Highly pathogenic avian influenza A(H5N1) virus infections on fur farms connected to mass mortalities of black-headed gulls, Finland, July to October 2023.

Highly pathogenic avian influenza (HPAI) has caused widespread mortality in both wild and domestic birds in Europe 2020-2023. In July 2023, HPAI A(H5N1) was detected on 27 fur farms in Finland. In total, infections in silver and blue foxes, American minks and raccoon dogs were confirmed by RT-PCR. The pathological findings in the animals include widespread inflammatory lesions in the lungs, brain and liver, indicating efficient systemic dissemination of the virus. Phylogenetic analysis of Finnish A(H5N1) strains from fur animals and wild birds has identified three clusters (Finland I-III), and molecular analyses revealed emergence of mutations known to facilitate viral adaptation to mammals in the PB2 and NA proteins. Findings of avian influenza in fur animals were spatially and temporally connected with mass mortalities in wild birds. The mechanisms of virus transmission within and between farms have not been conclusively identified, but several different routes relating to limited biosecurity on the farms are implicated. The outbreak was managed in close collaboration between animal and human health authorities to mitigate and monitor the impact for both animal and human health.

Risk of COVID-19 in different groups of healthcare professionals between February 2020 and June 2021 in Finland: a register-based cohort study.

Background: During the Coronavirus Disease 2019 (COVID-19) pandemic, healthcare workers (HCWs) have been a risk group for COVID-19. Aim: To assess the cumulative incidence in different groups of HCWs and the risk factors and outcomes of COVID-19 in HCWs between February 2020 and June 2021 in Finland. Methods: We linked two national registers, National Infectious Diseases Register (NIDR) and Register of Social Welfare and Healthcare Professionals (Terhikki), using national identity codes. COVID-19 cases were identified from NIDR notifications made by laboratories and physicians, and their healthcare professions from Terhikki. We categorized healthcare professions into seven groups and calculated cumulative incidences using Kaplan-Meier estimate during three periods (1/2/2020-30/6/2020, 1/7/2020-31/12/2020, 1/1/2021-30/6/2021). We identified risk factors in a multivariable model using Cox's regression. Findings: We identified 8,009 COVID-19-cases among HCWs, with cumulative incidence of 1.79%; 83% were female, median age was 40.9 years (interquartile range, 31.2-51.6). Most COVID-19-cases occurred in nursing assistants (53%) and nurses (17%), with the highest cumulative incidences 2.07% (95%CI, 2.01-2.13%) and 1.82% (95%CI, 1.73-1.91%), respectively. Risk factors were male sex (hazard ratio (HR) 1.2; 95%CI, 1.1-1.3), foreign native language (HR 2.5; 95%CI, 2.2-2.9) and foreign country of birth (HR 1.2; 95%CI, 1.1-1.4). Physician notification data was available for 6,113/8,009 cases (76.3%); 244/6,113 (4.0%) were hospitalized and 37/6,113 (0.6%) in intensive care. Conclusion: Nurses and nursing assistant, especially men and professionals with foreign background, were at higher risk of COVID-19. This should be specifically addressed during training and implementing infection control measures to protect themselves and patients.

Pre-Diagnostic Saliva Microbiota of School-Aged Children Who Developed Type 1 Diabetes or Inflammatory Bowel Diseases.

Altered commensal microbiota composition has been associated with pediatric type 1 diabetes mellitus (T1D) and inflammatory bowel diseases (IBD), but the causal relationship is still unclear. To search for potential pre-diagnostic biomarkers for pediatric T1D or IBD, we compared microbiota in saliva samples in a nested case-control design comprising children developing T1D (nchildren = 52) or IBD (nchildren = 21) and controls with a similar age, sex, and residential area (nchildren = 79). The pre-diagnostic saliva microbiota alpha- and beta-diversity of children who would develop T1D (nsamples = 27) or IBD (nsamples = 14) minimally varied from that of controls. The relative abundances of Abiotrophia were higher, while those of Veillonella, Actinomyces, Megasphaera, Butyrivibrio, and Candidatus ancillula were lower in children who would develop T1D. Within 2 years before diagnosis, the metabolic PWY-5677 pathway (converting succinate into butyrate) was lower in pre-T1D samples than in controls (q = 0.034). No significant pre-IBD differences were found. In conclusion, saliva microbiota diversity or composition were not successful predictors for pediatric T1D nor IBD. Intriguingly, the succinate fermentation pathway was predicted to be lowered before the onset of T1D. Thus, investigating functional pathways might provide a better approach in searching for biomarkers for autoimmune disease in the future.

Risk of lymphoid malignancies increased after Puumala virus infection in Finland, 2009-2019: A retrospective register-based cohort study.

OBJECTIVES: The Puumala virus (PUUV) is a hantavirus that causes hemorrhagic fever with renal syndrome. Studies showing an increased risk of lymphoid malignancies after hantavirus infection, together with the observation that PUUV infects B cells, motivated us to study the risk of lymphoid malignancies after PUUV infection. METHODS: We linked data from the Finnish Cancer Registry and National Infectious Diseases Register for 2009-2019. We used a time-dependent Cox regression model to evaluate the hazard of the lymphoid malignancies grouped according to the HAEMACARE classification. RESULTS: We identified 68 cases of lymphoid malignancies after PUUV infection among 16,075 PUUV-infected individuals during 61,114,826 person-years of observation. A total of 10 cases occurred within 3-<12 months and 38 within 1-<5 years after PUUV infection, and the risk of lymphoid malignancies increased with hazard ratios (HRs) of 2.0 (95% confidence interval [CI], 1.1-3.7) and 1.6 (95% CI, 1.2-2.3), respectively. The group of mature B cell neoplasms showed an increased risk 3-<12 months and 1-<5 years after PUUV infection, HR 2.2 (95% CI, 1.2-4.3) and HR 1.8 (95% CI, 1.3-2.5), respectively. CONCLUSION: PUUV infection is associated with lymphoid malignancies in the Finnish population, supporting the earlier studies. Further research is required to understand the pathophysiological mechanisms behind this association.

Tap water as the source of a Legionnaires' disease outbreak spread to several residential buildings and one hospital, Finland, 2020 to 2021.

In Finland, all microbiology laboratories notify Legionella findings and physicians notify Legionnaires' disease (LD) cases to the National Infectious Disease Register. All cases are interviewed, and water samples obtained from potential places of exposure. Legionella isolates from humans and water are compared by whole genome sequencing (WGS). In March 2021, Legionella pneumophila serogroup 1 (Lp 1) pneumonia cases increased in one Finnish city (120,000 inhabitants) where single LD cases are detected annually. We identified 12 LD cases, nine living in different residential buildings and three nosocomial, linked by identical human and/or water isolates. Three of these cases were from January 2020, October 2020 and February 2021 and identified retrospectively. Eleven were diagnosed by urinary antigen test, 10 by PCR and five by culture; age ranged between 52 and 85 years, and 10 had underlying diseases. Nine of 12 homes of LD cases and 15 of 26 water samples from the hospital were positive for Lp 1, with concentrations up to 640,000 cfu/L. Water samples from regional storage tanks were negative. Positivity in homes and the hospital suggested inadequate maintenance measures. Enhanced surveillance combined with WGS was crucial in detecting this unusual LD outbreak related to domestic and hospital water systems.

Antibiotic exposures and the development of pediatric autoimmune diseases: a register-based case-control study.

BACKGROUND: Antibiotics have been associated with several individual autoimmune diseases (ADs). This study aims to discover whether pre-diagnostic antibiotics are associated with the onset of ADs in general. METHODS: From a cohort of 11,407 children, 242 developed ADs (type 1 diabetes, autoimmune thyroiditis, juvenile idiopathic arthritis (JIA), or inflammatory bowel diseases) by a median age of 16 years. Antibiotic purchases from birth until the date of diagnosis (or respective date in the matched controls n = 708) were traced from national registers. RESULTS: Total number of antibiotic purchases was not related to the onset of ADs when studied as a group. Of specific diagnoses, JIA was associated with the total number of antibiotics throughout the childhood and with broad-spectrum antibiotics before the age of 3 years. Intriguingly, recent and frequent antibiotic use (within 2 years before diagnosis and ≥3 purchases) was associated with the onset of ADs (OR 1.72, 95% CI 1.08-2.74). Regardless of frequent use in childhood (40% of all antibiotics), penicillin group antibiotics were not related to any ADs. CONCLUSIONS: Use of antibiotics was relatively safe regarding the overall development of ADs. However, broad-spectrum antibiotics should be used considerately as they may associate with an increased likelihood of JIA. IMPACT: Increasing numbers of antibiotic purchases before the age of 3 years or throughout childhood were not associated with the development of pediatric autoimmune diseases. Broad-spectrum antibiotics were related to the development of autoimmune diseases, especially juvenile idiopathic arthritis in children, while penicillin group antibiotics were not. The use of broad-spectrum antibiotics in children should be cautious as they may carry along a risk for autoimmune disease development.

Salmonella Typhimurium outbreak associated with frozen tomato cubes at a restaurant in western Finland, January to February 2021.

Several individuals reported gastrointestinal symptoms following meals consumed in late January 2021 at a restaurant in western Finland. We conducted a retrospective cohort study and defined a case as a person who ate at the lunch restaurant between 27 and 29 January 2021 and had stomach pain, vomiting or diarrhoea and/or a laboratory-confirmed Salmonella Typhimurium infection within 2 weeks after the exposure. We collected faecal and food samples for microbiological analysis. Salmonella isolates were characterised in detail using whole genome sequencing (WGS) and cluster analysis by core genome multilocus sequence typing (cgMLST). Altogether, 393 meals were sold and 101 people (who ate 142 meals) participated in the cohort study. There were 49 cases; 23 were laboratory-confirmed infections with a multidrug-resistant S. Typhimurium. The S. Typhimurium isolates from cases and frozen tomato cubes used uncooked in salads were closely related and clustered together in cgMLST comparison. These salads were consumed by 76% of the cases. Based on the cgMLST clustering, they were the suggested source of the outbreak. Statistical association was not significant between eating the salads and being a case. Following the outbreak investigation, the producer decided to recommend cooking of their frozen tomato products before consumption.

An outbreak caused by the SARS-CoV-2 Delta variant (B.1.617.2) in a secondary care hospital in Finland, May 2021.

An outbreak caused by the SARS-CoV-2 Delta variant (B.1.617.2) spread from one inpatient in a secondary care hospital to three primary care facilities, resulting in 58 infections including 18 deaths in patients and 45 infections in healthcare workers (HCW). Only one of the deceased cases was fully vaccinated. Transmission occurred despite the use of personal protective equipment by the HCW, as advised in national guidelines, and a high two-dose COVID-19 vaccination coverage among permanent staff members in the COVID-19 cohort ward.

Clinical characteristics and evaluation of the incidence of cryptococcosis in Finland 2004-2018.

BACKGROUND: Cryptococcosis is one of the major causes of mortality among HIV patients worldwide. Though most often associated with late stage HIV infection/AIDS, a significant number of cases occur in other immunocompromised patients such as solid organ transplant recipients and patients with hematological malignancies. Immunocompromised patients are a heterogeneous group and their number increases constantly. Since little is known about the incidence and the clinical features of cryptococcosis in Northern Europe, our aim was to investigate the clinical characteristics of cryptococcosis patients in Finland. METHODS: We retrospectively reviewed the laboratory confirmed cryptococcosis cases in Finland during 2004-2018. Only those who were treated for cryptococcosis were included in the study. Initial laboratory findings and medical records were also collected. RESULTS: A total of 22 patients with cryptococcosis were included in our study. The annual incidence of cryptococcosis was 0.03 cases per 100,000 population. Ten patients were HIV-positive and 12 out of 22 were HIV-negative. Hematological malignancy was the most common underlying condition among HIV-negative patients. CONCLUSIONS: To our knowledge, this is the first study of the clinical presentation and incidence of cryptococcosis in Finland. We demonstrate that invasive cryptococcal infection occurs not only in HIV/AIDS patients or otherwise immunocompromised patients but also in immunocompetent individuals. Even though cryptococcosis is extremely rare in Finland, its recognition is important since the prognosis depends on rapid diagnostics and early antifungal therapy.