Molecular evolution of emerging Banna virus.

Banna virus (BAV) is an emerging pathogen that causes human viral encephalitis and has been isolated from types of blood-sucking insects and mammals in Asia. However, there are no reported systematic studies that describe the origin and evolution of BAV. Here, a phylogenetic analysis of BAVs isolated from a variety of potential vectors and vertebrate hosts worldwide revealed that BAVs emerged in the beginning of the 20th century and do not exhibit a species barrier. The mean substitution rate of BAVs was 2.467×10-2substitution/site/year (95% HPD, 1.093×10-3 to 5.628×10-2). The lineage is mainly composed of BAVs from high-latitude regions, which are the most recently emerged viruses with significantly higher substitution rates compared with the lineage comprised of the isolates from middle or low-latitude regions. The genetic differences between BAV strains are positively correlated with the geographic distribution. Strains from the same latitude regions are almost 100% identical, whereas the differences between strains from long distance regions with different latitudes could be >60%. Our results demonstrate that BAV is an emerging virus at a stage that involves rapid evolution and has great potential for introduction into non-endemic areas. Thus, enhanced surveillance of BAV is highly recommended worldwide.

Step-by-step vascular control for extracapsular resection of complex giant liver hemangioma involving the inferior vena cava.

Massive hemorrhage remains an important clinical problem in extracapsular resection of giant liver hemangiomas (GLHs), especially for those involving the proximal hepatic veins and/or inferior vena cava. Between July 2004 and March 2012, 87 patients with a complex GLH scheduled for surgical treatment were included in this study. All patients were underwent vascular preparation (Step 1), advanced hepatic artery clamping (Step 2), and stepwise vascular occlusion (Step 3). Intraoperative blood loss, blood transfusion volume, degree of ischemia-reperfusion injury, and postoperative complications were recorded. No patients required urgent vascular preparation to manage intraoperative bleeding. In total, 87, 64, and 21 patients had portal triad (PT), infrahepatic inferior vena cava (IVC), and suprahepatic IVC preparation; and 17, 43, and 11 patients had PT, PT and suprahepatic IVC, and all three (PT, infra-, and suprahepatic IVC) occlusions. The PT, infrahepatic IVC, and SIVC occlusion times were 12.1 ± 3.7 minutes, 7.9 ± 2.4 minutes, and 3.2 ± 1.4 minutes, respectively. Mean blood loss was 291.9 ± 124.5 mL, and only four patients received blood transfusions. No patients had life-threatening complications or died (Clavien-Dindo Grade 4, 5). Compared with paralleled studies, this technique has an advantage to decrease the blood loss in less liver ischemia time. For complex GLH resections, the described step-by-step vascular control technique was efficacious and feasible for controlling intraoperative bleeding.

Emergence of genotype I of Japanese encephalitis virus as the dominant genotype in Asia.

Japanese encephalitis virus (JEV), a mosquito-borne zoonotic pathogen, is one of the major causes of viral encephalitis worldwide. Previous phylogenetic studies based on the envelope protein indicated that there are four genotypes, and surveillance data suggest that genotype I is gradually replacing genotype III as the dominant strain. Here we report an evolutionary analysis based on 98 full-length genome sequences of JEV, including 67 new samples isolated from humans, pigs, mosquitoes, midges. and bats in affected areas. To investigate the relationships between the genotypes and the significance of genotype I in recent epidemics, we estimated evolutionary rates, ages of common ancestors, and population demographics. Our results indicate that the genotypes diverged in the order IV, III, II, and I and that the genetic diversity of genotype III has decreased rapidly while that of genotype I has increased gradually, consistent with its emergence as the dominant genotype.

Banna virus, China, 1987-2007.

Banna viruses (BAVs) have been isolated from pigs, cattle, ticks, mosquitoes, and human encephalitis patients. We isolated and analyzed 20 BAVs newly isolated in China; this finding extends the distribution of BAVs from tropical zone to north temperate climates and demonstrate regional variations in BAV phylogeny and mosquito species possibly involved in BAV transmission.

[Analysis on the molecular characteristics of Japanese encephalitis virus isolated in northwestern Yunnan province].

OBJECTIVE: To analyze the molecular characteristics of Japanese encephalitis virus (JEV) isolated in Northwestern Yunnan province, and to clarify the differences between the strains isolated in Northwestern and other parts of Yunnan province. METHODS: PrM, E and 3' untranslated region nucleotide acid sequences of the isolates were amplified by RT-PCR and then sequenced. Sequence alignment and phylogenetic analysis were performed by using Clustal 1.8X, DNASTAR, GENEDOC and Mega 3.1 programs. RESULTS: 12 of the 13 isolates of JEV obtained in Northwestern Yunnan were identified as genotype I, only one strain was genotype III of JEV. The 12 strains of genotype I were clustered in different branches with other isolates obtained in other parts of Yunnan province. Data from sequence analysis on E gene found that the nucleotide identity was 0.2%-13.9% between the Northwestern isolates and other Yunnan strains. There were two kinds of nucleotides deletion patterns at 3' untranslated region with three and one deletions was found after termination codon in genotype I and III isolates, respectively. CONCLUSION: There were two genotypes of I and III in 13 strains of JEV in this study and genotype I isolates were predominant (12/13). There were no apparent differences in E gene sequence between isolates obtained in the Northwestern and other parts of Yunnan. Three deletions were found in 3' untranslated region in genotypes I isolates and one deletion was in genotypes III.

[Arbovirus investigation in some regions of Shanxi province in 2007].

OBJECTIVE: To investigate arboviruses in some regions of Shanxi province, isolation and identification for arbovirus activity from mosquitoes was conducted. METHODS: Mosquitoes were collected from these area in 2007 and then used for virus isolation by cell culture. The virus isolates were identified by molecular biology and the sequences were analyzed by bioinformatics. RESULTS: Ten Banna virus (strains SX0765, SX0766, SX0767, SX0771, SX0789, SX0790, SX0793, SX0794, SX0795, SX0796) were isolated, and two Liaoning virus were also isolated from isolates SX0771, SX0794. Phylogenetic tree of the Banna virus isolates showed that ten strains are located in a distinct branch from all of the other Chinese Banna virus isolates. The homology is between 89.7% and 94.1%. CONCLUSION: Ten Banna virus and two Liaoning virus were isolated during this arbovirus investigation in Shanxi province. New Banna virus isolates showed a distinct phylogenetic relationship with the other Chinese Banna virus strains.

[Isolation and identification of arboviruses from mosquito pools in some regions of Liaoning province, China].

OBJECTIVE: To isolate and identify arboviruses from mosquito pools in some regions of Liaoning province. METHODS: Mosquitoes were collected from Shenyang, Yingkou, Panjin, Jinzhou and Dandong cities of Liaoning province in 2006. Viruses were isolated by inoculating the specimens onto C6/ 36 and BHK-21cells. The new isolates were identified using serological and molecular biological methods. RESULTS: 5410 mosquitoes were collected from the five cities in total. Three isolates produced CPE in C6/ 36 cell and five isolates produced CPE in both C6/36 and BHK-21 cell. Three isolates (LN0684, LN0688 and LN0689) were identified as Banna virus and one isolate (LN0636) was identified as Getah virus. Phylogenetic analysis showed that the three Banna virus strains were clustered into the same evolution branch as the other Chinese isolates. The identity of nucleotide sequence was between 91.2% and 94.7%, compared with other Banna virus strains. The new isolated Getah virus was clustered into the same branch with the strain of South Korea (swine). The identity of nucleotide sequence was 99.2%, when comparing with the strain of South Korea and was 95% to 99% with the strains from Russia, mainland of China and Taiwan region. Conclusion Eight virus isolates, including three Banna virus, one Getah virus and four unknown virus strains were isolated from mosquitoes in Liaoning province. Banna virus and Getah virus were reported for the first time in Liaoning province, while Getah virus showed the highest nucleotide homology with the South Korea strains.

[The first report of Kadipiro virus isolation in China].

5 strains of virus isolated from Culex tritaeniorhynchus, Anopheles sinensis and Armigeres subalbatus, which caused cytopathic effect in C6/36 cells, had been obtained in the survey of arboviruses in Northwestern Yunnan Province. China. The virus particles displayed 70 nanometers diameter (n=7) with no envelope but spikes on the surfaces. RNA-PAGE of the genomes of the isolates showed 6-5-1 profile. A fragment of the 12th segment sequence was amplified by a pair of specific primers for Kadipiro virus strain JKT-7075 in RT-PCR. The full length of the 12th segment was 758 nucleotides, BLAST analysis revealed the highest identity was 90% to JKT-7075. Phylogenetic analysis demonstrated that the isolates appeared to be Kadipiro viruses (Family Reoviridae). It was the first report of kadipiro virus isolation in China.

[Genotype 1 JEV was isolated again from Liaoning Province, China, 2007].

OBJECTIVE: To isolate Japanese encephalitis virus (JEV) from mosquitoes collected in Liaoning province and analysis the genotype of new isolated JEV strains and the characters of nucleotide and amino acid in the E gene. METHODS: Collected mosquitoes in Dandong Liaoning Province in August, 2006. Virus isolation was using issue culture cells. Isolated viruses were identified by using serological and molecular methods. RESULTS: Two new JEV strains, LNDG07-02 and LNDG07-16, were isolated from 1500 mosquitoes were belonging to genotype 1. The identity of nucleotide and amino acid of E gene between new JEV strains and live attenuated vaccine strain SA14-14-2 were 87.8-88% and 97.2%, respectively. Total 11 amino acid sites were differences in E gene between new isolates and SA14-14-2. However, there were no differentiation between the new JEV strains and the isolates in Donggang 2002. CONCLUSION: Genotype 1 JEV was isolated again from Donggang, since the first isolation of this genotype in 2002. Genotype 1 JEV continues in existence in Donggang Liaoning Province.