Search Results (85)

Speed is not only the primary objective of racehorse breeding but also a crucial indicator for evaluating racehorse performance. This study investigates a newly developed racehorse breed in China. Through whole-genome resequencing, we selected 60 offspring obtained from the crossbreeding of Thoroughbred horses and Xilingol horses for this study. This breed is tentatively named “Grassland-Thoroughbred”, and the samples were divided into two groups based on racing ability: 30 racehorses and 30 non-racehorses. Based on whole-genome sequencing data, the study achieved an average sequencing depth of 25.63×. The analysis revealed strong selection pressure on chromosomes (Chr) 1 and 3. Selection signals were detected using methods such as the nucleotide diversity ratio (π ratio), integrated haplotype score (iHS), fixation index (Fst), and cross-population extended haplotype homozygosity (XP-EHH). Regions ranked in the top 5% by at least three methods were designated as candidate regions. This approach detected 215 candidate genes. Additionally, the Fst method was employed to detect Indels, and the top 1% regions detected were considered candidate regions, covering 661 candidate genes. Functional enrichment analysis of the candidate genes suggests that pathways related to immune regulation, neural signal transmission, muscle contraction, and energy metabolism may significantly influence differences in performance. Among these identified genes, PPARGC1A, FOXO1, SGCD, FOXP2, PRKG1, SLC25A15, CKMT2, and TRAP1 play crucial roles in muscle function, metabolism, sensory perception, and neurobiology, indicating their key significance in shaping racehorse phenotypes. This study not only enhances understanding of the molecular mechanisms underlying racehorse speed but also provides essential theoretical and practical references for the molecular breeding of Grassland-Thoroughbreds. Full article

Cystic echinococcosis is a zoonosis caused by the cestode Echinococcus granulosus sensu stricto. Population genetic studies and phylogeographic patterns are essential to understanding the transmission dynamics of this parasite under varying environmental conditions. In this study, the genetic diversity of E. granulosus s.s. was evaluated using 46 hydatid cyst samples obtained from sheep, goats, cattle, and humans across three regions of Chile: Coquimbo, La Araucanía, and Magallanes. Mitochondrial cox1 gene sequences were analyzed and compared with reference sequences reported from South America, Europe, Africa, Asia, and Oceania. In Chile, the EG01 haplotype was the predominant haplotype. A total of four haplotypes were identified, with low haplotype diversity (Hd = 0.461 ± 0.00637) and low nucleotide diversity (π = 0.00181 ± 0.00036). The haplotype network displayed a star-like configuration, with the EG01 genotype at the center, suggesting a potentially ancestral or widely distributed lineage. In Coquimbo (Tajima’s D = −0.93302, p = 0.061; Fu’s Fs = −0.003, p = 0.502) and Magallanes (Tajima’s D = −0.17406, p = 0.386; Fu’s Fs = −0.121, p = 0.414), both neutrality tests were non-significant, indicating no strong evidence for recent population expansion or selection. Star-like haplotype network patterns were also observed in populations from Europe, the Middle East, Asia, Africa, and Oceania, with the EG01 genotype occupying the central position. The population genetic structure of Echinococcus granulosus s.s. in Chile demonstrates considerable complexity, with EG01 as the predominant haplotype. Further comprehensive studies are required to assess the intraspecific genetic variability of E. granulosus s.s. throughout Chile and to determine whether this variability influences the key biological traits of the parasite. This structure may prove even more complex when longer fragments are analyzed, which could allow for the detection of finer-scale microdiversity among isolates from different hosts. We recommended that future cystic echinococcosis control programs take into account the genetic variability of E. granulosus s.s. strains circulating in each endemic region, to better understand their epidemiological, immunological, and possibly pathological differences. Full article

Small rodents are known hosts of various pathogens, including Hepatozoon, but until now, in Brazil, only Hepatozoon milleri has been described in these animals. In this study, liver samples and blood smears were obtained from 289 rodents belonging to 14 Cricetidae and two Muridae species that had been captured in municipalities of the states of Paraná and Rio de Janeiro. Smears were stained with Giemsa, and gametocytes were detected via microscopy in 10.72% (n = 31/289) of samples, with these individuals representing three rodent species. Significant morphometric differences were observed in gametocyte measurements in Akodon rodents. Using conventional PCR, Hepatozoon spp. 18S rDNA fragments were amplified in 24.91% (n = 72/289) of samples, with those individuals representing seven rodent species. Phylogenetic analyses clustered 41 sequences from this study into a subclade with other sequences from small mammals in Brazil, identifying four distinct haplotypes, and, for the first time, a relationship between Hepatozoon haplotype and gametocyte length was observed. Based on phylogenetic analysis, this study reinforces the trophic relationship between rodents and reptiles as a possible link in the Hepatozoon transmission cycle in South America. Furthermore, our findings expand knowledge on Hepatozoon spp. hosts, describing Oxymycterus nasutus and Oxymycterus quaestor as new host species and identifying two novel circulating haplotypes in rodents from Paraná State, southern Brazil. Full article

Rodents are among the most abundant and ecologically diverse mammals, playing key roles in terrestrial ecosystems and often serving as reservoirs for various zoonotic and wildlife pathogens. Among these are protozoan parasites of the genera Hepatozoon and Theileria, which are known to infect a wide range of domestic and wild animals worldwide. However, little is known about the diversity and phylogenetic relationships of these hemoprotozoans in rodent hosts, particularly in the Arabian Peninsula. The aim of this study was to investigate the presence and genetic diversity of Hepatozoon sp. and Theileria sp. in rodents from different regions of Saudi Arabia and to determine potential reservoir species. A total of 111 rodents were captured and identified by molecular analysis of the mitochondrial 16S rRNA gene. Screening for parasites was performed using PCR amplification of the 18S rRNA gene, followed by sequencing, haplotype analysis, and phylogenetic reconstruction using both maximum likelihood and Bayesian inference methods. Our results represent the first molecular detection of Hepatozoon sp. in Arvicanthis niloticus (31.3%), Gerbillus cheesmani (26.5%), G. nanus (28.5%), and Rattus rattus (32.0%) and of Theileria sp. in G. nanus (21.5%) and R. rattus (24.0%) in Saudi Arabia. Haplotype network analysis revealed seven distinct Hepatozoon haplotypes forming a star-like cluster, suggesting host specificity. One divergent haplotype (Hap_2), 19 mutation steps apart, may represent a novel lineage. Phylogenetic analyses grouped Saudi Hepatozoon sequences with those from reptiles and rodents, forming a clade distinct from sequences isolated from felids and canids. In contrast, Theileria sequences showed low diversity, clustering with a single widespread haplotype found in rodents and ruminants in several regions. These findings significantly expand the current knowledge on rodent-associated apicomplexan parasites in Saudi Arabia, revealing novel Hepatozoon haplotypes and highlighting the role of rodents in the transmission of reptile-associated Hepatozoon spp. This study provides basic molecular data crucial to understanding host–parasite relationships and the potential public and veterinary health implications of these parasites in arid ecosystems. Full article

The detection of food sources of blood-sucking vectors is essential for a better understanding of the hosts, reservoirs, and other fauna that participate in the transmission web of hemoparasites. The molecular identification of triatomine blood meal sources (BMSs) has been shown to be highly sensitive and taxonomically specific when compared to the immunological method. The application of molecular cloning makes it possible to identify multiple BMS species and/or different individuals/haplotypes of the same vertebrate species in a single triatomine specimen. In Brazil, the molecular detection of BMSs is incipient, with insufficient genetic information on the species of animals involved in the transmission of Trypanosoma cruzi. In this work, we evaluated the sensitivity and specificity of a molecular approach using molecular cloning for the detection of multiple Brazilian mammalian species. The DNA was extracted from blood clots of 13 species of canids, bats, xenarthral, marsupials, and rodents. Serial proportions were used to formulate mixtures combining taxonomically close (belonging to the same family or order) and taxonomically distant (different families) species. The results showed that GenBank lacks reference sequences for some native species tested, such as the sylvatic rodent, Necromys lasiurus, and the wild canid, Lycalopex gymnocercus, for cytb and 12S rDNA, and the rodent Oecomys cleberi for 12S rDNA. The study also demonstrated that it is possible to detect multiple different species, even for those that are taxonomically close. This approach was proven to be efficient for the detection of species in equal and even in disparate unequal proportions, which could represent complementary information about the diversity of potential hosts of T. cruzi. The detection of multiple BMS species in mixed samples provides a more comprehensive and accurate landscape of T. cruzi transmission in nature. Full article

Early-life stress may increase the risk of neuropsychiatric disorders via immune activation. While the purinergic signaling pathway is implicated in psychiatric disorders, the specific role of the P2X7 receptor (P2X7R) in anxiety, depression, and childhood trauma still requires further clarification. Upon chronic stress, excessive ATP release activates purinergic P2X7R signalling in the brain contributing to long-lasting neuroinflammation, which potentially promotes the development of psychiatric disorders. There is also a putative link between the P2X7 receptor gene, located on chromosome 12q24, and the development of anxiety and depression. This review aims to systematically examine how P2X7R contributes to the pathophysiology of anxiety and depressive disorders, with a particular focus on early-life stress (ELS). It offers a comprehensive synthesis of the current findings, emphasizing the previously unexplored intersections between P2X7R signaling, early-life stress, and psychiatric disorders. These interactions may shape long-term neuroinflammation, contributing to the development of anxiety and depression, and offer new insights into potential therapeutic targets. The review integrates the role of P2X7R regarding both indirect mechanisms—such as the modulation and long-term transmission of neuroinflammation following environmental stressors and vulnerability—and direct genetic associations with psychiatric conditions, including the influence of single-nucleotide polymorphisms (SNPs), haplotypes, and other variants within the P2X7 gene. Special emphasis is placed on the impact of early-life stress, drawing primarily on preclinical findings to elucidate underlying mechanisms. Full article

Species of the widespread Obsoletus Complex (Culicoides subgenus Avarita Fox, 1955) have been implicated as potential key vectors during the bluetongue and Schmallenberg epidemics in Central Europe in 2006 and 2012. Although extensive efforts have been made to clarify vector–pathogen relationships, one of the most important steps in this process—correct species identification—remains difficult, due to the presence of isomorphic species within the Obsoletus Group. To overcome the difficulties in morphological species identification, several PCR tests were developed. With the aim of developing a high-throughput PCR, capable of differentiating all putative vector species and newly described haplotypes of the subgenus Avaritia present in Europe, a dataset of 4407 published sequences of the mitochondrial (mt) cytochrome c oxidase subunit I (COI) was used to develop specific primers and probes, which can either be applied in a singleplex PCR or in different multiplex PCR approaches. The real-time PCR achieved very high diagnostic sensitivity (100%) and specificity (91.7%) and reliably detected the three clades of C. obsoletus sensu stricto (s.s.) in a pool of specimens. Thus, the new real-time PCR approach will provide an excellent tool for large-scale monitoring, which could improve the understanding of the biology, geographical distribution, and habitat preference of European biting midge species involved in the transmission of bluetongue, Schmallenberg, and epizootic hemorrhagic disease viruses. Full article

(1) Background: Limited information on Echinococcus species among the wildlife in Tanzania has created a significant knowledge gap regarding their distribution, host range, and zoonotic potential. This study aimed to enhance the understanding of Echinococcus felidis transmission dynamics within the great Serengeti ecosystem. (2) Methods: A total of 37 adult Echinococcus specimens were collected from a leopard (Panthera pardus) (n = 1) in Maswa Game Reserve and 7 from a lion (Panthera leo) (n = 1) in Loliondo. Two hydatid cysts were also obtained from warthogs (n = 2) in the Serengeti National Park. (3) Results: Morphological examination revealed infertile cysts in warthogs that were molecularly identified as E. felidis. This marks the first molecular evidence of E. felidis in leopards and warthogs in Tanzania. Pairwise similarity analysis showed 98.7%–99.5% identity between Tanzanian, Ugandan, and South African isolates. Thirteen unique haplotypes were identified, with a haplotype diversity of (Hd = 0.9485) indicating genetic variability. Phylogenetic analysis grouped E. felidis into a single lineage, with the leopard isolate forming a distinct haplotype, suggesting leopards as an emerging host. Lion and warthog isolates shared multiple mutational steps, suggesting possible genetic divergence. (4) Conclusions: This study confirms African lions and leopards as definitive hosts and warthogs as potential intermediate hosts of E. felidis in the Serengeti ecosystem. Our findings highlight disease spillover risks and stress the importance of ecosystem-based conservation in wildlife–livestock overlap areas. Although E. felidis is believed to be confined to wildlife, the proximity of infected animals to pastoralist communities raises concerns for spillover. These findings highlight the importance of ecosystem-based surveillance, especially in wildlife–livestock–human interface areas. Full article

Background: Insecticide resistance challenges the vector control efforts towards malaria elimination and proving the development of complementary tools. Targeting the genes that are involved in mosquito fertility and susceptibility to Plasmodium with small molecule inhibitors has been a promising alternative to curb the vector population and drive the transmission down. However, such an approach would require a comprehensive knowledge of the genetic diversity of the targeted genes to ensure the broad efficacy of new tools across the natural vector populations. Methods: Four fertility and parasite susceptibility genes were identified from a systematic review of the literature. The Single Nucleotide Polymorphisms (SNPs) found within the regions spanned by these four genes, genotyped across 2784 wild-caught Anopheles gambiae s.l. from 19 sub-Saharan African (SSA) countries, were extracted from the whole genome SNP data of the Ag1000G project (Ag3.0). The population genetic analysis on gene-specific data included the determination of the population structure, estimation of the differentiation level between the populations, evaluation of the linkage between the non-synonymous SNPs (nsSNPs), and a few statistical tests. Results: As potential targets for small molecule inhibitors to reduce malaria transmission, our set of four genes associated with Anopheles fertility and their susceptibility to Plasmodium comprises the mating-induced stimulator of oogenesis protein (MISO, AGAP002620), Vitellogenin (Vg, AGAP004203), Lipophorin (Lp, AGAP001826), and Haem-peroxidase 15 (HPX15, AGAP013327). The analyses performed on these potential targets of small inhibitor molecules revealed that the genes are conserved within SSA populations of An. gambiae s.l. The overall low Fst values and low clustering of principal component analysis between species indicated low genetic differentiation at all the genes (MISO, Vg, Lp and HPX15). The low nucleotide diversity (>0.10), negative Tajima’s D values, and heterozygosity analysis provided ecological insights into the purifying selection that acts to remove deleterious mutations, maintaining genetic diversity at low levels within the populations. None of MISO nsSNPs were identified in linkage disequilibrium, whereas a few weakly linked nsSNPs with ambiguous haplotyping were detected at other genes. Conclusions: This integrated finding on the genetic features of major malaria vectors’ biological factors across natural populations offer new insights for developing sustainable malaria control tools. These loci were reasonably conserved, allowing for the design of effective targeting with small molecule inhibitors towards controlling vector populations and lowering global malaria transmission. Full article

Background: Anopheles stephensi, a primary malaria vector in South Asia, is expanding its geographic range, raising concerns about increased malaria transmission. However, critical aspects of its genetic diversity, population structure, and evolutionary dynamics remain poorly understood in Khyber Pakhtunkhwa (KP), Pakistan, an endemic malaria region where An. stephensi is adapting to urban settings, posing challenges for the development of targeted vector control strategies. This study addresses this gap by analyzing COI, COII (cytochrome oxidase subunit I and II), and ITS2 (internal transcribed spacer 2) sequences from An. stephensi populations in KP and comparing them with global isolates. Additionally, egg morphology analysis was conducted to identify the biological form. Methods: Mosquitoes were collected from malaria-endemic districts (Nowshera, Charsadda, and Peshawar) using ovitraps. Eggs were characterized morphologically, and DNA was extracted for PCR amplification of COI, COII, and ITS2 markers. Sequences from 17 Pakistani isolates, along with global sequences, were analyzed. Phylogenetic relationships, haplotype networks, genetic diversity, and neutrality tests (Tajima’s D and Fu’s Fs) were assessed. Results: Egg morphology confirmed the mysorensis form (13–15 ridges per egg) in KP. COI sequences clustered into two subclades (Punjab and KP), with >99% similarity to global isolates. COII and ITS2 sequences showed high similarity (99.46–100%) with populations from China, Iran, India, and Brazil, reflecting strong genetic connectivity rather than distinct regional clustering. Haplotype analysis identified six COI, ten COII, and ten ITS2 haplotypes, with Hap_2 (50.7%) and Hap_1 (43.3%) being the most prevalent in COI, Hap_7 (29.4%) in COII, and Hap_3 (80.8%) in ITS2. Population genetic analysis revealed higher COI diversity in Pakistan and India, with moderate diversity in COII. Neutrality tests suggested balancing selection in COI for both countries, while COII and ITS2 indicated population contraction in Iran. Conclusions: The findings reveal strong genetic connectivity within regions (e.g., Pakistan) and differentiation across global populations of An. stephensi, highlighting its potential for further expansion and adaptation. These insights are critical for informing global malaria control strategies, particularly in regions vulnerable to vector invasion. Full article

This study investigates the prevalence of parasitic helminths in free-ranging domestic cats and dogs near the Chi River and natural reservoirs in Maha Sarakham Province, Thailand. Fecal samples from 39 cats and 148 dogs were analyzed using a modified formalin-ether concentration technique (FECT). The overall prevalence of helminth infections was 64.1% in cats and 51.4% in dogs. Common parasites were detected including soil-transmitted species like Ancylostoma sp. (hookworm), Toxocara spp., and Strongyloides sp., as well as foodborne helminths such as Taenia sp., Hymenolepis sp., Spirometra sp., and Opisthorchis sp. Multiple parasitic infections were commonly found in dogs (57.9%) and cats (46.2%). Our findings suggest that domestic cats and dogs act as important reservoirs for zoonotic helminths in the region. Notably, Opisthorchis viverrini-like eggs were found exclusively in cats, with a prevalence of 23.1%. The intron 5 of domain 1 of the taurocyamine kinase gene (TkD1Int5) was used for genotyping O. viverrini-like eggs. All O. viverrini-like egg samples with TkD1Int5 haplotypes (Ov116–Ov123) were uniquely found in cats. Genetic analysis revealed that TkD1Int5 haplotypes were similar to those previously reported for Opisthorchis viverrini in various species of cyprinid fish across opisthorchiasis-endemic regions in Thailand and Lao PDR. Three TkD1Int5 haplogroups (I–III) were classified, with O. viverrini-like eggs from cats distributed across all haplogroups. Notably, one haplotype (Ov118) was genetically distinct from the others and did not cluster into any haplogroup. These findings highlight the crucial role of cats as reservoir hosts and their potential contribution to the transmission of the zoonotic liver fluke O. viverrini, posing a notable public health concern. Full article

This study evaluated the genetic diversity and potential drug resistance markers in Plasmodium vivax isolates from Panama, a country in Mesoamerica, aiming to eliminate local malaria transmission. We analyzed 70 P. vivax samples collected between 2004 and 2020 from endemic regions in Eastern and Western Panama, as well as imported cases. Four drug resistance genes (pvcrt-o, pvmdr1, pvdhfr, and pvdhps) were sequenced and analyzed. Our findings reveal low genetic diversity in P. vivax populations from Western Panama, indicating clonal expansion, while Eastern Panama exhibits higher diversity, influenced by higher transmission rates and imported cases. No mutations were detected in pvcrt-o, and the prevalence of pvmdr1 mutations (Y976F and F1076L) linked to chloroquine was observed at low frequencies, primarily in imported samples. In pvdhfr, antifolate-resistant mutations S117N and S58R were detected in 14.3% of samples, predominantly from Eastern Panama near the Colombian border. Phylogenetic and haplotype network analyses highlighted distinct genetic clustering, supporting the influence of imported cases on local parasite diversity. These results provide a baseline for the molecular surveillance of P. vivax in Panama and emphasize the need for the continued monitoring of genetic diversity and drug resistance to guide regional malaria elimination efforts, particularly in areas with high cross-border migration. Full article

Blastocystis is a common intestinal protist with a global distribution, frequently found in humans and various animals. Despite its prevalence, its role in human health remains debated, oscillating between being a harmless commensal and a potential pathogen. It has also been associated with gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). In Italy, the genetic and spatial diversity of Blastocystis remains understudied, despite the country’s diverse urbanized and environmental landscapes. This study investigates the haplotypic and spatial diversity of clinical isolates of Blastocystis across two different Italian regions, with an emphasis on subtype distribution and genetic variation. Using a network-based haplotype analysis, the study reveals a heterogeneous subtype distribution, with subtype ST4 (47.3%) being the most prevalent, followed by ST3 (20%), ST1 (16.4%), ST2 (12.7%), ST6 (1.8%) and ST7 (1.8%). The overall infection rate detected from symptomatic patients is 9.75%. Notably, ST4 shows limited haplotypic variation, suggesting a more stable population structure that is potentially linked to a human-adapted lineage. In contrast, ST1 and ST2 exhibit greater haplotypic diversity, likely due to ongoing zoonotic transmission. These findings enhance our understanding of the epidemiology of Blastocystis in Italy and underscore the need for further research on its pathogenic potential and transmission dynamics. Full article

Prion diseases, or transmissible spongiform encephalopathies (TSEs), are a group of invariably fatal neurodegenerative disorders. One of the candidate genes involved in prion diseases is the shadow of the prion protein (SPRN) gene. Raccoon dogs, a canid, are considered to be a prion disease-resistant species. To date, the genetic polymorphisms of the SPRN gene and the predicted protein structure of the shadow of prion protein (Sho) have not been explored in raccoon dogs. SPRN was amplified using polymerase chain reaction (PCR). We also investigated the genetic polymorphisms of SPRN by analyzing the frequencies of genotypes, alleles, and haplotypes, as well as the linkage disequilibrium among the identified genetic variations. In addition, in silico analysis with MutPred-Indel was performed to predict the pathogenicity of insertion/deletion polymorphisms. Predicted 3D structures were analyzed by the Alphafold2. We found a total of two novel synonymous single nucleotide polymorphisms and three insertion/deletion polymorphisms. In addition, the 3D structure of the Sho protein in raccoon dogs was predicted to resemble that of the Sho protein in dogs. This is the first study regarding the genetic and structural characteristics of the raccoon dog SPRN gene. Full article

In this review, we investigated the genetic diversity and evolutionary dynamics of the Orthomarburgvirus marburgense species that includes both Marburg virus (MARV) and Ravn virus (RAVV). Using sequence data from natural reservoir hosts and human cases reported during outbreaks, we conducted comprehensive analyses to explore the genetic variability, constructing haplotype networks at both the genome and gene levels to elucidate the viral dynamics and evolutionary pathways. Our results revealed distinct evolutionary trajectories for MARV and RAVV, with MARV exhibiting higher adaptability across different ecological regions. MARV showed substantial genetic diversity and evidence of varied evolutionary pressures, suggesting an ability to adapt to diverse environments. In contrast, RAVV demonstrated limited genetic diversity, with no detected recombination events, suggesting evolutionary stability. These differences indicate that, while MARV continues to diversify and adapt across regions, RAVV may be constrained in its evolutionary potential, possibly reflecting differing roles within the viral ecology of the Orthomarburgvirus marburgense species. Our analysis explains the evolutionary mechanisms of these viruses, highlighting that MARV is going through evolutionary adaptation for human-to-human transmission, alarmingly underscoring the global concern about MARV causing the next pandemic. However, further transdisciplinary One Health research is warranted to answer some remaining questions including the host range and genetic susceptibility of domestic and wildlife species as well as the role of the biodiversity network in the disease’s ecological dynamics. Full article