Antimicrobial resistance (AMR) poses a global health threat, with urban wastewater systems serving as key reservoirs for resistance dissemination. This study aimed to investigate the relationships among urban environments, bacterial communities, and AMR patterns, and evaluate the specific municipal-scale drivers of resistance gene distribution. Shotgun metagenomic analysis was conducted on 45 wastewater samples collected from 15 municipalities across Latvia to determine the composition of the resistome and its correlation with local factors. The analysis identified 417 distinct antibiotic resistance genes (ARGs) belonging to 108 families, with geographic location serving as the primary driver of ARG distribution, which explained 65.87% of community variation (p = 0.001). Local industrial factors demonstrated significant effects, with food industry wastewater significantly influencing both bacterial taxonomy and ARG profiles (p < 0.05). While the presence of a regional hospital did not shape the overall municipal resistome, hospital-associated wastewater showed 19 overlapping ARGs, including clinically critical carbapenemases. Municipal wastewater systems function as geographically structured reservoirs of AMR that are shaped by localized industrial and healthcare outputs. These findings support wastewater-based AMR surveillance as a valuable tool for tracking specific resistance sources.

Background: Sepsis and septic shock are medical emergencies with increasing incidence and high intrahospital mortality rates, as they are common causes of admission to the intensive care units (ICU). Early recognition and adequate treatment are important in reducing mortality. Limited data are available on characteristics and outcomes of community-acquired sepsis and septic shock in Latvia. Methods: In this single-center cohort study, we explore clinical characteristics and outcomes of 86 community-acquired sepsis and septic shock cases admitted to the ICU of a clinical university hospital between 2014 and 2018. Results: The ICU and intrahospital mortality rates were 45% and 58%, respectively. Respiratory tract infections, particularly pneumonia and abdominal and skin/soft tissue infections, were the most common sites of origin. Overall, 95% of patients initially received appropriate antibiotic treatment. However, the median time to antibiotics was 225 min (IQR 118-407 min), and only 10% received antimicrobial treatment within 1 h. Conclusions: The number of patients enrolled indicates that sepsis cases are underreported on a national level. The results also demonstrate high mortality rates among ICU patients with community-acquired sepsis and septic shock, compared to other reports. The analysis indicates that early recognition of sepsis signs and organ failure is crucial for improvements in treatment outcomes.

As digitalization and artificial intelligence advance, cybersecurity threats intensify, making malware—a type of software installed without authorization to harm users—an increasingly urgent concern. Due to malware's social and economic impacts, accurately modeling its spread has become essential. While diverse models exist for malware propagation, their selection tends to be intuitive, often overlooking the unique aspects of digital environments. Key model choices include deterministic vs. stochastic, planar vs. spatial, analytical vs. simulation-based, and compartment-based vs. individual state-tracking models. In this context, our study assesses fundamental infection spread models to determine those most applicable to malware propagation. It is organized in two parts: the first examines principles of deterministic and stochastic infection models, and the second provides a comparative analysis to evaluate model suitability. Key criteria include scalability, robustness, complexity, workload, transparency, and manageability. Using consistent initial conditions, control examples are analyzed through Python-based numerical methods and agent-based simulations in NetLogo. The findings yield practical insights and recommendations, offering valuable guidance for researchers and cybersecurity professionals in applying epidemiological models to malware spread.

Identifying patients for clinical studies evaluating strategies to reduce unnecessary antibiotic usage in hospitals is challenging. This study aimed to develop a predictive score to identify newly hospitalized patients with high likelihood of receiving antibiotics, thus improving patient inclusion in future studies focusing on antimicrobial stewardship (AMS) programs. This retrospective analysis used data from the PILGRIM study (NCT03765528), which included 1,600 patients across ten international sites. Predictive variables for antibiotic treatment during hospitalization were computed, and an additive score model was developed using logistic regression and 10-fold cross-validation. The PILGRIM score was validated in an independent cohort (validation cohort), with performance metrics assessed. Data from 1,258 patients was included. In the development cohort 52.8

Preventing infections caused by antimicrobial-resistant (AMR) pathogens is critical in healthcare settings, particularly in ICUs, where patients are highly susceptible to infections. Sink and pipeline systems display the potential to be the cause of point source outbreaks in intensive care units (ICUs). Here, we performed lab-and real-life experiments to investigate using TiO2 coating on the inner side of a U-shaped wastewater pipe as the reducer of clinically relevant multidrug-resistant (MDR) microorganisms. During the lab-scale experiments, we evaluated the efficacy of the TiO2 coating in combination with UVA/UVC light against both Gram(+) and Gram (-) bacterial strains commonly found in ICUs. At the same time, in the pilot experiments that were carried out in a real-life ICU setting, we monitored the changes in the diversity of the microbiological community within a sink that was equipped with the combination of TiO2 coating and UVA/UVC light source. The lab-scale results showed that TiO2 coating alone did not have an additional effect on bacteria reduction based on incubation time, power level, and usage time, while the pilot scale demonstrated that TiO2 coating combination with UVA/UVC light effectively reduced the microbial diversity in the pipeline system of the ICU sink. Overall, this study combines experiments in the laboratory and real-life ICU settings to investigate the effectiveness of a TiO2 coating and UVA/UVC light combination for eliminating MDR microorganisms, thus providing valuable knowledge that will aid the development of future infection control strategies. Additionally, this study emphasizes the importance of continuous maintenance and monitoring in preventing the growth of MDR bacteria.

This study explores the incidence, outcomes, and healthcare resource utilization concerning sepsis in Latvia’s adult population. Using a merged database from the National Health Service and the Latvian Centre for Disease Prevention and Control, sepsis-related hospitalizations were analyzed from 2015–2020. Findings revealed a 53.1% surge in sepsis cases from 2015–2018 with subsequent stabilization. This spike was more prominent among elderly patients. The age/sex adjusted case fatality rate rose from 34.7% in 2015 to 40.5% in 2020. Of the 7764 sepsis survivors, the one-year mortality rate was 12% compared to 2.2% in a reference group of 20,686 patients with infections but no further signs of sepsis. Sepsis survivors also incurred higher healthcare costs, driven by longer rehospitalizations and increased pharmaceutical needs, though they accessed outpatient services less frequently than the reference group. These findings underscore the growing detection of sepsis in Latvia, with survivors facing poorer outcomes and suggesting the need for enhanced post-sepsis outpatient care.

Background Antimicrobial stewardship (AMS) programmes are established across the world to treat infections efficiently, prioritize patient safety, and reduce the emergence of antimicrobial resistance. One of the core elements of AMS programmes is guidance to support and direct physicians in making efficient, safe and optimal decisions when prescribing antibiotics. To optimize and tailor AMS, we need a better understanding of prescribing physicians' experience with AMS guidance.Objectives To explore the prescribing physicians' user experience, needs and targeted improvements of AMS guidance in hospital settings.Methods Semi-structured interviews were conducted with 36 prescribing physicians/AMS guidance users from hospital settings in Canada, Germany, Israel, Latvia, Norway and Sweden as a part of the international PILGRIM trial. A socioecological model was applied as an overarching conceptual framework for the study.Results Research participants were seeking more AMS guidance than is currently available to them. The most important aspects and targets for improvement of AMS guidance were: (i) quality of guidelines; (ii) availability of infectious diseases specialists; and (iii) suitability of AMS guidance to department context.Conclusions Achieving prudent antibiotic use not only depends on individual and collective levels of commitment to follow AMS guidance but also on the quality, availability and suitability of the guidance itself. More substantial commitment from stakeholders is needed to allocate the required resources for delivering high-quality, available and relevant AMS guidance to make sure that the prescribers' AMS needs are met.

BACKGROUND: Increased life expectancy, developments in medicine and intracardiac devices, accessibility of cardiac surgery, decrease in the prevalence of rheumatic heart disease are changing infective endocarditis patient profile and thus risk factors for the adverse events. This single-center-based study covering the whole Latvian population aimed to assess the intrahospital and 3-year mortality of infective endocarditis patients who underwent cardiac surgery, as well as risk factors and laboratory indices predictive of adverse outcomes of the disease.METHODS: Clinical profiles, data of laboratory and instrumental analyses, operation and intensive care unit records of cardiac surgery patients treated in Pauls Stradins Clinical University Hospital, Riga, Latvia, between 2015 and 2019 were analyzed.RESULTS: We analyzed data from 242 episodes of surgically treated infective endocarditis in 233 patients. The median age of patients was 57.00 (45.00-68.00) years. The rate of intrahospital mortality was 11.16%. Risk factors associated with mortality in the univariate analyses were S. aureus infection (HR=2.27, 95% CI: 1.36-3.80; P=0.002) and systemic embolization of vegetations (HR=1.63, 95% CI: 1.00-2.64; P=0.048). Perivalvular complications (HR=1.98, 95% CI: 1.19-3.29; P=0.009) were found to be independently associated with mortality in multivariate analysis (HR=1.99, 95% CI: 1.05-3.78; P=0.035). One-year survival was 78.3%, whereas three-year -71.3%.CONCLUSIONS: Intrahospital mortality of surgically treated IE patients was 11.2%; however, one- and three-year mortality was 21.7 and 28.7%, respectively. Perivalvular complications were independently associated with mortality. Laboratory indices were not predictive of adverse outcomes.

Wastewater-based epidemiology (WBE) has regained global importance during the COVID-19 pandemic. The mobility of people and other factors, such as precipitation and irregular inflow of industrial wastewater, are complicating the estimation of the disease prevalence through WBE, which is crucial for proper crisis management. These estimations are particularly challenging in urban areas with moderate or low numbers of inhabitants in situations where movement restrictions are not adopted (as in the case of Latvia) because residents of smaller municipalities tend to be more mobile and less strict in following the rules and measures of disease containment. Thus, population movement can influence the outcome of WBE measurements significantly and may not reflect the actual epidemiological situation in the respective area. Here, we demonstrate that by combining the data of detected SARS-CoV-2 RNA copy number, 5hydroxyindoleacetic acid (5-HIAA) analyses in wastewater and mobile call detail records it was possible to provide an accurate assessment of the COVID-19 epidemiological situation in towns that are small (COVID-19 28-day cumulative incidence r = 0.609 and 35-day cumulative incidence r = 0.89, p < 0.05) and medium-sized towns (COVID-19 21-day cumulative incidence r = 0.997, 28-day cumulative incidence r = 0.98 and 35-day cumulative incidence r = 0.997, p < 0.05). This is the first study demonstrating WBE for monitoring COVID-19 outbreaks in Latvia. We demonstrate that the application of population size estimation measurements such as total 5-HIAA and call detail record data im- prove the accuracy of the WBE approach.

BACKGROUND:Up to 30% or even more of all infective endocarditis (IE) cases are recognized as blood culture negative, meaning that the causative agent is left unidentified. The prompt diagnosis together with the identification of causative microorganism and targeted antibiotic treatment can significantly impact the prognosis of the disease and further patient's health status. In some studies, blood culture negative endocarditis has been shown to be associated with delayed diagnosis, worse outcome and course of the disease, and a greater number of intra and postoperative complications.METHODS:We retrospectively analysed the medical records of all patients who underwent cardiac surgery for endocarditis between years 2016 and 2019. The aim of this study was to analyse short and long-term mortality and differences of laboratory, clinical and echocardiography parameters in patients with blood culture positive endocarditis (BCPE) and blood culture negative endocarditis (BCNE) and its possible impact on the clinical outcome.RESULTS:In our study population were 114 (55.1%) blood culture positive and 93 (44.9%) blood culture negative cases of infectious endocarditis. The most common pathogens in the blood culture positive IE group were S.aureus in 36 cases (31.6%), Streptococcus spp. in 27 (23.7%), E.faecalis in 24 (21.1%), and other microorganisms in 27 (23.7%). Embolic events were seen in 60 patients (28.9%). In univariate analyses, detection of microorganism, elevated levels of procalcitonin were found to be significantly associated with intrahospital death, however it did not reach statistical significance in multivariate analyses. Among microorganisms, S.aureus was significantly associated with intrahospital death in both univariate and multivariate analyses.CONCLUSIONS:There are no statistically significant differences between groups of BCPE and BCNE in terms of intrahospital mortality, hospital and ICU stay or 3-year mortality. There were higher levels of procalcitonin in BCPE group, however procalcitonin failed to show independent association with mortality in multivariate analysis. The most common microorganism in the BCPE group was S.aureus. It was associated with independently higher intrahospital mortality when compared to other causative microorganisms.

Reduction of COVID-19 incidence across Europe in the early spring months of 2021 led to substantial relaxation of restrictions in summer, despite the emergence and spread of the more transmissible SARS-CoV-2 delta variant. As expected, this relaxation led to a renewed increase in incidence. How should Europe act, what strategies should it adopt, and what specific risks should it consider moving forward?1Iftekhar E N Priesemann V Balling R et al.A look into the future of the COVID-19 pandemic in Europe: an expert consultation.Lancet Regional Health Europe. 2021; (published online July 29.)https://doi.org/10.1016/j.lanepe.2021.100185Summary Full Text Full Text PDF PubMed Scopus (82) Google Scholar These questions become even more pressing, since emerging data indicates the delta variant is more infectious and partially evades immune response. Europe needs a coherent and effective strategy before schools fully reopen and the transmission of SARS-CoV-2 further increases due to seasonality in autumn. Two opposing strategies are considered: either continue to rapidly lift restrictions, assuming the combination of past natural exposure and current vaccination coverage would allow a high incidence to continue, without overburdening health-care systems; or lift restrictions at the pace of vaccination progress with the core aim to keep incidence low, given this effectively and efficiently controls the pandemic via test-trace-isolate (TTI) programmes.2Kretzschmar M E Rozhnova G van Boven M Isolation and contact tracing can tip the scale to containment of COVID-19 in populations with social distancing.Front Phys. 2021; 8622485Crossref Scopus (34) Google Scholar, 3Contreras S Dehning J Loidolt M et al.The challenges of containing SARS-CoV-2 via test-trace-and-isolate.Nat Commun. 2021; 12: 1-13Crossref PubMed Scopus (104) Google Scholar Given immunisation levels as of August, 2021, the first strategy can lead to an incidence of several hundred cases per million per day, whereas the second strategy would require an incidence of well below one hundred cases per million per day. Such a discrepancy of incidence poses considerable friction to European cooperation, economy, and society: high incidence in one country puts the low-incidence strategy in a neighbouring country at risk. Because of this conflict of interest, some countries impose testing and quarantine requirements, hampering international exchange. Thus, either strategy can only work effectively if European countries stop acting as if they could fight the pandemic on their own. The EU's Digital Covid Certificate (EU DCC) has been introduced to facilitate cross-border travel. However, no vaccine is completely effective at preventing virus transmission. Therefore, the implementation of the EU DCC must be accompanied by systematic evaluation of its contribution to the spread of present and future variants of concern (VOCs).4Krueger T Gogolewski K Bodych M et al.Assessing the risk of COVID-19 epidemic resurgence in relation to the delta variant and to vaccination passes.medRxiv. 2021; (published online July 18.) (preprint).https://doi.org/10.1101/2021.05.07.21256847Google Scholar The development of a European strategy for testing travellers and commuters is therefore warranted.5Phelan A L COVID-19 immunity passports and vaccination certificates: scientific, equitable, and legal challenges.Lancet. 2020; 395: 1595-1598Summary Full Text Full Text PDF PubMed Scopus (195) Google Scholar The advantages of low incidence are known and include: (1) less mortality, morbidity, and long COVID; (2) solidarity with those not yet protected; (3) lower risk of new VOCs emerging and spreading; (4) increased feasibility of comprehensive TTI; (5) less workforce in quarantine and isolation, including those in health care; and (6) ensuring schools and childcare remain open during the coming autumn-winter season.6Priesemann V Balling R Brinkmann MM et al.An action plan for pan-European defence against new SARS-CoV-2 variants.Lancet. 2021; 397: 469-470Summary Full Text Full Text PDF PubMed Scopus (93) Google Scholar In contrast, a high incidence might still overwhelm hospitals and intensive care units in some countries, as estimated in the appendix. Given the clear benefits of low incidence, the insufficient vaccination coverage in many European countries, uncertainties regarding child vaccination, and the time required for full immunisation of adolescents, we recommend that all European countries act together to achieve low incidence, at least until everyone has had the opportunity to get vaccinated. A high incidence in one country challenges the pandemic response for others, in Europe and across the world. Maintaining low incidence is an act of solidarity and becomes easier with the advantage of increasing vaccination coverage. To improve measure effectiveness, three further challenges must be overcome: (1) vaccination availability, access, and hesitancy; (2) the widespread misconception that freedom would be maximised when ignoring high incidence as it has been recognised that low incidence facilitates containment and safeguards the freedom of all, including the most vulnerable; and (3) the lack of a coherent pandemic response and communication strategy. In terms of the latter challenge, perceived risk, motivation, and health literacy are important predictors of health-seeking behaviour and adherence to measures. Public trust must be maintained through timely, consistent, and persistent communications, including systematically developed counterspeech for misinformation. The pandemic is yet to be overcome, but an end is conceivable. Restrictions can be lifted when high vaccination coverage is reached, and if vaccines remain highly effective against VOCs. However, until then, the goal should be to minimise economic and societal costs for Europe and for the world. Maintaining and communicating a clear strategy is key, and pan-European coordination and common goals across countries are more important than ever. RB is a shareholder of the Information Technology For Translational Medicine research institute. SB reports grants from Netzwerk Universitätsmedizin. PB reports grants from the EU's SC1-PHE-CORONAVIRUS-2020 programme, Pfizer, GlaxoSmithKlein, and European Commission IMI, unrelated to this Correspondence. CL reports grants from the University of Oxford, the National Centre for Smoking Cessation and Training, Gilead Sciences, and the European Commission's Horizon 2020, unrelated to this Correspondence, all under the agreement and control of the Special Committee for Research Grants of the University of Crete, Greece. GNP's contribution is in his personal capacity; the opinions expressed are the author's own and do not reflect the views of the National Institutes of Health (NIH), the Department of Health and Human Services, or the US Government. GNP's patents and company interactions are managed through the NIH. EP reports grants from the European Commission and personal fees from the European Commission, Maastricht University, Charité – Universitätsmedizin Berlin, and the Swedish Healthcare Academy, unrelated to this Correspondence. MPi reports grants and personal fees from Wellcome and the Economic and Social Research Council, grants from the Medical Research Council, and personal fees from the Research Foundation Flanders, unrelated to this Correspondence. BP is a member of the Austrian National Bioethics Committee and has been a member of the European Group on Ethics in Science and New Technologies (2017–21). Projects in the laboratory of ESz are co-funded by Merck Healthcare. All other authors declare no competing interests. Acknowledgements of funding sources are stated in the appendix. Additional information about the estimation of ICU admissions and translated versions of this Correspondence is available in the appendix. Download .pdf (.18 MB) Help with pdf files Supplementary appendix A look into the future of the COVID-19 pandemic in Europe: an expert consultationHow will the coronavirus disease 2019 (COVID-19) pandemic develop in the coming months and years? Based on an expert survey, we examine key aspects that are likely to influence the COVID-19 pandemic in Europe. The challenges and developments will strongly depend on the progress of national and global vaccination programs, the emergence and spread of variants of concern (VOCs), and public responses to non-pharmaceutical interventions (NPIs). In the short term, many people remain unvaccinated, VOCs continue to emerge and spread, and mobility and population mixing are expected to increase. 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Remaining a major healthcare concern with nearly 29 million confirmed cases worldwide at the time of writing, novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused more than 920 thousand deaths since its outbreak in China, December 2019. First case of a person testing positive for SARS-CoV-2 infection within the territory of the Republic of Latvia was registered on 2nd of March 2020, 9 days prior to the pandemic declaration by WHO. Since then, more than 277,000 tests were carried out confirming a total of 1,464 cases of coronavirus disease 2019 (COVID-19) in the country as of 12th of September 2020. Rapidly reacting to the spread of the infection, an ongoing sequencing campaign was started mid-March in collaboration with the local testing laboratories, with an ultimate goal in sequencing as much local viral isolates as possible, resulting in first full-length SARS-CoV-2 isolate genome sequences from the Baltics region being made publicly available in early April. With 133 viral isolates representing ~9.1% of the total COVID-19 cases during the “first coronavirus wave” in the country (early March, 2020—mid-September, 2020) being completely sequenced as of today, here, we provide a first report on the genetic diversity of Latvian SARS-CoV-2 isolates.

How will the coronavirus disease 2019 (COVID-19) pandemic develop in the coming months and years? Based on an expert survey, we examine key aspects that are likely to influence the COVID-19 pandemic in Europe. The challenges and developments will strongly depend on the progress of national and global vaccination programs, the emergence and spread of variants of concern (VOCs), and public responses to non-pharmaceutical interventions (NPIs). In the short term, many people remain unvaccinated, VOCs continue to emerge and spread, and mobility and population mixing are expected to increase. Therefore, lifting restrictions too much and too early risk another damaging wave. This challenge remains despite the reduced opportunities for transmission given vaccination progress and reduced indoor mixing in summer 2021. In autumn 2021, increased indoor activity might accelerate the spread again, whilst a necessary reintroduction of NPIs might be too slow. The incidence may strongly rise again, possibly filling intensive care units, if vaccination levels are not high enough. A moderate, adaptive level of NPIs will thus remain necessary. These epidemiological aspects combined with economic, social, and health-related consequences provide a more holistic perspective on the future of the COVID-19 pandemic.

Background The number of COVID-19 cases is increasing globally and there is an urgency for a simple non-invasive method for the detection of SARS-CoV-2. Our study aimed to demonstrate that saliva can be used as a specimen for SARS-CoV-2 detection notably for the screening of extensive population groups via pooling. Methods We performed 36 serial measurements of 8 SARS-CoV-2 positive saliva samples to confirm the stability of the specimen and completed 37 pools of saliva samples by adding one positive specimen per pool. We collected paired nasopharyngeal/oropharyngeal swabs (NPS) and saliva specimens and processed them within 24 hours of collection. To demonstrate that saliva is an appropriate specimen for SARS-CoV-2 detection a field study including 3,660 participants was performed between September 29 and October 1, 2020. A new solution for distribution and collection of self-sampled saliva was designed, produced and installed. All methods were performed in accordance with the relevant guidelines and regulations. Results Saliva specimens were stable for testing for up to 24 hours. The results of saliva samples were consistent with those obtained from NPS from the same patient with 90% sensitivity (95% CI 68.3%-98.7%) and 100% specificity during the first two weeks after the onset of symptoms. Using pooling strategy 796 RT-PCR tests were performed. All pools showed 100% positivity in different pooling proportions. Overall, 44 saliva samples (1.2%) tested positive for SARS-CoV-2 during the field study. In total, between September 29 and April 10, 415 673 RT-PCR saliva tests were performed. The contactless self-service terminals were placed in hospitals, factories and municipalities as an additional way to submit self-collected saliva for testing. Conclusion Our findings demonstrate that saliva is an appropriate specimen for pooling and SARS-CoV-2 screening with accurate diagnostic performance. Patient-performed simple specimen collection allows testing an extensive number of people rapidly, obtaining results of the spread of SARS-CoV-2 and allowing authorities to take timely measures. Automated sample distribution and collection points are accessible 24/7 allowing safe, contactless and more efficient way to submit various kind of samples for testing.

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Background Severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2, the causative agent of coronavirus disease 2019 (COVID-19)] outbreak has been declared a global pandemic by the World Health Organization. The COVID-19 pandemic has highlighted problems of sustainable infection prevention and control measures worldwide, particularly the emerging issues with an insufficient supply of personal protective equipment. The aim of this study was to provide an action plan for mitigation of occupational hazards and nosocomial spread of SARS-CoV-2 through a failure mode analysis based on observations during in situ simulations. Methods A multicenter, cross-sectional, observational, simulation-based study was performed in Latvia from March 2 to 26, 2020. This study was conducted at 7 hospitals affiliated with Riga Stradiņš University. The presentation of a COVID-19 patient was simulated with an in situ simulations, followed by a structured debrief. Healthcare Failure Modes and Effects Analysis is a tool for conducting a systematic, proactive analysis of a process in which harm may occur. We used Healthcare Failure Modes and Effects Analysis to analyze performance gaps and systemic issues. Results A total of 67 healthcare workers from 7 hospitals participated in the study (range = 4–17). A total of 32 observed failure modes were rated using a risk matrix. Twenty-seven failure modes (84.4%) were classified as either medium or high risk or were single-point weaknesses, hence evaluated for action type and action; 11 (40.7%) were related to organizational, 11 (40.7%) to individual, and 5 (18.5%) to environmental factors. Conclusions Simulation-based failure mode analysis helped us identify the risks related to the preparedness of the healthcare workers and emergency departments for the COVID-19 pandemic in Latvia. We believe that this approach can be implemented to assess and maintain readiness for the outbreaks of emerging infectious diseases in the future.

The aim of our study was to demonstrate that saliva can be used as an effective material for SARS-CoV-2 testing and screening of large population groups to identify Covid-19 clusters. The most important aspect of saliva sampling approach is the convenience of obtaining material by self- sampling that is even possible at home. In our experiments, saliva was sufficiently stable for testing for at least 24 hours after collection. The results obtained from the saliva of a SARS-CoV-2 positive patient were consistent with those obtained from nasopharyngeal and oropharyngeal swabs from the same patient with the sensitivity 90% and specificity 100% during the first two weeks after the onset of symptoms. To demonstrate the usefulness of testing saliva material for mass screening, crowd sampling with pooling was performed on 3660 people in 3-day time (44 samples were tested positive). We conclude that saliva testing is an appropriate tool for screening campaigns and cluster detection, that is able to detect more infected people in a shorter period of time with little human resources and thus help to stop the epidemic spread more quickly.