Childhood screening for type 1 diabetes comparing automated multiplex Antibody Detection by Agglutination-PCR (ADAP) with single plex islet autoantibody radiobinding assays

BACKGROUND

Two or more autoantibodies against either insulin (IAA), glutamic acid decarboxylase (GADA), islet antigen-2 (IA-2A) or zinc transporter 8 (ZnT8A) denote stage 1 (normoglycemia) or stage 2 (dysglycemia) type 1 diabetes prior to stage 3 type 1 diabetes. Automated multiplex Antibody Detection by Agglutination-PCR (ADAP) assays in two laboratories were compared to single plex radiobinding assays (RBA) to define threshold levels for diagnostic specificity and sensitivity.

METHODS

IAA, GADA, IA-2A and ZnT8A were analysed in 1504 (54% females) population based controls (PBC), 456 (55% females) doctor's office controls (DOC) and 535 (41% females) blood donor controls (BDC) as well as in 2300 (48% females) patients newly diagnosed (1-10 years of age) with stage 3 type 1 diabetes. The thresholds for autoantibody positivity were computed in 100 10-fold cross-validations to separate patients from controls either by maximizing the χ2-statistics (chisq) or using the 98th percentile of specificity (Spec98). Mean and 95% CI for threshold, sensitivity and specificity are presented.

FINDINGS

The ADAP ROC curves of the four autoantibodies showed comparable AUC in the two ADAP laboratories and were higher than RBA. Detection of two or more autoantibodies using chisq showed 0.97 (0.95, 0.99) sensitivity and 0.94 (0.91, 0.97) specificity in ADAP compared to 0.90 (0.88, 0.95) sensitivity and 0.97 (0.94, 0.98) specificity in RBA. Using Spec98, ADAP showed 0.92 (0.89, 0.95) sensitivity and 0.99 (0.98, 1.00) specificity compared to 0.89 (0.77, 0.86) sensitivity and 1.00 (0.99, 1.00) specificity in the RBA. The diagnostic sensitivity and specificity were higher in PBC compared to DOC and BDC.

INTERPRETATION

ADAP was comparable in two laboratories, both comparable to or better than RBA, to define threshold levels for two or more autoantibodies to stage type 1 diabetes.

FUNDING

Supported by The Leona M. and Harry B. Helmsley Charitable Trust (grant number 2009-04078), the Swedish Foundation for Strategic Research (Dnr IRC15-0067) and the Swedish Research Council, Strategic Research Area (Dnr 2009-1039). AL was supported by the DiaUnion collaborative study, co-financed by EU Interreg ÖKS, Capital Region of Denmark, Region Skåne and the Novo Nordisk Foundation.

Antibody Cross-Reactivity in Auto-Immune Diseases

Autoimmunity is defined by the presence of antibodies and/or T cells directed against self-components. Although of unknown etiology, autoimmunity commonly is associated with environmental factors such as infections, which have been reported to increase the risk of developing autoimmune diseases. Occasionally, similarities between infectious non-self and self-tissue antigens may contribute to immunological cross-reactivity in autoimmune diseases. These reactions may be interpreted as molecular mimicry, which describes cross-reactivity between foreign pathogens and self-antigens that have been reported to cause tissue damage and to contribute to the development of autoimmunity. By focusing on the nature of antibodies, cross-reactivity in general, and antibody-antigen interactions, this review aims to characterize the nature of potential cross-reactive immune reactions between infectious non-self and self-tissue antigens which may be associated with autoimmunity but may not actually be the cause of disease onset.

Prevalence of Thyroid Peroxidase and Thyroglobulin Autoantibodies in the Swedish Population

Autoimmune thyroid disease (AITD) may be detected prior to clinical symptoms through the presence of autoantibodies against thyroid peroxidase (TPOab), thyroglobulin (TGab), or both.The present study aimed to develop a novel radiobinding assay (RBA) for TPOab and to determine the prevalence of TPOab and TGab in the Swedish population.Patient samples from 27 newly diagnosed Graves' disease patients in longitudinal follow-up and 124 AITD autoantibody-positive children in prospective follow-up for increased risk of type 1 diabetes were included to validate the novel RBA for TPO. The results of RBA were compared with those obtained by commercial radioimmunoassay (RIA) and electrochemiluminescence (ECL). Furthermore, 476 serum samples from adult blood donors and 297 from 13-year-old school children were analyzed for the presence of TPOab and TGab.Receiver operating characteristics analysis for the novel TPOab resulted in an area under curve (AUC) value of 0.82 (p<0.0001), a sensitivity of 77.8%, and a specificity of 91.9% in adult blood donors, and an AUC value of 0.70 (p<0.0001), a sensitivity of 53.2% and a specificity of 95.3% in the 13-year-old school children, respectively. TPOab levels in RBA correlated with both ECL (r=0.8950, p<0.0001) and RIA (r=0.9295, p<0.0001). The prevalence of TPOab and TGab was 6.3% and 7.6% in adult blood donors and 2.9 and 3.7% in 13-year-old school children.In conclusion, a novel RBA for the determination of TPOab was developed and validated with current methodologies. This study also reports an increasing prevalence of thyroid autoantibodies from adolescence to adulthood.

Effect of Epstein-Barr Virus Infection on Selected Immunological Parameters in Children with Type 1 Diabetes

Diabetes mellitus is a group of metabolic disorders with different etiologies, pathogeneses and clinical pictures, characterized by chronic hyperglycemia due to abnormal insulin secretion or action. Type 1 diabetes mellitus is the most common type of diabetes mellitus in children and adolescents, accounting for about 90% of diabetes in the population under the age of 18. The etiopathogenesis of type 1 diabetes is multifactorial. The disease occurs as a result of the interaction of three factors: genetic predisposition, environmental factors and the immune response. Research in recent years has focused on the involvement of Epstein-Barr virus (EBV) in the pathogenesis of type I diabetes. The goals of treating type 1 diabetes include maintaining blood-glucose, fructosamine and glycated hemoglobin (HbA1c) levels; therefore, the main purpose of this study was to evaluate the effect of EBV infection on the activation of selected immune cells, fructosamine levels and HbA1c levels in children with type I diabetes. Based on our study, we found a lower percentage of CD8+ T lymphocytes with expression of the CD69 molecule in patients with anti-VCA antibodies in the IgG class, and a lower percentage of CD8+ T lymphocytes with expression of the CD25+ molecule in patients with anti-EBNA-1 antibodies in the IgG class, which may indicate limited control of the immune system during EBV infection in patients. There was a lower percentage of CD3+CD4+ T lymphocytes secreting IL-4 in the study group, indicating that a deficiency in IL-4 production may be related to the development of type 1 diabetes. There was an increase in the percentage of CD4+CD3+IL-10 lymphocytes in the study group with anti-VCA antibodies present in the IgG class and anti-EBNA-1 antibodies in the IgG class compared to the patients without antibodies. In addition, there was a significant increase in fructosamine levels and higher glycated hemoglobin levels in the study group with antibodies to EBV antigens. In addition, an increase in the percentage of T lymphocytes with a CD4+CD3+IL-17+ phenotype in the patients with anti-VCA IgG antibodies was confirmed, and higher HbA1c levels may suggest that EBV infection is accompanied by an increase in IL-17 secretion.

Possible association of rotavirus IgG with cytokine expression levels and dyslipidemia in rotavirus-infected type 1 diabetic children

Background

Rotavirus (RV) has been postulated as a viral trigger for the onset of autoimmune disorders, such as type 1 diabetes (T1D). This study aimed to examine the conceivable association of RV IgG with cytokine levels and dyslipidemia in the pathogenesis of pediatric T1D.

Methods

This study included 30 healthy controls and 80 children with T1D who were divided into two groups based on the time since their T1D diagnosis: newly diagnosed (ND ≤ 1 year; n = 30) and previously diagnosed (PD > 1 year; n = 50). ND and PD patients were also separated into negative and positive according to IgG detection (RV IgG⁻, ND⁻, and PD⁻; RV IgG⁺, ND⁺, and PD⁺).

Results

Positive polymerase chain reaction for RVs was evidenced in 7.5% of children with T1D. Anti-RV IgG was 30% and 36% in ND and PD, respectively, compared to healthy controls (2 of 30, 6.6%; P < 0.05). Fasting blood sugar and hemoglobin A1c significantly increased in PD⁺ compared to PD⁻. Interferon-γ and interleukin (IL)-15 levels significantly increased. IL-12 and IL-22 mRNA expression was upregulated in ND⁺ patients compared to that in ND⁻ patients. IL-37 mRNA expression was significantly downregulated in ND⁻ and ND⁺ patients compared to that in healthy controls. Total cholesterol and high- and low-density lipoprotein-cholesterol levels were significantly lower in PD⁺ than in PD⁻; whereas triglyceride levels were higher than those in healthy controls.

Conclusions

This study suggested that anti-RV IgG may have a role in the pathogenesis, development, and progression of T1D, and RV infections are implicated in dyslipidemia and inflammation status.

Supplementary information

The online version contains supplementary material available at 10.1007/s11033-022-07573-0.

Neutralizing Ljungan virus antibodies in children with newly diagnosed type 1 diabetes

Ljungan virus (LV), a Parechovirus of the Picornavirus family, first isolated from a bank vole at the Ljungan river in Sweden, has been implicated in the risk for autoimmune type 1 diabetes. An assay for neutralizing Ljungan virus antibodies (NLVA) was developed using the original 87-012 LV isolate. The goal was to determine NLVA titres in incident 0-18 years old newly diagnosed type 1 diabetes patients (n=67) and school children controls (n=292) from Jämtland county in Sweden. NLVA were found in 41 of 67 (61 %) patients compared to 127 of 292 (44 %) controls (P=0.009). In the type 1 diabetes patients, NLVA titres were associated with autoantibodies to glutamic acid decarboxylase (GADA) (P=0.023), but not to autoantibodies against insulin (IAA) or islet antigen-2 (IA-2A). The NLVA assay should prove useful for further investigations to determine levels of LV antibodies in patients and future studies to determine a possible role of LV in autoimmune type 1 diabetes.

Viruses and Type 1 Diabetes: From Enteroviruses to the Virome

For over a century, viruses have left a long trail of evidence implicating them as frequent suspects in the development of type 1 diabetes. Through vigorous interrogation of viral infections in individuals with islet autoimmunity and type 1 diabetes using serological and molecular virus detection methods, as well as mechanistic studies of virus-infected human pancreatic β-cells, the prime suspects have been narrowed down to predominantly human enteroviruses. Here, we provide a comprehensive overview of evidence supporting the hypothesised role of enteroviruses in the development of islet autoimmunity and type 1 diabetes. We also discuss concerns over the historical focus and investigation bias toward enteroviruses and summarise current unbiased efforts aimed at characterising the complete population of viruses (the “virome”) contributing early in life to the development of islet autoimmunity and type 1 diabetes. Finally, we review the range of vaccine and antiviral drug candidates currently being evaluated in clinical trials for the prevention and potential treatment of type 1 diabetes.

New onset diabetes, type 1 diabetes and COVID-19

BACKGROUND AND AIMS

New data has emerged regarding higher risk of coronavirus disease 2019 (COVID-19), and its severity and complications in patients with type 2 diabetes mellitus (T2DM). However, there is a dearth of evidence regarding type 1 diabetes mellitus (T1DM). This article explores the possibility of COVID 19 induced diabetes and highlights a potential bidirectional link between COVID 19 and T1DM.

METHODS

A literature search was performed with Medline (PubMed), Scopus, and Google Scholar electronic databases till October 2020, using relevant keywords (COVID-19 induced diabetes; COVID-19 and type 1 diabetes; COVID-19 induced DKA; new-onset diabetes after SARS-CoV-2 infection) to extract relevant studies describing relationship between COVID-19 and T1DM.

RESULTS

Past lessons and new data teach us that severe acute respiratory syndrome coronaviruses (SARS-CoV and SARS-CoV-2) can enter islet cells via angiotensin converting enzyme-2 (ACE-2) receptors and cause reversible β-cell damage and transient hyperglycemia. There have been postulations regarding the potential new-onset T1DM triggered by COVID-19. This article reviews the available evidence regarding the impact and interlink between COVID-19 and Τ1DM. We also explore the mechanisms behind the viral etiology of Τ1DM.

CONCLUSIONS

SARS-CoV-2 can trigger severe diabetic ketoacidosis at presentation in individuals with new-onset diabetes. However, at present, there is no hard evidence that SARS-CoV-2 induces T1DM on it's own accord. Long term follow-up of children and adults presenting with new-onset diabetes during this pandemic is required to fully understand the type of diabetes induced by COVID-19.

Extending the Enterovirus Lead: Could a Related Picornavirus be Responsible for Diabetes in Humans?

We found an association between the abundance of rodents in the wild and onset of type 1 diabetes (T1D) in humans. A picornavirus named Ljungan virus (LV) was subsequently isolated from wild bank voles. Both picornavirus-like particles detected by electron microscopy and LV antigen visualized by immunohistochemistry was seen in islets of Langerhans in diabetic wild bank voles. LV antigen has also been found in islets of Langerhans in a patient with recent onset of T1D and in the commonly used Bio Breeding (BB) T1D rat model. We discuss the possibility of T1D and type 2 diabetes (T2D) as parts of a single disease entity. Antiviral compounds directed against picornavirus have been found to be an effective treatment of diabetes in BB rats. We propose using the same currently available antiviral compounds in clinical trials in humans. Antiviral treatment would have the potential to be both proof of concept for involvement of a picornavirus in diabetes pathogenesis and also present a first-generation therapy.

Effectiveness of Antivirals in a Type 1 Diabetes Model and the Move Toward Human Trials

A Picornavirus (Ljungan virus [LV]) originally found in bank voles has been associated with type 1 diabetes (T1D) in its wild rodent reservoir, but also associated with T1D in a laboratory rat model for the disease, the diabetes prone (DP) Bio Breeding (BB) rat. Successful treatment of diabetes in this rat model, using experimental antiviral compounds directed against picornavirus, has been reported. In the present study we show significant clinical response in DP-BB rats using antiviral compounds available for human use (Pleconaril, Efavirenz, and Ribavirin). Presence of LV picornavirus antigen has been detected in islets of Langerhans from both human and the T1D rat model with clear morphological similarity. Based on these data it would be of interest to test antiviral treatment in patients with newly diagnosed T1D. Successful outcome will offer both proof of concept regarding the role of virus involvement in the disease and possibly a first generation treatment interrupting a persistent infection and stopping β-cell destruction.

No Association Between Ljungan Virus Seropositivity and the Beta-cell Damaging Process in the Finnish Type 1 Diabetes Prediction and Prevention Study Cohort

BACKGROUND

Ljungan virus (LV) has not confirmed to associate with any human disease, but a possible connection with type 1 diabetes has been suggested. LV is a rodent-borne picornavirus that induces a diabetes-like condition in rodents. Approximately 30% of adults and 60% of children are seropositive in Finland. The Finnish Type 1 Diabetes Prediction and Prevention study enabled the use of very well characterized sample panels from children seroconverted to positivity for multiple islet autoantibodies during their prospective observation from birth; in addition, samples from age, sex, human leukocyte antigen (HLA), and residence area matched control children.

METHODS

We analyzed LV IgG seroprevalence in 102 case children (65 had also developed type 1 diabetes), in addition to nondiabetic control children. LV and human parechovirus (HPeV) immunofluorescence assays were used to analyze LV and HPeV-specific IgG from 102 plasma samples taken at the time of islet autoantibody appearance and from 204 samples from the matched control children.

RESULTS

Altogether 46.1% of the case and 50.7% of the control children were positive for LV IgG (odds ratio 0.8; 95% confidence interval, 0.47-1.36; P = 0.416) and 67.6% versus 79.8% were positive for HPeV IgG, respectively (odds ratio 0.49, 0.27-0.9, P = 0.023).

CONCLUSIONS

Thus, no risk associations between LV or HPeV-specific IgG and islet autoimmunity were observed. However, a trend for significantly higher prevalence of HPeV antibodies in control children (P = 0.023) suggests a possible protective association of this virus with islet autoimmunity.

Pet exposure in the family during pregnancy and risk for type 1 diabetes-The prospective ABIS study

BACKGROUND

The autoimmune process later leading to type 1 diabetes (T1D) seems to start very early in life. Different viruses have been suspected to contribute to the development of T1D, some already during pregnancy. As viruses may be hosted by animals and from them transferred to humans we decided to investigate if exposure to pets during pregnancy is related to later development of T1D.

METHODS

ABIS (All Babies in Southeast Sweden)-is a prospective population-based cohort study of unselected children born in southeast Sweden between Oct first 1997 to Oct first 1999. Parents of 16 384 children answered a questionnaire within 3 days after birth including information about exposure to different pets. The ABIS registry has been connected to the National Registry of diagnosis and also the national Registry of Drug prescriptions so we know that 137 children have got T1D, and they were compared with the non-diabetic population.

RESULTS

During pregnancy, 45.5% of the mothers had pet animals at home. Most common were cats (25.0%) and dogs (18.7%). Neither exposure to dogs (OR = 1.27, P = 0.23) or cats (OR = 0.81, P = 0.31) were associated to later T1D risks. However, exposure to hamsters increased the T1D risk (OR 4.21, P = 0.0007). In a multiple regression this association remained (P = 0.005) when adjusted for other possible risk factors.

CONCLUSIONS

Exposure to hamster during pregnancy seems to increase the risk of T1D in the child. One possibility could be infection by virus hosted by the pet.

Type 1 diabetes and viral infections: What is the relationship?

Type 1 diabetes (T1D) is the most common chronic metabolic disorder in children. Epigenetic and environmental factors capable of altering the penetrance of major susceptibility genes or capable of increasing the penetrance of low-risk genes are currently thought to play a role in triggering autoimmunity and T1D development. This paper discusses the current knowledge of the role of viruses in T1D. Most studies that have evaluated the potential association between viral infections and T1D have indicated that it is highly likely that some of these infectious agents play a role in T1D development. However, most T1D cases are immune-mediated, and it is supposed that the initial viral infection is capable of creating, in genetically predisposed subjects, a particular condition in which chronic local inflammation occurs through the persistence of the infecting virus in pancreatic tissue and the activation of autoimmunity by means of molecular mimicry, bystander activation, or both. Theoretically, this knowledge could lead to possible prophylaxis and therapy for T1D. Further studies devoted to evaluating which infectious agents are linked to T1D and which immune mechanisms induce or protect against the disease are needed before adequate prophylactic and therapeutic measures can be developed.

Intestinal virome changes precede autoimmunity in type I diabetes-susceptible children

Viruses have long been considered potential triggers of autoimmune diseases. Here we defined the intestinal virome from birth to the development of autoimmunity in children at risk for type 1 diabetes (T1D). A total of 220 virus-enriched preparations from serially collected fecal samples from 11 children (cases) who developed serum autoantibodies associated with T1D (of whom five developed clinical T1D) were compared with samples from controls. Intestinal viromes of case subjects were less diverse than those of controls. Among eukaryotic viruses, we identified significant enrichment of Circoviridae-related sequences in samples from controls in comparison with cases. Enterovirus, kobuvirus, parechovirus, parvovirus, and rotavirus sequences were frequently detected but were not associated with autoimmunity. For bacteriophages, we found higher Shannon diversity and richness in controls compared with cases and observed that changes in the intestinal virome over time differed between cases and controls. Using Random Forests analysis, we identified disease-associated viral bacteriophage contigs after subtraction of age-associated contigs. These disease-associated contigs were statistically linked to specific components of the bacterial microbiome. Thus, changes in the intestinal virome preceded autoimmunity in this cohort. Specific components of the virome were both directly and inversely associated with the development of human autoimmune disease.

DISTRIBUTION AND SEASONAL VARIATION OF LJUNGAN VIRUS IN BANK VOLES (MYODES GLAREOLUS) IN FENNOSCANDIA

Ljungan virus (LV) is a picornavirus originally isolated from Swedish bank voles ( Myodes glareolus ) in 1998. The association of LV with human disease has been debated ever since, but fundamental data on the ecology of the virus are still lacking. Here we present results of the first intensive study on the prevalence of LV in bank voles trapped in Fennoscandia (Sweden and Finland) from 2009-12 as determined by PCR. Using an LV-specific real-time reverse transcriptase PCR, LV was detected in the liver of 73 out of 452 (16.2%) individuals and in 13 out of 17 sampling sites across Sweden and Finland (mean per site prevalence 16%, SE 3%, range 0-50%). We found more infected animals in autumn compared to spring, and lighter and heavier individuals had a higher prevalence than those with intermediate body masses. The result that LV prevalence is also lower in heavier (i.e., older) animals suggests for the first time that LV infection is not persistent in rodents.

Lymphocytic choriomeningitis, Ljungan and orthopoxvirus seroconversions in patients hospitalized due to acute Puumala hantavirus infection

BACKGROUND

The emergence and re-emergence of zoonotic and vector-borne diseases are increasing in Europe. Prominent rodent-borne zoonotic viruses include Puumala hantavirus (PUUV; the causative agent of nephropathia epidemica, NE), lymphocytic choriomeningitis virus (LCMV), and orthopoxviruses (OPV). In addition, Ljungan virus (LV) is considered a potentially zoonotic virus.

OBJECTIVE

The aim of this study was to compare clinical picture between acute PUUV patients with and without additional rodent-borne viral infections, to investigate if concurrent infections influence disease severity.

STUDY DESIGN

We evaluated seroprevalence of and seroconversions to LCMV, LV and OPV in 116 patients hospitalized for NE. Clinical and laboratory variables were closely monitored during hospital care.

RESULTS

A total of five LCMV, 15 LV, and one OPV seroconversions occurred. NE patients with LCMV seroconversions were younger, and had lower plasma creatinine concentrations and platelet counts than patients without LCMV seroconversions. No differences occurred in clinical or laboratory findings between patients with and without seroconversions to LV and OPV. We report, for the first time, LCMV seroprevalence in Finland, with 8.5% of NE patients seropositive for this virus. Seroprevalences for LV and OPV were 47.8% and 32.4%, respectively.

CONCLUSION

Cases with LCMV seroconversions were statistically younger, had milder acute kidney injury and more severe thrombocytopenia than patients without LCMV. However, the low number of seroconversion cases precludes firm conclusions. Concurrent LV or OPV infections do not appear to influence clinical picture for NE patients.

The viral paradigm in type 1 diabetes: Who are the main suspects?

Type 1 diabetes (T1D) is an autoimmune disease characterized by the loss of pancreatic beta cells in the islets of Langerhans. Although genetic predisposition plays an important role in T1D development, studies of identical twins suggest that environmental factors such as viruses and other pathogens may be critical triggers either through direct cytolytic effect and gradual beta cell destruction, or by bystander activation of the immune system. In addition, viruses may circumvent the host immune response and have the capacity to establish chronic lifelong infections. The association of various viral infections with the induction of T1D has been extensively studied at the serological and epidemiological level. However, there is still little evidence from studies of human pancreas to confirm their presence or a causal role in disease pathogenesis. In this review, we identify possible suspects for viral triggers of disease and explain their potential roles in the "viral paradigm" of T1D.

Anthropogenic and temporal components in a complex trigger of type 1 diabetes suggest the active participation of antipyretics

Tremendous efforts in research without a conclusion on the cause of type 1 diabetes allow the presumption that there is still a blind spot in the development of T1D that is not covered by current hypotheses. The review of geographical knowledge suggests that there is a well-expressed anthropogenic element within the complex environmental trigger of T1D. On the other hand, the initiation of T1D's directed autoimmunity is temporally related to the organism's immune response, induced by entero-viruses, most expectedly. Consequently, the searched for anthropogenic environmental factor is a player temporally linked to enteroviral infections. This paper discusses the participation of antipyretic medicines, and especially paracetamol, with a whole century's history of growing sales and popularity, including indirect influence through phenacetin during the first half of the 20th century. As proposed by several independent studies, the use of pharmaceuticals to reduce fever may counteract with the protective features of the immune system and create favourable conditions for a virus to spread within the organism and damage specific tissue. A preliminary comparison of paracetamol sales with the incidence of T1D data in Lithuania and the other countries in the North-eastern Baltic region supports this hypothesis.

Islet autoantibodies present in association with Ljungan virus infection in bank voles (Myodes glareolus) in northern Sweden

Bank voles are known reservoirs for Puumala hantavirus and probably also for Ljungan virus (LV), a suggested candidate parechovirus in type 1 diabetes etiology and pathogenesis. The aim of this study was to determine whether wild bank voles had been exposed to LV and if exposure associated to autoantibodies against insulin (IAA), glutamic acid decarboxylase 65 (GADA), or islet autoantigen-2 (IA-2A). Serum samples from bank voles (Myodes glareolus) captured in early summer or early winter of 1997 and 1998, respectively, were analyzed in radio binding assays for antibodies against Ljungan virus (LVA) and Puumala virus (PUUVA) as well as for IAA, GADA, and IA-2A. LVA was found in 25% (189/752), IAA in 2.5% (18/723), GADA in 2.6% (15/615), and IA-2A in 2.5% (11/461) of available bank vole samples. LVA correlated with both IAA (P = 0.007) and GADA (P < 0.001), but not with IA-2A (P = 0.999). There were no correlations with PUUVA, detected in 17% of the bank voles. Compared to LVA negative bank voles, LVA positive animals had higher levels of both IAA (P = 0.002) and GADA (P < 0.001), but not of IA-2A (P = 0.205). Levels of LVA as well as IAA and GADA were higher in samples from bank voles captured in early summer. In conclusion, LVA was detected in bank voles and correlated with both IAA and GADA but not with IA-2A. These observations suggest that exposure to LV may be associated with islet autoimmunity. It remains to be determined if islet autoantibody positive bank voles may develop diabetes in the wild. J. Med. Virol. 89:24-31, 2017. © 2016 Wiley Periodicals, Inc.

Isolation of a sp. nov. Ljungan virus from wild birds in Japan

Ljungan virus (LV) has been isolated/detected from rodents in a limited area including European countries and the USA. In this study, we isolated an LV strain from faecal samples of wild birds that had been collected in Japan, and determined the nearly complete sequence of the genome. Sequence analyses showed that the isolate possesses an LV-like genomic organization: 5UTR-VP0-VP3-VP1-2A1-2A2-2B-2C-3A-3B-3C-3D-3UTR. Phylogenetic and similarity analyses based on the VP1 region indicated that the strain constitutes a novel genotype within LV. In addition, we identified species origin of the faeces as gull species by using the DNA barcoding technique. These data suggested that the novel LV strain infected a gull species, in which the virus had not been identified. Taken together, this study has provided the first evidence of the presence of a novel LV in Japan, highlighting the possibility of LV infection in birds.