Metavirome of 31 tick species provides a compendium of 1,801 RNA virus genomes.

The increasing prevalence and expanding distribution of tick-borne viruses globally have raised health concerns, but the full repertoire of the tick virome has not been assessed. We sequenced the meta-transcriptomes of 31 different tick species in the Ixodidae and Argasidae families from across mainland China, and identified 724 RNA viruses with distinctive virome compositions among genera. A total of 1,801 assembled and complete or nearly complete viral genomes revealed an extensive diversity of genome architectures of tick-associated viruses, highlighting ticks as a reservoir of RNA viruses. We examined the phylogenies of different virus families to investigate virome evolution and found that the most diverse tick-associated viruses are positive-strand RNA virus families that demonstrate more ancient divergence than other arboviruses. Tick-specific viruses are often associated with only a few tick species, whereas virus clades that can infect vertebrates are found in a wider range of tick species. We hypothesize that tick viruses can exhibit both 'specialist' and 'generalist' evolutionary trends. We hope that our virome dataset will enable much-needed research on vertebrate-pathogenic tick-associated viruses.

First description of the mitogenome and phylogeny:Aedes vexansand Ochlerotatus caspius of the Tribe Aedini (Diptera: Culicidae).

Culicidae, the mosquito family, includes more than 3600 species subdivided into the subfamilies Anophelinae and Culicinae. One-third of mosquitoes belong to the Aedini tribe, which is subordinate to the subfamily Culicinae, which comprises common vectors of viral zoonoses. The tribe of Aedini is extremely diverse in morphology and geographical distribution and has high ecological and medical significance. However, knowledge about the systematics of the Aedini tribe is still limited owing to its large population and the similar morphological characteristics of its species. This study provides the first description of the complete mitochondrial (mt) genome sequence of Aedes vexans and Ochlerotatus caspius belonging to the Aedini tribe. The mt genomes of A. vexans and O. caspius are circular molecules that are 15,861 bp and 15,954 bp in size, with AT contents of 78.54% and 79.36%, respectively. Both the circular mt genomes comprise 37 functional subunits, including 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes (tRNAs), and a control region (also known as the AT-rich region). The most common start codons are ATT/ATG, apart from cox1 (TCG) and nad5 (GTG), while TAA is the termination codon for all PCGs. All tRNAs have a typical clover leaf structure, except tRNA Ser1. Phylogenetic analysis of the concatenated, aligned amino acid sequences of the 13 PCGs showed that A. vexans gathered with Aedes sp. in a sister taxon, and O. caspius gathered with Ochlerotatus sp. in a sister taxon. The findings from the present study support the concept of monophyly of all groups, ratify the current taxonomic classification, and provide vital molecular marker resources for further studies of the taxonomy, population genetics, and systematics of the Aedini tribe.

Multiple biochemical indices and metabolomics of Clonorchis sinensis provide a novel interpretation of biomarkers.

BACKGROUND: Clonorchiasis, an infectious disease caused by the liver fluke Clonorchis sinensis, may lead to the development of liver and gallbladder diseases, and even cholangiocarcinoma (CCA). However, the pathogenesis, host-pathogen interaction, and diagnostic markers for clonorchiasis remain unclear. METHODS: Eighteen rabbits were randomly divided into control group (n = 9) and C. sinensis-infected group (n = 9), and their plasma samples were collected at 7, 14, 28, and 63 days post-infection (dpi). Biochemical indices and metabolites in different infection periods were detected. A non-targeted ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach was employed to investigate the metabolic profiles of plasma in rabbits, and related metabolic pathways of differential metabolites and correlation between candidate biochemical indices and differential metabolites were analyzed. Finally, the candidate biomarkers were verified with human samples using a targeted metabolomics method. RESULTS: The result of biochemical indices indicated C. sinensis infection would affect the liver function biochemical indices, especially alanine aminotransferase, aspartate transaminase (AST), glutamyl transpeptidase (GGT), total bile acid, high-density lipoprotein, and cholinesterase. The metabonomic results showed that 58, 212, 23, and 21 differential metabolites were identified in different phases of the infection. Multivariate statistical analysis of differential metabolites revealed distinct metabolic signatures during different phases of infection, with most of these signatures being observed at 14 dpi, which mainly influences the amino acid metabolisms. For metabolites and biochemical indices, AST, GGT, hypoxanthine, L-pipecolic acid, and D-glucuronate represented potential noninvasive biomarkers for the diagnosis of C. sinensis (P < 0.05 and AUC > 0.8). Furthermore, GGT and D-glucuronate levels were positively correlated with the infection (r(28) = 0.98, P < 0.0001) and showed excellent diagnostic performance (AUC = 0.972; 95% confidence interval, 0.921 to 1.000). CONCLUSIONS: The present results provide new insights into plasma metabolic changes in rabbits during C. sinensis infection, and the potential biomarker may be used for developing an effective method to diagnose clonorchiasis in the future.

The complete mitochondrial genome of Prosthogonimus cuneatus and Prosthogonimus pellucidus (Trematoda: Prosthogonimidae), their features and phylogenetic relationships in the superfamily Microphalloidea.

Prosthogonimus cuneatus and Prosthogonimus pellucidus (Trematoda: Prosthogonimidae) are common flukes of poultry and other birds which can cause severe impacts on animal health and losses to the poultry industry. However, there are limited studies on the molecular epidemiology, population genetics, and systematics of Prosthogonimus species. In the present study, the complete mitochondrial (mt) genomes of P. cuneatus and P. pellucidus were determined to be 14,829 bp and 15,013 bp in length, respectively. Both mt genomes contain 12 protein-coding genes (PCGs) (cox1-3, nad1-6, nad4L, cytb, and atp6), 22 transfer RNA genes, two ribosomal RNA genes, and one non-coding region. Our comparative analysis shows that the atp6 genes of P. cuneatus and P. pellucidus are longer than any previously published atp6 genes of other trematodes. The lengths of the atp6 genes of P. cuneatus and P. pellucidus in this study seem unusual, and should therefore be studied further. The mt genes of P. cuneatus and P. pellucidus are transcribed in the same direction, and the gene arrangements are identical to those of Plagiorchis maculosus, Tamerlania zarudnyi, and Tanaisia sp., but different from those of Eurytrema pancreaticum, Dicrocoelium chinensis, and Brachycladium goliath. The mt genome A + T contents of P. cuneatus and P. pellucidus are 64.47% and 65.34%, respectively. In the 12 PCGs, ATG is the most common initiation codon, whereas TAG is the most common termination codon. The sequence identity of the same 12 PCGs among the eight trematodes (P. cuneatus, P. pellucidus, Pl. maculosus, D. chinensis, E. pancreaticum, B. goliath, T. zarudnyi, Tanaisia sp.) of Xiphidiata are 55.5%-81.7% at the nucleotide level and 43.9%-82.5% at the amino acid level. The nucleotide similarities among the complete mt genomes of the eight trematodes range from 54.1%-81.5%. Phylogenetic analysis based on the aligned concatenated amino acid sequences of the 12 PCGs shows that P. cuneatus and P. pellucidus cluster together and are sister to T. zarudnyi and Tanaisia sp., and this clade is more closely related to E. pancreaticum, Dicrocoelium spp. and Lyperosomum longicauda in the family Dicrocoeliidae, than it is to species in the families Plagiorchiidae and Brachycladiidae. These are the first reported complete mt genomes of Prosthogonimidae, and these data will provide additional molecular resources for further studies of Prosthogonimidae taxonomy, population genetics, and systematics.

Complete mitochondrial genome of Dermanyssus gallinae (Arthropoda: Dermanyssidae) isolate from China.

The complete mitochondrial genome of Dermanyssus gallinae isolated from China is reported for the first time in this study. Its entire mitogenome is 16, 184 bp in length, contained 13 protein-coding genes, 2 ribosomal RNA genes, 21 transfer RNA genes, and 1 non-coding region. The phylogenetic analysis by maximum likelihood method show that D. gallinae isolated from China is in the same clade with the genus of Psoroptes. This is the first complete mitochondrial genome of D. gallinae.

Integrative Transcriptomics and Proteomics Analyses to Reveal the Developmental Regulation of Metorchis orientalis: A Neglected Trematode With Potential Carcinogenic Implications.

Metorchis orientalis is a neglected zoonotic parasite of the gallbladder and bile duct of poultry, mammals, and humans. It has been widely reported in Asian, including China, Japanese, and Korea, where it is a potential threat to public health. Despite its significance as an animal and human pathogen, there are few published transcriptomic and proteomics data available. Transcriptome Illumina RNA sequencing and label-free protein quantification were performed to compare the gene and protein expression of adult and metacercariae-stage M. orientalis, resulting in 100,234 unigenes and 3,530 proteins. Of these, 13,823 differentially expressed genes and 1,445 differentially expressed proteins were identified in adult versus metacercariae. In total, 570 genes were differentially expressed consistent with the mRNA and protein level in the adult versus metacercariae stage. Differential gene transcription analyses revealed 34,228 genes to be expressed in both stages, whereas 66,006 genes showed stage-specific expression. Compared with adults, the metacercariae stage was highly transcriptional. GO and KEGG analyses based on transcriptome and proteome revealed numerous up-regulated genes in adult M. orientalis related to microtubule-based processes, microtubule motor activity, and nucleocytoplasmic transport. The up-regulated genes in metacercariae M. orientalis were mainly related to transmembrane receptor protein serine/threonine kinase activity, transmembrane receptor protein serine/threonine kinase signaling pathway. Transcriptome and proteome comparative analyses showed numerous up-regulated genes in adult stage were mainly enriched in actin filament capping, spectrin, and glucose metabolic process, while up-regulated genes in metacercariae stage were mainly related to cilium assembly, cilium movement, and motile cilium. These results highlight changes in protein and gene functions during the development of metacercariae into adults, and provided evidence for the mechanisms involved in morphological and metabolic changes at both the protein and gene levels. Interestingly, many genes had been proved associated with liver fibrosis and carcinogenic factors were identified highly expressed in adult M. orientalis, which suggests that M. orientalis is a neglected trematode with potential carcinogenic implications. These data provide attractive targets for the development of therapeutic or diagnostic interventions for controlling M. orientalis.

Identification of Myoferlin, a Potential Serodiagnostic Antigen of Clonorchiasis, via Immunoproteomic Analysis of Sera From Different Infection Periods and Excretory-Secretory Products of Clonorchis sinensis.

Clonorchiasis, which is caused by Clonorchis sinensis, is an important foodborne disease worldwide. The excretory-secretory products (ESPs) of C. sinensis play important roles in host-parasite interactions by acting as causative agents. In the present study, the ESPs and sera positive for C. sinensis were collected to identify proteins specific to the sera of C. sinensis (i.e., proteins that do not cross-react with Fasciola hepatica and Schistosoma japonicum) at different infection periods. Briefly, white Japanese rabbits were artificially infected with C. sinensis, and their sera were collected at 7 days post-infection (dpi), 14 dpi, 35 dpi, and 77 dpi. To identify the specific proteins in C. sinensis, a co-immunoprecipitation (Co-IP) assay was conducted using shotgun liquid chromatography tandem-mass spectrometry (LC-MS/MS) to pull down the sera roots of C. sinensis, F. hepatica, and S. japonicum. For the annotated proteins, 32, 18, 39, and 35 proteins specific to C. sinensis were pulled down by the infected sera at 7, 14, 35, and 77 dpi, respectively. Three proteins, Dynein light chain-1, Dynein light chain-2 and Myoferlin were detected in all infection periods. Of these proteins, myoferlin is known to be overexpressed in several human cancers and could be a promising biomarker and therapeutic target for cancer cases. Accordingly, this protein was selected for further studies. To achieve a better expression, myoferlin was truncated into two parts, Myof1 and Myof2 (1,500 bp and 810 bp), based on the antigenic epitopes provided by bioinformatics. The estimated molecular weight of the recombinant proteins was 57.3 ku (Myof1) and 31.3 ku (Myof2). Further, both Myof1 and Myof2 could be probed by the sera from rabbits infected with C. sinensis. No cross-reaction occurred with the positive sera of S. japonica, F. hepatica, and negative controls. Such findings indicate that myoferlin may be an important diagnostic antigen present in the ESPs. Overall, the present study provides new insights into proteomic changes between ESPs and hosts in different infection periods by LC-MS/MS. Moreover, myoferlin, as a biomarker, may be used to develop an objective method for future diagnosis of clonorchiasis.

Proteomic Analysis of Fasciola hepatica Excretory and Secretory Products Co-Immunoprecipitated Using Time Course Infection Sera.

Fasciola hepatica is a widespread pathogen that is known for its harmful effects on the health and productivity of ruminant animals. To identify the proteins present in all periods of infection with F. hepatica but not in those with Fasciola gigantica by shotgun liquid chromatography-tandem mass spectrometry (LC-MS/MS), we collected the ESPs and sera of F. hepatica and F. gigantica. In this study, the sheep were artificially infected with F. hepatica and the sera were collected at five different periods: 3 days post-infection (dpi), 7 dpi, 21 dpi, 63 dpi, and 112 dpi. The interacting proteins were pulled down from the sheep sera of all five periods and the sera with F. gigantica by co-immunoprecipitation (Co-IP) assay, before being identified by LC-MS/MS analysis. Thirty, twenty-two, twenty-three, twenty-seven, and twenty-two proteins were pulled down by the infected sera at 3 dpi, 7 dpi, 21 dpi, 63 dpi, and 112 dpi, respectively. Among them, 12 proteins existed in all periods, while six proteins could be detected in all periods in F. hepatica but not in F. gigantica. Protein relative pathway analysis revealed that these proteins mainly refer to the metabolism, regulation of genetic activity, and signal transduction of F. hepatica. In conclusion, this study provides meaningful data for the diagnosis of fasciolosis and to understand the interactions between F. hepatica and the host.

Distribution of Dermacentor silvarum and Associated Pathogens: Meta-Analysis of Global Published Data and a Field Survey in China.

Dermacentor silvarum is an obligate blood sucking arthropod and transmits various pathogens to humans and domestic animals. Recently several new viruses were detected in D. silvarum as an emerging disease threat. In this study, we aimed to analyze its geographical distribution and associated pathogens. Data were collected from multiple sources, including a field survey, reference book, and literature review. We searched various electronic databases with the terms "Dermacentor silvarum" OR "D. silvarum" for studies published since 1963 and the positive rates for Dermacentor silvarum-associated pathogens were estimated by meta-analysis. D. silvarum was found only in four countries in Eurasia, ranging from 22° N to 57° N latitude. At least 20 human pathogens were associated with D. silvarum, including five species of spotted fever group rickettsiae, three species in the family of Anaplasmataceae, three genospecies in the complex Borrelia burgdorferi sensu lato, Francisella tularensis, Babesia venatorum, Coxiella buenetii, Borrelia miyamotoi, and five species of virus. Among them, Rickettsia raoultii was widely detected in D. silvarum, showing the highest pooled positive rate (25.15%; 95% CI 13.31-39.27). Our work presents the most comprehensive data and analysis (to our knowledge) for the geographical distribution of D. silvarum and associated pathogens, revealing an emerging threat to public health and stocking farming. Continued surveillance and further investigations should be enhanced.

The Role of Ranged Horses in Eco-Epidemiology of Rickettsia raoultii Infection in China.

Rickettsia raoultii is a tick-borne pathogen that infects humans; however, the vertebrate hosts of this pathogen have not been clearly defined. Our molecular examination of Rickettsia spp. infecting mammals and ticks in China, identified the gltA, ompA, and 17KD gene sequences of R. raoultii in horses and their ticks. This indicates a role of horses in R. raoultii epidemiology.

Prevalence of Multiple Tick-Borne Pathogens in Various Tick Vectors in Northeastern China.

Background: Tick-borne bacteria and protozoa can cause a variety of human and animal diseases in China. It is of great importance to monitor the prevalence and dynamic variation of these pathogens in ticks in ever-changing natural and social environment. Materials and Methods: Ticks were collected from Heilongjiang and Jilin provinces of northeastern China during 2018-2019 followed by morphological identification. The presence of Rickettsia spp., Anaplasma spp., Ehrlichia spp., Borrelia spp., Babesia spp., and Theileria spp. was examined by PCR and Sanger sequencing. The obtained sequences were subjected to phylogenetic analysis through Mega 7.0. Statistical analysis was performed using SPSS 24.0. Results: A total of 250 ticks from 5 species of 3 genera were collected. Ixodes and Haemaphysalis ticks carried more species of pathogens than Dermacentor, and the pathogens detected in Haemaphysalis japonica varied significantly among different sampling sites. The infection rates of Rickettsia spp., Anaplasma spp., Ehrlichia spp., Borrelia spp., Babesia spp., and Theileria spp. were 41.2%, 0, 2.0%, 7.2%, 1.2%, and 7.2%, respectively. Twelve pathogens were identified, among which Rickettsia raoultii (29.6%), Candidatus Rickettsia tarasevichiae (9.2%), and Theileria equi (4.4%) were the three most common ones. Rickettsia had its dominant vector, that is, R. raoultii had high infection rates in Dermacentor nuttalli and Dermacentor silvarum, Ca. R. tarasevichiae in Ixodes persulcatus, and Rickettsia heilongjiangensis in H. japonica. Interestingly, unclassified species were observed, including a Rickettsia sp., an Ehrlichia sp., a Borrelia sp., and a Babesia sp. Coinfections with different pathogens were identified in 9.2% of all tested ticks, with I. persulcatus most likely to be coinfected (23.8%) and Rickettsia spp. and Borrelia spp. as the most common combination (16.7%). Conclusions: The results of this study reflect high diversity and complexity of pathogens in ticks, which are useful for designing more targeted and effective control measures for tick-borne diseases in China.

Prevalence of Clonorchis sinensis infection in fish in South-East Asia: A systematic review and meta-analysis.

Clonorchis sinensis, an important fish-borne zoonotic trematode, is widely distributed in South-East Asia, especially in China. Infections from human and animal reservoir hosts occur due to the consumption of raw or undercooked fish with C. sinensis metacercariae. This study aimed to evaluate the prevalence of C. sinensis metacercariae in fish in South-East Asia via systematic review and meta-analysis. We searched PubMed, ScienceDirect, China National Knowledge Infrastructure, Wanfang and Chongqing VIP databases for studies published between 1976 and 2020 that are related to the prevalence of C. sinensis metacercariae in fish. Studies were screened with keywords based on inclusion and exclusion criteria. Seventy-one eligible articles were identified, covering three countries: China, Korea and Vietnam. The pooled prevalence of C. sinensis metacercariae in fish from South-East Asia was 30.5%, with 35.1% in China, 29.7% in Korea and 8.4% in Vietnam. In subgroup analyses of climate, season, water source and publication date, the highest prevalence was identified in the Dwb climate type (43.3%), summer (70.2%), river (34.5%) and pre-2001 publications (38.9%), respectively. In comparison, the lowest prevalence was found in the Dfa climate type (14.5%), winter (19.5%), lake (8.0%) and post-2001 publications (23.8%). Meta-regression results indicated that country (p = .009), the published time (p = .035) and water source subgroups (p = .003) may be the source of heterogeneity. Overall, our study indicates that a high prevalence of C. sinensis infections occurs in fish in China, Korea and Vietnam, illuminating a significant public health concern in these countries.

Large-Scale Comparative Analyses of Tick Genomes Elucidate Their Genetic Diversity and Vector Capacities.

Among arthropod vectors, ticks transmit the most diverse human and animal pathogens, leading to an increasing number of new challenges worldwide. Here we sequenced and assembled high-quality genomes of six ixodid tick species and further resequenced 678 tick specimens to understand three key aspects of ticks: genetic diversity, population structure, and pathogen distribution. We explored the genetic basis common to ticks, including heme and hemoglobin digestion, iron metabolism, and reactive oxygen species, and unveiled for the first time that genetic structure and pathogen composition in different tick species are mainly shaped by ecological and geographic factors. We further identified species-specific determinants associated with different host ranges, life cycles, and distributions. The findings of this study are an invaluable resource for research and control of ticks and tick-borne diseases.

Comparative analyses of complete ribosomal DNA sequences of Clonorchis sinensis and Metorchis orientalis: IGS sequences may provide a novel genetic marker for intraspecific variation.

Both Clonorchis sinensis and Metorchis orientalis are the fish-borne zoonotic trematodes, and have a wide distribution of southeastern Asia, especially in China. Due to the similar morphology, life cycle, and parasitic positions are difficult to differentiate between both metacercariae. In the present study, the complete rDNA sequences of five C. sinensis and five M. orientalis were obtained and compared for the first time. And the IGS rDNA sequences were tested as a genetic marker. The results showed complete rDNA lengths of C. sinensis were range from 8049 bp to 8391 bp, including 1991 bp, 1116 bp, 3854 bp, and 1088-1430 bp belonging to 18S, ITS, 28S and IGS, respectively. And the complete rDNA lengths of M. orientalis were range from 7881 bp to 9355 bp, including 1991 bp, 1077 bp, 3856 bp, and 957-2431 bp belonging to 18S, ITS, 28S and IGS, respectively. Comparative analyses reveal length difference main in IGS, which has higher intraspecific and interspecific variations than other ribosomal regions. Forty four repeat (forward and inverted) sequences were found in the complete rDNAs of C. sinensis and M. orientalis. The phylogenetic analyses showed that the sequences of ITS1, ITS2, 18S and 28S could be used as different level genetic markers. In IGS phylogenetic tree, Opisthorchiidae, Paramphistomidae, Dicrocoeliidae, and Schistosomatidae formed monophyletic groups, and the same length sequences were clustered together in the same species. These findings of the present study provide the new molecular data for studying the complete rDNA of C. sinensis and M. orientalis, and indicate IGS sequences may used as a novel genetic marker for studying intraspecific variation in trematodes.

The complete mitochondrial genome of Echinostoma miyagawai: Comparisons with closely related species and phylogenetic implications.

Echinostoma miyagawai (Trematoda: Echinostomatidae) is a common parasite of poultry that also infects humans. Es. miyagawai belongs to the "37 collar-spined" or "revolutum" group, which is very difficult to identify and classify based only on morphological characters. Molecular techniques can resolve this problem. The present study, for the first time, determined, and presented the complete Es. miyagawai mitochondrial genome. A comparative analysis of closely related species, and a reconstruction of Echinostomatidae phylogeny among the trematodes, is also presented. The Es. miyagawai mitochondrial genome is 14,416 bp in size, and contains 12 protein-coding genes (cox1-3, nad1-6, nad4L, cytb, and atp6), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and one non-coding region (NCR). All Es. miyagawai genes are transcribed in the same direction, and gene arrangement in Es. miyagawai is identical to six other Echinostomatidae and Echinochasmidae species. The complete Es. miyagawai mitochondrial genome A + T content is 65.3%, and full-length, pair-wise nucleotide sequence identity between the six species within the two families range from 64.2-84.6%. The Es. miyagawai sequences is most similar to Echinostoma caproni. Sequence difference are 15.0-33.5% at the nucleotide level, and 8.6-44.2% at the amino acid level, among the six species, for the 12 protein-coding genes. ATG and TAG are the most common initiation and termination codons, respectively. Twenty of the Es. miyagawai transfer RNA genes transcribe products of the conventional cloverleaf structure, while two of the transfer RNA genes, namely trnS1(AGC) and trnS2(UGA), have unpaired D-arms. Phylogenetic analyses using our mitochondrial data indicate that Es. miyagawai is closely related to other Echinostomatidae species, except for Echinostoma hortense, which forms a distinct paraphyletic branch, and Echinochasmus japonicus, which is outside the clade containing all other Echinostomatidae species. These phylogenetic results support the elevation of subfamily Echinostomatidae. Our dataset also provides a significant resource of molecular markers to study the taxonomy, population genetics, and systematics of the echinostomatids.

The complete mitochondrial genome of Amblyomma geoemydae (Ixodida: Ixodidae).

The complete mitochondrial genome of Amblyomma geoemydae is reported for the first time in this study. Its entire mitogenome is 14,780 bp in length, contained 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and two non-coding regions. The phylogenetic analysis by Maximum-likelihood method show that A. geoemydae and the others of genus Amblyomma are in the same clade, indicating that A. geoemydae belongs to the genus Amblyomma.

Human Babesiosis Caused by a Babesia crassa-Like Pathogen: A Case Series.

Background: Human babesiosis is an emerging health problem in China. Methods: Babesia were identified in ticks, sheep, and humans in northeastern China using polymerase chain reaction (PCR) followed by genetic sequencing. We enrolled residents who experienced a viral-like illness after recent tick bite or were healthy residents. We defined a case using the definition for babesiosis developed by the US Centers for Disease Control and Prevention. Results: A Babesia crassa-like agent was identified in Ixodes persulcatus and Haemaphysalis concinna ticks using PCR followed by sequencing. The agent was characterized through phylogenetic analyses of the 18S rRNA gene, the ß-tubulin gene, and the internal transcribed spacer region. We tested sheep as a possible reservoir and found that 1.1% were infected with the B. crassa-like agent. We screened 1125 human participants following tick bites using B. crassa-specific PCR and identified 31 confirmed and 27 suspected cases. All the patients were previously healthy except for 1 with an ovarian tumor. Headache (74%), nausea or vomiting (52%), and fever (48%) were the most common clinical manifestations of confirmed cases. Six of 10 cases remained PCR positive for B. crassa-like infection 9 months after initial diagnosis. Asymptomatic infections were detected in 7.5% of 160 local residents. Conclusions: We identified B. crassa-like infection in people in northeastern China that caused mild to moderate symptoms. The possibility of more severe disease in immunocompromised patients and of transmission through the blood supply due to asymptomatic infections justifies further investigation of this reported infection.

De novo assembly and functional annotations of the transcriptome of Metorchis orientalis (trematoda: Opisthorchiidae).

Metorchis orientalis is a neglected zoonotic parasite, living in the gallbladder and bile duct of poultry and some mammals as well as humans. In spite of its economic and medical importance, the information known about the transcriptome and genome of M. orientalis is limited. In this study, we performed de novo sequencing, transcriptome assembly and functional annotations of the adult M. orientalis, obtained about 77.4 million high-quality clean reads, among which the length of the transcript contigs ranged from 100 to 11,249 nt with mean length of 373 nt and N50 length of 919 nt. We then assembled 31,943 unigenes, of which 20,009 (62.6%) were annotated by BLASTn and BLASTx searches against the available database. Among these unigenes, 19,795 (62.0%), 3407 (10.7%), 10,620 (33.2%) of them had significant similarity in the NR, NT and Swiss-Prot databases, respectively; 5744 (18.0%) and 4678 (14.6%) unigenes were assigned to GO and COG, respectively; and 9099 (28.5%) unigenes were identified and mapped onto 256 pathways in the KEGG Pathway database. Furthermore, we found that 98 (1.08%) unigenes were related to bile secretion and 5 (0.05%) to primary bile acid biosynthesis pathways category. The characterization of these transcriptomic data has implications for the better understanding of the biology of M. orientalis, and will facilitate the development of intervention agents for this and other pathogenic flukes of human and animal health significance.

The complete mitochondrial genome of Haemaphysalis concinna (Ixodida: Ixodidae).

The complete mitochondrial genome of Haemaphysalis concinna is reported for the first time in this study. Its entire mitogenome is 14,675 bp in length, contained 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and two non-coding regions. Among the 13 protein-coding genes, apart from the nad1, nad4, nad4L, and nad5 gene encoded on the L-strand, the remaining protein-coding genes were encoded on the H-strand. The phylogenetic analysis by Bayesian inference method shows that Amblyomma sphenodonti and H. parva formed one clade, while H. concinna and other species of genus Haemaphysalis formed the other clade, indicating that H. concinna belong to the genus Haemaphysalis.