Acta Parasitologica最新文献

Purpose

Blastocystis spp. is the most commonly identified protozoan in humans, yet its clinical significance and pathogenicity remain controversial. While often asymptomatic, it has been associated with gastrointestinal symptoms and urticaria. Metronidazole is the most frequently used first-line treatment; however, increasing reports of resistance and treatment failure have led to growing interest in alternative therapeutic options.

Methods

In this systematic review, we searched the Web of Science, Scopus, and PubMed databases using relevant keywords in article titles to identify studies related to the treatment of Blastocystis spp.

Results

A total of 195 records were retrieved. After removing duplicates and applying inclusion and exclusion criteria, 39 studies were deemed eligible. Data extracted included author, publication year, country, number of participants or samples, diagnostic method, subtype, treatment agent, dosage, intervention details, and clinical and parasitological outcomes. Of the included studies, 17 were human studies (14 clinical trials and 3 case reports), and 22 were in vitro or animal studies.

Conclusion

Our findings suggest that metronidazole may be inappropriate as a first-line treatment, as it can increase the number of viable parasites and promote their transformation into apoptosis-resistant granular or more pathogenic amoeboid forms. Alternative agents—such as ronidazole, satranidazole, and C17 (2-position 5-nitroimidazoles), as well as ornidazole, secnidazole, and tinidazole (1-position 5-nitroimidazoles with different side chains compared with metronidazole)—show potential efficacy. Trimethoprim-sulfamethoxazole and nitazoxanide have also demonstrated promising results. Further studies, particularly subtype-specific and human clinical trials, are needed to assess the safety and efficacy of these alternative agents against Blastocystis spp.

Toxoplasma gondii is a widespread zoonotic parasite with significant public health and veterinary importance. This cross-sectional study was conducted between November 2023 and October 2024 to determine the seroprevalence of Toxoplasma gondii infection and associated risk factors in sheep from Nineveh Governorate, northern Iraq. A total of 507 serum samples from 30 herds were tested using a commercial indirect enzyme-linked immunosorbent assay (ELISA) kit. The overall seroprevalence was 38.1% (95% CI: 34.0–42.4), with 83.3% of herds having at least one seropositive animal. Statistical analysis revealed significant associations between seropositivity and flock size, grazing system, water source, cat presence, and season. Larger flocks, open grazing, untreated water, presence of cats, and spring season were all strongly linked to higher prevalence. In contrast, host age and sex were not significant predictors. These findings highlight the importance of flock-level and environmental factors in disease transmission. Practical control measures such as improved water management, limiting cat access, and farmer education are essential to reduce infection risk.

Purpose

Cryptosporidium and Giardia are significant causes of gastrointestinal diseases in humans and animals worldwide, especially in pigs. This study investigated the molecular occurrence, genetic diversity, and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in domestic pigs in the Chattogram Hill Tracts (CHT), Bangladesh.

Methods

A total of 408 fecal samples were collected from Rangamati, Khagrachari, and Bandarban districts and examined using nested PCR, targeting the SSU rRNA gene for Cryptosporidium and the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes for G. duodenalis. Nucleotide sequencing and phylogenetic analysis were conducted for molecular characterization.

Results

The prevalence of Cryptosporidium was 3.43%, and G. duodenalis was 23.52%. The prevalence varied by several factors, although the variations were not significant for Cryptosporidium. Age, anthelmintic administration, and diarrheal status of the pigs had a significant influence on the occurrence of Giardia. Among the 14 Cryptosporidium and 96 Giardia isolates, two Cryptosporidium species (C. suis and C. scrofarum) and three G. duodenalis assemblages (A, B, and E) were found, among which assemblage A (56.25%) was the most prevalent. Additionally, 13 novel genotypic variations were identified at the bg, gdh, and tpi genes of G. duodenalis.

Conclusion

Pigs in the CHT region harbor Cryptosporidium and Giardia with notable genotypic diversity and zoonotic potential. Addressing this issue requires further research within a One Health framework, focusing on integrated surveillance and the development of evidence-based policies for pig farming to reduce transmission and safeguard animal and public health.

Graphical Abstract

DNA methylation is a key epigenetic mechanism regulating gene expression during spermatogenesis. This study investigated the effects of experimental amebiasis induced by Entamoeba histolytica and its treatment with metronidazole (MTZ) on the methylation status of the Spermatogenesis Associated 6 (SPATA6) gene and male reproductive function. Twenty-four adult male rats were assigned to control, infected, and MTZ-treated groups. Following treatment, testicular tissues were analyzed for SPATA6 promoter methylation via bisulfite sequencing, infection confirmation by PCR, histopathological changes by hematoxylin and eosin (H&E) staining, Inhibin B and Androgen-Binding Protein (ABP) expression by immunohistochemistry, and sperm quality indices. The infected group exhibited distinct non-CpG methylation at a SPATA6 locus, confirmed reproductive tract infection, severe testicular damage, increased expression of Inhibin B and ABP, and significantly impaired sperm parameters. MTZ treatment successfully cleared the parasite and partially restored testicular architecture and sperm count; however, residual abnormalities in sperm motility, histology, and SPATA6 methylation persisted. While these findings suggest that parasitic infection and its treatment may induce epigenetic dysregulation in the testis, the direct functional link between the observed methylation change and reproductive outcomes remains inconclusive due to the limited scope of analysis. These results underscore the need for genome-wide methylation and transcriptomic profiling to better characterize the molecular basis of infection- and treatment-related reproductive effects. The study provides initial insights into infection-associated epigenetic modulation in male reproduction, with potential implications for fertility and reproductive health.

Babesiosis is endemic in Pakistan and significantly impacts bovine health, leading to economic losses and high mortality rates among young animals. This study aimed to determine the prevalence of Babesia bigemina and identify associated risk factors in Pakistani bovines. A total of 663 blood samples were collected systematically from 430 cattle and 233 buffaloes in the Lahore district of Punjab province. The samples were analyzed using microscopy and by PCR targeting the amplification of the apical membrane antigen (AMA-1) gene followed by gene sequencing. The overall prevalence of B. bigemina was 19%, with higher rates in cattle (21.86%) compared to buffaloes (13.73%). (Odds Ratio: 181.18, 95% Confidence Interval: 34.30–957.05). Male animals were more prone to infection than female animals, with an Odds Ratio of 1.65 (95% CI 1.08–2.53). Phylogenetic analysis revealed that local B. bigemina strains closely resemble a previously reported Pakistani strain, differing from global isolates. Age, sex, species, season, and tick control practices were identified as significant risk factors (Adjusted Odds Ratio > 1). Age, sex, species, season, and tick control practices were identified as significant risk factors (Adjusted Odds Ratio > 1). The study underscores the need for public awareness strategies to reduce B. bigemina prevalence, improving livestock health and productivity.

Purpose

Entomopathogenic nematodes are promising biocontrol agents offering environmentally sustainable alternatives to chemical insecticides. The present study aimed to isolate, identify, and evaluate the bioefficacy of a new Steinernema sp. DA-1 isolate from a forest ecosystem in Bihar, India, with potential application in the management of major lepidopteran pests.

Methods

A new isolate of S. abbasi was recovered through Galleria baiting from soil samples. Morphological and morphometric analyses were conducted to confirm its identity, followed by molecular characterization using the Internal Transcribed Spacer region marker. Phylogenetic relationships were analyzed to determine genetic divergence from other known S. abbasi isolates. Laboratory bioefficacy assays were conducted against different larval instars (3rd, 4th, and 5th) of Mythimna separata and Spodoptera litura. Average time taken to kill and LD₅₀ (lethal dose for 50% mortality) values were calculated.

Results

Morphological, morphometric, and molecular analyses confirmed the identity of the isolate as S. abbasi. Phylogenetic analysis placed it within the S. abbasi clade, showing subtle genetic divergence, indicating local adaptation, except for certain isolates (accession no. KR029837, KR029836, KR029837), which exhibited high divergence. Bioefficacy assays demonstrated significant dose- and age-dependent mortality in both M. separata and S. litura. LD₅₀ values at 48 h post-infection was 30, 35 and 42 infective juveniles (IJs) and 30, 36 and 41 IJs per larva for third, fourth, and fifth instars of M. separata and S. litura respectively. The highest concentration (T5) caused mortality within 28.8 h in third-instar larvae, significantly faster compared to lower concentrations.

Conclusion

This study provides the first validated report of S. abbasi from Bihar, India, revealing its strong virulence against major lepidopteran pests under laboratory conditions. These findings highlight its potential as a biological control agent, warranting further pot and field evaluations before its possible inclusion in regional sustainable pest management programs.

Introduction

Anisakiasis is a zoonotic parasitic disease transmitted through consumption of fish, with increasing global cases. While thorough cooking kills Anisakis larvae, thermo-stable allergens can still cause allergic reactions. Traditional Mediterranean seafood methods such as marinating, salting, and brining, which lack heat treatment, pose a high risk of anisakiasis.

Materials and methods

This study investigated the antilarval effects of nanoemulsions made from thyme, garlic, and grape seed essential oils combined with brines on Anisakis L3 larvae in vitro.

Results

Larvae were collected from mackerel, chub mackerel, anchovy, horse mackerel, and sardine, with 1746 larvae examined, mostly Anisakis type I and molecularly identified as A. pegreffii. Thyme oil’s main components, carvacrol and thymol, showed strong antimicrobial and antioxidant effects and superior larvicidal activity at lower doses compared to garlic and grape seed oils. Garlic oil, rich in organosulfur compounds, was more effective in Lakerda samples. High salt brine alone inactivated larvae within 24 h. The thyme oil nanoemulsion had droplet sizes below 90 nm, enhancing stability, whereas garlic and grape seed oils had larger droplets.

Conclusion

These results indicate that nanoemulsified essential oils, especially thyme oil, are promising natural agents to control Anisakis larvae in traditional sea-food products.

Purpose

This study aims to investigate the trematode species of white (Ciconia ciconia) and black storks (Ciconia nigra) in Turkey by morphological and molecular methods. This study aims to present new molecular characterizations of species, previously described only morphologically, and to enhance knowledge of the parasitic fauna of storks, which have an important place among migratory birds.

Methods

A total of nine stork cadavers (eight white and one black) were parasitologically examined. The trematodes obtained were washed in physiological saline, preserved in 70% ethanol, and then followed by morphological analyses. DNA extraction was performed from selected individuals, and phylogenetic analyses used partial 28S rDNA and cox1 gene regions. Species identification was supported by both morphometric and molecular data.

Results

A total of four trematode species were identified using morphological and molecular methods, namely Cathaemasia longivitellata (Plagiorchiidae), Chaunocephalus ferox (Echinostomatidae), Georduboisia syriaca (Cyathocotylidae), and Stomylotrema pictum (Stomylotrematidae). Partial cox1 gene region (for Ch. ferox and G. syriaca), and partial 28S rDNA gene region (for Ca. longivitellata, G. syriaca, and S. pictum) were successfully sequenced. This study provides the first molecular data for G. syriaca and S. pictum and the first cox1 gene data for Ch. ferox and.

Conclusion

The findings extend the existing knowledge on the trematode fauna of storks and reveal the importance of using morphological methods in combination with molecular approaches. This study provides preliminary information for future ecological and epidemiological studies on bird trematodes.

Purpose

Rhipicephalus microplus is a bovine ectoparasite that causes economic losses due to direct damage to the host, the cost of treatments, and the transmission of diverse pathogens. We have previously identified the protein VDAC (BmVDAC) from the midgut of R. microplus. Furthermore, we demonstrated the efficacy of BmVDAC in a bovine vaccination trial. Additionally, BmVDAC interacts with the sexual stages of Babesia bigemina, and its expression increases in ticks during infection with the parasite. Hence, we are interested in studying the function of this protein.

Methods

Molecular docking was used to predict that BmVDAC binds to the Kringle 5 (K5) domain of plasminogen, ligand blotting techniques, and inhibition of binding assays with the lysine analog εACA were performed to demonstrate the specificity of the binding.

Results

The docking analysis predicted the binding of the BmVDAC to the K5 domain, with a lysine participating in this interaction. The ligand blotting and inhibition assays demonstrated the specificity of the binding of the two proteins. Additionally, the results of a plasminogen activation assay showed that BmVDAC increases plasminogen activation.

Conclusion

This is the first report of a VDAC protein from a nonmammalian organism that interacts with and enhances the activation of plasminogen. The results indicate that the binding of the two proteins is specific, and the binding of BmVDAC promotes the conversion of plasminogen into active plasmin.

The anticoccidial potential of Opuntia ficus-indica seed oil (OFI-SO) and its hexane extract from seed press cake (OFI-HexPC) was evaluated against Eimeria spp. using integrated in vitro and in silico approaches. Sporulated Eimeria oocysts were exposed to increasing concentrations (2–64 mg/mL) of OFI-SO and OFI-HexPC in Hank’s balanced salt solution. Oocyst viability was determined by microscopic counting, while membrane integrity was assessed by quantifying the release of 273 nm-absorbing substances. Toltrazuril (25 mg/mL) was used as a positive control. GC–MS profiling of both extracts revealed linoleic acid (54.2%) and oleic acid (25.7%) as the main bioactive fatty acids. GC–MS profiling revealed that linoleic acid (69.63%) was the major fatty acid in OFI-SO, while oleic acid (44.20%) predominated in OFI-HexPC. Both OFI-SO and OFI-HexPC significantly reduced oocyst counts and induced a dose-dependent increase in DNA release. In silico molecular docking was performed against three key Eimeria enzymes (EtDHODH, CDPK, and PKA). Identified fatty acids showed moderate binding affinities through hydrophobic interactions. Redocking validation (RMSD < 2 Å) confirmed the reliability of the docking protocol. ADMET predictions indicated favorable pharmacokinetics and safety profiles. These findings suggest that OFI-SO and OFI-HexPC act via a dual mechanism involving membrane disruption and enzymatic inhibition, supporting their potential as natural alternatives to synthetic anticoccidials in poultry production.