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At least 37 records · Page 2Linked to original sources

PubMed1978

Razdan virus, a new ungrouped bunyavirus isolated from Dermacentor marginatus ticks in Armenia.

A virus, designated Razdan, was isolated from Dermacentor marginatus ticks in the Armenian S.S.R. in 1973. The complement fixation tests revealed no antigenic relationships to 74 tick-borne arboviruses. The size of the virus is about 100 nm; it agglutinates goose erythrocytes at pH 5.5--7.0, is pathogenic for newborn, 14-day-old and adult white mice and multiplies in primary and continuous cell cultures. Morphological properties of the virus permit its classification as a member of the family Bunyaviridae.

Animals↗

PubMed1976

Experimental infection of monkeys with viruses of the tick-borne encephalitis complex: degenerative cerebellar lesions following inapparent forms of the disease or recovery from clinical encephalitis.

Rhesus, patas and vervet monkeys were infected i.c. or i.n. with three viruses of the tick-borne encephalitis complex (TBE) as follows: Turkish tick-borne encephalitis virus (TTE), Louping-ill virus and Central European tick-borne encephalitis virus (CETE). The incidence of overt clinical signs of disease varied according to the virus that was used for the inoculations. TTE proved to be more pathogenic for monkeys than the other two members of the complex, whilst CETE was the least pathogenic. Injections of specific antiserum soon after infection tended to increase both the incidence of clinical signs and the moratlity. A proportion of animals with inapparent infections and a number of monkeys that recovered from the acute phase of the disease developed degenerative lesions in the cerebellum, often superimposed on the involuting inflammatory changes. The changes affected either a few only or many folia of the cerebellum and consisted of neuronal and spongy degeneration of the Purkinje and granular layers, usually accompanied by marked astrocytic proliferation and hypertrophy in the granular and molecular layers.

Animals↗

PubMed1975

Characteristics of tick-borne encephalitis virus cirulating in Poland.

An attempt of chacteristization of tick-borne encephalitis virus strains, isolated in Poland in 1955--1970, was based on the determination and analysis of neurovirulence for white mice at intracerbral and subcutaneous virus inoculation, neuroinvasion, antigenic properties, cytopathogenic abilities, susceptibility to nonspecific hemagglutination inhibitors, susceptibility to temperature of 50degree and to 2M urea. Strains isolated in different regions of the country showed certain differentiation in pathogenic and antigenic properties as well in susceptibility to nonspecific inhibitors.

Animals↗

PubMed2026

Emerging tick-borne viral diseases in East Asia: pathology-driven insights into pathogenesis and disease causality.

SUMMARYTick-borne viral infections have emerged as a significant and growing public health concern. In East Asia, severe fever with thrombocytopenia syndrome (SFTS) has served as a prototypical disease in which pathological analyses have substantially advanced the understanding of disease pathogenesis. SFTS is characterized by profound immune dysregulation driven by viral tropism for plasmablast-lineage B cells, leading to cytokine storm and hemophagocytic syndrome. Complementary analyses of human clinical specimens and experimental animal models, including cats and ferrets, have provided critical insights into the immunopathogenesis of SFTS. The recent identification of additional tick-borne viruses, including Oz virus (OZV), Yezo virus (YEZV), and Alongshan virus (ALSV), has further expanded the spectrum of emerging infections in this region. Notably, pathological investigation of a fatal human case of OZV infection demonstrated direct viral localization within cardiomyocytes, establishing a causal link between infection and fulminant myocarditis and highlighting a distinct organ-specific pathogenic mechanism. Despite the advances in genomic technologies that enable rapid detection of novel viruses, establishing causal relationships between viral presence and disease remains a major challenge. Tissue-based pathological approaches, particularly in situ localization of viral components, are, therefore, essential for defining disease mechanisms and confirming etiological roles. This review provides a comprehensive synthesis of tick-borne viral infections in East Asia, with particular emphasis on Japan, integrating pathological, virological, and clinical perspectives. It also identifies key knowledge gaps and underscores the importance of a synergistic One Health framework that incorporates both human and veterinary pathology to advance the understanding and control of these emerging diseases.

One Health↗

PubMed1976

[Peculiarities of carbohydrate metabolism in rabbits following prolonged immunization with viral antigens].

Prolonged, for a period of 5 cycles, immunization of rabbits with tick-borne encephalitis virus, reproduced in the brain of albino mice, caused diabetogenic reaction of the carbohydrate metabolism. It was expressed in hyperglycemia, reduction of hexokinase activity and of glycolysis of hepatic tissue and activation of phosphorylase, glycogenolysis and pentous way of carbohydrate transformation. Metabolic changes were accompanied by a reduction of insulin activity of the immunized rabbit serum. An analogous administration of a more pathogenic virus (of western equine encephalomyelitis) led to changes (equal in value) in the functional condition of the pancreas with much lesser shifts in the biochemical idices of the carbohydrate metabolism.

Animals↗

PubMed1976

[Metabolic features of the liver and spleen and antibody formation in animals following hyperimmunization with viral antigens].

Hyperimmunization with the tick encephalitis and Western horse encephalomyelitis viruses reproduced in the brain of albino mice, intensified the protein synthesis in the splenic tissue during the productive phase of the immunogenesis (the 7th day). An accumalation of protein, activation of aniuno-acyl-t-RNA-ligases, a reduction of the concehtration of some amino acids was noted, An analogous reaction was distinct in the tissue of the liver only when an intact brain suspension was used as an antigen. Formation of specific antibodies coursed more intensively after the administration of a more pathogenic virusof Western equine encephalomyelitis.

Adenosine Triphosphate↗

PubMed1975

Experimental mixed infection with two tick-borne viruses and interferon-mediated interference.

Tick-borne encephalitis virus (TEV), a Flavivirus, and Lipovník virus (LV), a member of the Kemerovo group and complex and possible member of the Rioviridae, were used to infect chick embryo cell (CEC) cultures. LV reproduction was inhibited by preinfection with TEV, mainly in aged cultures. In young CEC cultures, TEV production was stimulated slightly and interferon was sometimes depressed by this superinfection; on the contrary, in aged cultures the superinfecting LV stimulated interferon also when infective LV was not produced because of interference. Double staining by the fluorescent antibody (FA) technique localized both viral antigens often in the same cells. Interference between TEV and LV (and vice versa) was observed in cerebrally infected adult mice. The pathogenicity of LV, when injected first, was increased by TEV superinfection. Examination by the FA technique confirmed interference between TEV and LV also in suckling mouse brains and demonstrated both viral antigens in the same brains when TEV and LV were injected simultaneously.

Animals↗

PubMed2026

Emergence of Babesia naoakii infection in Indonesian domestic cattle, a new host record in water buffaloes, and characterization of complete mitochondrial protein-coding genes.

Babesia (B.) naoakii, previously referred to as Babesia sp. Mymensingh, is a recently characterized tick-borne haemoprotozoan parasite of cattle. In Indonesia, we first reported its presence in 2022 from clinically affected cattle in Central Java. To investigate the wider epidemiology of this neglected ruminant-associated Babesia species, we surveyed apparently healthy cattle (Bos indicus) and water buffaloes (Bubalus bubalis) across three districts of Java, Indonesia. A PCR assay targeting the B. naoakii-specific apical membrane antigen 1 (ama1) gene detected the parasite occurrence in 34.39% of assessed cattle (87/253; 95% CI: 28.80-40.44%) and 30.77% of water buffaloes (12/39; 95% CI: 18.47-46.52%). These results represent the first record of B. naoakii infection in water buffaloes in the country and confirm that the parasite circulates in subclinically infected bovine hosts. To characterise this apicomplexan parasite further at the molecular level, we assembled in full length the three mitochondrial protein-coding genes (PCGs): cytochrome c oxidase subunits 1 (cox1) and 3 (cox3), as well as cytochrome b (cytb). These genes were reconstructed by next-generation sequencing of blood DNA collected during the acute haemolytic-phase of B. naoakii infection, from calves that subsequently succumbed to the disease in the endemic area. Phylogenetic analyses of the concatenated amino-acid sequences of cox1, cox3, and cytb placed the Indonesian isolates within a well-supported monophyletic clade, distinct from all previously characterised ruminant-associated Babesia species and sister to the Babesia bigemina/Babesia ovata lineage. This placement confirmed species identity and reinforced the genetic distinctiveness of B. naoakii in Indonesia. Notably, although B. naoakii circulates in peripheral blood and mirrors the diagnostic behaviour of the mild pathogen B. bigemina, its clinical impact more closely resembles that of the severe pathogenic B. bovis, particularly in young animals. This diagnostic-clinical discordance highlights the need for B. naoakii-specific molecular surveillance and species-level differentiation in regions of co-endemicity. Given the high prevalence in subclinically B. naoakii-infected adults, the documented severity of babesiosis in calves, and the potential for substantial economic losses, broader epidemiological investigations and species-specific control measures for B. naoakii are urgently performed. The same holds true for future epizootiological investigations of underdiagnosed B. naoakii-infections possibly circulating in Indonesian endemic ruminant bovids such as the banteng (Bos javanicus), the lowland anoa (Bubalus depressicornis) and the tamaraw (Bubalus mindorensis).

Animals↗

PubMed1978

The isolation of Central European encephalitis (tick-borne encephalitis) virus from Ixodes ricinus (L.) ticks in southern-Germany.

During the years 1972--1976 a total of 14.692 ticks of the species Ixodes ricinus (L.), (2.738 adults and 11.954 nymphs) was collected. They were taken from five areas where human Central European encephalitis virus (CEE) infections had occurred. By means of, intracerebral (IC) and subcutaneous (SC) isolation experiments with suckling mice 19 agents, exhibiting the pathogenic characteristics of CEE virus, were isolated from these ticks. In neutralization tests with suckling mice these isolates could be identified as CEE virus strains. From the 14.692 ticks at least 1.29% were virus carriers as evidenced by the number of isolated virus strains. By the same reasoning at least 3.6% of the adults and 0.76% of the nymphs must have contained virus. We were successful in each of the five areas, rather distant from each other, to isolate the virus. The favorable ecological conditions for the main vector Ixodes ricinus in the Federal Republic of Germany give rise to the assumption that this medically important tick-borne disease might be permanently present in many areas.

Animals↗

PubMed1992

Enhanced neurovirulence of tick-borne orbiviruses resulting from genetic modulation.

The genome of orbiviruses (Reoviridae family) comprises 10 segments of double-stranded RNA. The fourth largest segment of the tick-borne Kemerovo (KEM) group orbiviruses is the genetic determinant of neurovirulence in experimentally infected mice, and segment 6 determines serotype. Reassortant viruses derived from a cross between two KEM-related viruses, Great Island (GI) and Wexford (WEX), that had the heterotypic gene combination W4G6 (segment 4 of WEX virus and segment 6 from GI virus) were nonpathogenic in mice. This apparent genetic modulation of neurovirulence may have resulted from steric interaction between the two outer capsid proteins of nonpathogenic reassortants. Further data are consistent with this hypothesis. Reassortants generated from additional KEM group viruses showed various degrees of enhanced neurovirulence in terms of their PFU/LD50 (ratio of infectivity in cell culture and in mice) and ASTmax (the average survival time at the highest virus dilution resulting in 100% mortality). Some reassortants were more pathogenic than either of their parental viruses. The results indicate that the gene determining neurovirulence dictates ASTmax, and the PFU/LD50 is a measure of the interaction between the products of the gene determining neurovirulence and that determining serotype. The nonpathogenic phenotype of a low passage isolate (St. Abb's 84-34 virus), derived from a single tick, generated neurovirulent reassortants. This result indicates that genetic modulation of KEM group viruses may occur in nature.

Animals↗

PubMed2026

Widespread circulation of Alongshan virus in Austria and serological evidence for infection in humans: a nationwide molecular and serological observational study.

BACKGROUND: Alongshan virus, a segmented RNA virus in the Jingmenvirus group of flaviviruses, was first identified in 2017 in China in patients with tick-borne encephalitis-like illness. Alongshan virus has since been detected in ticks and mammals in several European countries. In this study, we aimed to characterise the temporal and geographical distribution of Alongshan virus in Austria through nationwide tick surveillance combined with serological and molecular screening in individuals with suspected tick-borne encephalitis or tick exposure. METHODS: In this nationwide molecular and serological observational study, we conducted a PCR-based screening of ticks collected across Austria in 2024, using flagging, animal hosts, and citizen submissions. We also collated genomic data from stored nucleic acid extracts from ticks collected in Austria in 2005 and 2013 in previous surveillance studies and stored extracts of paired tick-human samples collected between 2015 and 2018. Alongshan virus-positive tick samples were subjected to whole-genome sequencing and phylogenetic analysis. In addition to tick samples, blood samples from Austrian patients with reported tick bite or suspected tick-borne encephalitis, submitted to the National Reference Center for Human Arbovirus Infections, Austria, were screened for Alongshan virus infection and subjected to serological and molecular testing. FINDINGS: 2952 ticks were collected between Feb 1, 2024, and Dec 6, 2024, from 29 (83%) of 35 NUTS-3 regions in Austria; the median detection rate for Alongshan virus was 1·2% (IQR 0·4-3·5). In addition, 1816 archived tick samples were analysed, with three testing positive for Alongshan virus. For the virus-positive samples, phylogenetic analysis showed that sequences from Austria grouped within the European clade, with Austrian sequences from the same region showing high sequence similarity. 1361 human serum samples collected between March 1, 2023, and May 16, 2025, were assessed for anti-Alongshan virus IgG antibodies. Two individuals had high antibody titres against Alongshan virus proteins VP1a and VP2. INTERPRETATION: Our study shows detection of Alongshan virus in archived tick samples dating back to 2005, representing the earliest documented occurrence of the virus to date and suggesting that Alongshan virus has been circulating in Austria for at least two decades. The detection of Alongshan virus-specific antibody titres in two individuals suggests past infection and previously unrecognised exposure. These results highlight the need for continued molecular surveillance of tick populations and serological monitoring in humans to define the epidemiology and public health relevance of Alongshan virus in Europe. FUNDING: One Health surveillance and Vector monitoring for cross-border pathogens (OH SURVector) and UNITED4Surveillance.

Adolescent↗

PubMed1992

Virus safety of human immunoglobulins: efficient inactivation of hepatitis C and other human pathogenic viruses by the manufacturing procedure.

Human immunoglobulins are plasma derivatives with a low risk of transmitting viral infections. To the present, no proven case of human immunoglobulins transmitting human immunodeficiency viruses has been reported. However, there have been a few reports on the transmission of hepatitis C virus by these plasma proteins. To improve further the safety of both 5s iv human immunoglobulins and 7s im immunoglobulins, we introduced a 10-hour heat treatment of the aqueous solutions at 60 degrees C (i.e., pasteurization) into the manufacturing procedure. This treatment was not added to the manufacturing procedure of 7s iv immunoglobulin that already contained the S-sulfonation as a virus inactivating method. We now report on experimental data that show that the whole manufacturing procedures of the above immunoglobulins inactivate efficiently hepatitis C virus and that the specific virus inactivation methods alone, namely, pasteurization or S-sulfonation, also inactivate completely viruses of the flavivirus family, to which the hepatitis C virus belongs. The inactivation of the Flaviviridae bovine viral diarrhea virus, tick-borne encephalitis virus, and yellow fever virus by pasteurization or S-sulfonation was at least 10(5). The clearance of HCV achieved by the entire manufacturing process of each of these immunoglobulins was also at least 10(5). The experiments therefore show that pasteurization or S-sulfonation provides a high margin of safety to human immunoglobulins regarding the transmission of hepatitis C virus.

Animals↗

PubMed2025

Surveillance of tick-borne viruses in the border regions of the Tumen River Basin: Co-circulation in ticks and livestock.

BACKGROUND: The unique eco-geographical patterns and climatic conditions of the China-Tumen River border region, combined with frequent cross-border tourism and trade activities, collectively establish this area as a recognized hotspot for tick-borne disease outbreaks. However, critical knowledge gaps persist regarding the eco-epidemiology of emerging tick-borne viruses and the distribution of their potential reservoir hosts within this trinational ecosystem spanning China, North Korea, and Russia. METHODS: We collected a total of 2,004 ticks from the study area, along with blood samples obtained from 42 sheep and 45 cattle. Following viral metagenomic analysis of the ticks, dual verification of target pathogens in all samples was performed using qRT-PCR and RT-PCR assays. Phylogenetic trees were constructed and nucleotide sequences were analyzed to delineate relationships between the obtained virus strains and reference sequences. RESULTS: Viral metagenomics identified three viruses in ticks: Dabieshan tick virus (DBTV), Songling virus (SGLV), and Yanggou tick virus (YGTV). PCR analysis detected DBTV exclusively in Hunchun ticks (minimum infection rates, MIR:4.73%) and YGTV in Antu specimens (MIR:0.97%). Conversely, SGLV was detected in ticks from all four regions, with MIR of 1.68% (Helong), 0.74% (Hunchun), 1.61% (Antu), and 4.79% (Longjing). Concurrently, SGLV was detected in 19 sheep blood samples from Longjing, yielding a positivity rate of 45.24%, while YGTV was identified in 13 cattle blood samples from Antu, with a positivity rate of 28.89%. Phylogenetically, the DBTV strain clustered with previously reported DBTV and Yongjia tick virus 1 isolates. Sheep-derived SGLV strains shared close evolutionary ties with tick-borne SGLV, whereas YGTV from cattle and ticks formed a distinct cluster with Russian strains but diverged into two branches from Chinese variants, suggesting evolutionary instability. CONCLUSION: These findings address critical knowledge gaps in the transmission dynamics and genetic diversity of emerging arboviruses while providing vital insights for developing cross-border surveillance strategies with significant public health implications.

Animals↗

PubMed1979

The influence of specific antisera and unheated guinea pig serum on the pathogenicity of "Runde" virus for mice.

Antisera from various animal species containing antibodies to "Runde" virus were not able to neutralize virus infection in newborn mice, the outcome of which is an acute, fatal CNS disease. There was, however, one noticeable exception. Mixtures of virus and hyperimmune mouse serum or ascitic fluid inoculated intracerebrally into newborn mice resulted in a persistent infection and a chronic disease which had previously only been recognized in 2 to 3-week-old mice inoculated with "Runde" virus. A serum pool from persistently infected mice had the same effect, though this was less pronounced. The addition of unheated guinea pig serum to the virus-hyperimmune serum mixtures reinforced the tendency to persistence and chronic disease, and unheated guinea pig serum alone modified the infection in the same way. The results suggest an immunological basis for the virus persistence and chronic disease in suckling mice.

Age Factors↗

PubMed1975

[Pathogenic factors in viral diseases of the central nervous system].

The possible immunological significance of the different kinds of cells participating in the inflammatory reaction in cerebrospinal infections is to be considered. Presence of plasma cells and occasional perivenous microglial seams in early stages of the neurotropic virus diseases must be regarded as immunological manifestations. The brainstem nuclei are sites of predilection both in entero- and in arbovirus diseases. The aetiologically different neurotropic virus diseases obtain their individual character from the involvement of certain neurones. Neural pathways are to be taken into consideration mainly for the propagation of enteroviruses, but may have a part also in the propagation of arboviruses. With massive invasion by highly cytopathogenic viruses inflammatory reaction may fail to appear in the immature nervous tissue. Some encephalitides, of both viral and non-viral aetiology, in which the prevalence of plasma cells in the infiltrations bears evidence of an intense immune process, may be interpreted as immunologically determined late diseases.

Animals↗

PubMed2025

Establishment of reverse genetics systems for Colorado tick fever virus.

The Colorado tick fever virus (CTFV), which has 12-segmented double-stranded RNA genomes, is a pathogenic arbovirus that causes severe diseases in humans. However, little progress has been made in the analysis of replication mechanisms and pathogenicity. This virological constraint is due to the absence of a reverse genetics system for CTFV; therefore, we aimed to establish the system. Initially, the efficacy of CTFV replication was investigated in various cell lines. CTFV was found to grow in many cell types derived from different hosts and organs. Subsequently, BHK-T7 cells stably expressing T7 RNA polymerase were transfected with plasmids encoding each of the 12 CTFV gene segments, expression plasmids encoding all CTFV proteins, and a vaccinia virus RNA-capping enzyme. Following transfection, the cells were co-cultured with Vero or HeLa cells. Using this system, we rescued monoreassortants and recombinant viruses harboring peptide-tagged viral proteins. Furthermore, an improved system using Expi293F cells expressing T7 RNA polymerase was established, which enabled the generation of recombinant reporter CTFVs. In conclusion, these reverse genetics systems for CTFV will greatly contribute to the understanding of viral replication mechanisms, pathogenesis, and transmission, ultimately facilitating the development of rational treatments and candidate vaccines.

Animals↗

PubMed1975

Plaque production by arboviruses in Singh's Aedes albopictus cells.

We report plaquing tests of 124 virus strains, mostly arboviruses of 21 serological groups, in Singh's line of Aedes albopictus cells. Thirty of these plaqued: all were arboviruses of six groups and were known or presumed to be mosquito borne. Failing to plaque were 86 strains of arboviruses, mostly tick borne, two strains of insect pathogens, and six animal viruses not classified as arboviruses. Among mosquito-borne agents, plaquing ability appeared related to serological classification. California group and most A-group viruses failed to plaque, but nearly all members of B and Bunyamwera groups readily plaqued. Within serological group B, 14 of 16 mosquito-borne agents plaqued, but none of 13 tick-borne or vector-unassociated viruses did so. Some implications of these results for recognition and classification of arboviruses are discussed.

Aedes↗

PubMed1992

Identification of the tick-borne relapsing fever spirochete Borrelia hermsii by using a species-specific monoclonal antibody.

Borrelia hermsii causes a relapsing fever in humans and is one of several species of tick-borne spirochetes known to occur in the western United States. Spirochetes observed in the peripheral blood of patients acutely ill have been presumptively identified in the past by the geographic location of exposure and the probable species of tick vector. We describe a monoclonal antibody (H9826) that bound to the flagellar protein of B. hermsii but not to those of any of the other species tested, which included B. parkeri, B. turicatae, B. coriaceae, B. anserina, B. burgdorferi, and Leptospira interrogans serovar ballum. This antibody bound efficiently to B. hermsii in an indirect immunofluorescence assay and was used to rapidly detect and identify this spirochete in the peripheral blood of experimentally infected mice and in the central ganglia of Ornithodoros hermsi ticks. H9826 can rapidly confirm the identification of B. hermsii to increase our understanding concerning the geographic distribution, vector specificity, and epidemiological significance of this zoonotic human pathogen.

Antibodies, Bacterial↗