Acta Parasitologica最新文献

The excessive application of various synthetic pesticides led to control difficulties, including insect resistance and environmental contamination. This study aimed to evaluate the insecticidal and repellent activities of twelve botanical powders and aqueous extracts against Tribolium castaneum, with a focus on acetylcholinesterase and glutathione-S-transferase detoxification enzyme activities. Toxicity tests revealed that Azadirachta indica dry powder was the most harmful, having the lowest LD₅₀ value of 2.09% w/w, while in aqueous extract A. indica was the most toxic, with an LC₅₀ of 2.20% after 24 h. Repellency tests demonstrated that A. indica exhibited the highest repellent effect in both powder and aqueous forms (86.66%). As a result of the most effective botanical application, biochemical analyses showed that acetylcholinesterase activity remained highest (6.17 ± 0.17 U/min/g) in A. indica-treated insects, whereas glutathione-S-transferase enzyme activity peaked in response to Eucalyptus tereticornis (85.00 U/min/g), indicating a strong physiological defense response. These results indicate that plants like A. indica, D. stramonium, E. tereticornis, and Ar. nilagirica can be used as promising bio-insecticides options for controlling T. castaneum in stored products.

Purpose

The aim of the study was to assess Sarcocystis prevalence in brains of small mammals from Lithuania and to comprehensively characterize their genetic variability.

Methods

Brain samples of 687 small mammals (mice, voles and shrews) from Lithuania were analysed for Sarcocystis spp. using light microscopy and DNA sequence analysis. Parasites isolated were genetically characterised at nuclear 18S rRNA, 28S rRNA, ITS1, ITS2, mitochondrial cox1 and cytb, and apicoplast rpoB.

Results

Microscopic and molecular examination revealed the presence of S. glareoli in three rodent species (Apodemus flavicollis, Clethrionomys glareolus and Microtus arvalis), with a total prevalence of 2.6%, (95% CI 1.4–4.4) and in single eulipotyphlan species (Sorex araneus), with a total prevalence of 0.65% (95% CI 0.02–3.6). Among the investigated hosts, the highest 13.0% (95% CI 6.4–22.6) infection rates occurred in C. glareolus. This study constitutes the first documented case of S. glareoli infecting a member of the order Eulipotyphla on a global scale. Additionally, we provide first ITS2, cox1, cytb, and rpoB sequences of S. glareoli. Only minor intraspecific genetic variability was observed in ITS1 and ITS2. Phylogenetic analyses placed S. glareoli in close relation to S. jamaicensis, S. microti, and several undescribed Sarcocystis species.

Conclusion

The result of the present work is significant for the epidemiology and distinguishment of S. glareoli from genetically similar species and for phylogenetic studies of Sarcocystis spp. with small mammals as their intermediate hosts.

Background

Toxoplasma gondii is a major foodborne parasite of global public health relevance; however, data regarding its circulation in retail meat from tropical regions of southern Mexico remain limited. This study provides updated molecular evidence on the presence of T. gondii in meats commonly sold for human consumption and evaluates retail-level and meat-specific risk factors within a One Health framework.

Methods

Between February and July 2024, a total of 276 meat samples (pork, chicken, beef, lamb, and horse meat) were collected from butcher shops, local markets, and supermarkets in Veracruz, Mexico. DNA was extracted using Chelex-based protocols, and T. gondii detection was performed by PCR targeting the B1 gene, followed by sequencing and phylogenetic analysis. Prevalence estimates were calculated using Wilson’s score and Clopper–Pearson confidence intervals, while associations with potential risk factors were evaluated using Fisher’s exact test and Firth penalized logistic regression.

Results

T. gondii DNA was detected in 30 samples (10.9%). Pork showed the highest positivity rate (28.0%), whereas chicken (3.1%), lamb (1.4%), and horse meat (25.0%) exhibited lower detection frequencies; no beef samples tested positive. Contamination was significantly associated with the retail environment, with butcher shops (adjusted OR = 22.50) and local markets (adjusted OR = 12.55) presenting markedly higher odds of detection compared with supermarkets. Phylogenetic analysis revealed low genetic diversity, with all local isolates clustering within a single monophyletic clade.

Conclusions

Pork, particularly when sold in butcher shops and local markets, represents the primary source of T. gondii exposure among retail meats in tropical southern Mexico. These findings underscore the need for improved biosecurity in small-scale production systems, enhanced hygiene practices in informal retail settings, and strengthened public education on safe meat handling and cooking. Future studies incorporating parasite viability assays and expanded sampling are warranted to refine consumer risk assessments.

Purpose

A new species of Gussevia Kohn et Paperna, 1964 (Monopisthocotyla, Dactylogyridae) is described based on specimens recovered from the gills of Astronotus ocellatus (Agassiz, 1831) (Cichliformes, Cichlidae) collected in the Ubaldinho weir, state of Ceará, Brazil.

Materials and methods

Some obtained monopisthocotylans were mounted on slides using Gray and Wess medium and studied using an optical microscope with a phase-contrast. Illustrations were made using a drawing tube attached to a Leica DM750 microscope and vectorized using Inkscape 1.4 software.

Results

Gussevia lamarckii n. sp. is characterized by having an accessory piece nonarticulated with the MCO base, comprising two dorsal subunits, one Y-shaped and the other one rod-shaped; and an elongated peduncle. Furthermore, the new species can be easily distinguished from the other congeners by possessing (1) a ventral anchor with an external protuberance at the junction between the root and the shaft, and (2) a superficial groove at the base of the dorsal anchor.

Conclusions

This study presents a new species of the genus Gussevia, the fourth described from Astronotus fish and the first from A. ocellatus and the aquatic ecosystems of the Caatinga domain.

Purpose

This study evaluated the effects of chronic infestation with Psoroptes ovis on sexual behavior, testosterone levels, and physiological parameters in New Zealand male rabbits. P. ovis is a common ectoparasite in domestic rabbits (Oryctolagus cuniculus); however, its impact on physiological parameters and sexual behavior, relevant to reproduction and animal welfare, as well as experimental validity, remains poorly understood.

Methods

Twenty-three male rabbits were randomly assigned to control (n = 11) or experimentally infested (n = 12) groups and monitored for 77 days. Behavioral assessments included open-field and sexual behavior tests. Physiological data included serum testosterone, temperature, liver enzymes, and lipid profile.

Results

Infested rabbits showed significant reductions in locomotor activity (− 23.2%), chin marking (− 38.3%), and exploratory activity (− 31.2%). Sexual performance was impaired, with an increase in both reaction time and ejaculation latency, while ejaculations decreased by 30.1% and serum testosterone levels by 58%. No significant changes were found in body weight, food intake, liver enzymes, or lipid markers.

Conclusions

These findings indicate that P. ovis infestation alters behavior and endocrine function in male rabbits, with implications for reproductive health and animal welfare, highlighting the need for early detection and control of ectoparasites in rabbits and underlining the importance that ectoparasitic infections could have on sexual performance in other species.

Background

Lernaea spp., commonly referred to as anchor worms, are widespread ectoparasitic copepods known for their broad host range and high morphological variability, which complicates accurate taxonomic identification.

Purpose

The hypothesis of this study was to accurately identified lernaea and differentiate at the species level using 18S rRNA gene sequencing, thereby overcoming the limitations and ambiguities of conventional morphological identification.

Methods

In this study, approximately 200 Lernaea specimens were collected from infected carps at fish farms in the Kasur district of Pakistan. Parasites were detached from hosts using potassium permanganate (KMnO₄) treatment and preserved in 70% ethanol for both morphological and molecular analyses. Initial morphological assessment was conducted under a stereomicroscope, focusing on key diagnostic features such as the structure of the anchor-shaped holdfast. For molecular characterization, genomic DNA was extracted using the Thermo Scientific GeneJET Genomic DNA Purification Kit. DNA quality and concentration were evaluated with a NanoDrop spectrophotometer. The partial 18S rRNA gene was amplified via polymerase chain reaction (PCR), and the products were visualized through agarose gel electrophoresis before sequencing. Sequence data were edited using BioEdit v7.0 and subjected to BLAST analysis against the NCBI GenBank database.

Results

Phylogenetic relationships were inferred using the neighbor-joining method, revealing the presence of three Lernaea species: L. cyprinacea, L. polymorpha, and L. ctenopharyngodonis.

Conclusion

The findings underscore the effectiveness of molecular tools particularly 18S rRNA gene analysis in resolving morphological ambiguities and provide novel sequence data that helps to explain Lernaea diversity in Pakistan.