Trypanosoma cruzi infection, which causes Chagas' disease, induces an immune response in the host whose efficiency is important for the infection to persist or be eliminated. Alcohol consumption produces a great impact on the immune system, inducing alterations in the determination of T lymphocyte effector function, directing the profile of these cells to tolerance or inflammation. Our study aimed to evaluate, in C57BL/6 mice, the cytokine production in splenic leukocytes from T. cruzi infected and treated (EtOH) for 15 days and controls. Twenty-four mice were randomised into four groups, with 12 animals each: (1) Non-Infected Control (NI), (2) Control Infected (CI), (3) Experimental Non-Infected (EtOH-NI), and (4) Experimental Infected (EtOH-I). Ethanol-pre-exposed infected mice exhibited elevated parasitaemia during the patent period compared to controls. Adaptive immunity was characterised by increased IL-4, IL-10 and IFN-γ production by CD8+ T lymphocytes, while innate immunity showed reduced cytokine production, particularly in NK cells and macrophages. Ethanol amplified IL-10 and IFN-γ responses in macrophages yet suppressed TNF-α production in dendritic cells and macrophages during infection. These findings suggest ethanol modulates the immune response by enhancing adaptive immunity while impairing innate mechanisms, contributing to altered host-pathogen dynamics in T. cruzi infection.

Ascaris infection-ascariasis-is the most common human parasitic worm infection worldwide and induces damage and cellular changes within the stomach. Helicobacter pylori is a bacterium of the stomach that also causes gastric pathologies globally. Importantly, Ascaris, H. pylori, and gastric diseases all disproportionatelyaffect individuals in resource-limited settings. However, the associations between ascariasis, H. pylori infection, and gastric diseases remain relatively unexplored.We synthesized the existing research associating Ascaris infection with H. pylori infection and/or gastric pathologies. Records were identified in OVID Medline, Embase and Web of Science using search terms for ascariasis, H. pylori infection, and gastric abnormalities and additional citation searching. Blinded screening and extraction were performed by two independent reviewers. We found 410 unique citations, of which 86 (21.0%) were included. A total of 24 articles (27.9%) associated ascariasis with H. pylori infection, 68 (79.1%) associated ascariasis with gastric abnormalities, and 6 (7.0%) associated ascariasis with both H. pylori infection and gastric abnormalities. Although predominantly comprised of case reports and observational studies, these data supported significant co-endemicity of ascariasis and H. pylori infection, co-infections with both pathogens, and concurrency of ascariasis with gastric pathologies in human and non-human host organisms. The available literature thus supports associations between ascariasis, H. pylori infections, and gastric pathology, warranting further epidemiologic and mechanistic studies.

Toxocara canis is the most prevalent intestinal roundworm of dogs and other canids, with significant zoonotic potential for humans. In the present study, two recombinant antigens, rTc-CTL-1 and rTES-120, were developed from the larvae of T. canis excretory-secretory (TES) antigens by amplifying, cloning and expressing the respective genes in Escherichia coli. The native TES antigen was prepared from invitro cultivation of larvae. A total of 170 serum samples were collected from dogs above 6 months of age (n = 90) and below 6 months of age (n = 80) in the Chennai region, Tamil Nadu. The serodiagnostic potential of the recombinant rTc-CTL-1 and rTES-120 antigens was compared with that of the native TES antigen using ELISA for the detection of anti-Toxocara IgG antibodies. The rTc-CTL-1 antigen-based ELISA showed that 40% of dogs above 6 months and 28.8% of dogs below 6 months were positive, whereas the rTES-120 antigen detected 35.6% and 22.5% positivity in the respective age groups. In comparison, the native TES antigen-based ELISA detected 58.9% positivity in dogs above 6 months and 38.8% in dogs below 6 months of age. Among the three antigens, the highest percentage of seropositivity as well as the highest antibody titre was detected with the native TES antigen, followed by the recombinant rTc-CTL-1 antigen and the lowest with the TES-120 antigen. Statistical analysis showed a highly significant difference in seropositivity between the recombinant and native TES antigens (χ2 = 15.52, p < 0.01), while no significant difference was observed between the recombinant antigens (χ2 = 1.09, p > 0.05). However, a highly significant difference was observed between the age groups of dogs when using the native TES antigen (χ2 = 6.87, p < 0.01). Detection of T. canis eggs in faecal samples revealed that only 12.2% of adult dogs were positive, whereas 60% of pups were positive. In contrast, the IgG ELISA test detected more positive cases in adult dogs compared to faecal examination. It was concluded that the IgG-based ELISA using either recombinant or native TES antigens is a reliable tool for detecting migratory larval infection in adult dogs, with a fairly high degree of sensitivity.

The thymus is a vital organ for T-cell development that undergoes significant changes during malaria infection, including atrophy and disrupted structure, which weaken immune responses. This study examines the mechanisms behind thymic atrophy during Plasmodium chabaudi AS infection, focusing on cellular and molecular changes across different parasitemia stages. Our results show that thymic atrophy is marked by a substantial decrease in thymus weight and cellularity, especially at 20%-30% parasitemia levels. A significant loss of DP and SP thymocytes mainly causes this atrophy. Histological analysis revealed notable cortical shrinkage and DNA fragmentation in thymic cells, indicating increased apoptosis. Elevated serum cytokines and chemokines, including IFN-γ, TNF-α, IL-6 and CXCL9, were observed throughout the infection, with higher levels correlating with the degree of thymic atrophy. Also, early release of thymocytes into peripheral tissues, especially the spleen, worsened the decrease in thymic cellularity. However, after parasitemia resolved, the thymus recovered, restoring its structure and thymocyte populations. These results highlight the complex interaction between parasite-induced inflammation and immune cell behaviour, suggesting that even though P. c. chabaudi AS infection is not lethal, a prolonged parasitic burden can cause severe thymic dysfunction, possibly impairing immune system function.

Leishmania amazonensis is one of the etiological agents of cutaneous leishmaniasis in its localised form. Moreover, this parasite can cause more severe disease conditions, such as diffuse and disseminated cutaneous leishmaniasis. The development of more severe clinical manifestations is associated with the parasite's ability to establish a chronic infection and disseminate to cutaneous tissues distal to the site of primary infection. This ability is dependent on host immune factors but is also influenced by intrinsic factors of the parasite related to pathogenicity and evasion of the immune system. This review discusses immunological and parasitological factors associated with the latency and dissemination of L. amazonensis infection and the consequent development of severe forms of cutaneous disease.

Theileria orientalis, long considered a benign haemoprotozoan, is now recognised as an emerging pathogen causing clinical theileriosis in cattle across the globe. This study investigated the clinical presentation and immunopathological responses associated with natural T. orientalis infections in northern Kerala, India. Blood samples were collected from clinically suspected (n = 52) and healthy cattle (n = 148). Infection was confirmed via Giemsa-stained blood smear examination, species-specific PCR targeting the major piroplasm surface protein (MPSP) gene, and subsequent sequencing. Among clinically suspected cases, 63.5% were smear-positive and PCR-confirmed, while subclinical infection was identified in 46.6% of healthy cattle. Morphological analysis revealed marked polymorphism of intraerythrocytic piroplasms. Clinical signs included anaemia, pyrexia, lymphadenopathy, and systemic debilitation. To elucidate host immune responses, expression levels of key pro-inflammatory cytokines (IL-6, IL-1β, TNF-α) were quantified in peripheral blood mononuclear cells using SYBR Green-based quantitative real-time PCR. Clinically affected animals exhibited significantly elevated expression of IL-6 and IL-1β (p < 0.05), indicative of a heightened inflammatory response, whereas TNF-α expression showed a non-significant downward trend. Correlation analysis revealed that parasite burden was positively associated with IL-6 and IL-1β expression but not with TNF-α, linking parasite load to the inflammatory response. The suppressed TNF-α response suggests a possible immune evasion strategy unique to T. orientalis, contrasting with the elevated TNF-α typically seen in T. annulata and T. parva infections. These findings indicate that IL-6 and IL-1β may serve as potential biomarkers of severe oriental theileriosis. These findings provide new insights into the immunopathogenesis of oriental theileriosis and suggest that cytokine dysregulation contributes to clinical disease severity. Furthermore, the high prevalence of subclinical infections underscores the role of carrier animals in sustaining transmission cycles, complicating disease control efforts in endemic regions. This study highlights the need for improved diagnostic strategies and targeted immunomodulatory interventions in managing T. orientalis infections.

Trypanothione reductase (TryR) is a unique and key redox protein of Leishmania donovani, the causative agent of visceral Leishmaniasis. In this work, we have developed a promising multiepitope vaccine using TryR. Multiple epitopes from TryR were identified using different bioinformatics tools to stimulate both humoral and cellular immune responses. An adjuvant was also included to enhance the antigen presentation and immune activation. Using bioinformatics tools, immunodominant T-cell and B-cell epitopes of TryR were predicted, and based on the findings, a chimeric multi-epitope vaccine construct was designed. The structural stability of the final construct was validated using different bioinformatics tools. Furthermore, a docking study was conducted with the human TLR4 receptor to assess the affinity of the multi-epitope construct. The Ramachandran plot analysis, Z score, and ERRAT support the stability of the multi-epitope vaccine candidate. Furthermore, in silico analysis showed that the multi-epitope vaccine candidate has high affinity with the human TLR4 receptor and has broad efficacy based on the population coverage. Immune stimulation confirmed the pro-inflammatory response with T- and B-cell activation.

Mir-10a acts in signalling pathways regulating transcription, translation, and RNA-mediated gene silencing, while IFNG acts in the T-cell receptor signalling pathway. Thus, both can be considered potential targets for understanding regulatory processes in chronic inflammation in patients with schistosomiasis. Populations in endemic areas receive mass and indiscriminate praziquantel treatment, and yet patients often have a history of multiple infections. To investigate the regulatory and prognostic capacity of miR-10 and IFNG in patient immunity, we evaluated the expression of miR-10a and IFNG as biomarkers of inflammation and their correlation with praziquantel treatment. miR-10a did not present evidence as a biomarker of inflammation in the therapeutic follow-up in schistosomiasis. However, the levels of IFNG expression were significantly higher before treatment.