of paratyphoid fever was considerably affected by a large outbreak of paratyphoid B in a Turkish tourist resort in 1999. The youngest children were at highest risk for typhoid fever (odds ratio 44.2), whereas youths ages 7 to 18 years were at highest risk for paratyphoid fever (odds ratio 9.7). CONCLUSIONS: Detailed risk data for enteric fever after travel could form the basis for travel advice. Vaccination against typhoid fever should always be considered for travelers to the Indian subcontinent, the Middle East, and Africa but should not routinely be given to travelers to the Malay Peninsula.