No abstract available.
Encephalitis, Tick-Borne*

No abstract available.
Encephalitis, Tick-Borne* ; Humans ; Immunoglobulin M*

Biomedical Research ; China ; Encephalitis, Tick-Borne ; Humans

China ; Coltivirus ; Encephalitis, Tick-Borne ; virology ; Humans

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system and is caused by tick bites, usually after travel to rural or forested areas. The disease is prevalent in Scandinavia, Western Europe, Central Europe and the former Soviet Union and East Asia including Japan. In Malaysia, so far there are no reported cases of TBE. In the present time, many illnesses have been attributed to traveling to other parts of the world. Thus it is important to carry out TBE prevalence study to determine whether the virus is present among Malaysian population. Samples (sera and CSF) from patients admitted to major MOH hospitals in Peninsular Malaysia and Sabah with a clinical diagnosis of encephalitis but is IgM negative for JE, were tested for TBEV IgM ELISA and TBEV IgG ELISA (DRG, Germany). Out of the 600 samples screened for TBEV IgG, all were non-reactive. In addition, out of the 100 samples screened for TBEV IgM, all the samples were also non-reactive. Our results indicate that currently TBE is not present in the Malaysian population. Among the reasons for this could be lack of the infection agent, absence of the suitable vector or subjects selected for the study did not fit the criteria of possible exposure to TBE infections. Hence we recommend that for any future study, the selection of subjects should include those who returned from tick-infested forested areas.
Encephalitis ; Ticks ; Tick-Borne Encephalitis Virus ; MALAYSIAN ; Immunoglobulin M measurement

Three dimensional structures of envelope protein from Korean isolates and Nakayama-NIH strain of Japanese encephalitis virus (JEV) were deduced by a computer program (HyperChem 4.0 Chemplus 1.0) based on the data of the three dimentional structure of Tick-borne encephalitis virus. In the three dimensional structure of envelope protein, neutralizing epitope and T-helper cell recognition site of C-terminal region of Korean isolates were structually similar to those of Nakayama-NIH but the N-terminal region was not. Korean JE isolates were compared with Nakayama-NIH strain by using cross-neutralization antibody test. Neutralizing activities of Korean isolates derived from guinea pigs were higher than those of Nakayama-NIH strain against Korean isolates, although the polyclonal antibody titers of Nakayama-NIH showed 1:160 to 1:640 against Korean isolates. According to the results from three dimentional structures and cross-neutralization analyses, the antigenic difference between Korean JE isolates and Nakayama-NIH strain may be dependent on structural difference of envelope protein.
Animals ; Encephalitis Virus, Japanese ; Encephalitis Viruses* ; Encephalitis Viruses, Tick-Borne ; Encephalitis* ; Guinea Pigs ; Korea*

OBJECTIVETo investigate the recent emerged endemic region of tick-borne encephalitis (TBE) regarding its natural reserves, in Charles Hilary, northern Xinjiang and to isolate and characterize the viral geographic strain.

METHODSUsing indirect fluorescent assay to detect tick-borne encephalitis virus (TBEV) specific IgG antibodies from serum of local residents including 2 unconfirmed viral encephalitis patients in 2011 spring-summer. Viruses were isolated from tick samples by inoculating BALB/c mice and BHK-21 cells. For phylogenetic analysis. TBEV NS1 gene fragments were detected by RT-PCR and then subjected to sequence alignment.

RESULTS1760 ticks were captured from the fields to have found that Ixodes persulcatus were dominated among the tick population. Two viral encephalitis patients were diagnosed as TBEV infection. In addition, 35.4% (23/65) local residents were detected positive for presence of TBEV specific-IgG antibodies in serum. After inoculation, morbidity and mortality of BALB/c mice were 72.9% (70/96) and 55.7% (44/79), respectively. TBEV specific-fragments were amplified from brain tissue of dead mice and cells culture supernatant. NS1 sequence alignment showed that the viral isolates were clustered into TBEV far-eastern sub-type, phylogenetically, and were mostly close to the isolates from northeastern China (99%) and Russian strain (98%).

CONCLUSIONIn this study, a new endemic loci of TBE was firstly described in Charles Hilary natural reserve, northern Xinjiang. TBEV geographic isolates belonged to TBEV far-eastern subtype while Ixodes persulcatus and Dermacentor silvarum played crucial roles for disease transition.

Adult ; Animals ; China ; epidemiology ; Encephalitis Viruses, Tick-Borne ; genetics ; immunology ; isolation & purification ; Encephalitis, Tick-Borne ; epidemiology ; transmission ; virology ; Female ; Humans ; Male ; Mice ; RNA, Viral ; genetics

Until the recent emergence/re-emergence of human-pathogenic viruses in ticks, tick-borne viruses have been neglected as causative agents of human disease (particularly in China). To gain insight into the diversity of tick-borne viruses in Xinjiang Uygur Autonomous Region (northwestern China), we conducted illumina deep sequencing-based screening for virus-derived small RNAs in field-collected Ixodes persulcatus ticks. We found 32, 631 unique virus-matched reads. In particular, 77 reads mapped to the tick-borne group within the genus of Flavivirus, and covered 3.8%-2.4% viral genomes. In addition, 32 unique reads were specific to the Siberian subtype of tick-borne encephalitis viruses (TBEV-Sib) which have never been reported in Chinese TBE loci. We confirmed the potential existence of TBEV-Sib by amplification (using reverse transcription-polymerase chain reaction) of genomic fragments from the envelope gene or 3' genomic terminus from the pools of examined ticks. Both sequences demonstrated high homology to TBEV-Sib strains attached geographically to southern Siberia with nucleotide identity of 97.2%-95.5% and aminoacid identity of 99.4%-98.3%, respectively. In conclusion, we report, for the first time, detection of TBEV-Sib in the natural TBE loci of China. These novel data may provide genetic information for further isolation and epidemiologic investigation of TBEV-Sib.
Animals ; Arachnid Vectors ; virology ; China ; Encephalitis Viruses, Tick-Borne ; classification ; genetics ; isolation & purification ; Encephalitis, Tick-Borne ; transmission ; virology ; Genome, Viral ; Humans ; Ixodes ; virology ; Molecular Sequence Data ; Phylogeny

OBJECTIVE: Tick-borne encephalitis virus (TBEV) is an emerging pathogen in Europe and North Asia that causes tick-borne encephalitis (TBE). A simple, rapid method for detecting TBEV RNA is needed to control this disease. METHODS: A reverse-transcription recombinase-aided amplification (RT-RAA) assay was developed. This assay can be completed in one closed tube at 39 °C within 30 minutes. The sensitivity and specificity of RT-RAA were validated using non-infectious synthetic RNA representing a fragment of the NS5 region of the wild-type (WT) TBEV genome and the Senzhang strain. Additionally, 10 batches of tick samples were used to evaluate the performance of the RT-RAA assay. RESULTS: The analytical limit of detection of the assay was 20 copies per reaction of the TBEV synthetic transcript and 3 plaque-forming units (pfu) per reaction of TBEV titers. With the specific assay, no signal due to other arboviruses was observed. Of the 10 batches of tick samples obtained from the Changbai Mountains of China, three were TBEV-positive, which was consistent with the results of the quantitative real-time PCR assay. CONCLUSION A rapid, highly sensitive, specific, and easy-to-use method was developed for the detection of the TBEV Far-Eastern subtype.
Encephalitis Viruses, Tick-Borne ; genetics ; isolation & purification ; Nucleic Acid Amplification Techniques ; RNA, Viral ; analysis

Objective: To summarize the clinical characteristics, diagnosis and treatment of forest encephalitis, and provide basis for revising relevant diagnostic criteria. Methods: From January to December 2020, the clinical characteristics, diagnosis and treatment of forest encephalitis cases in the data of China National Knowledge Infrastructure (CNKI) and Wanfang Chinese journals from 2009 to 2020 were retrospectively analyzed. The measurement data are expressed in Mean±SD, numbers, and the counting data of gender, region and occupation are expressed in numbers and composition ratio. Descriptive analysis of relevant data is carried out. Results: There were 1 153 confirmed cases of forest encephalitis reported in domestic literature, including 910 males and 243 females. Age: 16-78 years old; Cases were mainly distributed in Jilin Province, Inner Mongolia Autonomous Region and Heilongjiang Province. The cases included forest rangers (112/518), freelancers (104/518) and loggers (88/518). The common symptoms and signs were fever 81.2% (936/1153), headache 70.3% (811/1153), meninges irritation 29.0% (334/1153), vomiting 25.3% (292/1153), nausea 21.8% (251/1153), etc. Only 48.1% (555/1153) of the patients obtained positive pathogenic test results from blood and/or cerebrospinal fluid specimens. 42.1% (485/1153) had definite diagnosis grade, 354 cases were mild, 58 cases were moderate, and 73 cases were severe. Among 730 patients with forest encephalitis who received complete treatment, 511 cases were cured, 148 cases were improved, 48 cases were not cured, and 23 cases died. Conclusion: The epidemic of forest encephalitis has strict regional, seasonal and occupational characteristics. Early diagnosis and treatment can reduce the mortality and disability rate.
Male ; Female ; Humans ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Retrospective Studies ; Encephalitis, Tick-Borne ; Encephalitis/epidemiology* ; Headache ; Fever