Acta Parasitologica最新文献

Purpose

Henneguya sp. is a crucial myxosporean parasite known to cause milky flesh or tapioca disease in the freshwater fish population, leading to heavy mortality. Studies to investigate its host range and to monitor their prevalence in wild and aquacultured fish are necessary.

Methods

The infected orange-spotted snakehead (Channa aurantimaculata) fish samples showing clinical signs such as severe ulceration and open wounds on the mouth and operculum were collected from an ornamental fish-rearing unit in Chennai, Tamil Nadu. The sample was diagnosed with myxosporean infection by microscopic observation, morphological records and DNA sequencing followed by phylogenetic analysis.

Results

The Henneguya infection was identified in C. aurantimaculata for the first time. Necropsy of the infected fish revealed characteristic multifocal whitish-yellow, oval-shaped cysts measuring 3–5 mm in length on the liver and spleen. The wet mount of cysts showed numerous mature Henneguya spores that were uninucleate, elongated, lenticular and ellipsoidal with the bluntly rounded anterior end gradually tapering off to the posterior with a caudal elongation. The spore body measured 12.1 ± 0.9 μm (10.1–14.7 μm) × 7.1 ± 0.6 μm (5.3–8.5 μm) with two slightly unequal pyriform polar capsules of 6.1 ± 0.5 μm (5.1–7.4 )× 2.5 ± 0.4 μm (1.6–3.9) (large); 6.0 ± 0.4 μm (5.2–6.4) × 2.5 ± 0.3 μm (1.7–3.1) (small) and a caudal elongation of 16.1 ± 1.2 μm in length. The parasite was confirmed to be a Henneguya sp. by PCR amplification of SSrRNA followed by gene sequencing. The sequence generated was submitted in the GenBank under accession number PP852214.1 The maximum likelihood analysis revealed that the obtained sequence is a close relative of H. exilis with pairwise sequence variation of 3.3% and a homology of 99.04%.

Conclusion

The findings highlight the potential impact of Henneguya sp. on ornamental fish health, underscoring the need for vigilant monitoring and management in India.

Haemonchus contortus has caused significant economic losses in many regions. The emergence of drug resistance has created new difficulties for the prevention and control of parasitic diseases in cattle and sheep. The mechanism of drug resistance to ivermectin in H. contortus is not clear; therefore, it is of great significance to study it. Non-coding RNAs, especially microRNAs (miRNAs), play important roles in drug resistance in some human tumors and insects. However, few studies have investigated whether miRNAs are involved in the regulation of drug resistance to ivermectin. In the early stages of this study, four miRNAs that may be involved in the regulation of ivermectin resistance in H. contortus were identified by high-throughput sequencing analysis of ivermectin-sensitive and -resistant strains of H. contortus. To verify whether these miRNAs are indeed related to ivermectin resistance in H. contortus, RNA interference (RNAi) experiments were performed on these miRNAs. The expression of candidate drug-resistance-related miRNA target genes before and after RNAi was detected by quantitative polymerase chain reaction. The resistance of the third-stage larvae (L3s) of H. contortus before and after RNAi was detected using 0.5% dimethyl sulfoxide and 100 µg/mL ivermectin treatment. The locomotion behavior of the L3s of H. contortus before and after RNAi was detected by counting the frequency of head thrashes and body bending. Finally, we confirmed that miR-10,025-y, miR-5960-z, miR-27-y, and miR-276-y were involved in and regulate ivermectin resistance in H. contortus.

Purpose

Acanthamoeba species are eucaryotic protozoa found predominantly in soil and water. They cause ulceration and vision loss in the cornea (Acanthamoeba keratitis) and central nervous system (CNS) infection involving the lungs (granulomatous amoebic encephalitis). Antiparasitic drugs currently used in the treatment of infections caused by Acanthamoeba species are not effective at the desired level in some anatomical regions such as the eye and CNS. The existence of an agent effective against both cysts and trophozoites has not yet been proven. Drugs used for treatment of Acanthamoeba infrections are still limited.

Method

The present study investigates amoebicidal activites of various concentrations of ethanolic fruit extract of E. umbellata (EU) (40, 20, 10, 5, 2.5, 1.25, 0.625 mM/mL), silver nanoparticles (AgNP) that are synthesized from EU and confirmed with characterization tests (20, 10, 5, 1, 0.5 mM/mL), and lauric acid (LA) in EU detected with gas chromatography–mass spectrometry (GC–MS) against A. castellanii trophozoites. In addition, DNA-preserving activities of EU, AgNP and LA were studied on pBR322 plasmid DNA, following damage induced with hydroxyl radical (–OH). Cytotoxicity of EU over HeLa cells was examined with 3–(4,5–dimethylthiazol–2–yl)–2,5–diphenyltetrazolium bromide (MTT). Furthermore, the effects over the expression of SOD and CAT genes, which are coding oxidative stress enzymes in trophozoites, and expression of genes responsible for pseudocyst and cyst formation (CSII and CSP21, respectively) were investigated following methanol-induced stress, with reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR).

Results

At highest concentrations, EU, AgNP and LA showed lethal effects against majority of trophozites at 24 th h and against all trophozoites at 48th hour. EU at 5 mg/mL concentration and LA at 1, 0.8, 0.6, 0.4 mM/mL concentrations prevented DNA damage. A dose-dependent decrease in cell viability was observed, EU was found to be non-cytotoxic for 53.82% of HeLa cells at 72 nd h even at 40 mg/mL concentration. Greatest inhibitory effects were found with EU, AgNP and LA on CSII, EU on CAT, LA on CSP21, and hydrogen peroxide (H₂O₂) on SOD genes.

Conclusion

The findings of this study show that EU, LA and AgNPs can be used in a controlled manner to combat A. castellanii infections by reducing or blocking the activity of the parasite’s antioxidant enzymes (SOD and CAT), without giving the parasite a chance to initiate the process of pseudocyst or proper cyst formation.

Purpose

Cryptosporidium spp. and Giardia duodenalis are zoonotic protozoan parasites that are widely seen in domestic and wild animals worldwide. While these pathogens, which affect the digestive system of the hosts, cause high economic losses in animal breeding, they are also considered an important public health problem. In recent years, molecular-based studies revealed that 120 genotypes belonging to 44 Cryptosporidium species and eight G. duodenalis assemblages (G. duodenalis A–H) circulate among hosts. The aim of the study was to determine the presence and prevalence of cryptosporidiosis and giardiosis in buffaloes, for which there was only one previous study on the subject in Türkiye.

Methods

In this study, Cryptosporidium spp. and Giardia duodenalis were researched in water buffaloes using polymerase chain reaction (PCR) and DNA sequencing. A total of 510 water buffalo stool samples were obtained from Sivas province, an important water buffalo breeding center in Türkiye.

Results

Cryptosporidium spp. were detected in 20 samples (3.92%), whereas five samples (0.98%) were found to be infected with G. duodenalis. DNA sequence analyses of 18S rRNA and β-giardin genes revealed that five Cryptosporidium species, C. occultus (n = 1), C. andersoni (n = 1), C. ryanae (n = 16), C. parvum (n = 1), and C. bovis (n = 1), and G. duodenalis assemblages E were circulated in water buffaloes in Türkiye, respectively. In this work, C. ryanae was the most prevalent Cryptosporidium species, and DNA sequence analyses of these samples showed that 100% nucleotide identities were present between them. Cryptosporidium occultus (PP754270), C. andersoni (PP754271), C. ryanae (PP754272–PP754279, PP754281–PP754285, PP754287–PP754289), C. parvum (PP754280), and C. bovis (PP754286) obtained from water buffaloes in this study shared 98.59–100%, 99.88–100%, 99.49–100%, 99.62–100%, and 99.87–100% nucleotide similarity with isolates present in GeneBank, respectively. In addition, G. duodenalis (PP798352–PP798356) isolates had 99.56–100% (β-giardin) nucleotide identities with G. duodenalis isolates.

Conclusion

The existence of cryptosporidiosis (the five species) in water buffaloes was reported for the first time in the country. Moreover, one species (C. occultus) has been reported for the first time in Türkiye.

Purpose

A comprehensive survey was conducted to assess the prevalence of Schistosoma japonicum infection in humans, water buffaloes, and snails in the two endemic municipalities of Talibon and Trinidad in Bohol, Philippines, which are nearing elimination.

Methods and Results

Human stool and blood samples were collected from barangays with snail breeding sites, and results showed higher positivity rates using the rSjTPx-1-ELISA compared to the Kato-Katz technique. Human stool examination for showed a 0.57% positivity rate for S. japonicum in San Vicente, Trinidad, while no cases were found in San Roque, Talibon. On the other hand, 3.43% of human serum samples from San Vicente, Trinidad, and 46.20% from San Roque, Talibon tested seropositive. Similarly, water buffalo samples revealed 16.95% seropositivity in Talibon and 10% in Trinidad. Additionally, snail infection was determined microscopically from collected Oncomelania hupensis quadrasi snails in Talibon, but no schistosome parasites were detected in the crushed snail tissues.

Conclusion

These findings highlight that despite progress towards elimination, schistosomiasis transmission persists in these areas, emphasizing the need for continued surveillance and targeted interventions.

Background

Intestinal parasitic infections are a significant public health concern, especially among food handlers, who can transmit these infections to the public through food preparation and handling. This systematic review and meta-analysis aimed to determine the pooled prevalence and associated factors of intestinal parasitic infections among food handlers in the East African region.

Methods

A systematic review and meta-analysis on intestinal parasitic infections among food handlers involved a comprehensive search across various databases, including Scopus, PubMed, ScienceDirect, Google Scholar, and the institution’s library registers. Forty relevant articles were identified and analyzed using STATA Software version 17.0. Sensitivity analysis, publication bias assessment with Egger’s test, and the Trim-and-fill meta-analysis for bias adjustment were conducted. Heterogeneity across the studies was assessed using Cochran’s Q statistic and I² statistics, and subgroup analysis computed for significant heterogeneity (I² value ≥ 50%). A random effect model was used to determine the pooled prevalence of intestinal parasitic infections.

Results

The pooled prevalence of intestinal parasitic infections among food handlers was 32.27% (95% CI 27.90–36.65). The most prevalent parasites were Entamoeba histolytica/dispar 20.83% (95% CI 13.66–28%), Ascaris lumbricoides 13.84% (95% CI 10–17.68%), Giardia lamblia 8.55% (95% CI 6.03–11.06%), and hookworm 6.43% (95% CI 3.93–8.93%). Using a common knife for cutting raw meat (AOR = 2.27, 95% CI 1.21–4.31), food handler’s untrimmed fingernails (AOR = 2.14, 95% CI 1.50–2.78), and no hand washing practices with soap after using the toilet (AOR = 2.25, 95% CI 1.33–3.18) were associated with higher rates of intestinal parasitic infections among food handlers.

Conclusions

Parasitic infections among food handlers were found to be significantly prevalent. Factors contributing to this high prevalence included food handlers’ untrimmed fingernails, poor hand hygiene practices, and using a shared knife for chopping various food items, including raw meat. These findings emphasize the need for proper personal hygiene and sanitation practices among food handlers to prevent transmitting parasitic infections to consumers.

Purpose

The current study aimed to investigate the trophocidal and cysticidal activities of cinnamaldehyde (Cinn), a natural compound with known antimicrobial properties, against environmental and reference strains of Acanthamoeba castellanii. Additionally, we explored the potential benefits of Cinn formulated as a nanoemulsion (Cinn-NE) in enhancing its efficacy.

Methods

Cinn-NE was prepared using the ultrasonic emulsification method. The amoebicidal effect of Cinn was evaluated against both trophozoites and cysts of reference and environmental strains of Acanthamoeba, along with an assessment of whether nanotechnology enhances this effect.

Results

Our results demonstrated that Cinn exhibited strong activity against both trophozoites and cysts of Acanthamoeba. Importantly, Cinn-NE showed enhanced activity compared to pure Cinn, possibly due to increased surface area and improved interaction with microbial membranes. In this study, the difference in susceptibility to Cinn and Cinn-NE between the environmental and the reference strain of A. castellanii was observed. Acanthamoeba cysts were more resistant to the effects of Cinn or Cinn-NE than trophozoites. Additionally, we found that nutrient availability in the medium influenced the susceptibility of Acanthamoeba to Cinn and Cinn-NE. A nutrient-deficient medium reduced their vulnerability to destruction, suggesting a role for nutrient availability in the response of Acanthamoeba to antimicrobial agents.

Conclusion

In conclusion, our study highlights the potential of Cinn and Cinn-NE as effective agents for combating Acanthamoeba infections. Further research is needed to elucidate the specific mechanisms underlying the differential susceptibility to Cinn, optimize its use as a treatment or surface disinfectant, and explore Acanthamoeba's cellular and molecular responses to nutrient availability.

Purpose

The aim of the present study was to establish a SYBR Green-based real-time PCR assay for detection of the Nc5 segment from the Neospora caninum genome.

Methods

The oligonucleotides sequences targeting the Nc5 gene previously reported and designed in-house were validated. Two Primer sets were evaluated and tested in four different combinations. The NP7/NP10 assay was selected and reaction conditions optimized. Efficiency, analytical sensitivity, precision and specificity were assessed. The assay was evaluated in triplicate, in three independent PCR runs performed by two technicians to generate robust results.

Results

The standard curve determined by tenfold serial dilutions (1 to 1 × 10–⁷) established a reaction efficiency (E) of 102.34%, a correlation coefficient (R²) of 0.999 and a slope of -3.267. LOD of the real-time PCR assay was 0.456 tachyzoites DNA per reaction, as compared to 45.62 for the conventional method. SYBR green real-time PCR was 100 times more sensitive than the conventional method. Precision analysis showed 100% intra- and inter-assay repeatability at the minimum detection limit. The mean assay coefficient of variation (CV%) was 4.19% and standard deviation (SD) 1.67%. No significant differences between the means of Cq in the replicates and technicians (P > 0.05) was found, indicating that the assay is robust and accurate. The applicability of the assay was tested and N. caninum DNA was detected in milk, blood, amniotic fluid, placenta and different tissue samples.

Conclusion

The protocol had high specificity, confirmed by melting curve analysis and no cross-reactions with other tested microorganisms. The SYBR Green-based PCR protocol standardized in this study is a highly sensitive and specific method, reproducible and applicable for the detection of N. caninum in different biological samples.

Purpouse

This study aimed to assess the influence of the presence of synanthropic flies in food preparation environments on the transmission of potentially zoonotic gastrointestinal protozoa.

Methods

Flies were captured using a glass containing water, fruits, and pieces of protein.

Results

Approximately 260 flies from four different species were captured: Musca domestica (76.92%; 200/260), Cochliomyia hominivorax (17.31%; 45/260), Lucilia cuprina (3.85%; 10/260), and Hydrotaea aenescens (1.92%; 5/260). Protozoa were identified through microscopic analysis after macerating these arthropods contained in their respective eppendorfs, using two techniques, namely Mini-FLOTAC^® and centrifugal sedimentation with Ziehl–Neelsen staining. The analysis revealed a concerning scenario regarding the epidemiological chain of gastrointestinal protozoa in Sergipe, Northeast Brazil. The positivity rate was 26.92% (14/52) of the pools, with 100.00% (5/5) in Aracaju, 30.00% (3/10) in Nossa Senhora do Socorro, 27.27% (3/11) in Nossa Senhora da Glória, 12.50% (2/16) in Carmópolis, and 10.00% (1/10) in Nossa Senhora das Dores. Two species of protozoa were identified, namely Cryptosporidium spp. (23.08%; 12/52) and Entamoeba spp. (9.62%; 5/52). The involvement of two fly species in the maintenance of the life cycle of these protozoa was noticeable, specifically M. domestica (27.50%; 11/40) and C. hominivorax (22.22%; 2/9).

Conclusions

Counties analyzed had an human development index (HDI) considered medium; however, they still faced socioeconomic problems such as absence of sanitation systems, waste accumulation in the streets, and illegal waste disposal, which could favor the proliferation of these vectors and the spread of these gastrointestinal protozoa.