Search Results (469)

The carcinogenic liver fluke Opisthorchis viverrini underlies one of the world’s heaviest burdens of bile duct cancer, yet for decades it was treated as a single, genetically uniform parasite whose transmission was shaped mainly by environment and human behavior. However, advances in molecular biology have fundamentally reshaped this conceptual model. Evidence accumulated over the past three decades demonstrates that O. viverrini comprises geographically structured populations linked to hydrological connectivity, host distribution, and long-term evolutionary processes across interconnected river systems of mainland Southeast Asia, particularly within the Lower Mekong Basin. This review synthesizes research on the systematics and population structure of O. viverrini and its Bithynia snail hosts, tracing the transition from early allozyme studies to contemporary DNA-based and genomic approaches. Collectively, mitochondrial, nuclear, microsatellite, and intron markers reveal strong spatial structuring among parasite populations, while genetic patterns observed in snail hosts show partial geographic concordance with parasite population structure, suggesting that both may be influenced by shared hydrological organization, ecological isolation, and host connectivity across endemic aquatic systems. Population structure is strongly scale-dependent, with local panmixia often occurring within connected aquatic systems but pronounced differentiation emerging across broader geographic regions. Together, these findings indicate that transmission dynamics are shaped not only by environmental and behavioral factors, but also by evolutionary and landscape-level processes influencing host and parasite connectivity. Finally, we emphasize the increasing significance of population genomics and landscape genetics in understanding how transmission systems persist, disperse, reconnect, and respond to environmental change across endemic landscapes. Full article

Toxoplasmosis remains one of the most common parasitic infections affecting humans, with significant implications for pregnancy and fetal health. Maternal primary infection during gestation can result in transplacental transmission of Toxoplasma gondii, leading to a wide spectrum of congenital disease. The risk of vertical transmission increases with gestational age, whereas disease severity is inversely related—early infections causing severe neurological and ocular damage, and late infections often resulting in subclinical forms. Advances in serological testing, including IgG avidity assays and molecular diagnostics such as PCR on amniotic fluid, have improved early detection and management. Prenatal treatment with spiramycin or pyrimethamine–sulfadiazine–folinic acid combinations has been associated with reduced transmission and less severe fetal disease in several studies, although the magnitude of benefit remains debated. Long-term follow-up is essential, as late-onset manifestations, particularly chorioretinitis and neurodevelopmental impairment, are common. This narrative review was based on a comprehensive literature search of major medical databases and summarizes current knowledge on the epidemiology, pathophysiology, diagnosis, treatment, and outcomes of toxoplasmosis in pregnancy. Particular emphasis is placed on high-prevalence countries, where greater parasite genetic diversity, distinct epidemiological patterns, and a higher burden of congenital disease pose unique clinical and public health challenges. Despite progress in understanding parasite biology, pathogenesis, and treatment efficacy, congenital toxoplasmosis continues to be underdiagnosed and underreported, especially in low-resource settings. Ongoing challenges include optimizing screening strategies, ensuring access to standardized therapies, and strengthening surveillance systems. Full article

Toxoplasma gondii is an apicomplexan parasite that causes toxoplasmosis, a widespread zoonotic disease leading to serious public health concerns and economic losses to animal husbandry. Currently, highly effective vaccines against toxoplasmosis remain unavailable. This study aimed to investigate the safety, immunogenicity, and protective efficacy of the gra47-deficient mutant strain PruΔgra47 as a live-attenuated vaccine candidate. We evaluated the virulence of PruΔgra47 in a mouse model, determined the optimal immunization dose, and measured serum antibody levels and cytokine profiles. Then, mice immunized with PruΔgra47 were challenged with different T. gondii strains to assess protection against acute and chronic infection. PruΔgra47 displayed significantly attenuated virulence and its ability to form cysts was weakened. Vaccination with 5 × 10⁶ tachyzoites elicited predominantly Th1-skewed immune responses. Immunization with PruΔgra47 provided complete protection against challenge infection with relatively low-virulent PYS strain and homologous Pru strain, prolonged survival against the highly virulent RH strain, and achieved a 90% survival rate with reduced brain cyst burden under chronic challenge. In conclusion, PruΔgra47 is relatively safe and immunogenic in the murine model, and is worth being evaluated in food-producing animals and cats. Full article

This study investigated the associations among dam lactation number, passive immunity transfer, internal parasite burden, and weaning performance in female calves. Early consumption of high-quality colostrum is critical for effective passive immunity transfer, calf health, and long-term productivity. Colostrum composition may vary with management practices and dam lactation number, potentially influencing immunity and disease susceptibility. Forty-five cows and their female offspring (n = 45) were allocated to three groups by lactation number: first lactation (LAC1), second lactation (LAC2), and third lactation (LAC3) (15 cows and 15 calves per group). Calf birth weight was recorded. Colostrum immunoglobulin G (IgG) concentration was measured using a colostrometer and refractometer, and chemical composition (fat, protein, and non-fat solids) was analyzed. Fecal samples collected at 30, 60, and 90 days of age were examined for Eimeria spp. Colostrum IgG concentration, °Brix percentage, specific gravity, and non-fat solids did not differ among lactation groups (p > 0.05). LAC3 cows had higher colostrum protein content, while LAC1 cows had greater fat concentration (p < 0.05). Calves from LAC1 dams were lighter at birth than those from LAC2 and LAC3 dams (p < 0.001). The prevalence of Eimeria spp. was not influenced by lactation number, birth weight, or colostrum quality (p > 0.05), but treatment costs were higher in calves from LAC3 dams (p < 0.01). In conclusion, lactation number affected colostrum composition and calf growth but did not alter IgG concentration, underscoring the importance of effective colostrum management to improve calf performance and dairy system sustainability. Full article

Background: Toxoplasmosis is a prevalent zoonotic disease worldwide, affecting approximately one-third of the global human population. Primary infection with Toxoplasma gondii during pregnancy can induce miscarriage or congenital infection, leading to irreversible damage to the foetus. Moreover, reactivation of T. gondii infection in immunosuppressed individuals can result in fatal outcomes. No vaccine exists to prevent human disease caused by this parasite. Thus, a vaccine that could induce complete and lasting protection against human toxoplasmosis is an unmet need. Method: In this work, BALB/cByJ mice were intranasally immunised with a subunit vaccine consisting of T. gondii membrane proteins (TGMP) from the T. gondii Me49 strain plus CpG-oligodeoxynucleotide adjuvant (CpG). Antibody responses were analysed by ELISA, while T-cell responses were evaluated by flow cytometry. The immunogenic proteins present in TGMP were identified by mass spectrometry, and parasite burden was quantified by qPCR. Result: The results showed raised TGMP-specific serum IgG and intestinal IgA antibody levels, and parasite-specific IFN-γ-producing CD4⁺ and CD8⁺ memory T cells. Dense granule proteins (GRA) 2 and 7, surface antigen (SAG)-related sequences 25, 29B, and 34A, microneme protein (MIC) 10, toxofilin, nascent polypeptide-associated complex (NAC) domain-containing protein, and NAC subunit beta were identified as immunogenic proteins. Mice immunised with TGMP+CpG were challenged with T. gondii tachyzoites and showed a significant reduction in the parasitic burden in the peritoneal exudate, spleen, and lungs, compared to mice sham-immunised with CpG alone. Conclusions: Altogether, these results indicate that mucosal immunisation with TGMP plus CpG adjuvant is worth exploring as a vaccination approach to prevent toxoplasmosis. Full article

Objectives: Patients with thalassemia major are at high risk of developing blood-borne infections, including toxoplasmosis, due to their dependence on frequent blood transfusions and underlying immune system disorders. This study was designed to investigate this hidden risk and provide data for policymaking in blood transfusion services in a region with a high endemicity. Methods: A total of 300 blood samples from thalassemia patients in northern Iran were collected. Serological testing was conducted to detect IgG and IgM antibodies. DNA extraction followed, with molecular screening performed via PCR. Finally, genotyping of T. gondii was carried out using nested PCR focused on the GRA6 gene. Results: The serological analysis revealed 59.7% of patients exhibited IgG against T. gondii, while only 0.6% tested positive for IgM. The results of the molecular screening revealed 2.7% of patients had DNA of T. gondii. The results of genetic analysis showed 75% had type II, 12.5% had type I, and 12.5% belonged to type III. Conclusions: This study provides serological and molecular evidence of a high chronic Toxoplasma gondii burden in thalassemia patients from northern Iran, an endemic region. A significant association between blood transfusion history and seropositivity, along with parasite DNA detection, suggests elevated exposure risk, though direct transfusion transmission remains unproven. Finding’s support integrating nested PCR with routine serology for diagnosing infection in this population. Full article

Chagas disease, caused by Trypanosoma cruzi (T. cruzi), includes clinically relevant intestinal inflammation; however, the mechanisms associated with tissue injury remain incompletely understood. ArtinM is an immunomodulatory lectin with known effects on innate and adaptive immunity, although its intestinal role during acute T. cruzi infection remains unclear. This study investigated whether ArtinM modulates the intestinal inflammatory response during acute experimental T. cruzi infection. In vivo, BALB/c mice were allocated to Saline control, T. cruzi + Saline, and T. cruzi + ArtinM groups. Intestinal inflammatory infiltrate and tissue concentrations of TNF-α, IFN-γ, IL-12p40, and IL-10 were quantified. Acute infection markedly increased TNF-α, IFN-γ, IL-12p40, and inflammatory infiltrate, whereas ArtinM significantly attenuated these responses. TNF-α, IFN-γ, and IL-12p40 remained associated with group after adjustment for infiltrate, whereas IL-10 reached statistical significance only in the adjusted model and was therefore interpreted cautiously. In parallel, an exploratory analysis of a public murine intestinal scRNA-seq dataset (GSE319934; GSM9529706 and GSM9529707), derived from a chronic infection setting, was performed to provide pathway-level context for inflammatory mediators assessed in vivo. This transcriptomic analysis indicated that related inflammatory, innate immune, chemotactic, and adhesion-associated genes were detectable in intestinal single-cell data from T. cruzi infection. However, because this dataset was not temporally matched to the acute model, it was not interpreted as a phase-matched comparator, mechanistic validation, or temporal extension of the experimental findings. Together, the results support that ArtinM treatment is associated with attenuation of acute intestinal inflammatory outcomes in experimental T. cruzi infection. Because local intestinal parasite burden was not measured, these findings should be interpreted as evidence of inflammatory modulation rather than as direct evidence of local antiparasitic activity. The public scRNA-seq analysis provides only exploratory contextual information for related inflammatory pathways. Full article

Schistosomiasis remains the second leading cause of death among parasitic diseases globally, contributing substantially to chronic morbidity and disability. South Africa (SA) is endemic for schistosomiasis, with ongoing efforts to expand mass drug administration. In the absence of true prevalence data, this study retrospectively analysed public sector laboratory-confirmed schistosomiasis cases from 2019 to 2024. Over this period, 73,680 cases were microscopically diagnosed, with Schistosoma haematobium accounting for 99.9% of infections. The test positivity rate of 20 per 100,000 population is lower than previously reported, with the burden concentrated among boys aged 5–19 years, particularly in the KwaZulu-Natal, Limpopo, and Mpumalanga provinces. These findings highlight a persistent burden within defined demographic groups and geographic areas, while also suggesting possible early signs of improvement that are potentially linked to public health interventions. The results provide valuable evidence to inform the scale-up of national schistosomiasis control programmes and the prioritisation of interventions towards the most affected populations. Full article

This paper investigates the accuracy of conventional inductive current transformers (iCTs) and Rogowski coils (RCs) in measuring distorted currents, evaluating compliance with the WB0 (up to the 13th harmonic) and WB1 (up to the 60th harmonic) accuracy classes according to the IEC 61869-1 standard. A custom reference iCT, calibrated via the ampere-turns method to achieve a superior baseline accuracy (0.02%), served as the primary benchmark. A zero-flux electronic transducer was utilized strictly to verify this reference. Despite inherent core nonlinearity, tested conventional iCTs with reduced to minimum secondary burdens successfully met the class 0.5-WB1 requirements. In the case of tested Rogowski coils, the study reveals that their wideband performance depends on physical design of the particular type. High-sensitivity coils suffer from increased parasitic capacitance and self-inductance, causing significant additional phase shift at higher frequencies, whereas low-sensitivity, small-diameter coils offer superior linearity. Overall, the tested RCs generally ensured compliance with the 0.5-WB1 class across the evaluated frequency range, with certain units successfully achieving the more restrictive 0.2-WB1 class. Ultimately, conventional iCTs remain a highly reliable solution for metering purposes in low-voltage networks, while properly selected Rogowski coils provide a valuable alternative for power quality analysis and harmonic distortion measurements. Full article

Porcine cysticercosis, caused by the larval stage of the zoonotic parasite Taenia solium, poses a public health and economic burden in endemic regions. This study explored stakeholder perspectives on porcine cysticercosis control and risk factors in Busia County and documented proposed control measures with relevance to endemic regions. A qualitative design was used, involving eight key informant interviews (KIIs) and twelve focus group discussions (FGDs). Data were analyzed qualitatively by identifying emerging themes. The study found that smallholder semi-confined pig farming is the dominant system in the area, driven mainly by economic constraints, which elevates the risk of porcine cysticercosis. Poor hygiene, inadequate sanitation, and lack of safe water also contribute, alongside informal pig slaughter and weak meat inspection, compromising pork safety. Low public awareness limits preventive practices and hinders effective public health interventions. These findings highlight the need for integrated control measures, including community education on preventive behaviors and practices; strengthened veterinary services; improved sanitation; and enforced meat inspection. Coordinated One Health actions across public health, veterinary services, and communities are crucial to mitigate these interconnected health risks. The findings may guide interventions in comparable endemic settings and offer insights for managing other zoonotic diseases with similar transmission dynamics. Full article

Background/Objectives: Cryptosporidium parvum (C. parvum), a waterborne intestinal parasite, causes severe, persistent infections in immunocompromised hosts and has been linked to the onset of ileocecal adenocarcinoma. However, the molecular pathways linking chronic infection to carcinogenesis remain unclear. Nitazoxanide (NTZ), the only FDA-approved drug for this infection, shows limited efficacy. In contrast, azithromycin (AZM) possesses both antiparasitic and anticancer activity, though conclusive evidence supporting its effectiveness against cryptosporidiosis is still lacking. This study aimed to investigate the therapeutic potential of AZM against chronic cryptosporidiosis and its associated tumorigenic sequelae. Methods: Immunosuppressed mice were infected with C. parvum and treated with NTZ or AZM. Parasite burden was assessed by quantifying fecal oocyst shedding. Ileocecal tissues were analyzed for histopathology, inflammation (IL-6 and TNF-α), autophagy markers (LC3II, Beclin-1, and Atg7), PI3K/AKT signaling, and apoptotic markers (Bcl2, Bax, cleaved caspase-3, DR4, and DR5) using ELISA, real-time PCR, and Western blot. Results: Chronic C. parvum infection induced Vienna 4.4 adenocarcinoma, activated autophagy and PI3K/AKT signaling, and suppressed intrinsic and TRAIL-mediated apoptosis. AZM significantly reduced the parasitic load by 87%, outperforming NTZ (62%). It also restored epithelial integrity, attenuated inflammation, and counteracted pro-tumorigenic effects by inhibiting autophagy, downregulating the PI3K/AKT pathway, and stimulating apoptosis. Conclusions: AZM counteracted parasite-driven tumorigenic mechanisms by disrupting survival pathways and promoting apoptosis in infected and transformed cells. These findings provide evidence that AZM exerts dual antiparasitic effects and counteracts pro-tumorigenic signaling in chronic cryptosporidiosis, highlighting its potential as a therapeutic agent to prevent infection-associated ileocecal carcinogenesis. Full article

Vector-borne protozoal infections—including babesiosis, theileriosis, hepatozoonosis, trypanosomosis, and leishmaniosis—impose a substantial burden on livestock and companion animal health worldwide and carry important zoonotic and public health implications. Accurate diagnosis is essential yet challenging, given the diversity of parasite genera, their markedly different tissue tropisms, and the uneven distribution of diagnostic resources across veterinary settings. This review provides an integrated overview of the principal diagnostic approaches available, structured around the biological logic that guides test selection in practice. Microscopic examination remains the first-line method; its strengths and limitations are discussed for intraerythrocytic parasites (Plasmodium spp., Babesia spp., Theileria spp., Cytauxzoon spp.—the latter two with additional extra-erythrocytic schizont stages in leukocytes and tissue macrophages, respectively), leukocyte-associated forms (Hepatozoon spp.), extracellular trypanosomes, and tissue-stage parasites, including emerging applications of artificial intelligence. Serological methods—enzyme-linked immunosorbent assay (ELISA), indirect fluorescence antibody test (IFAT), and point-of-care lateral flow assays—are evaluated for their role in exposure detection, population screening, and international trade certification, with attention to cross-reactivity and the active-versus-past-infection distinction. Molecular diagnostics, encompassing conventional PCR, qPCR, droplet digital PCR, isothermal amplification, and next-generation sequencing, are reviewed with respect to target selection, sensitivity, and point-of-care applicability. Finally, diagnostic challenges are contextualised within a One Health framework, highlighting the fragmentation of veterinary surveillance and the need for integrated, cross-sector approaches to detect emerging threats. Full article

Background: Neglected diseases caused by protozoan parasites remain a major public health burden, particularly in low- and middle-income countries. Among the chemical motifs explored in antiparasitic drug discovery, guanidine-containing compounds have attracted considerable attention due to their strong cationic character, high capacity for hydrogen bonding, and versatility in interacting with biological targets. Methodology: This review summarizes advances reported in the last decade regarding guanidine derivatives with activity against pathogens associated with Chagas disease, human African trypanosomiasis, Leishmaniasis, tuberculosis, toxoplasmosis, dengue and schistosomiasis. Results: Evidence gathered from synthetic, natural, and drug-repurposing studies indicates that the guanidine, guanidine-containing and guanidine-related compounds contribute to modulating biological activity by changing electrostatic interactions, hydrogen-bonding networks, and physicochemical properties, with enzymes, nucleic acids, and membrane-associated targets essential for parasite survival. Across the analyzed studies, several emerging structure–activity relationship trends were identified, including the contribution of polycationic or dicationic architectures, the influence of halogenated or lipophilic substituents, and the dependence of biological activity on the complete molecular framework, including heterocyclic systems, macrocycles, peptide conjugates, hybrid scaffolds, and repurposed drugs. In addition to direct antiparasitic effects, certain guanidine-containing and guanidine-related compounds demonstrate immunomodulatory or host-protective properties, expanding the therapeutic relevance of this class. Despite promising in vitro results, protonation trapping, efflux pump susceptibility, and pharmacokinetic limitations such as poor oral absorption, high polarity, plasma protein binding and limited membrane permeability remain significant challenges for clinical translation. Nonetheless, the integration of medicinal chemistry, computational modeling, and biological screening continues to accelerate the identification of optimized scaffolds. Conclusions: Overall, guanidine-based compounds constitute a promising scaffold for the development of new therapeutic strategies targeting neglected parasitic diseases, and further structural optimization may enable the emergence of candidates with improved efficacy, selectivity, and drug-like properties. Full article

Characterizing the specific interactions of Leishmania species with different host systems is essential for the development and validation of experimental infection models and for identifying potential therapeutic targets. Leishmania parasites elicit diverse host immune responses that result in different levels of disease severity. Here, we developed a murine model of L. panamensis infection and compared the responses of BALB/c and C57BL/6 mice following intradermal ear inoculation. BALB/c mice developed progressive ulcerative lesions associated with high parasite burden, whereas C57BL/6 mice exhibited a transient edema and maintained low parasite levels detected only at early stages of infection. C57BL/6 mice displayed early production of IL-13, IL-4, and IL-10, followed by delayed IFN-γ secretion. In contrast, BALB/c mice showed a mixed Th1/Th2 response at later stages of infection. Humoral responses also differed between strains, with BALB/c mice developing an early and sustained IgG1-dominated response, while C57BL/6 mice exhibited weak and delayed antibody production. These findings suggest that resistance to L. panamensis infection in C57BL/6 mice is associated with an early and transient Th2/regulatory response accompanied by a weak and delayed antibody production. Full article

Cutaneous leishmaniasis remains a major therapeutic challenge due to drug toxicity, resistance, and limited efficacy against intracellular parasites. This study evaluated the therapeutic potential of nanoformulated Walterinnesia aegyptia (WA) venom using hyaluronic acid-based (WA-HA) and silver-based (WA-Ag) nanoparticles. Nanoparticles were synthesized and characterized by scanning and transmission electron microscopy and energy-dispersive X-ray spectroscopy. The antipromastigote activity of crude WA venom was assessed by MTT assay, and apoptosis induction was analyzed using Annexin V-FITC/propidium iodide flow cytometry. In vivo efficacy was evaluated in BALB/c mice infected with Leishmania major, with outcomes assessed by lesion progression, biochemical markers, histopathology, and PCR-based parasite detection. WA venom exhibited potent dose-dependent cytotoxicity (IC50 = 26.73 µg/mL) and induced predominantly apoptotic cell death. In vivo, nanoformulated WA significantly enhanced therapeutic outcomes compared with crude venom, with WA-HA achieving near-complete lesion resolution comparable to Amphotericin B. Treatment also reduced parasite burden, normalized liver enzyme levels, and restored hepatic and splenic architecture. These findings demonstrate that nanocarrier-based delivery markedly improves the therapeutic performance and systemic safety of WA venom, highlighting its potential as a promising nanotherapeutic strategy for cutaneous leishmaniasis. Full article