Acta Parasitologica最新文献

Purpose

This study aimed to identify and analyze the role of Ferric reductase inBlastocystis sp. subtype 2 (ST2) and explore the relationship between the parasite and iron metabolism.

Methods

The location of Ferric reductase in Blastocystis sp. was determined using the indirect immunofluorescence assay (IFA). Transmission electron microscopy was employed to reveal the effect of iron ions on the cell membrane of Blastocystis sp.. For the first time, RNA interference technology was used to explore the relationship between Ferric reductase and iron ions.

Results

Ferric reductase was distributed in the membrane and cytoplasm of the parasite. Iron reduces the thickness of the Blastocystis sp.'s cell membrane. After silencing the Ferric reductase gene, there was no significant difference in the morphology of the parasite strain compared with the control group. The expression level of the Ferric reductase gene does not play a decisive role in maintaining the morphology of the parasite, but the deletion of the Ferric reductase gene reduces the ability of the parasite to absorb iron ions.

Conclusions

This study fills the gap in the research field of iron metabolism inBlastocystis sp. among parasites, lays a foundation for the research on the gene function of Blastocystis sp., and provides new candidate factors for the development of Blastocystis sp. vaccines.

Introduction

The objective of the World Health Organization is to achieve the interruption of human African trypanosomiasis (HAT) transmission by 2030.

Methods

This review aims to update knowledge on HAT, through a synthesis on the epidemiology, diagnostic tools and drugs of HAT.

Results

From 1960 to 2024 approximately 132,063 cases of HAT have been reported across Africa. The majority of HAT patients live in the Democratic Republic of Congo (DRC). The Card Agglutination Test for Trypanosomiasis (CATT) remained for a long time the reference serology test for field screening. The immune trypanolysis test (ITL) test is an accurate serodiagnostic tool increasingly used for medical surveillance of sleeping sickness, but it is reserved for reference laboratories. Prototypes of TDRs such as SD BIOLINE HAT and, HAT Sero-K-SeT have been developed to respond to constraints posed with CATT and ITL, but lack specificity. Parasitological diagnosis techniques such as the mini-Anion Exchange by Centrifugation technique (mAECT) are used for mandatory confirmation of the disease before the initiation of treatment, but their sensitivity is low. To date, the active molecules against HAT are: pentamidine, suramin, melarsoprol, eflornithine and nifurtimox. The use of these molecules does not guarantee healing and generates many side effects. A new molecule has appeared in the therapeutic arsenal. This is fexinidazole, which was approved by the WHO in 2019 for the treatment of HAT due to T.b. gambiense. The WHO recommends the oral administration of this molecule in the first stage of the disease and in the second stage for non-severe cases. Since 2024, this molecule has also been approved by the WHO for the treatment of HAT due to T. b. rhodesiense.

Conclusion

All these difficulties raised raise questions about the need to develop new diagnostic tools that are more specific, more sensitive and better suited to field screening. They also call out the urgency of finding new drugs that are less toxic, easy to administer and more effective.

Toxoplasma gondii, as an obligatory intracellular protozoan, can infect a diverse array of individuals and warm-blooded creatures. Considering the worldwide public health implications caused by T. gondii infection, it is an important goal to develop effective diagnostic tests or vaccines. The application of natural antigens derived from the parasite in these assessments encounters challenges, including the complexities of culturing the parasites, strain differences, and the high cost of kits produced based on natural antigens. The current bioinformatic study aimed to develop a multi-epitope T. gondii protein based on various immunoinformatic web servers to improve serodiagnosis. The linear and conformational B-cell epitope prediction of Surface Antigens 1(SAG1) and 2(SAG2), Dense granule proteins 2 (GRA2), 6 (GRA6), and 7 (GRA7), was conducted by the ABCpred and BepiPred servers, respectively. A variety of web servers were then accessed to predict antigenicity, solubility, and physicochemical properties, as well as to analyze secondary and tertiary structures, refine the 3D model, and validate the findings. Consequently, conformational B-cell epitopes were identified to explore potential protein-antibody interactions. In conclusion, further experimental evaluation is necessary for this multi-epitope construct for its subsequent incorporation in commercial serodiagnostic kits.

Purpose

Taenia pisiformis cysticerci have been reported in the female reproductive tract of rabbits, and this parasitosis is known to alter reproductive behavior and reduce embryo implantation; however, tissue-based studies relating the immune system to the implantation site during infection have not been previously addressed. Therefore, our research provides new information on the interaction between pregnancy and parasitic infection.

Methods

This study evaluated the recruitment of immune cells in uterine tissue during T. pisiformis infection. Fourteen female rabbits were experimentally infected with 1,000 T. pisiformis eggs and mated with a male on day 50 post-infection. Eight days after mating—corresponding to the mesometrial stage of implantation— tissue samples were collected from the middle third of the right uterine horn at the site of embryonic implantation, following the sampling rationale described in previous literature. Samples were fixed and processed using paraffin-embedding techniques, and histological sections were stained with hematoxylin and eosin. Three sections per rabbit were analyzed across 18 fields per group, each field measuring 2,960 μm². Mucosal height was measured, and lymphocytes and macrophages were quantified in the mucosa based on morphological criteria.

Results

The results showed a significant increase in lymphocyte and macrophage infiltration at the implantation sites of infected does compared to controls (p < 0.05), along with a 49% increase in mucosal height. No cysticerci were found in the uterine tissue, but metacestodes were observed in the pelvic region in 33% of infected animals, with a mean of 3.1 ± 2.6 cysticerci per animal.

Conclusion

These findings suggest an increased immune cell infiltration and marked uterine mucosal remodeling in infected does, potentially interfering with embryo establishment and development. We acknowledge that hormonal and cytokine measurements were not performed in this study; therefore, future research should address these parameters to clarify the underlying mechanisms.

Background

The whole plant of Evolvulus nummularius is traditionally used to treat helminth infections in Assam, India. This study was taken to evaluate the efficacy of its methanolic extract in suitable models in vitro and in vivo.

Methods

Hymenolepis diminuta exposed in vitro to E. nummularius were also studied for damages to its tegument using scanning electron microscopy. Also, the plant extract’s ability to inhibit AChE activity was assessed. The extract was later processed for GC-MS analysis to detect the phytocompounds present.

Results

In vitro study showed significant efficacy against H. diminuta and in vivo study revealed 76.93% and 71% reduction in eggs and worm counts respectively against juvenile H. diminuta worms, whereas, the extract caused 80% and 79.25% reduction in these parameters against H. diminuta adult worms. The extract also showed to cause 55.73% reduction in AChE activity. H. diminuta worms exposed to plant extract showed deformities in the suckers, tegument, microtriches and suckers. Its GC-MS study revealed the presence of (-)-deoxyephedrine, methamphetamine, 1-(5-methoxy-2-methylphenyl)-N-methylpropan-2-amine, ethyl vanillin, 3,4-dihydroxypropiophenone, and 1-(1,4-cyclohexadienyl)-2-methylaminopropane.

Conclusion

The results infer that E. nummularius possess significant anthelmintic activity and may be used in traditional medicine.

Introduction

This study aimed to investigate the influence of benznidazole (BZN) origin on its in vitro potency against various Trypanosoma cruzi strains.

Methods

Pure BZN, purified BZN, and the pharmaceutical formulation Abarax were evaluated for their activity against several parasite strains.

Results

Results demonstrated significant variability in BZN’s effectiveness, contingent upon both its specific form and the T. cruzi strain under investigation. Half-maximal inhibitory concentrations (IC₅₀ values) exhibited a wide range, indicating that the potency of BZN is not uniform across all its forms or against all parasite strains.

Conclusion

In conclusion, this study elucidates the complex interaction between BZN and T. cruzi. The parasite’s response to BZN can vary even within a single strain, influenced by the drug’s specific presentation. These findings underscore the critical importance of considering both parasite diversity and drug formulation when assessing the efficacy of treatments in laboratory assays.

Purpose

Molecular epidemiological studies focusing on the phylogenetic characterization of Theileria annulata are crucial for understanding the evolutionary history of the parasite worldwide. The current study reveals genetic diversity among Indian isolates of T. annulata based on the cyt b gene.

Method

In the present study, cyt b gene from 6 calf isolates of T. annulata was amplified; custom sequenced and accession numbers: MH778940-MH778945 were obtained.

Result

Two haplotypes were identified, differing by nucleotide substitutions at positions 710 (thymine to adenine) and 1076 (cytosine to guanine). Isolates from Northern India formed a distinct cluster on the phylogenetic tree compared to those from Southern India and showed closer phylogenetic similarity to Iranian isolates than to other Asian counterparts.

Conclusion

Important phylogenetic data has been generated from the present study suggestive of marked genetic variability in T. annulata isolates across the globe.

Purpose

Blastocystis is one of the most prevalent intestinal protists detected in humans and animals worldwide, and its role in human health and disease has become an increasingly debated topic in parasitology. The study investigated the therapeutic potential of Allium tuncelianum extract, an endemic plant of Turkey, as an alternative treatment for Blastocystis ST3 infections.

Methods

The experimental animals were infected with Blastocystis ST3. The animals were divided into six groups: healthy control (G1), infected control (G2), infected Allium tuncelianum extract treatment (G3a, G3b, and G3c) and infected Metronidazole treatment (G4). Microscopic examination and qPCR methods were used to determine Blastocystis load in fecal samples.

Results

The G3c group (250 mg/kg/day Allium tuncelianum) complete (100.0%) microscopic clearance of Blastocystis load in fecal samples was achieved by day 12th, whereas the Metronidazole group (G4), showed only an 84.1% reduction. Moreover, qPCR results revealed lower Blastocystis loads in groups G3c and G3b compared to Metronidazole. A statistically significant decrease in fecal Blastocystis load was observed in all treated groups compared to the infected group (G2) (p < 0.0001). Blastocystis load in fecal sample reduction exhibited a dose-dependent pattern across all Allium tuncelianum treatment groups, confirming the dose-dependent therapeutic effect of the extract. Allium tuncelianum extract, especially at higher doses, may serve as a natural, effective, and safer alternative or supplement to Metronidazole in the management of Blastocystis infection.

Conclusion

This study demonstrated that Allium tuncelianum extract exhibited superior therapeutic efficacy against Blastocystis ST3 compared to Metronidazole. The findings suggest that regular dietary consumption of Allium tuncelianum could represent a promising natural alternative for managing Blastocystis infections.

Objective

Aedes (Stegomyia) albopictus, commonly known as the Asian Tiger mosquito, is native to tropical and subtropical regions of South and East Asia and has rapidly spread globally. Due to its role as a vector of several medically important arboviruses, understanding its genetic diversity and dispersal patterns is crucial for effective disease control. This study aimed to evaluate the genetic structure insights of Ae. albopictus populations in southeastern Brazil.

Methods

Mosquito samples from five populations in southeastern Brazil were analyzed using two mitochondrial genes: cytochrome c oxidase subunit 1 (COI) and NADH dehydrogenase subunit 5 (ND5). Phylogenetic analysis and population genetic metrics were employed to assess patterns of genetic diversity and population structure.

Results

Moderate haplotype diversity was observed, with five COI haplotypes (Hd = 0.43) and eleven ND5 haplotypes (Hd = 0.52), along with low nucleotide diversity. Neutrality tests for ND5 yielded significantly negative values (Fs = -2.435*). Phylogenetic trees identified two major clades, with ND5 haplotypes from Paranaguá and Guaraqueçaba clustering together. A positive correlation between genetic and geographic distance (COI r = 0.78; ND5 r = 0.69) proposing isolation by distance.

Conclusion

The close genetic relationships and limited variation among Brazilian Ae. albopictus populations indicate ongoing gene flow and a shared ancestry. The association of Paraná haplotypes with Asian lineages suggests a genetic link to the region of origin of species, although the timeline of introduction remains uncertain. These results provide important molecular insights to support vector surveillance and control efforts in southern Brazil.

A cross-sectional study was conducted in three governorates of the Nile Delta region in Egypt from January to December 2024. The objective was to determine the seroprevalence of bovine trypanosomosis and evaluate associated risk factors. A total of 540 cattle blood samples were examined using the CATT/T. evansi test, and relevant animal data were analyzed to identify risk associations. The overall prevalence of trypanosomosis was 24.4% (132/540), with the highest rate observed in Kafr El-Sheikh governorate at 26.1% (49/188). The prevalence was significantly associated with age, packed cell volume (PCV), and body condition score (P < 0.05). Multivariable logistic regression analysis showed that the likelihood of infection increased fourfold in cattle older than 3 years, twofold in anemic animals, and threefold in those with poor body condition. The findings indicate that bovine trypanosomosis is a prevalent among examined cattle in the area studied. Therefore, the implementation of strategic prevention and control programs is essential to improve livestock health and productivity.