Parasitologia

Parasites of the genus Trichinella are widely distributed and infect a wide range of domestic and wild animals. Their presence spans across various continents, impacting agricultural and wildlife ecosystems alike. In Argentina, Trichinella spiralis, Trichinella patagoniensis, and Trichinella pseudospiralis have been detected infecting both domestic and wild animals. The aim of the present study is to detect Trichinella spp. in samples from domestic pigs and wildlife across Argentina between 2019 and 2024 and to identify these parasites at the species level. A total of 216 samples from domestic and wild animals underwent artificial digestion. In cases where a positive result was obtained, muscle larvae were further processed using PCR targeting the ESV region. Samples originating from 16 animals were analyzed. Among the animals tested, 52 were positive for Trichinella spp., including two pumas infected with T. patagoniensis; 43 domestic pigs, with 34 identified as T. spiralis at the species level; and seven wild boars, with five identified as T. spiralis at the species level. The present study enhances our understanding of the distribution and transmission dynamics of Trichinella among domestic and wild animals in Argentina. Full article

Metacyclogenesis is a critical process in the Trypanosoma cruzi life cycle. This transition naturally occurs in an insect vector’s gut. Although Triatomine Artificial Urine (TAU) medium is the widely adopted approach to metacyclogenesis in vitro, its efficiency decreases with prolonged epimastigote culture, limiting the availability of metacyclic trypomastigotes for study. We aimed to establish a practical and efficient method for generating high concentrations and purities of metacyclic trypomastigotes in vitro. Epimastigotes of the Dm28c strain were exposed to pH shifts in nutrient-rich (MT-LIT) and nutrient-poor (M16) media, under static or agitated conditions. Both media promoted higher metacyclogenesis rates than TAU, with epimastigotes’ adherence to the substrate being a crucial factor. Metacyclogenesis efficiency varies depending on the strains and culture conditions. Notably, both LIT and M16 at pH 6 produced metacyclic trypomastigotes with infective capacity on Vero cells. Under these conditions, a variety of intermediate forms were observed compared to those induced by TAU metacyclogenesis. Our findings further emphasize the strain-dependent nature of optimal in vitro metacyclogenesis conditions and offer new opportunities for studying the intermediate forms involved in this essential process. Full article

Dogs harbour a wide range of endoparasites, many of which pose a significant risk to public health globally due to their zoonotic potential. Addressing the dynamics of zoonotic parasites comprehensively requires epidemiological studies under the One Health paradigm, incorporating multidisciplinary methodologies to explore the complex interactions among humans, animals and the environment. The present study aimed to investigate the presence of canine parasites in public green places (PGPs) in Tandil, Argentina, using epidemiological and geographical tools to enhance efforts towards the prevention and control of canine parasitic diseases impacting public health. Between August 2024 and January 2025, 893 canine faecal samples were collected through a randomised two-stage sampling process from 92 public green places. The overall prevalence of intestinal parasites was 29.9% and the identified parasites were Trichuris vulpis, Ancylostoma caninum, Eucoleus spp., Uncinaria stenocephala, Toxascaris leonina, and Cystoisospora sp. Risk factors identified included the presence of playgrounds and a higher dog density, while protective factors comprised sampling during spring vs. winter and presence of areas of bare soil on the public green places. Spatial analysis revealed clusters of high prevalence in areas with lower socioeconomic status, and clusters of low prevalence in higher socioeconomic areas. These findings emphasise the need for targeted preventive measures, including responsible pet ownership policies. Moreover, the methodological approach adopted could be replicated in other regions to enhance public health protection and mitigate the risks associated with zoonotic parasitic diseases. Full article

Strongyloidiasis represents a public health problem in tropical and subtropical regions. The medicinal plants demonstrate the potential of plants as a source of molecules with helminthic activity. In this research, we assessed the potential of five extracts medicinally used in Mexico against Strongyloides venezuelensis third-stage infective larvae (L3). Plant methanol (MeOH) extracts of Argemone mexicana (chicalote), Jatropha dioica (Sangre de Drago), Lippia graveolens (oregano), Thymus vulgaris (tomillo), and Kalanchoe daigremontiana (aranto) were prepared by the maceration technique. The toxicity of the extracts was evaluated in human red blood cells by the hemolysis test and in monkey kidney epithelial cells (Vero cells) using the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In addition, we showed their antioxidant potential by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The methanolic extracts of A. mexicana, J. dioica, L. graveolens, and T. vulgaris exhibited significant activity against L3 cultures at 72 and 96 h post-incubation. None of the extracts showed hemolytic effects on red cells or Vero cells. L. graveolens demonstrated the strongest antioxidant activity, with an EC₅₀ of 19.80 µg/mL. Plant MeOH extracts used in this study showed a promising anthelmintic effect in vitro, making it a suitable candidate for future research in nematocidal therapies. Full article

The genus Polystoma includes parasites with direct life cycles that involve a short-lived free-living, aquatic oncomiracidia, post-larvae infecting the gill chambers of tadpoles, and adults parasitizing the urinary bladder of adult anurans. Despite the high diversity of anurans in the South American sub-continent, less than 20 species of Polystoma have been reported to date, and, particularly, in Argentina, only five species have been described from adult frogs. The aim of this work was to describe and characterize taxonomically the specimens found parasitizing tadpoles and frogs living in a well in Chicoana, Salta province, Argentina. Parasites were observed under optical and scanning electron microscopy and characterized genotypically by sequencing ITS1 and COI fragments. Frogs and tadpoles were characterized by morphology and sequencing a partial fragment of the cytochrome B region, confirming that the hosts corresponded to Pleurodema borellii. Given their morphology and the strict specificity of Polystoma species for their hosts, the identity of the parasites was established as P. borellii. The morphology of oncomiracidia and post-larvae was described, expanding adults’ description with insights provided by COI and ITS1 molecular analysis. The present work summarizes a complete description of the life cycle, with the genetic characterization of Polystoma borellii in Salta, Argentina. Full article

The Gran Acuario Mazatlán (GAM), Mexico’s largest aquarium, is located at the entrance of the Gulf of California. In April 2023, fish in the Ocean Tank (OT) began exhibiting disease symptoms, followed by significant mortality, primarily affecting Caranx caninus, Chaetodipterus zonatus, and Lutjanus colorado. Parasitological examinations identified heavy infestations of Neobenedenia sp. (Monogenea: Capsalidae), with parasites extensively covering body surfaces and gills of some individuals. To control the outbreak, an environmental management strategy was implemented, involving a gradual reduction in water temperature (from 26 °C to 22 °C) and salinity (from 35 ppt to 26 ppt), increased cleaning frequency, and parasite egg abundance monitoring. Over time, egg abundance declined, and by July, fish behavior and feeding rates had returned to normal, with parasite-associated mortality dropping below 2%. Preventive measures, including strict quarantine protocols for new fish, have been implemented to maintain optimal conditions in the OT. This case highlights the challenges of managing parasite outbreaks in large, multi-species aquaria and underscores the importance of environmental control strategies in marine animal care. Full article

A significant portion of women encounter vaginal infections at some point in their lives. These infections have many effects such as infertility, pelvic inflammatory disease (PID), severe disseminated infections, and complications affecting fetal health during pregnancy. Vaginal infections can be symptomatic or asymptomatic, thereby concealing their presence. This study aimed to determine the frequency and causative agents of vaginal infections in symptomatic and asymptomatic women in Konya. The study included 200 patients aged > 18 years who visited the gynecology clinic for any reason and provided informed consent. Patients who reported at least one of the symptoms of vaginal discharge, burning, or itching were categorized into the symptomatic group, while those without any of these complaints were categorized into the asymptomatic group. Vaginal swab samples collected from the patients were evaluated for bacterial vaginosis (BV) using the Nugent scoring method on Gram-stained smears. Trichomonas vaginalis was investigated through Giemsa-stained microscopic examination and polymerase chain reaction (PCR) analysis. Samples were also cultured on routine media to analyze fungal and bacterial growth. A total of 74% of the patients were symptomatic, and 26% were asymptomatic and were admitted to the gynecology outpatient clinic for reasons other than vaginitis. According to the Nugent scoring system, BV was observed in 21.6% of the symptomatic group and 13.5% of the asymptomatic group. T. vaginalis was detected in only seven patients (3.5%) through microscopic examination and PCR. Among the patients with T. vaginalis, five were in the symptomatic group, and two were in the asymptomatic group. The rate of vaginal candidiasis was found to be 34.5% in the symptomatic group and 21.2% in the asymptomatic group. Aerobic vaginitis was observed in 12.8% of the symptomatic group and 7.7% of the asymptomatic group. The positivity rates for BV, vaginal candidiasis, and trichomoniasis in asymptomatic patients are concerning. Considering the fetal complications and chronic effects of vaginal infections, the decision to establish screening programs in the asymptomatic patient group should be based on national data, considering the prevalence of the pathogen in the region and its outcomes. Full article

Equine Piroplasmosis (EP) is a significant tick-borne disease affecting horses, and one of the causative protozoan parasites is Theileria equi, hence the need to understand the prevalence and associated factors influencing it. Considering the population of horses in the study areas, a sample size of 272 horses comprising 171 and 101 horses from Taif and Jeddah was estimated. Thin and thick blood smears were made from the animals’ whole blood for microscopic examination. At the same time, serum samples were prepared and examined for antibodies to antigens using commercial Theileria equi antibody test kit ELISA. The relationships of gender and age with the presence or absence of T. equi parasite infection were determined using the chi-square test. The results revealed no significant association between gender and T. equi prevalence using both microscopic (χ² = 2.748, p = 0.07) and ELISA (χ² = 2.412, p = 0.096) diagnostic methods. In Taif, the microscopic results revealed that 86% of female horses tested negative, while 14% tested positive. In contrast, 75% of male horses tested negative, with 25% testing positive for T. equi. In terms of age groups of horses, a significant association (χ² = 31.966, p = 0.032) between age groups and the prevalence of T. equi in samples from Jeddah using the ELISA method was recorded. Understanding the relationship between the prevalence of T. equi and factors such as gender and age is crucial for developing effective control measures and improving equine health management, especially in Saudi Arabia. Full article

Introduction: Freshwater snails, particularly snails from the genus Biomphalaria, play a key role in the transmission of schistosomiasis, a parasitic disease prevalent in tropical regions. Schistosomiasis poses a significant public health challenge in these regions, leading to chronic illness, reduced productivity, and impaired childhood development, particularly in communities with limited access to healthcare and sanitation. Understanding the seasonal and spatial variations in snail populations and infection rates is crucial for controlling schistosomiasis, especially in areas like Southwest Ethiopia, where the disease burden is high. Methods: This study was conducted in Mizan Aman, Southwest Ethiopia, across two seasons, dry and wet. A total of 1150 snail samples were collected from 20 freshwater sites, and their species, abundance, and infection status were assessed. Environmental parameters, including temperature, pH, salinity, and conductivity, were measured to analyze their impact on snail populations. Results: Four snail species were identified, Biomphalaria pfeifferi, Biomphalaria sudanica, Lymnaea natalensis, and Bulinus globosus, with B. pfeifferi and B. sudanica being the most prevalent. Snail abundance varied by site and season, with 598 in the dry season and 552 in the wet season. Snail abundance and species composition showed significant spatial variation, with higher counts in sites like Sasin and Agu 1, while some sites had no snails. Biomphalaria snails, particularly B. pfeifferi, are the principal intermediate host for Schistosoma mansoni. The overall prevalence of Biomphalaria snails exceeded 85% in both seasons, and their average infection rate in Mizan Aman was 13.5%. This infection rate showed a strong correlation (r = 0.733, p < 0.001) with the incidence of schistosomiasis cases in the community. Seasonal variation in environmental factors, such as temperature and pH, had no significant effect on snail abundance; however, water salinity showed to be correlated with snail abundance during the dry season. Furthermore, community-led vegetation clearance at selected sites significantly reduced snail abundance. Conclusions: This study highlights the seasonal and spatial dynamics of freshwater snails, particularly Biomphalaria species, in relation to schistosomiasis transmission in Mizan Aman, Southwest Ethiopia. The findings confirm that B. pfeifferi species is the predominant intermediate host for schistosoma in this region and that schistosomiasis infection rates among snails significantly correlate with human cases in the community. While environmental factors such as temperature and pH showed no significant influence on snail abundance, water salinity had an impact during the dry season. Additionally, community-led vegetation clearance was an effective intervention in reducing snail populations. These results emphasize the need for targeted, site-specific control measures integrating ecological and community-based interventions to sustainably reduce schistosomiasis transmission. Full article

Nematode cys-loop ligand-gated chloride channels are important targets for anthelmintic drugs as many subtypes are not present in mammals. We report the isolation and functional characterization of a novel member of the cys-loop ligand-gated chloride channel family (Hco-LGC-40) from the parasitic nematode Haemonchus contortus. Electrophysiological analysis of the channel expressed in Xenopus oocytes revealed that it responds to both acetylcholine and choline with EC₅₀ values in the low micromolar range. Hco-LGC-40 can also associate with a member of a separate family of acetylcholine-gated chloride channels, Hco-ACC-1, to produce a heteromeric channel with a lower sensitivity to acetylcholine. In silico analysis reveals several residues that may play a role in forming a unique cholinergic binding pocket. Overall, these results suggest that choline may act as a neurotransmitter by binding to cys-loop receptors in parasitic nematodes. Full article

The resistance of small ruminants to synthetic anthelmintics and helminthosis poses considerable challenges to global livestock production. Integrating biological control with nematophagous fungi, particularly Duddingtonia flagrans, is crucial in addressing worm infestations. Although effective in experiments, the absence of a commercial product has been a limitation. The introduction of Bioverm^®, the first commercial product using D. flagrans in Brazil, marks a significant advancement. This study on a Brazilian sheep farm evaluated a 167-day Bioverm^® treatment, following moxidectin application, focusing on eggs per gram of feces (EPG), FAMACHA score, and sheep weight (WEIGHT). Statistical results showed marked improvements in all parameters after 80 days with Bioverm^®. EPG values gradually declined, demonstrating successful biological control, while FAMACHA increased steadily, stabilizing after 130 days. Minor weight changes indicated effective nutritional management. These outcomes suggest Bioverm^® significantly reduces dependence on chemical anthelmintics and addresses resistance issues. D. flagrans thus emerges as a promising tool for managing nematode infestations without negatively impacting animal weight. This research enhances the understanding of Bioverm^®’s role, confirming its practicality as a viable alternative for helminth control in varied environments, thereby reinforcing its strategic importance in livestock management. Full article

The nematode Spinitectus inermis (Zeder, 1800), a specific gastrointestinal parasite of Anguilla anguilla, has been recorded for the first time in the Italian Peninsula. The study was conducted in the Mesima River, located in the southwestern part of the Calabria region (southern Italy). Over a five-month period, 162 specimens of European eel were sampled, revealing an overall prevalence of 47.53%, a mean intensity of 9.51 (±13.88), and a mean abundance of 4.55 (±10.69). The nematode was present throughout the five months analyzed, with prevalence rates ranging from 32.0% to 57.14%. The overall prevalence in the Mesima River was higher than in most previous studies, and the mean abundance of infection was also higher. The highest prevalence of infection was observed in September (56.7%), October (57.14%), November (48.57%), and December (40.54%), with the lowest in March (32.0%). In conclusion, Spinitectus inermis appears to be well established in the eel population of the Mesima River, exhibiting high prevalence and intensity year-round despite ecological variations, though its intermediate hosts remain unknown. Full article

Leishmania is a protozoan parasite causing a spectrum of pathologies in humans grouped under the name leishmaniasis. Clinical outcomes range from the self-healing cutaneous form to the visceral one that is fatal in the absence of treatment. The leishmaniases are endemic in 98 countries in the tropics, subtropics, and Southern Europe, where 3 million new cases and more than 50,000 deaths are recorded yearly. Control of this disease is challenging as there is no approved vaccine coupled with toxic chemotherapeutics and the development of parasite resistance to some available drugs. It is, therefore, evident that the identification of new control methods, including new therapeutics, should be strongly encouraged. In the present study, thiol organic compounds were synthesized and tested for their activity against Leishmania major, the causative agent of human cutaneous leishmaniasis. Of the 21 compounds tested, 13 were active against L. major promastigotes in vitro at 100 μg/mL. Selected compounds tested in a dose-response assay showed activity at concentration as low as 25 μg/mL, a level of activity similar to that of Amphotericin B, a drug of choice for the treatment of human leishmaniasis. Structure–activity analysis shows that the addition of certain substituents, such as a methoxy group, to a compound that is biologically active renders it inactive. Together, our data demonstrate that functionalized thiols have an in vivo anti-Leishmania activity that is directly linked to their chemical structure. Full article

This study investigates the parasitic biodiversity of the fish species Astyanax bimaculatus and Psalidodon fasciatus in a stream located in the Chapada do Araripe Environmental Protection Area (APA), state of Ceará, Brazil, contributing to the understanding of parasitic fauna diversity of freshwater fish in neotropics. In total, 292 fish specimens were collected and analyzed, identifying 13 parasite taxa in A. bimaculatus and 11 in P. fasciatus. Several parasite groups were identified, including myxozoans, monogeneans, digeneans, and nematodes. The host A. bimaculatus exhibited a higher number of parasite taxa and abundance compared to P. fasciatus. The lower sample size for P. fasciatus reflects its naturally lower abundance in the wild, but the analyses accounted for sampling bias, ensuring comparisons of the parasite communities of these two fish species. The parasite communities of both species showed high similarity, indicating potential host-switching or co-evolutionary patterns. Positive correlations were observed between parasite diversity, species richness, abundance, and host weight/length. The study expands the knowledge of parasite–host associations and the geographical distribution of parasite species in Northeastern Brazil, a region where such data remain underreported. Full article

Rhipicephalus (Boophilis) microplus (also known as southern cattle tick or Asian blue tick) is one of the most detrimental and prolific tropical cattle parasites. Currently, chemical acaricides used against these ticks have been less effective due to increased pesticide resistance stemming from overuse of these treatments. We propose a novel tick repellent to address the waning efficacy of chemical treatments for R. (B.) microplus on cattle. In the search for an alternative, seven concentrations (100%, 50%, 25%, 12.5%, 6.25%, 3.13%, and 1.57%) of babaçu (Attalea speciosa) residue bio-oil were produced by hydrothermal pyrolysis at 180 °C. The repellency of these bio-oil concentrations was assessed using a tick climbing test. Additionally, toxicity tests were performed by organic chemical analysis and polyaromatic hydrocarbon analysis. The repellency to R. (B.) microplus tick larvae was 100% for concentrations higher than 3.13% babaçu residue bio-oil concentration. However, the 1.57% concentration can be promising even with less repellent effects (though still being 93.7% effective) due to lower toxicity. This is an innovative approach for overcoming drug resistance in these ticks. Future research can test other bio-oils and pyrolysis products as tick repellents and botanical acaricides to further diversify options for better managing these parasites in Brazil and elsewhere in the tropics. Full article

Two related P-type ATPases, designated as ATPase1 and ATPase3, were identified in Plasmodium falciparum. These two ATPases exhibit very similar gene and protein structures and are most similar to P5B-ATPases. There are some differences in the predicted substrate-binding sites of ATPase1 and ATPase3 that suggest different functions for these two ATPases. Orthologues of ATPase3 were identified in all Plasmodium species, including the related Hepatocystis and Haemoproteus. ATPase3 orthologues could also be identified in all apicomplexan species, but no clear orthologues were identified outside of the Apicomplexa. In contrast, ATPase1 orthologues were only found in the Laverania, avian Plasmodium species, and Haemoproteus. ATPase1 likely arose from a duplication of the ATPase3 gene early in the evolution of malaria parasites. These results support a model in which early malaria parasites split into two clades. One clade consists of mammalian malaria parasites and Hepatocystis but excludes P. falciparum and related Laverania. The other clade includes Haemoproteus, avian Plasmodium species, and Laverania. This contrasts to recent models that suggest all mammalian malaria parasites form a monophyletic group, and all avian malaria parasites form a separate monophyletic group. ATPase1 may be a useful taxonomic/phylogenetic character for the phylogeny of Haemosporidia. Full article

Colpodella species are predatory biflagellates phylogenetically related to pathogenic Apicomplexans. Following the attachment of Colpodella sp. to its prey, cytoplasmic contents of the prey are aspirated into a posterior food vacuole during myzocytosis. Trophozoites also endocytose nutrients as demonstrated by the uptake of 40 and 100 nm nanoparticles in Colpodella sp. ATCC 50594. This nutrient uptake is actin-mediated. However, the markers of myzocytosis and endocytosis are unknown. Furthermore, the relationship between Colpodella sp. ATCC 50594 and Colpodella sp. identified in arthropods, humans, and animals are unknown. In this study, we investigated the conservation of the coronin and Kelch 13 genes in Colpodella sp. ATCC 50594 using polymerase chain reaction (PCR). Kelch 13 distribution in Colpodella sp. ATCC 50594 was investigated using anti-Kelch 13 antibodies by immunofluorescence. Both genes were amplified from Colpodella sp. ATCC 50594. We amplified DNA encoding 18S rRNA with similarity to 18S rRNA amplified using piroplasm primers from the Italian Colpodella sp. identified in cattle and ticks. The detection of the coronin and Kelch 13 genes in Colpodella sp. provides, for the first time, markers for actin binding and endocytosis in Colpodella species that can be investigated further to gain important insights into the mechanisms of nutrient uptake in Colpodella sp. Full article

Dioctophyme renale, also known as the giant red kidney worm, is a parasitic nematode that infects various mammalian hosts, including dogs, and is associated with an important renal pathology. This case report describes the first known D. renale parasitism in a 5-month-old puppy from Uruguay. The animal presented with hematuria and was diagnosed through abdominal ultrasonography, which revealed characteristic ring-like structures in the right kidney, and urine sedimentation, which confirmed the presence of D. renale eggs. The dog underwent nephrectomy to remove the adult female parasite. While D. renale is typically associated with a prepatent period of 3.5 to 6 months in canines, this case is notable for the early presence of a mature parasite in a young dog. This finding suggests the possibility of a shorter prepatent period or alternative transmission routes, such as transplacental or lactogenic transmission. The case highlights the importance of including dioctophymosis in the differential diagnosis of young puppies in endemic areas, especially near freshwater sources. Given the zoonotic potential of D. renale, this case emphasizes the need for surveillance of this parasite, particularly in regions where untreated water and fish consumption pose risks to both animals and humans. Full article

The genus Ancistrohaptor was proposed to accommodate monopisthocotylans flatworms parasitic on the gills of species of the genus Triportheus in Manaus, Amazonas state, Brazil. Its main characteristics are (a) an accessory piece of the male copulatory organ composed of two distinct parts; (b) dextral or dextroventral vaginal openings; and (c) large ventral anchors with elongated shafts. A new species of Ancistrohaptor was found to parasitize the gills of Triportheus signatus collected from the Salgado River, Ceará State, Brazil. A new species of Monopisthocotyla was collected and described. Ancistrohaptor forficata sp. n. is primarily characterized by having a male copulatory organ with less than one turn, the presence of an articulated accessory piece with a concave rod-shaped termination, and a free accessory piece that is clamp shaped and bifurcated, as well as a dorsal bar with shading present in its medial part. This is the fourth species description of the genus Ancistrohaptor for fish of the genus Triportheus and the first record for T. signatus and the aquatic ecosystems of the Caatinga domain. Full article