Parasitology Research最新文献

Invertebrate mitogenomes are generally fixed with formal 37 genes: 13 PCGs encoded subunits of OXPHOS, 2 ribosomal RNA (rRNA) functional in the translation of these PCGs and 22 transfer RNA (tRNA) genes. The order of these genes varies greatly among organisms and named rearrangement. Rearrangement patterns of mitochondrial genomes may shed light on mutation processes and evolutionary relationships of organisms. Mitochondrial gene organization is highly variable among Acari, so rearrangement is a very common mitogenomic pattern in this group. In this study, 258 unique Acari (Acariformes + Parasitiformes) mitogenomes were downloaded from NCBI and studied about rearrangement patterns. Sixty-seven mitotypes were determined among Acari and the most rearranged genes were trnL1 and nad2. Following that, trnI, trnS1, trnN, trnE, trnT, and trnP genes are remarkably mobile (RF > 95%). Conversely, atp6, cox3, trnG, and cytb genes also appears to be quite stable (RF < 20%). Within Acari, mean distance calculations are varied from 1.210 in atp8 to 0.155 in rrnS. Contrary to expectations, among Acari mobile tRNA genes appear to be conserved in sequences, whereas PCGs have higher distance values and seem to be mutated. Consistently, tRNA genes seem saturated, but some PCGs (atp6, cox genes, cytb, nad1, and nad6) are not saturated. These values do not correlate with each other (p > 0.005). This discrepancy may indicate that the genes were rearranged after mutation load; consistent with this, DAMBE saturation values are also not correlated with RF values. Parasitiformes mitogenomes are more mobile than Acariformes mitogenomes and may be under the effect of selective sweeping.

In Xinjiang, previous reports of cystic echinococcosis (CE) in livestock have focused on West and Middle Tianshan Mountains. In contrast, there is an absence of research on CE in the East Tianshan Mountains. To determine the epidemiology and genetic diversity of Echinococcus granulosus sensu stricto (s.s.) in domestic animals in the East Tianshan Mountains, Xinjiang, China, the livers and lungs of 1773 domestic animals were examined, between January 2023 and March 2023, and 40 cysts were collected. Polymerase chain reaction was used for the molecular diagnosis of the cysts. Statistical results showed that the overall prevalence of echinococcosis in sheep was 6.92% (114/1646), which was significantly higher than that in cattle (1.57%, 2/127). A total of 40 cyst isolates were obtained, including 38 from sheep and 2 from cattle. Genomic DNA was extracted, and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was amplified by PCR to obtain the target 850 bp fragment. The results revealed that all the isolates had the G1 genotype, with similarities ranging from 98.88-100%. Haplotype network analysis revealed 32 haplotypes of the cox1 gene, among which Hap_7 was the main haplotype. Furthermore, haplotype diversity (Hd = 0.313 ± 0.093) and nucleotide diversity (π = 0.00173 ± 0.00079) were lower in the East Tianshan Mountains than in other regions, indicating that the populations are genetically less differentiated. Tajima's D and Fu's Fs tests were negative (p ≤ 0.01), indicating an expansion of the population in the East Tianshan Mountains of Xinjiang, similar to the results previously reported for Xinjiang. The low fixation index (Fst) ranged from negative values (Gansu Province) to 0.30346 (Mongolia), indicating that the genetic differentiation between the East Tianshan Mountains and Gansu, and Tibet, Xinjiang was relatively low, with frequent gene flow. In this survey, two 'new' haplotypes were identified in the East Tianshan livestock. In addition, two different haplotypes of liver and lung infections were found in one cattle. This survey provides information on the epidemiology and genetic diversity of E. granulosus s.s. in the East Tianshan Mountains of Xinjiang, China.

Egress represents a crucial process employed by Neospora caninum in the establishment of infection. Dense granule proteins (GRAs), secreted by the dense granule, play significant roles in modifying the parasitophorous vacuole, maintenance of morphology, and regulating host-cell interactions. However, their precise involvement in tachyzoite egress remains inadequately characterized. In this study, we identified a homologous gene, Ncgra41, corresponding to the dense granule protein 41 (GRA41) of Toxoplasma gondii, which is associated with egress, utilizing NCBI and ToxoDB databases. NcGRA41 is localized extracellularly within dense granules and intracellularly within parasitic vacuoles. Deletion of NcGRA41 did not affect tachyzoites invasion or proliferation but significantly reduced egress capacity and pathogenicity in mice. The phenotypic characteristics were restored in a complementary strain. Further investigation revealed that the absence of NcGRA41 reduced gliding motility and the transcription level of the subtilisin-like protein (SUB1). A microneme secretion assay demonstrated a significant decrease in NcMIC1 secretion, along with reduced expression levels of NcMIC1, NcMIC4, and NcMIC8. These findings demonstrate that NcGRA41, a novel dense granule protein in N. caninum, modulates tachyzoites egress and influences pathogenicity by regulating microneme secretion.

Babesia spp. and Theileria spp. are tick-borne apicomplexan protozoa that can cause disease in animals and humans. Deer are considered reservoirs for a wide variety of Piroplasmida species, including some potentially zoonotic. This study aimed to investigate the occurrence and genetic diversity of piroplasmids in wild deer sampled in four Brazilian states (São Paulo, Mato Grosso do Sul, Paraná and Goiás). For this purpose, extracted DNA samples from 181 deer buffy coat samples (138 Blastocerus dichotomus, 26 Subulo gouazoubira, 4 Mazama jucunda, 3 Mazama rufa and 10 Ozotocerus bezoarticus) were subjected to a nested PCR (nPCR) assay based on the 18S rRNA gene in order to perform a screening for piroplasmids and characterized based on the near-complete 18S rRNA, hsp70 and cox-3 genes. As a result, 75.14% (136/181) samples were positive for piroplasmids. Of these, 108 (79.41%), 101 (74.26%) and 67 (49.26%) were positive to near complete 18S rRNA, hsp70 and cox-3 genes, respectively. Phylogenetic analyses based on three molecular markers showed similar topology to each other. All sequences obtained in the present study were positioned into the Theileria sensu stricto clade, forming a distinct clade, albeit close to T. cervi. Most sequences grouped together into a large clade divided into subclades, which were often related to deer genus/species, showing that Theileria lineages seemed to show specificity according to deer genus/species. Two 18S rRNA sequences (one obtained from S. gouazoubira and another from M. jucunda) were positioned into a different clade, apart from other sequences detected in this study, indicating that different species of Theileria occur in deer from Brazil. Two subclusters were observed in the phylogenetic analysis based on the hsp70 gene: the first containing only sequences detected in marsh deer and the second grouping sequences detected in brocket deer (Mazama spp. and S. gouazoubira). The latter was also divided into smaller clades that grouped Theileria genotypes according to deer species (M. jucunda, M. rufa and S. gouazoubira). This study provides the first molecular evidence of Theileria infection in M. jucunda, as well as co-infection by distinct Theileria (sub)species/genotypes in the same deer was evidenced. Finally, this study expanded the knowledge on the diversity of Theileria spp. infecting deer from South America.

Asymptomatic carriers of Plasmodium falciparum represent important parasite reservoirs maintaining malaria transmission in the community. This study aimed on the one hand to screen the other household members living with children under seasonal malaria chemoprevention (SMC) coverage in order to determine the level of malaria infection in this population and on the other hand to determine the appropriate type of rapid diagnostic test (RDT) for this screening to detect these asymptomatic carriers in the community. During the 2022 SMC campaign (July to October), a cross-sectional survey was carried out in 745 participants who were screened by ultrasensitive rapid diagnostic test (usRDT), standard rapid diagnostic test (rRDT) and microscopy. Out of them, 395 had microscopy results available and were included in the data analysis. The prevalence of asymptomatic carriers of asexual forms of Plasmodium falciparum was 26.58% (105/395) while sexual forms were found in 5.32% (21/395) of the study population. Children from 5 to 15 years had the highest prevalence of P. falciparum asexual forms 35.76% (59/165) compared with older participants. Malaria positivity rate for rRDT and usRDT was 29.40% (219/745) and 40.49% (305/745) respectively. The usRDT had a higher sensitivity than the rRDT (72.38% (95% CI 62.8-80.66) vs. 60.95% (95% CI 50.94-70.33)). In terms of specificity, rRDT had a higher specificity 82.41% (95% CI 77.53-86.62) versus 69.66% (95% CI 64.01-74.89) for usRDT. This study reports a high prevalence of parasite carriers in household members of children under SMC coverage in Nanoro, Burkina Faso. In conclusion, usRDT seems more appropriate for strategies based on detection and treatment of parasite carriers within the community.

Perkinsus marinus, a parasite myzozoa native from the Atlantic Ocean, has spread across various bivalve species in the Pacific Ocean. In the Gulf of California, clams like Larkinia grandis and Leukoma grata have become a secondary fishery, experiencing demand. During annual sampling (August 2017 - July 2018, n = 30/month), the Ray's fluid thioglycollate medium (RFTM) revealed presumptive hypnospores of Perkinsus sp. in L. grandis, with a low parasite prevalence (4.16%) and density (≤ 3.14 hypnospores g^-1 tissue). From summer 2020 to summer 2021, P. marinus was seasonally identified in L. grata via staining and PCR tests, showing mean prevalence and density of 48.33% and 48 hypnospores g^-1 tissue, respectively. The infection level was light in both clams. This parasite's presence in these new hosts within the southeastern Gulf of California confirms its ability to expand into non-native places, signaling a need for intervention strategies in managing and transporting mollusk species within the region.

Ovine toxoplasmosis caused by Toxoplasma gondii is a zoonotic disease responsible for triggering reproductive problems in sheep with great public health impact. The zoonotic risk for humans occurs through the ingestion of meat contaminated with bradyzoites, water and vegetables contaminated with oocysts, or by ingesting unprocessed sheep milk contaminated with tachyzoites. The study aimed to determine the seroprevalence, isolate, and genetically characterize T. gondii from sheep in northeastern Brazil. Blood and tissue samples, including the liver, heart, brain, lung, and diaphragm, were collected from 256 sheep in slaughterhouses. The presence of anti-T. gondii IgG antibodies was assessed by the indirect fluorescent antibody test (IFAT), and sera with titers ≥ 1: 64 were considered positive. Tissue samples from seropositive sheep were digested in acidic pepsin solution and inoculated into two Swiss mice for T. gondii isolation and further characterized by molecular methods. The prevalence of anti-T. gondii antibodies in sheep was 31.64% and the isolation rate was 40.7%. Sixteen out of 33 isolates were submitted to mnRFLP-PCR using ten genetic markers. Four isolates were fully genotyped, and four isolates were amplified at least in one marker. All isolates were characterized as atypical genotypes, and ToxoDB #57 (n = 3) and #143 (n = 1) were identified. The detection of viable T. gondii in sheep from slaughterhouses in Brazil highlights the risk of human exposure. There is the need for proactive control and prevention measures to mitigate the risk of human exposure, considering the importance of sheep meat as a source of protein to humans.

Medicinal leeches of the genus Hirudo inhabit large areas of the Palaearctic realm. The distribution range of Hirudo troctina includes the southern Iberian peninsula and the northwestern regions of Africa. H. troctina is used for medical purposes, but only very little is known about the components of its salivary gland secretion. Hirudins, bivalent inhibitors of thrombin, are probably the best known leech-derived bioactive factors. Hirudin-like factors (HLFs) represent another class of salivary gland components that share characteristic genetic and structural markers with hirudins. Hirudin is not a single entity but exists in at least four different variants. However, there are differences among the European members of the genus Hirudo with respect to the actual number of hirudin and HLF genes that are present within their genomes. Here, we describe the identification and molecular cloning of 11 genes that encode for putative hirudin and HLF variants in H. troctina. Three of the genes consist of exons and introns that originate from different "archetype" genes and are likely the result of recombination events. The diversity of hirudin and HLF genes in H. troctina surpasses that of all other European members of the genus Hirudo. The putative hirudin variants and representatives of the HLFs of H. troctina were expressed as recombinant proteins, purified and functionally characterized for their thrombin-inhibiting potencies. Phylogenetic analyses based on hirudin and HLF gene sequences of the leech genera Hirudo, Hirudinaria, and Whitmania supported the hypothesis that hirudins and HLFs diverged early in leech evolution.