Systematic investigation of the Borrelia miyamotoi spirochetes in ticks, wildlife and domestic animal hosts in Yunnan province, Southwest China.

Background: Borrelia miyamotoi is a spirochete species transmitted via hard ticks. Following its discovery in Japan, this pathogen has been detected around the world, and is increasingly confirmed as a human pathogen causing febrile disease, namely relapsing fever. Its presence has been confirmed in the Northeast China. However, there is little information regarding the presence of B. miyamotoi and other hard-tick-borne relapsing fever spirochetes in southern China including Yunnan province, where tick and animal species are abundant and many people both inhabit and visit for recreation. Methods: For the present study, we collected samples of ticks, wildlife, and domestic animal hosts from different counties in Yunnan province. Nucleic acids from samples were extracted, and the presence of B. miyamotoi and other relapsing fever spirochetes was confirmed using polymerase chain reaction (PCR) for the 16S rRNA specific target gene fragment. The positive samples were then amplified for partial genome of the flaB and glpQ genes. Statistical differences in its distribution were analyzed by SPSS 20 software. Sequence of partial 16S rRNA, flaB and glpQ genome were analyzed and phylogenetic trees were constructed. Results: A total of 8260 samples including 2304 ticks, 4120 small mammals and 1836 blood of domestic animal hosts were collected for screening for infection of B. miyamotoi and other relapsing fever spirochetes. Cattle and sheep act as the main hosts and Rhipicephalus microplus, Haemaphysalis nepalensis, H. kolonini and Ixodes ovatus were identified as the important vector host with high prevalence or wide distribution. Only one Mus caroli (mouse) and one Sorex alpinus (shrew) were confirmed positive for relapsing fever spirochetes. Evidence of vertical transmission in ticks was also confirmed. Two known strains of B. miyamotoi and one novel relapsing fever spirochetes, B. theileri-like agent, were confirmed and described with their host adaptation, mutation, and potential risk of spreading and spillover for human beings. Conclusions: Our results provide new evidence of relapsing fever spirochetes in vector and animal hosts in Yunnan province based on large sample sizes, and offer guidance on further investigation, surveillance and monitoring of this pathogen.

The complete mitochondrial genome of Rhipicephalus haemaphysaloides and its phylogenetic analysis.

We conducted an analysis of the complete mitochondrial genome of Rhipicephalus haemaphysaloides, a tick species known for transmitting various bacteria and viruses. The mitochondrial genome of R. haemaphysaloides has a length of 14,739 bp and consists of 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and 2 control regions. By utilizing the maximum likelihood method, we established the phylogenetic relationship among R. haemaphysaloides and other species within the Rhipicephalus genus of the Ixodidae family. This analysis revealed that R. haemaphysaloides and other Rhipicephalus species belong to the same clade, further affirming the taxonomic placement of R. haemaphysaloides within the Rhipicephalus genus. Furthermore, we compared the mitochondrial genomes of R. haemaphysaloides isolates from Changning, Yunnan Province, China, with isolates from Yangxin, Ganzhou, and Yingtan, Hubei Province, China. In summary, our investigation offers genetic proof endorsing the taxonomic categorization and phylogenetic placement of Ixodidae by assessing the entire mitochondrial genome of R. haemaphysaloides.

The genetic diversity of Oncomelania hupensis robertsoni, intermediate hosts of Schistosoma japonicum in hilly regions of China, using microsatellite markers.

BACKGROUND: The elimination of schistosomiasis remains a challenging task, with current measures primarily focused on the monitoring and control of Oncomelania hupensis (O. hupensis) snail, the sole intermediate host of Schistosome japonicum. Given the emerging, re-emerging, and persistent habitats of snails, understanding their genetic diversity might be essential for their successful monitoring and control. The aims of this study were to analyze the genetic diversity of Oncomelania hupensis robertsoni (O. h. robertsoni) using microsatellite DNA markers; and validate the applicability of previously identified microsatellite loci for O. hupensis in hilly regions. METHODS: A total of 17 populations of O. h. robertsoni from Yunnan Province in China were selected for analysis of genetic diversity using six microsatellite DNA polymorphic loci (P82, P84, T4-22, T5-11, T5-13, and T6-27). RESULTS: The number of alleles among populations ranged from 0 to 19, with an average of 5. The average ranges of expected (He) and observed (Ho) heterozygosity within populations were 0.506 to 0.761 and 0.443 to 0.792, respectively. The average fixation index within the population ranged from - 0.801 to 0.211. The average polymorphic information content (PIC) within the population ranged from 0.411 to 0.757, appearing to be polymorphic for all loci (all PIC > 0.5), except for P28 and P48. A total of 68 loci showed significant deviations from Hardy-Weinberg equilibrium (P < 0.05), and pairwise Fst values ranged from 0.051 to 0.379. The analysis of molecular variance indicated that 88% of the variation occurred within snail populations, whereas 12% occurred among snail populations. Phylogenetic trees and principal coordinate analysis revealed two distinct clusters within the snail population, corresponding to "Yunnan North" and "Yunnan South". CONCLUSIONS: O. h. robertsoni exhibited a relatively high level of genetic differentiation, with variation chiefly existing within snail populations. All snail in this region could be separated into two clusters. The microsatellite loci P82 and P84 might not be suitable for classification studies of O. hupensis in hilly regions. These findings provided important information for the monitoring and control of snail, and for further genetic diversity studies on snail populations.

The clinical features of severe COVID-19 with respiratory failure: A Chinese single-center retrospective study.

The global pandemic of COVID-19, caused by the novel coronavirus SARS-CoV-2, has resulted in widespread alterations to public health measures worldwide. This observational study aimed to assess the clinical features and results of respiratory failure in patients with severe COVID-19. A single-center observational study was performed at a Chinese hospital between November 1, 2022, and February 31, 2023. All 182 enrolled patients were diagnosed with respiratory failure, 84 patients were infected with COVID-19, and the other 98 patients were not infected. A review of available medical records at admission and discharge, including neuroimaging, laboratory values at admission, mortality, length of hospitalization, and hospital costs, was conducted during the COVID-19 pandemic. All 182 eligible patients completed the follow-up. There was no significant difference in baseline characteristics between respiratory failure combined with COVID-19 (P > .05). Respiratory failure combined with COVID-19 infection may lead to higher 30-day mortality (16.36% vs 7.14%, P = .005), longer hospital stays (22.5 ±â€…5.9 vs 12.8 ±â€…4.2, P < .001), larger hospitalization costs (P < .001), and increased hospitalization complications, such as pulmonary embolism (10.30% vs 4.76%, P = .039), deep vein thrombosis (33.33% vs 18.57%, P = .001), incidence of 7-day delirium (69.70% vs 46.19%, P < .001), and respiratory failure (38.18% vs 24.77%, P = .005). If respiratory failure occurs while the patient is infected with COVID-19, treatment and prognosis worsen. Our understanding of COVID-19 and the care we provide to patients with respiratory failure is crucial to better prepare for a potential pandemic.

Prediction of Oncomelania hupensis distribution in association with climate change using machine learning models.

BACKGROUND: Oncomelania hupensis is the sole intermediate host of Schistosoma japonicum. Its emergence and recurrence pose a constant challenge to the elimination of schistosomiasis in China. It is important to accurately predict the snail distribution for schistosomiasis prevention and control. METHODS: Data describing the distribution of O. hupensis in 2016 was obtained from the Yunnan Institute of Endemic Disease Control and Prevention. Eight machine learning algorithms, including eXtreme Gradient Boosting (XGB), support vector machine (SVM), random forest (RF), generalized boosting model (GBM), neural network (NN), classification and regression trees (CART), k-nearest neighbors (KNN), and generalized additive model (GAM), were employed to explore the impacts of climatic, geographical, and socioeconomic variables on the distribution of suitable areas for O. hupensis. Predictions of the distribution of suitable areas for O. hupensis were made for various periods (2030s, 2050s, and 2070s) under different climate scenarios (SSP126, SSP245, SSP370, and SSP585). RESULTS: The RF model exhibited the best performance (AUC: 0.991, sensitivity: 0.982, specificity: 0.995, kappa: 0.942) and the CART model performed the worst (AUC: 0.884, sensitivity: 0.922, specificity: 0.943, kappa: 0.829). Based on the RF model, the top six important variables were as follows: Bio15 (precipitation seasonality) (33.6%), average annual precipitation (25.2%), Bio2 (mean diurnal temperature range) (21.7%), Bio19 (precipitation of the coldest quarter) (14.5%), population density (13.5%), and night light index (11.1%). The results demonstrated that the overall suitable habitats for O. hupensis were predominantly distributed in the schistosomiasis-endemic areas located in northwestern Yunnan Province under the current climate situation and were predicted to expand north- and westward due to climate change. CONCLUSIONS: This study showed that the prediction of the current distribution of O. hupensis corresponded well with the actual records. Furthermore, our study provided compelling evidence that the geographical distribution of snails was projected to expand toward the north and west of Yunnan Province in the coming decades, indicating that the distribution of snails is driven by climate factors. Our findings will be of great significance for formulating effective strategies for snail control.

Zoonotic pathogens identified in rodents and shrews from four provinces, China, 2015-2022.

Rodents and shrews are major reservoirs of various pathogens that are related to zoonotic infectious diseases. The purpose of this study was to investigate co-infections of zoonotic pathogens in rodents and shrews trapped in four provinces of China. We sampled different rodent and shrew communities within and around human settlements in four provinces of China and characterised several important zoonotic viral, bacterial, and parasitic pathogens by PCR methods and phylogenetic analysis. A total of 864 rodents and shrews belonging to 24 and 13 species from RODENTIA and EULIPOTYPHLA orders were captured, respectively. For viral pathogens, two species of hantavirus (Hantaan orthohantavirus and Caobang orthohantavirus) were identified in 3.47% of rodents and shrews. The overall prevalence of Bartonella spp., Anaplasmataceae, Babesia spp., Leptospira spp., Spotted fever group Rickettsiae, Borrelia spp., and Coxiella burnetii were 31.25%, 8.91%, 4.17%, 3.94%, 3.59%, 3.47%, and 0.58%, respectively. Furthermore, the highest co-infection status of three pathogens was observed among Bartonella spp., Leptospira spp., and Anaplasmataceae with a co-infection rate of 0.46%. Our results suggested that species distribution and co-infections of zoonotic pathogens were prevalent in rodents and shrews, highlighting the necessity of active surveillance for zoonotic pathogens in wild mammals in wider regions.

The complete mitochondrial genome of Morishitium polonicum (Trematoda, Cyclocoelidae) and its phylogenetic implications.

Trematodes can adversely impact the health and survival of wild animals. The trematode family Cyclocoelidae, which includes large digenean bird parasites, lacks molecular analysis, and reclassifications have not been supported. This study produced the first fully assembled and annotated mitochondrial genome sequence for the trematode Morishitium polonicum. The whole length of the M. polonicum (GenBank accession number: OP930879) mitogenome is 14083 bp, containing 22 transfer ribonucleic acids (tRNAs), 2 ribosomal RNAs (rRNAs, rrnL and rrnS), and a noncoding control section (D-loop) 13777 to 13854 bp in length. The 12 PCG areas have 3269 codons and a total length of 10053 bp, which makes up 71.38% of the mitochondrial genome's overall sequence. Most (10/12) of the PCGs that code for proteins begin with ATG, while the nad4L and nad1 genes have a GTG start codon. Phylogenetic analysis using the concatenated nucleotide sequences of 12 PCGs, and the ML tree analysis results showed that M. polonicum is more closely related to with Echinostomatidae and Fasciolidae, which indicates that the family Cyclocoelidae is more closely associated with Echinochasmidae. This study provides mtDNA information, and analysis of mitogenomic structure and evolution. Moreover, we aimed to understand the phylogenetic relationships of this fluke.

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.

Molecular Genetic Analysis of Para-Bombay Phenotype in Chinese: Identification of a Novel FUT1 Allele.

BACKGROUND: The goal was to identify a novel FUT1 allele and to study serologic and gene feature of the para-Bombay blood type of one expectant mother in Xinjiang, China. METHODS: ABO and Lewis groups were recognized by standard serologic techniques in an ABO typing discrepancy specimen from one person at the Tianjin Blood Center. DNA (deoxyribonucleic acid) was collected and polymerase chain reactions with sequence-specific primers (PCR-SSP) were performed to sequence exons 6 and 7 of ABO gene, exon 4 of FUT1 gene, and exon 2 of FUT2. PCR products were sequenced to identify ABO groups and the variation sites. The genotype was determined by family study. RESULTS: In our laboratory testing, erythrocytes from the proposita did not react with anti-A and anti-B reagents. B antigen was discovered only after adsorption and elution. Red cells were nonreactive with monoclonal anti-H. The sera of the proposita contained anti-A and were weakly agglutinated by B cells. The hybrid 902 A>G mutation was detected in the proposita's father and mother. The proposita has the same mutation 902 A>G, which was conjectured as homozygosity for 902 A>G. CONCLUSIONS: One novel mutation of FUT1 gene was observed in our laboratory. It has never been reported previously. The para-Bombay phenotype in the proposita originating from Xinjiang (China) results from homozygosity for FUT1 902 A>G, together with 357 C>T of FUT2.

The risk surveillance of schistosomiasis in Yunnan, 2021 / 中国热带医学

@#Abstract: Objective　To evaluate the potential transmission risk of schistosomiasis in Yunnan Province, and to provide strategic basis for the prevention and control. Methods　Based on the prevalence of schistosomiasis, the social and environmental factors that may lead to the epidemic, 1-3 villages from 3 provincial-level and 15 county-level counties (cities and districts) were selected as the evaluated villages in 2021. The risk of schistosomiasis spread was analyzed comprehensively by consulting, reviewing and collecting routine surveillance data of schistosomiasis in the villages, combined with snail and wild feces survey. The risk level was evaluated for the positive snails, positive wild feces, resident infection, average density of live snails and snail frame occurrence rate. Results　Totally 7 snail counties schistosomiasis transmission was blocked of 18 epidemic counties and the rest were eliminated counties. A total of 152 447 snail frames were investigated and 3 043 frames with snails, 15 895 snails were captured and included 15 727 live snails in the 32 evaluated villages. The total area of snail was 58.87 hm2 and the area of reoccurrence was 34.19 hm2 with snail frame occurrence rate of 2.00% and average density of live snails 0.103 2/0.11 m2, and no positive snails were found by loop-mediated isothermal amplification (LAMP) assay. A total of 1 374 wild feces were collected in 27 evaluated villages of 14 epidemic counties, mainly from cattle, dogs, sheep, equine animals, pigs and so on, all of which were negative. According to the risk assessment of epidemic spread, Yongle Village and Yongsheng Village in Eryuan County, Zhiming Village in Chuxiong City were Ⅱ risk, and the rest were Ⅲ risk. Conclusions　Although the risk of transmission is low in Yunnan Province, the risk of transmission and spread still exists. It is necessary to strengthen the risk monitoring, control of snail and effective management of livestock to prevent the rebound of the epidemic.

Hedgehogs as Amplifying Hosts of Severe Fever with Thrombocytopenia Syndrome Virus, China.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tickborne bandavirus mainly transmitted by Haemaphysalis longicornis ticks in East Asia, mostly in rural areas. As of April 2022, the amplifying host involved in the natural transmission of SFTSV remained unidentified. Our epidemiologic field survey conducted in endemic areas in China showed that hedgehogs were widely distributed, had heavy tick infestations, and had high SFTSV seroprevalence and RNA prevalence. After experimental infection of Erinaceus amurensis and Atelerix albiventris hedgehogs with SFTSV, we detected robust but transitory viremias that lasted for 9-11 days. We completed the SFTSV transmission cycle between hedgehogs and nymph and adult H. longicornis ticks under laboratory conditions with 100% efficiency. Furthermore, naive H. longicornis ticks could be infected by SFTSV-positive ticks co-feeding on naive hedgehogs; we confirmed transstadial transmission of SFTSV. Our study suggests that the hedgehogs are a notable wildlife amplifying host of SFTSV in China.

Complete mitochondrial genome and phylogenetic analysis of Ixodes ovatus (Acari: Ixodidae).

Ixodes ovatus is referred to as an obligatory blood-sucking ectoparasite that is capable to infest both humans and animals. In the present study, the complete mitochondrial genome of I. ovatus was sequenced and analyzed using next-generation sequencing (NGS) technology. With a size of 14,520 bp, the entire mitogenome contains 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and 3 control regions (D-loops). Based on the 13 PCGs nucleotide sequences, the phylogenetic relationship of I. ovatus was analyzed using Maximum-likelihood. As suggested by the results of the obtained phylogenety, I. ovatus is most closely associated with Ixodes hexagonus. This study is expected to promote further studies on the evolution of Ixodidae.

Complete mitogenomes and phylogenetic relationships of Haemaphysalis nepalensis and Haemaphysalis yeni.

The mitochondrial genome may include crucial data for understanding phylogenetic and molecular evolution. We sequenced the complete mitogenome of Haemaphysalis nepalensis and Haemaphysalis yeni for the first time. H. nepalensis and H. yeni's complete mitogenomes were 14,720 and 14,895 bp in size, respectively, and both contained two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and 13 protein-coding genes (PCG). Haemaphysalis nepalensis have one control region (D-loop). The adenine + thymine concentration of the genomes of H. nepalensis and H. yeni was 77.75 and 78.41%, respectively. The codon use pattern and amino acid content of proteins were both observed to be affected by the AT bias. Genes in the mitogenome were organized and located in a comparable manner to previously known genes from Haemaphysalis ticks. Mitochondrial PCGs were used to perform phylogenetic relationships based on the Minimum Evolution (ME) approach using MEGA 7.0 software, the results reveal that H. nepalensis has tight links with H. tibetensis, H. yeni and H. kolonini share a sister group relationship, and that H. nepalensis and H. yeni belong to Haemaphysalis. The results of this study include the following: (i) discovered and supplied new tick records (H. nepalensis) for China, (ii) provided the first complete mitochondrial genome for H. nepalensis and H. yeni and revealed their phylogenetic relationships, and (iii) the features of the mitochondrial genome of H. nepalensis and H. yeni provided more genetic reference for Phylogeography, systematics, and population genetics of the Haemaphysalis species.

Effect of clinical application of anti-CD38 and anti-CD47 monoclonal antibodies on blood group detection and transfusion therapy and treatment.

BACKGROUND: To investigate the effect of anti-CD38 monoclonal antibodies (mAb) (daratumumab, DARA) and anti-CD47 mAb combined with azacytidine on blood transfusion compatibility tests, transfusion effects in the treatment of multiple myeloma or acute myeloid leukemia and the corresponding management strategy. MATERIALS AND METHODS: Among the 19 patients who were treated with DARA and anti-CD47 mAb, 4 patients with cross matching incompatibility were selected. The ABO blood group, the Rh blood group, irregular antibody screening and direct antiglobulin test (DAT) and cross matching testing were performed before and after the application of mAbs using serological methods. Then, irregular antibody screening and microcolumn gel cross matching tests were performed with donor and recipient erythrocytes and serum treated with DL-dithiothreitol (DTT) and Immucor kit, respectively. The transfusion effect was monitored. RESULTS: 21.05% (4/19) patients had mismatched cross-matching results after mAb treatment. The agglutination intensity of irregular antibody screening tests (3 + ∼ 4 +) after anti-CD47 mAb was higher than that (1 + ∼ 2 +) after DARA. In the DARA group, treating RBCs with 0.2 mol L-1 DTT eliminated the DARA interference with antibody screening. In the anti-CD47 mAb group, the antibody screening, cross-matching test and DAT had been strongly interfered, and using Immucor kit eliminated the interference with antibody screening testing. There was no difference in the transfusion effect. CONCLUSION: The application of mAb drugs led to incompatibility of cross matching tests, and the transfusion effect was not affected.

Coinfection of Two Rickettsia Species in a Single Tick Species Provides New Insight into Rickettsia-Rickettsia and Rickettsia-Vector Interactions.

Rickettsiae are obligate intracellular bacteria that can cause life-threatening illnesses. There is an ongoing debate as to whether established infections by one Rickettsia species preclude the maintenance of the second species in ticks. Here, we identified two Rickettsia species in inoculum from Haemaphysalis montgomeryi ticks and subsequently obtained pure isolates of each species by plaque selection. The two isolates were classified as a transitional group and spotted fever group rickettsiae and named Rickettsia hoogstraalii str CS and Rickettsia rhipicephalii str EH, respectively. The coinfection of these two Rickettsia species was detected in 25.6% of individual field-collected H. montgomeryi. In cell culture infection models, R. hoogstraalii str CS overwhelmed R. rhipicephalii str EH with more obvious cytopathic effects, faster plaque formation, and increased cellular growth when cocultured, and R. hoogstraalii str CS seemed to polymerize actin tails differently from R. rhipicephalii str EH in vitro. This work provides a model to investigate the mechanisms of both Rickettsia-Rickettsia and Rickettsia-vector interactions. IMPORTANCE The rickettsiae are a group of obligate intracellular Gram-negative bacteria that include human pathogens causing an array of clinical symptoms and even death. There is an important question in the field, that is whether one infection can block the superinfection of other rickettsiae. This work demonstrated the coinfection of two Rickettsia species in individual ticks and further highlighted that testing the rickettsial competitive exclusion hypothesis will undoubtedly be a promising area as methods for bioengineering and pathogen biocontrol become amenable for rickettsiae.

Rh Phenotype and Allele Frequencies Among 88,856 Patients in China.

BACKGROUND: This study was performed to provide information on the frequencies of Rh antigens, alleles, and phenotypes from our region in Tianjin, China. METHODS: This observational study was conducted on patients from January 2018 to March 2021 using a fully automated system for ABO and Rh typing of blood cells. The phenotypes of C, c, E, and e were detected by the slide method. The data were collected and calculations done to determine the antigen, phenotypes and allele frequencies. RESULTS: Four hundred thirty-three cases of Rh (D) negative phenotype were confirmed in 88,856 patients. Of the four Rh antigens (C, c, E, e) that were phenotyped by serological methods, the "e" antigen was found to have the highest frequency (99.74%). The most common Rh negative phenotype observed was ccdee, followed by Ccdee. The prevalence of Rh phenotypes ccdEe, CCdee, CcdEe, CCdEe, ccdEE were found to be rare in our population with percentages of 0.0473%, 0.018%, 0.018%, 0.0034%, and 0.0011%, respectively. CONCLUSIONS: Knowledge of red cell antigen phenotype frequencies in a population is helpful in terms of their ethnic distribution. We have determined the prevalence of Rh antigens and Rh phenotypes in China. The Rh blood group distribution in this population was different from that in other populations.

Complete mitochondrial genome and phylogenetic analysis of Ixodes acutitarsus (Acari: Ixodidae).

Ixodes acutitarsus is regarded as the largest Ixodes tick around the world. I. acutitarsus is capable to transmit a wide range of animal and human pathogens. This research pioneered sequencing of the complete mitochondrial genome of I. acutitarsus. With a length of 14,475 bp, the complete mitochondrial genome encodes 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and one replication-initiating region. The phylogenetic relationship was established using the Maximum-likelihood method to indicate that I. acutitarsus and the others of the genus Ixodes fit into the same branch, which confirms the inclusion of I. acutitarsus in the genus Ixodes. The complete mitogenome of sequenced I. acutitarsus provides molecular evidence for the taxonomic status and phylogenetic position of several Ixodes species.

Characterization of the complete mitochondrial genome of Ixodes granulatus (Ixodidae) and its phylogenetic implications.

Ticks are deemed to be second only to mosquitoes as the most common vector of human infectious diseases worldwide that give rise to human and animal diseases and economic losses to livestock production. Our understanding of the phylogenetic analysis between tick lineages has been restricted by the phylogenetic markers of individual genes. Genomic data research could help advance our understanding of phylogenetic analysis and molecular evolution. Mitochondrial genomic DNA facilitated the phylogenetic analysis of eukaryotes containing ticks. In this study, we sequenced and assembled the circular complete mitogenome information of Ixodes granulatus. The 14,540-bp mitogenome consists of 37 genes, including 13 protein-coding genes (PCGs), two genes for ribosomal RNA (rRNAs), and 22 genes for transfer RNA (tRNAs), and the origin of the L-strand replication region. The directions of the coding strand and component genes in the non-Australasian Ixodes mitochondrial genome were similar to those found in most other Australasian Ixodes, except for the loss of a lengthy control region. The phylogenetic tree based on maximum likelihood (ML) and Bayesian inference (BI) computational algorithms showed that I. granulatus exhibits a close relationship with I. hexagonus and I. ricinus. To our knowledge, this is the first study exploring the complete mitogenome for the species I. granulatus. Our results provide new insights for further research on the evolution, population genetics, systematics, and molecular ecology of ticks.

High Diversity and Prevalence of Borrelia burgdorferi sensu lato in Wildlife Hosts, Domestic Animals, and Ticks in Yunnan Province, Southwestern China.

Borrelia burgdorferi sensu lato (BBSL), the causative agent of Lyme disease, is commonly found in wild and domestic mammals and ticks worldwide. In China, human cases of Borrelia burgdorferi infections have been identified across a wide geographic range including Yunnan Province, but few studies have examined BBSL in reservoirs and vectors in southwestern China. Here we conducted a thorough and broad-range investigation of BBSL in small mammals, domestic mammals, and ticks collected from 159 sample sites across 42 counties in Yunnan Province. DNA was extracted from spleen tissue of small mammals, blood from domestic mammals, and homogenized ticks. Nested PCR targeting the 5S-23S rRNA intergenic spacer gene of BBSL was used for screening, with amplicons sequenced directly and analyzed using a BLAST algorithm. A total of 8,478 samples were collected, which were composed of 5,044 mammals belonging to 68 species, 1,927 livestock belonging to five species, and 1, 507 ticks belonging to 14 species. BBSL was detected in 147 mammals (2.9%) from 30 different species, 20 of which represent the first reported detection in that species. A total of 52 (2.7%) livestock samples were positive for BBSL, with dogs having the highest detection rate (6.3%, 43/687), and 103 ticks (6.8%) tested positive with high prevalence in Ixodes granulatus (44.2%, 23/52), Haemaphysalis nepalensi (33.3%, 3/9) and Haemaphysalis kolonini (19.0%, 31/163). Sequence analysis revealed six genospecies of BBSL including B. afzelii, B. burgdorferi sensu stricto, B. japonica, B. garinii, B. sinica, and B. valaisiana. Significant differences in prevalence rates of BBSL were observed by species, landscape types, altitude, and season. Our findings indicate a wide distribution of multiple endemic BBSL genospecies based on a large-scale survey within Yunnan, which underline the need to expand surveillance efforts for human in southwestern China.

Characterization of the complete mitochondrial genome of Haemaphysalis (Alloceraea) kolonini (Ixodidae) and its phylogenetic implications.

Ticks transmit diverse pathogens that cause human and animal diseases, leading to an increasing number of new challenges around the world. Genomic data research could help advance our learning of phylogenetic analysis and molecular evolution. Mitochondrial genome DNA has been helpful in illustrating the phylogenetic analysis of eukaryotes containing ticks. In this research, we sequenced and assembled the circular complete mitogenome information of Haemaphysalis kolonini. The 14,948-bp mitogenome consists of 37 genes which included 13 genes for protein-coding, two genes for ribosomal RNA, 22 genes for transfer RNA, and two control regions (D-loops). Overall, the composition and arrangement of genes were compared with Haemaphysalis ticks previously recorded in Genbank. The phylogenetic tree based on Maximum likelihood (ML) and Bayesian inference (BI) computational algorithms showed that H. kolonini has a close relationship with Haemaphysalis inermis. The complete mitogenome data provide a preferable perception to the phylogenetic relationship than the single-gene data analysis. To our knowledge, this is the first research exploring the complete mitogenome for the species H. kolonini. Our results provide new insights for further research on the evolution, population genetics, systematics, and molecular ecology of ticks.