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PubMed2026

Metagenomic analysis of the midgut microbiome in Dermacentor abaensis ticks at different feeding states.

Ticks are blood-sucking ectoparasites of humans and animals, ranking second only to mosquitoes as vectors of diseases. Dermacentor abaensis is distributed in Sichuan, Qinghai, and Gansu, China. Because D. abaensis harbors several pathogens, it poses a threat to public health and livestock production. However, the midgut microbiota of D. abaensis at distinct feeding states remains poorly characterized. Adult D. abaensis ticks at various feeding states were collected from yaks in Gansu Province, China. Genomic DNA was extracted from midguts and midgut contents of unfed, partially fed, and fully engorged female D. abaensis. A metagenomic sequencing approach was employed to profile the midgut microflora among three groups. A total of 83 phyla, 908 genera, and 1857 species were annotated across the three groups. At the phylum level, Pseudomonadota, Mucoromycota, and Ascomycota were the most abundant. At the species level, common bacterial species such as Klebsiella pneumoniae and Anaplasma phagocytophilum, alongside viruses and eukaryotes, were detected in all three groups. Unique microorganisms were also observed in each group: unfed (n = 305), partially fed (n = 59), and fully engorged (n = 20). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis suggested that the D. abaensis microbiome contains a relatively high abundance of functional genes involved in lipid and amino acid metabolism across the three different feeding states. These findings indicate that while core microbial taxa are shared in the midgut of female D. abaensis, observable trends suggest variations in microbial diversity and composition as blood-feeding progresses. The present study provides a descriptive baseline of the midgut microbial composition of D. abaensis, which may inform future studies on tick biology and the ecology of tick-borne pathogens.

Animals↗

PubMed2024

A series of patients infected with the emerging tick-borne Yezo virus in China: an active surveillance and genomic analysis.

BACKGROUND: Yezo virus (YEZV) is an emerging tick-borne pathogen, which was initially reported in Japan in 2021. Only one patient had been reported in China so far. We aimed to describe the epidemiological, clinical, and laboratory findings of a series of patients, and to characterise the viral genomes of YEZV. METHODS: In this active surveillance and genomic analysis, we conducted active surveillance at Mudanjiang Forestry Central Hospital, Heilongjiang Province of northeast China. Participants were eligible for inclusion if they sought medical care for a recent tick bite between May 1 and July 31, in 2022 and 2023, and between May 1 and July 10, in 2024. We collected sera from participants to detect YEZV infection by meta-transcriptomic sequencing, real-time RT-PCR, and indirect immunofluorescence assay. We isolated YEZV by cell culture and characterised the pathogen by morphological and phylogenetic analyses. FINDINGS: A series of 18 patients with YEZV infection (12 male and six female; median age 53 years, IQR 45-60) were identified among 988 participants. The patients presented with fever (18 patients, 100%), headache (ten patients, 56%), dizziness (nine patients, 50%), malaise (three patients, 17%), lumbago (three patients, 17%), and cough (three patients, 17%). Nine (50%) patients had rash around the tick bite site and four (22%) had lymphadenopathy. Nine (50%) patients had gastrointestinal symptoms, and five (28%) had neurological symptoms. We observed leukopenia in ten (63%) and thrombocytopenia in five (31%) of 16 assessed patients. Elevated hepatic transaminase concentrations were identified in 13 (72%) of all 18 patients, lactate dehydrogenase or α-hydroxybutyric dehydrogenase in nine (50%), serum amyloid protein A in 13 (72%), and hypersensitive C-reactive protein in ten (56%). Eight (7%) of 119 Ixodes persulcatus ticks removed from participants were positive for YEZV. Three YEZV strains were isolated from the sera of patients. Ten viral genomes were obtained from five patients, a blood-sucking I persulcatus removed from a participant, and four host-questing tick samples collected in the areas where patients were identified or in the adjacent region. Phylogenetic analyses revealed that YEZVs in either patients or ticks were divided into two clades, each with distinct mutations. INTERPRETATION: Awareness of YEZV infection is important and clinicians should consider the virus when diagnosing patients with suitable symptoms. FUNDING: National Key Research and Development Program of China. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Humans↗

PubMed2024

Identification and epidemiological study of an uncultured flavivirus from ticks using viral metagenomics and pseudoinfectious viral particles.

During their blood-feeding process, ticks are known to transmit various viruses to vertebrates, including humans. Recent viral metagenomic analyses using next-generation sequencing (NGS) have revealed that blood-feeding arthropods like ticks harbor a large diversity of viruses. However, many of these viruses have not been isolated or cultured, and their basic characteristics remain unknown. This study aimed to present the identification of a difficult-to-culture virus in ticks using NGS and to understand its epidemic dynamics using molecular biology techniques. During routine tick-borne virus surveillance in Japan, an unknown flaviviral sequence was detected via virome analysis of host-questing ticks. Similar viral sequences have been detected in the sera of sika deer and wild boars in Japan, and this virus was tentatively named the Saruyama virus (SAYAV). Because SAYAV did not propagate in any cultured cells tested, single-round infectious virus particles (SRIP) were generated based on its structural protein gene sequence utilizing a yellow fever virus-based replicon system to understand its nationwide endemic status. Seroepidemiological studies using SRIP as antigens have demonstrated the presence of neutralizing antibodies against SAYAV in sika deer and wild boar captured at several locations in Japan, suggesting that SAYAV is endemic throughout Japan. Phylogenetic analyses have revealed that SAYAV forms a sister clade with the Orthoflavivirus genus, which includes important mosquito- and tick-borne pathogenic viruses. This shows that SAYAV evolved into a lineage independent of the known orthoflaviviruses. This study demonstrates a unique approach for understanding the epidemiology of uncultured viruses by combining viral metagenomics and pseudoinfectious viral particles.

Animals↗

PubMed2025

Borrelia burgdorferi loses essential genetic elements and cell proliferative potential during stationary phase in culture but not in the tick vector.

The Lyme disease agent Borrelia burgdorferi is a polyploid bacterium with a segmented genome in which both the chromosome and over 20 distinct plasmids are present in multiple copies per cell. This pathogen can survive for at least 9 months in its tick vector in an apparent dormant state between blood meals, without losing cell proliferative capability when re-exposed to nutrients. Cultivated B. burgdorferi cells grown to stationary phase or resuspended in nutrient-limited media are often used to study the effects of nutrient deprivation. However, a thorough assessment of the spirochete's ability to recover from nutrient depletion has been lacking. Our study shows that starved B. burgdorferi cultures rapidly lose cell proliferative ability. Loss of genetic elements essential for cell proliferation contributes to the observed proliferative defect in stationary phase. The gradual decline in copies of genetic elements is not perfectly synchronized between chromosomes and plasmids, generating cells that harbor one or more copies of the essential chromosome but lack all copies of one or more non-essential plasmids. This phenomenon likely contributes to the well-documented issue of plasmid loss during in vitro cultivation of B. burgdorferi. In contrast, B. burgdorferi cells from ticks starved for 14 months showed no evidence of reduced cell proliferative ability or plasmid loss. Beyond their practical implications for studying B. burgdorferi, these findings suggest that the midgut of the tick vector offers a unique environment that supports the maintenance of B. burgdorferi's segmented genome and cell proliferative potential during periods of tick fasting.IMPORTANCEBorrelia burgdorferi causes Lyme disease, a prevalent tick-borne illness. B. burgdorferi must survive long periods (months to a year) of apparent dormancy in the midgut of the tick vector between blood meals. Resilience to starvation is a common trait among bacteria. However, this study reveals that, in laboratory cultures, B. burgdorferi poorly endures starvation and rapidly loses viability. This decline is linked to a gradual loss of genetic elements required for cell proliferation. These results suggest that the persistence of B. burgdorferi in nature is likely shaped more by unique environmental conditions in the midgut of the tick vector than by an innate ability of this bacterium to endure nutrient deprivation.

Borrelia burgdorferi↗

PubMed1978

Morphological characteristics of the infection of animals with tick-borne encephalitis virus persisting for a long time in cell cultures.

The pathogenicity of the Soph-K strain of tick-borne encephalitis (TBE) virus produced by the persistently infected HEp-2-Soph cell culture was investigated in monkeys, white mice and hamsters. The persistent infection of this culture with TBE virus has been maintained for 17 years. The Soph-K strain was shown to retain its pathogenic properties for mice of different ages and hamsters. Morphological examinations of the brains and spinal cords of these animals infected with the Soph-K strain revealed acute and subacute forms of encephalitis. Monkeys inoculated with the Soph-K strain intracerebrally showed an asymptomatic infection with the pathomorphological picture of subacute disseminated meningoencephalitis with a progredient course for 3 months of observation. This chronic TBE infection in monkeys offers an interesting model for investigations on progressive degenerative disease of the nervous system.

Animals↗

PubMed1976

Eyach--an arthropod-borne virus related to Colorado tick fever virus in the Federal Republic of Germany.

From Ixodes ricinus ticks collected in a tick-borne encephalitis focus in Baden-Württemberg, an agent pathogenic exclusively for suckling mice was isolated. Obviously a virus, it passed membrane filters with a pore width of 200 nm. It was resistant to ether and sodium deoxycholate, but not to chloroform. In the complement fixation test it showed a close, and in the neutralisation test a more one-sided relationship to Colorado tick fever virus.

Animals↗

PubMed1977

Studies on Theileriidae (Sporozoa) in Tanzania. X. A large-scale field trial on immunization against cattle Theileriosis.

50 cattle immunized by an infection and treatment method with 3 strains of Theileria parva (Mugaga, Kiambu 5 and Serengeti transformed), together with 19 controls, were exposed to natural tick infestation in Tanzania, in a site where a continuous influx of infected ticks from different regions of the country may be expected to occur. Exposure lasted for 2 months, monitoring continued for 3 more weeks after exposure ended. All 19 controls contracted East Coast Fever and died. 40 of the 50 immunized animals survived the whole period of monitoring; the other 10 died of accidents (2), heartwater (3) and unidentified causes (5); none died of ECF. It is recommended that this method of immunization be routinely applied to protect valuable animals at risk. An attempt to immunize against pathogenic Theileria mutans, by injecting blood containing piroplasms of a strain of low pathogenicity, showed that this method may protect against high parasitaemias caused by natural tick-borne infections and may be useful in eliminating the confusing factor of T. mutans in future trials on East Coast Fever.

Animals↗

PubMed1979

[Intensification of antibacterial and antiviral nonsusceptibility and of the immune response with an officinal RNA preparation].

Sodium nucleinate increased essentially the insusceptibility of mice to pathogenic escherichia, strain O26, Pr. vulgaris, Ps. aeruginosa, Ser. marcescens, and produced a total stimulating effect on the nonspecific bacterial resistance; analogous stimulating activity was found in the homologous low polymeric RNA from the liver. Sodium nucleinate intensified the insusceptibility of the animals to the tick-born encephalitis and encephalomyelitis viruses, and increased the antibody-forming cells count. The side-effect of heat-inactivated vaccine from pathogenic escherichia was reduced in animals inoculated with sodium nucleinate preliminarily.

Animals↗

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↗

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↗

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↗

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↗

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↗