Search Results (271)

Pachysandra terminalis (P. terminalis), a plant belonging to the Buxaceae family, is known as a great source of aminosteroid alkaloids. In a previous communication, we reported on the isolation of a variety of aminosteroids from P. terminalis, which presented interesting activity against the protozoan pathogens, Trypanosoma brucei rhodesiense and Plasmodium falciparum. In the present study, variations in the alkaloid profile of P. terminalis related to seasonal changes as well as differences between plant organs (leaves and twigs) and between plant populations were investigated to prioritize candidates for targeted isolation in further studies. For this purpose, sample material of P. terminalis was collected from the two nearby populations in monthly intervals over one year. The ethanolic (75%) extracts were analyzed using UHPLC/+ESI-QqTOF-MS/MS, and the resulting data converted to variables encoding the intensity of MS signals in particular m/z and retention time (t_R) intervals over the chromatographic runs. The very large and complex data matrix of these <t_R:m/z> variables was evaluated using multivariate data analysis, especially principal component analysis (PCA) and volcano plot analysis of t-test data. The results of these analyses, for the first time, allowed a holistic analysis of variation in the alkaloid profiles in P. terminalis organs over the vegetation period. The evaluation of the PCA scores and loadings plots of principal components 1 through 3, as well as of volcano plots, highlighted 25 different compounds, mostly identified as aminosteroid alkaloids, that were most relevant for the differences between leaves and twigs and between the two populations and mainly determined the changes in their chemical profiles over the vegetation period. Full article

Neonatal calf diarrhoea (NCD) is the leading cause of mortality in calves under 30 days old. Although several pathogens are usually involved in outbreaks, most previous research has focused on specific enteropathogens or on the four agents traditionally associated with this syndrome. This study aimed to determine the prevalence of thirteen enteropathogens in 420 diarrhoeic calves under a month of age from north-western Spain and to identify the most frequent co-occurrences. Four diarrhoeagenic pathotypes of Escherichia coli, bovine rotavirus A, coronavirus, norovirus, nebovirus and torovirus were identified using qPCR. Presence of Salmonella spp. was studied using a serum agglutination test. A direct immunofluorescence assay was employed to identify Cryptosporidium and Giardia duodenalis oo/cysts. Eimeria oocysts were found by the floatation technique. Our results confirm the co-occurrence of agents in most cases of NCD. A total of 172 pathogen combinations, involving up to seven agents, were identified. Cases involving one or more viral agents and Cryptosporidium parvum were predominant, maybe because viral immunosuppression facilitates the protozoan life-cycle. The frequent detection of agents typically overlooked in the aetiological diagnosis of NCD suggests that they may play a role in this syndrome and thus should be included in routine diagnostic panels, allowing implementing the most effective control measures. Full article

Trypanosoma cruzi is a hemoflagellate protozoan and the causative agent of Chagas disease, also known as American trypanosomiasis. Transmission occurs through the feces of triatomine insects, its biological vector. It is estimated that around 7 million people are infected across Mexico, Central America, and South America. This study aimed to identify and characterize T. cruzi isolates obtained from wild triatomine vectors collected in Aguascalientes, Mexico. Molecular identification was performed at different developmental stages—epimastigotes in culture media, metacyclic trypomastigotes in triatomine feces, and amastigotes in mouse cardiac tissue—using endpoint PCR targeting satDNA and mtCytB regions. In addition, next-generation sequencing was employed to analyze variable regions of kinetoplast DNA minicircles. The pathogenicity of the isolated and identified T. cruzi strain was assessed in a murine model, where trypomastigote stages were detected in peripheral blood and amastigote stages in muscle tissue. Molecular analyses confirmed the presence of T. cruzi across different developmental stages from wild vectors, demonstrating that the isolated wild strain possesses pathogenic potential when completing its life cycle in an experimental mammalian host, specifically BALB/c mice. Full article

Sterol biosynthesis is crucial for the function of biological membranes and an important target for anti-protozoan/anti-fungal drugs. In the trypanosomatid parasite Leishmania major, the deletion of sterol C14-demethylase (C14DM) results in hypersensitivity to heat, increased plasma membrane fluidity, profound mitochondrial dysfunctions, and reduced virulence in mice. In this study, we show that C14DM-null mutants are defective in their tolerance to membrane-disrupting agents and osmotic stress and their ability to form autophagosomes. In addition, C14DM-null mutants exhibit a heightened sensitivity to anti-trypanosomatid drugs including antimony, ethidium bromide, and pentamidine. The combination of itraconazole (a C14DM antagonist) and pentamidine synergistically inhibits the growth of Leishmania parasites. These findings reveal new insight into the roles of sterol synthesis in protozoan pathogens and highlight the potential of using drug combinations to achieve better treatment outcomes. Full article

Tritrichomonas foetus is an anaerobic flagellated protozoan that infects multiple animal hosts, primarily cattle and cats, with occasional isolation from pigs. It causes bovine trichomonosis, a venereal disease associated with infertility, abortion, and economic losses in cattle herd. In cats, T. foetus infects the gastrointestinal tract, causing chronic diarrhea which can be difficult to treat. Despite its broad impact, the pathogen is difficult to control because it evades immune responses and persists in host tissues. Recent advances in omics technologies, including genomics, transcriptomics, and proteomics, have contributed to a better understanding of the parasite’s genetic structure, virulence, drug resistance mechanisms, and metabolic pathways. These findings have identified potential drug targets and paved the way for targeted therapies. However, the biology, pathogenicity, and host interactions with T. foetus are still not fully understood, and many aspects of its life cycle and molecular mechanisms remain to be elucidated. This review summarizes the latest omics research on T. foetus, highlighting its genetic diversity and host-specific adaptations, and outlines the gaps in our understanding. Full article

Neonatal calf diarrhea (NCD) represents a major cause of economic loss in dairy cattle herds worldwide. The condition is primarily associated with several key pathogens, including enterotoxigenic Escherichia coli (ETEC), viral agents such as bovine rotavirus (BRV) and bovine coronavirus (BCoV), and the protozoan Cryptosporidium parvum. This study aimed to assess the prevalence of NCD-associated pathogens in Italian dairy farms over the period 2020–2022. Among the 598 farms affected by NCD and included in the investigation, ETEC strains were detected in 17.2% of cases. The prevalence of BRV, BCoV, and Cryptosporidium spp. was 22.2%, 20.2%, and 32.3%, respectively. Co-infections were also frequently observed and are considered to significantly exacerbate the clinical severity of the disease. Ongoing surveillance of NCD pathogens is essential to generate reliable and updated epidemiological data, which are critical for guiding effective control and prevention strategies. Full article

Coastal fecal contamination is a global public health concern, particularly due to waterborne protozoan parasites such as Giardia duodenalis and Blastocystis sp. Concepcion Bay (Chile) is an important recreational and productive area in Chile. Nevertheless, it is impacted by two submarine outfalls and a rural sewage treatment plant, which may contribute to fecal pollution. This study evaluated the presence of waterborne parasites in Aulacomya atra mussels intended for human consumption. The mussels were collected from three sectors of the bay: northern, central, and southern. A total of 600 mussels were analyzed as accumulators using PCR targeting SSU-rDNA and β-giardin genes for the detection of Blastocystis sp. and G. duodenalis, respectively. Additionally, thermotolerant coliforms were quantified using the most probable number (MPN) method. Both parasites and coliforms were detected in all sectors, with the southern zone showing the highest number of positive samples, indicating a localized public health concern. This is the first report of these protozoa in mussels from Concepción Bay. The findings highlight the need for regulatory frameworks to control protozoan discharge and reduce pathogen transmission risks in coastal ecosystems, especially in areas with high recreational and economic activity, both in Chile and worldwide. Full article

Human milk, especially colostrum, is a biologically complex fluid with potent protective properties against gastrointestinal disturbances in infants. Among intestinal protozoa transmitted via the fecal–oral route, this review focuses on Giardia lamblia and Entamoeba histolytica, as the protective role of milk-derived factors against these parasites is the most extensively documented. Its protective effects result from a wide range of bioactive components, including mucins, lactoferrin, human milk oligosaccharides, melatonin, and secretory IgA, which support the integrity of the intestinal barrier, regulate immune responses, and inhibit the adhesion and activity of pathogens. The composition of human milk can be influenced by maternal factors such as nutritional status, stress, sleep quality, and physical activity, which may modulate its immunological potential. Dietary intake of micronutrients, fermentable fibers, and fermented foods also appears to play a role in shaping the milk’s protective properties. This review discusses the molecular mechanisms by which selected milk components contribute to the defense against protozoan infections in early life and considers how maternal health and lifestyle may affect the effectiveness of these protective mechanisms. Full article

Migratory birds play a key role in the ecology of tick-borne pathogens, serving as both hosts for ticks and as potential carriers of a wide range of infectious agents that can affect wildlife, domestic animals, and humans. Their long-distance movements contribute to the dispersal of ticks and the pathogens they harbor, with potential implications for the emergence and spread of zoonotic disease. This study focuses on the prevalence of Rickettsia spp. and Babesia/Theileria spp. in ticks collected from migratory birds in Sardinia, Italy, during two consecutive migration seasons (April–May and October–November 2021), corresponding to the spring and autumn migratory periods. A total of 961 ticks, primarily Ixodes ricinus, was collected from various bird species. Molecular analyses using polymerase chain reaction (PCR) and sequencing enabled the detection and identification of multiple Rickettsia species, with R. helvetica, R. monacensis, and R. aeschlimannii being the most frequently identified. Protozoan pathogens, including B. venatorum and Theileria ovis, were also detected in the tick samples. These findings underscore the diversity of pathogens in bird-associated ticks and the role of migratory birds in the geographical spread of these diseases. These results also provide valuable insights into pathogen transmission dynamics and stress the importance of monitoring migratory birds to assess and mitigate the risks of zoonotic diseases. Further research is needed to clarify the ecological interactions among birds, ticks, and pathogens across different geographic regions. Full article

Research is required to determine whether the coinfections by Fasciola spp. and other parasite species result from poor rural hygiene or reflect underlying epidemiological patterns and causes. Therefore, the role of fascioliasis is analyzed concerning coinfection complexity, risk of multiparasitism, parasite associations, pathogenic implications and their multifactorial causes. Helminth and protozoan coinfections are studied in 2575 previously untreated individuals from four rural hyperendemic areas (Northern Bolivian Altiplano, Peruvian Altiplano and Cajamarca valley, and the Egyptian Nile Delta). This cross-sectional study was conducted from January 2011 to December 2023. Coinfections were coprologically assessed by the merthiolate–iodine–formalin and formol–ether concentration techniques. Infection intensity was measured as eggs/gram of feces (epg) with the Kato–Katz technique. Parasite and coinfection prevalences were stratified by age, sex and geographical location. High mixed infections, fascioliasis prevalences and very low non-coinfected Fasciola-infected subjects were associated with the following regions: Bolivian Altiplano, 96.5%, 16.8% and 3.5%; Peruvian Altiplano, 100%, 24.6% and 0%; Cajamarca valley, 98.7%, 21.4% and 1.8%; Nile Delta, 84.1%, 13.0% and 15.9%. Transmission routes and human infection sources underlie fascioliasis associations with protozoan and other helminth infections. Prevalence pattern of protozoan–helminth coinfections differed between Fasciola-infected individuals and individuals not infected with Fasciola, presenting higher prevalences in individuals with fascioliasis. Multiparasitism diagnosed in Fasciola-infected subjects included coinfections by up to nine parasite species, eight protozoan species, and five helminth species. The most prevalent pathogenic protozoan was Giardia intestinalis. The most prevalent helminth species differ according to environmental conditions. Several parasites indicate fecal environmental contamination. When the fascioliasis burden increases, the total number of parasite species also increases. The fascioliasis risk increases when the total helminth species number/host increases. Fasciola-infected subjects may present a modification in the clinical phenotypes of coinfecting parasitic diseases. Fascioliasis coinfection factors include transmission ways and immunological, environmental and social aspects. Coinfections must be considered when assessing the health impact of fascioliasis, including the analysis of the fascioliasis effects on malnutrition and physical/intellectual child development. Fascioliasis-control schemes should, therefore, integrate control measures mainly against other helminthiases. Full article

Toxoplasma gondii is an intracellular protozoan found worldwide that is capable of infecting nearly all warm-blooded animals, including humans. Its parasitic success lies in its capacity to create chronic infections while avoiding immune detection, altering host immune responses, and disrupting programmed cell death pathways. This review examines the complex relationship between T. gondii and host immunity, focusing on how the parasite influences innate and adaptive immune responses to survive in immune-privileged tissues. We present recent findings on the immune modulation specific to various parasite strains, the immunopathology caused by imbalanced inflammation, and how the parasite undermines host cell death mechanisms such as apoptosis, necroptosis, and pyroptosis. These immune evasion tactics enable prolonged intracellular survival and pose significant challenges for treatment and vaccine development. We also review advancements in therapeutic strategies, including host-directed approaches, nanoparticle drug delivery, and CRISPR-based technologies, along with progress in vaccine development from subunit and DNA vaccines to live-attenuated candidates. This review emphasizes the importance of T. gondii as a model for chronic infections and points out potential avenues for developing innovative therapies and vaccines aimed at toxoplasmosis and similar intracellular pathogens. Full article

Giardia lamblia is a flagellated protozoan and the etiological agent of giardiasis, a leading cause of epidemic and sporadic diarrhoea globally. The clinical and public health relevance of giardiasis underscores the need for robust methodologies to investigate and manage this pathogen. This study reviews the main methodologies described in the literature for studying the life cycle of G. lamblia, focusing on isolation, purification, axenization, excystation, and encystation. A systematic literature review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) statement. Searches were performed in MEDLINE, ScienceDirect, and Web of Science Core Collection databases. A total of 43 studies were included, revealing 58 methods for isolation and purification, 7 for excystation, 2 for axenization, and 5 for encystation. Isolation and purification methods exhibited significant variability, often involving two phases: an initial separation (e.g., filtration and centrifugation) followed by purification using a density gradient for faecal samples or immunomagnetic separation for water samples. Method effectiveness differed depending on the sample source and type, limiting comparability across studies. In contrast, methods used for other life cycle stages were more consistent. These findings underscore the need for standardised methodologies to enhance the reproducibility and reliability of research outcomes in this field. Full article

In Thailand, domestic cats are frequently exposed to vectors that transmit a variety of pathogens. In this study, the prevalence of vector-borne pathogens (VBPs) and their association with feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) were investigated in 187 domestic cats from animal hospitals across five northeastern provinces. Twelve pathogens, including viruses, bacteria, and protozoa, were screened using PCR assays. FIV was identified in 2.67% of the cats, while FeLV exhibited a notably higher prevalence of 29.95%. Among the bacterial pathogens, Bartonella henselae was the most frequently detected (94.65%), followed by Rickettsia felis (34.22%). Protozoan infections such as Babesia canis (8.02%) and Cytauxzoon felis (3.21%) were less prevalent. Co-infections were common, with numerous cats hosting multiple pathogens. Correlation analysis revealed moderate associations between FIV and Babesia microti (r = 0.43), Babesia canis (r = 0.35), and Mycoplasma spp. (r = 0.33), indicating potential co-infection or predisposition. Although significant differences in the total white blood cell counts were not observed, leukopenia was more commonly found in FeLV/FIV-positive cats. These findings indicate that a high burden of infection and co-infection exists in the feline population, supporting the need for expanded pathogen screening and enhanced vector control strategies. Full article

Although Dientamoeba fragilis is a common protozoan in humans, its pathogenicity and clinical significance in human diseases remain poorly understood. This study aimed to determine the frequency of D. fragilis in adult ulcerative colitis patients and to assess its relationship with clinical findings, disease characteristics, and biochemical parameters. Patient data were analysed in a prospective, single-centre, cross-sectional design. Faecal samples were consecutively collected from June to December 2024 and screened for D. fragilis positivity using polymerase chain reaction. Of the 110 patients, 33 (30%) were in the active stage of the disease, while 77 (70%) were in remission. The overall frequency of D. fragilis was 10.9% (n = 12), with all isolates classified as genotype 1 according to SSU rRNA sequence analysis. Other protozoa identified were Blastocystis sp. (n = 5, 4.5%), Entamoeba coli (n = 1, 0.9%), and Iodamoeba bütschlii (n = 1, 0.9%). Two patients were co-infected with D. fragilis and Blastocystis. No significant associations were found between D. fragilis positivity and the disease stage, gastrointestinal symptoms, treatment response, or biochemical findings. In conclusion, despite the relatively small sample size, these findings highlight a limited clinical role of D. fragilis in adult ulcerative colitis patients. Full article

The intestinal microbiota of fish is predominantly composed of prokaryotic microorganisms, with research historically focused on bacteria. In contrast, the role of microeukaryotic organisms in the fish gut remains largely unexplored. This review synthesizes current knowledge on the diversity, ecology, and potential functions of intestinal microeukaryotes, particularly fungi and protozoans, in teleost fish. Fungi, especially Ascomycota and Basidiomycota phyla members, are consistently identified across species and may contribute to digestion, immune modulation, and microbial homeostasis. Protists, though often viewed as pathogens, also exhibit potential commensal or immunoregulatory roles, including the modulation of bacterial communities through grazing. Other eukaryotic taxa, including metazoan parasites, microalgae, and zooplankton, are commonly found as transient or diet-derived members of the gut ecosystem. While many of these organisms remain poorly characterized, emerging evidence suggests they may play essential roles in host physiology and microbial balance. The review highlights the need for improved detection methodologies, functional studies using gnotobiotic and in vitro models, and multi-kingdom approaches to uncover fish gut microeukaryotes’ ecological and biotechnological potential. Full article