Parasitology International最新文献

The expansion of land use in Brazil has caused biodiversity loss and increased human interaction with parasites and pathogens previously restricted to natural ecosystems. Chigger mites are ectoparasites during the larval stage and can cause skin reactions or transmit pathogens to their hosts, including humans. This study aimed to evaluate the diversity of chiggers collected from all five Brazilian biogeographical regions, along with pathogen surveillance. Specimens were subjected to both morphological taxonomy and endogenous control, followed by PCR assays targeting pathogens of the genera Borrelia, Orientia, and Rickettsia. The analyses revealed a high species richness, including two novel records in Brazil: the genus Boshkerria and the species Quadraseta antillarum. Additionally, the genus Quadraseta tested positive for Rickettsia sp., while tests for the other agents were negative. This is the first report of a Rickettsia sp. agent detected in a Quadraseta nymph.

Tick-borne infections such as babesiosis, theileriosis, and anaplasmosis in cattle, and babesiosis, hepatozoonosis, and ehrlichiosis in dogs, remain significant constraints to the animal health and productivity in India. This review summarizes the recent updates on molecular epidemiology, genetic diversity, and transmission dynamics of these infections. Babesia bigemina, Theileria annulata and Anaplasma marginale are the most important bovine pathogens, while B. gibsoni and E. canis are the major canine pathogens. Molecular studies reveal genetic variation and high haplotype diversity, with implications for diagnosis, treatment, and control. Continued surveillance and integrated control strategies are urgently needed.

Cutaneous leishmaniasis (CL) is a neglected tropical disease associated with significant morbidity, primarily due to chronic skin lesions, scarring, and psychosocial consequences. This study aimed to investigate the in vitro and ex vivo antileishmanial effects of thymol (1-500 μM) against Leishmania tropica (MHOM/TR/2012/CBCL-LT) infection. Thymol's in vitro efficacy was assessed on both promastigote (Haemocytometry and CellTiter-Glo assays) and amastigote (Giemsa staining and Parasite Rescue Transformation Assay) forms of L. tropica. Additionally, its immunomodulatory effects were evaluated by analyzing cytokine secretion (IFN-γ, IL-12, IL-10, and IL-4) and infectivity in THP-1 macrophages using ELISA. Cytotoxicity was determined by calculating the 50 % cytotoxic concentration (CC₅₀) in THP-1 cells. The in vitro inhibitory concentration (IC₅₀) value against L. tropica promastigotes was determined as 79.41 μM, while the ex vivo IC₅₀ value against amastigotes was 105.2 μM. Incubation of infected macrophages with thymol resulted in a dose-dependent increase in IFN-γ and IL-12 levels, along with a significant reduction in IL-10 and IL-4 secretion (p < 0.05). The CC₅₀ value of thymol in THP-1 cells was 160.7 μM, indicating low cytotoxicity. Moreover, the selectivity index (SI) values greater than 1 confirmed the compound's preferential action against amastigotes while exhibiting minimal toxicity toward macrophages. These findings highlight thymol's potential as an antileishmanial agent by effectively eliminating and controlling Leishmania parasites in both in vitro and ex vivo models. Due to its immunomodulatory properties and low cytotoxicity, thymol represents a promising starting point for the development of novel antileishmanial agents and alternative therapeutic strategies against CL caused by L. tropica.

Sika deer, primarily animals of Japanese origin, have been introduced into Europe and, following release into the wild, established free-ranging populations in several countries, including Germany. In addition to the wild populations, sika deer are still maintained in deer parks and there are also deer farms carrying sika deer for venison production. However, to date there is no information about the parasite fauna that infect farmed sika deer and only little knowledge on parasites of sika deer in parks. This work summarizes the results of the examination for endoparasites of viscera and muscle samples of 33 sika deer from five farms and 11 sika deer from five parks in Germany. Eight species of nematodes (Ostertagia leptospicularis, Spiculopteragia asymmetrica, Spiculopteragia boehmi, Spiculopteragia houdemeri, Trichostrongylus askivali, Oesophagostomum sikae, Oesophagostomum venulosum, Trichuris globulosa) and one species of coccidia (Eimeria austriaca) were isolated from the gastrointestinal tract. Sarcocystis cysts were identified in cardiac and/or diaphragm myocytes of 6/11 park deer while no cysts were detected in heart and/or diaphragm samples from 24 farmed deer. No cestodes, lungworms, liver flukes and rumen flukes were found. The nematode community was dominated by the polymorphic ostertagids residing in the abomasum, but the total burden (adults plus mucosal larval stages) was overall very low with geometric mean counts of 62 and 117 in the farmed deer (range, 0 to 2340) and park deer (range, 26 to 629), respectively. Spiculopteragia houdemeri, index ostertagid of sika deer of Japanese origin, made more than 80 % of the total nematode burden in both farmed and park sika deer.

Chagasic cardiomyopathy, caused by Trypanosoma cruzi, is influenced by host-parasite genetics and environmental factors such as diet. High-fat diets can intensify inflammation via pathways involving IRAK-1 and PPARs (α/γ). This study examined the impact of monounsaturated (olive oil) and saturated (lard) fat-rich diets on the expression of IRAK-1, PPAR-α, and PPAR-γ in cardiac and adipose tissues of mice infected with the Colombian strain of T. cruzi. Mice received control, olive oil, or lard diets during the experiment, and the infection was evaluated for 30 or 100 days. Infection increased IRAK-1 expression in both tissues at 30 dpi and a cardiac reduction at 100 dpi. PPAR-α and PPAR-γ were suppressed at both time points, while PPARs were decreased in the presence of T. cruzi. In infected mice, fat-rich diets further decreased PPAR-α in cardiac tissue, while olive oil upregulated PPAR-γ in cardiac tissue (30 dpi), and lard did so with both PPARs in adipose tissues (100 dpi). These results highlight the phase-specific and fat-type-specific modulation of inflammatory pathways by lipid diets, underlining the potential role of nutrition in Chagas disease progression.

Opisthorchis viverrini (Ov) infection is a major public health concern in the Greater Mekong Subregion, with cats as key reservoir hosts. Although machine learning (ML) is widely used in human medicine, its application in veterinary epidemiology remains limited. This study aimed to develop interpretable ML models to predict Ov infection and to identify key risk factors in cats using data from 175 households in endemic areas. Five ML algorithms-Classification Tree, Random Forest, Ridge Logistic Regression (Ridge LR), eXtreme Gradient Boosting, and Support Vector Machine (SVM)-were optimized using feature selection methods, hyperparameter tuning, and SMOTE. The results demonstrated that Ridge LR with Minimum Redundancy Maximum Relevance (mRMR), tuned Ridge LR, and tuned SVM achieved reliable performance, with ROC-AUC values exceeding 0.7. Specifically, default Ridge LR with mRMR achieved strong balanced accuracy (0.722), while tuned Ridge LR attained the highest sensitivity (0.667). Tuned SVM with mRMR yielded a test ROC-AUC of 0.723 and PR-AUC of 0.473, along with a balanced accuracy of 0.682. SHapley Additive exPlanations (SHAP) analysis identified key risk factors, including residence in flooded areas, feeding fish scraps to cats, and annual rainfall, emphasizing the role of environmental factors in Ov transmission. These findings highlight the potential of ML in veterinary epidemiology and emphasize the importance of selecting appropriate methods based on data characteristics. The study suggests that targeted, risk-based interventions focusing on these key risk factors are crucial for effective Ov control in endemic regions.