Acta Parasitologica最新文献

Purpose

Continuous surveillance of Plasmodium falciparum Kelch 13 (pfk13) mutations associated with artemisinin resistance is essential for monitoring the emergence of drug-resistant parasites in malaria-endemic regions. Herein, we have assessed the prevalence of point mutations in the pfk13 gene linked to artemisinin resistance in Iranian P. falciparum isolates, 18 years following the nationwide introduction of artemisinin-based combination therapies (ACTs).

Methods

A total of 60 finger-prick blood samples were obtained from Iranian patients with symptomatic, uncomplicated P. falciparum malaria during the period of 2022 to 2023. A nested polymerase chain reaction (PCR) assay was employed to verify infections by amplifying the 18 S small subunit ribosomal RNA (18 S ssrRNA) gene. Nested PCR was utilized to amplify the pfk13 gene, followed by sequencing of the amplicons to identify both previously reported and novel mutations.

Results

Of the successfully sequenced samples (n = 50), 98% (49/50) carried the wild-type allele. One sample harbored a novel nonsynonymous mutation, R513C, corresponding to a C1537T nucleotide change.

Conclusion

No validated pfk13 mutations indicative of artemisinin resistance were detected in the study population. These findings suggest that artemisinin remains effective for treating P. falciparum malaria in this region. Continued molecular surveillance is warranted to ensure early detection of emerging resistance.

Objective

To document cases of free-living amoebae (FLA) infections in humans diagnosed at a Reference Parasitology Laboratory in Argentina, contributing to the epidemiological understanding of these infections in the country.

Methods

A retrospective analysis was performed on 43 samples from suspected cases of FLA infection collected between October 2022 and June 2025. The samples included 4 ocular specimens, 20 brain biopsies, 12 cerebrospinal fluid samples, 6 skin biopsies, and 1 liver biopsy. FLA culture was carried out only in suspected keratitis cases, using liquid Page’s solution supplemented with fresh Escherichia coli culture. In all cases, multiplex real-time PCR (qPCR) was employed for the simultaneous detection of Acanthamoeba spp., Naegleria fowleri, and Balamuthia mandrillaris. The cases were analyzed together with the information provided in the epidemiological forms that accompanied the samples.

Results

Of the 43 analyzed samples from suspected cases, 5 tested positive (11.6%), including 1 case of keratitis caused by Acanthamoeba spp. and 4 cases of granulomatous amebic encephalitis (GAE) due to B. mandrillaris. The GAE cases involved immunocompetent children and one adult with a functional immunosuppression risk factor (chronic alcoholism). One patient presented with chronic skin lesions prior to the CNS infection, and another case involved co-infection with Toxoplasma gondii. Neuroimaging in all GAE patients showed lesions consistent with mass or infectious processes, and brain biopsy samples were essential for diagnosis. Two of the GAE patients survived following combined therapy.

Conclusions

Infections caused by FLA are rare but highly severe, particularly non-keratitis presentations. Early clinical suspicion, rapid and accurate diagnosis, and aggressive treatment are crucial to improving patient outcomes.

Purpose

Livestock sustainability intersects environmental, economic, and social dimensions, particularly through its influence on animal health. This study aimed to evaluate the diversity of eukaryotic gastrointestinal parasites and microbiota in domestic animals from productive systems located within Colombian conservation areas, where livestock coexist with wild mammals such as primates, pumas, Andean bears, and tapirs. Specifically, we examined how natural vegetation fragmentation relates to parasite diversity, richness, and equitability.

Methods

Fecal samples from cattle, horses, and domestic dogs were analyzed using metabarcoding of the 18S rRNA gene via Nanopore sequencing, focusing on protozoa as key indicators. Microscopy was used to confirm molecular findings. Epidemiological descriptors, including prevalence, mean intensity, and mean abundance, were estimated, and Bayesian Poisson regression models were applied to assess associations between landscape metrics and parasite or fungal diversity.

Results

From 50 collected samples, 27 yielded usable sequences, revealing 11, 12, and 3 parasite taxa in cattle, horses, and dogs, respectively. The diversity of eukaryotic microbiota and parasites in cattle and horses correlated positively with native forest cover and negatively with forest shape irregularity, indicating that larger and more compact forest patches favor greater parasite diversity.

Conclusion

Parasite transmission between livestock and wild mammals in conservation landscapes represents a bidirectional ecological risk. Although extensive forest cover enhances ecosystem integrity, it may also increase parasite diversity, with potential implications for livestock health and disease management strategies.

Purpose

Cutaneous leishmaniasis (CL) is an endemic disease in Algeria. In southeastern regions, data concerning this infection are limited. Therefore, we aimed to assess the epidemiological status and identify the causative Leishmania spp. in El Meghaier province.

Methods

A retrospective study was conducted between 2023 and 2024. Diagnosis was confirmed by microscopic examination. For patients with positive results, clinical and demographic data were recorded. Molecular analysis was then carried out on DNA extracted from Giemsa-stained slides to identify the Leishmania species.

Results

In total 722 suspected cases were analyzed and only 118 were positive cases. A predominance in males was detected, and the most affected group age was [≥ 20] years old (N = 51; 43.2%). The statistical analysis showed strong association between age group and the positivity rate (X² = 37.59, P < 0.0001). Multiple lesions were observed in 72 patients (61.1%), most frequently located on the feet (76 cases; 64.4%) and hands (15 cases; 12.7%). Among the 118 microscopically positive samples, 53 were included for molecular analysis. Of these, 29 yielded a positive PCR amplification. Initial parasite typing was performed using PCR-ITS1, which detected Leishmania DNA in 14 samples (26.4%), predominantly L. major (92.8%). Samples negative by PCR-ITS1 were subsequently analyzed using nested ITS1-PCR, which identified 15 additional positives (38.5%). Sequencing of the amplified products confirmed the presence of L. major (66.6%) and L. infantum (13.3%).

Conclusion

These findings confirm, for the first time, the occurrence of both L. major and L. infantum in the study area. Further studies are needed to investigate the potential vectors and reservoirs involved.

Introduction

Toxoplasma gondii and Neospora caninum are apicomplexan protozoan parasites belonging to the family Sarcocystidae. Toxoplasma gondii is a significant zoonotic pathogen responsible for abortion and congenital infections in both humans and animals worldwide. Transmission to humans occurs through ingestion of tissue cysts (bradyzoites) in raw or undercooked meat, oocysts in felid faeces, transplacental transmission from infected mothers, or consumption of milk containing tachyzoites. Neospora caninum is a major cause of reproductive failure in cattle, manifesting as abortion, stillbirth, infertility, early foetal death, and decreased milk production. The parasite has been identified as a leading cause of bovine abortions, particularly in European dairy herds. Although N. caninum is not definitively proven to be zoonotic, its close phylogenetic and biological relationship with T. gondii raises concerns about potential human infection risk that warrant investigation.

Materials and methods

This study investigated the presence of T. gondii and N. caninum DNA in milk samples from dairy animals in Samsun province, Turkey. Between September 2022 and June 2024, raw milk samples (10 ml) were collected from cattle (n = 107), sheep (n = 100), and buffaloes (n = 100) at various local dairies. DNA extraction and PCR amplification were performed using Tox4-Tox5 and Np6-Np21 primer pairs for T. gondii and N. caninum, respectively.

Results

Toxoplasma gondii DNA was detected in 21% (21/100) of buffalo, 19% (19/100) of sheep, and 14.95% (16/107) of cattle milk samples. Neospora caninum DNA was found in 16% (16/100) of sheep, 13.8% (14/107) of cattle, and 12% (12/100) of buffalo milk samples. These findings indicate a substantial prevalence of both parasites in raw milk intended for human consumption in the region.

Conclusion

Given the potential viability of tachyzoites in unpasteurised milk and dairy products, consumption of raw milk may represent a significant risk factor for human infection with T. gondii and possibly N. caninum. Further comprehensive and systematic studies are needed to better characterize the public health risks associated with these parasites in raw milk and dairy products.

Hydatidosis is an infection caused by the parasite Echinococcus granulosus (E. granulosus). The liver and lungs are the most commonly affected organs. However, ovarian hydatid cyst (OHC) is a relatively rare manifestation. Herein, we report a case of primary OHC in a 65-year-old woman. Additionally, upon review of reported OHC cases in Iran, a total of 13 cases have been documented in various studies, with our case being the second reported from Tehran. Most cases originated from different regions of Iran, except for the southwest and southeast, with an average patient age of 38 years. The predominant symptom was abdominal pain, and approximately 77% of the initial diagnoses were unclear. Notably, our patient represents the oldest reported case to date and presented with a right-sided OHC, a first reported in Iran. Gynecologists, radiologists, and pathologists should have a high degree of suspicion for hydatid cysts when evaluating septated cystic pelvic masses. To ensure accurate preoperative diagnosis, a combined approach using imaging, serologic tests, and clinical evaluation is recommended in endemic echinococcosis regions.

Purpose

Bovine piroplasmosis is a highly prevalent tick-borne disease caused by Theileria spp. and Babesia spp., which inflicts significant losses on the beef and dairy cattle industries globally. Therefore, the aim of this study was to investigate the prevalence of bovine piroplasmosis in southern Xinjiang.

Methods

A total of 595 blood samples were collected from 10 farms of southern Xinjiang in February of 2023. Various genetic markers combined with PCR were utilized to identify the species of piroplasms. Based on the sequenced data, a phylogenetic tree was constructed by using MEGA11.

Results

The results indicated that 231 samples (38.82%) were positive for piroplasms, including 195 positive samples of Theileria annulata (32.77%), 33 positive samples of T. orientalis (5.55%), one positive sample of Babesia spp. (0.17%), and 2 positive samples of T. ovis (0.34%). Subsequently, a qPCR method was used to detect the distribution of buparvaquone-resistant strains of T. annulata. The results showed that 39.49% (77/195) of positive samples of T. annulata were detected to be resistant to buparvaquone. Three T. orientalis genotypes were identified: type 1 (Chitose), type 2 (Ikeda), and type 3 (Buffeli). The above results revealed that bovine piroplasmosis was widespread in this region, with the farm-level prevalence ranging from 24.2% to 50.5%.

Conclusion

This study confirms the prevalence of piroplasms in bovine blood samples from endemic regions of southern Xinjiang, and will provide scientific data for the prevention and control of bovine piroplasmosis, especially for T. annulata.

Background

Clinostomum complanatum (Trematoda: Clinostomidae) infects freshwater fishes, causing metabolic stress and economic loss. Data on its morphology and physiological impact on Channa punctata in Lucknow wetlands are limited.

Objectives

To identify C. complanatum using light and scanning electron microscopy (SEM) and assess its effect on host protein levels.

Methods

Fifty C. punctata were collected from the Kallipaschim wetland, Lucknow. Parasites were morphologically and ultrastructurally characterized. Protein concentrations in liver, muscle, and parasite tissues were analyzed using the Bradford assay and compared between infected and uninfected fish.

Results

C. complanatum showed a dorsoventrally flattened body with distinct oral and ventral suckers and spined tegument. Infected fish exhibited elevated protein concentrations liver (2.5 µg/ml), muscle (5.29 µg/ml), and parasite (3.95 µg/ml) indicating metabolic stress, immune activation, and tissue repair. The parasite’s high protein level reflected dependence on host nutrients.

Conclusion

C. complanatum infection causes significant biochemical and structural alterations in C. punctata, impairing health and reducing aquaculture productivity. Regular monitoring and parasite control are crucial for sustainable fish farming.

Purpose

Enterocytozoon bieneusi is recognized as the most common microsporidian parasite, exhibiting a broad host spectrum that includes a wide range of animal species, as well as humans. However, no comprehensive data are available on the prevalence, age-related distribution, or genotype diversity of E. bieneusi in preweaned calves in Türkiye. Therefore, this study aimed to provide comprehensive data and expand current knowledge on E. bieneusi in preweaned calves from different age groups.

Methods

We screened a total of 240 fecal samples collected from preweaned calves using nested PCR to determine the occurrence and age-related distribution of E. bieneusi. Genotyping of the detected isolates and evaluation of their zoonotic potential were subsequently performed based on ITS sequence analysis.

Results

Enterocytozoon bieneusi was identified in 38 out of 240 fecal specimens, corresponding to an overall prevalence of 15.8%. Sequence analyses revealed the presence of two known genotypes, BEB8 and J. While genotype J was identified as the predominant genotype circulating among calves in the study area, genotype BEB8 was detected for the first time in a mammalian host in Türkiye. Phylogenetic analysis further revealed that both genotypes clustered within Group 2, which includes ruminant-adapted genotypes.

Conclusion

This is the first comprehensive report on the occurrence, age-related distribution, and genotyping of E. bieneusi in preweaned calves in Türkiye, highlighting the potential role of calves as reservoirs or carriers of this pathogen.

Introduction

Given the need to identify parasites that may affect commercially important fish, and to contribute to knowledge of the parasitic fauna in Amazonian fish species, the main objective of this research was to study parasites from the gills of Brachyplatystoma tigrinum (Britski, 1981) (Siluriformes: Pimelodidae) what led to the discovery of a new species.

Material and Methods

Five B. tigrinum with 20–30 (25 cm) were collected in the section between Gran Perú, near the town of Tamishiyacu, in the Amazonas River (3°47′20.70″S 73°15′40.90″W), in Loreto, Peru. The collected fish were transported in boxes with ice to the laboratory for parasitological analyses.

Results

One species of the Dactylogyridae was registered: Peruanella jorgepanduroi n. sp. The new species differs from its congener Peruanella madredediosensis Cruces, Santillán, Silvera, Morey, Rubin and Chero, 2024 by the termination of the MCO and the accessory piece, which in the new species have a pointed, almost straight termination, while in P. madredediosensis, both the MCO and the accessory piece bend forward; additionally, the presence of striations on the surface of the shaft and the point of anchors in P. madredediosensis is absent in the new species.

Conclusions

The results of this study constitute the second report of a dactylogyrid species parasitizing B. tigrinum, and at the same time, the second species of Peruanella Cruces, Santillán, Silvera, Morey, Rubin and Chero, 2024 described. This increases the knowledge of the biodiversity of monogenoids reported for Peru and the Neotropical region.