Accurate diagnosis of diarrheal viruses from histopathological images is critical for veterinary medicine and animal disease control. Existing deep learning approaches, however, often rely solely on visual features, lacking integration of clinical semantics and struggling with limited annotated data. To overcome these limitations, we propose LLM2image, a multimodal framework that enhances pathological image classification by integrating visual features with semantically rich textual descriptions generated by large language models (LLMs). The framework comprises: (1) a pixel-level MLP encoder for image representation, (2) GPT-4.0 for generating class-specific pathological descriptions, and (3) a cross-modal fusion transformer that aligns visual and textual features via multi-head attention. Evaluated on an in-house dataset of 516 porcine intestinal images across four categories healthy, ETEC, PDCoV, and PoRVour method achieved an accuracy of 89.51%, surpassing state-of-the-art models and matching the diagnostic performance of veterinarians with 10 years of experience. External validation on the public PAIP2020 colorectal cancer dataset further confirmed its generalizability, with 87.42% accuracy. Ablation studies and visual attention analysis demonstrate that the inclusion of LLM-generated text significantly improves both classification accuracy and interpretability. The model has been deployed as a lightweight Android application, supporting offline rapid diagnosis, highlighting its potential for real-world veterinary and medical applications.

Eimeria tenella, one of the most virulent causative agents of coccidiosis, specifically colonizes the cecum and imposes substantial economic losses on the poultry industry. Toll-like receptors (TLRs), key mediators of the innate immune response, initiate rapid defense against invading parasites. However, their roles during E. tenella infection remain poorly defined. In this study, coccidiosis infection parameters (cecal lesions, oocyst output, and clinical signs) were monitored, and the expression profiles of 10 chicken TLRs (chTLRs) and related immune genes in the cecum and spleen of E. tenella-infected chickens were characterized at multiple time points using quantitative real-time polymerase chain reaction (PCR) and histopathological analysis. Spearman correlation analysis was performed to evaluate associations between TLR expression and pathogenicity parameters. Infected chickens exhibited marked clinical signs, although no mortality occurred in either group. Cecal lesions became apparent by 96 h post-infection (hpi), peaking at 144 hpi, and were accompanied by significant epithelial necrosis and extensive inflammatory cell infiltration. Most TLR genes showed distinct expression patterns between the cecum and spleen: cecal TLRs were upregulated during the middle phase (24–72 hpi) of infection, whereas splenic TLRs were downregulated in later stages (96–168 hpi). Key proinflammatory cytokines—interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ—were elevated in the cecum during early infection but declined in the spleen during later phases. Infection also induced dynamic expression changes in the downstream signaling molecules myeloid differentiation factor 88 (MyD88) and nuclear factor-kappa B (NF-κB) p65 in both tissues. Spearman correlation analysis revealed that, in the cecum, chTLR7 positively correlated with both oocyst output and lesion scores, whereas chTLR2a positively correlated with lesion scores. By contrast, chTLR1a, chTLR1b, chTLR15, and chTLR21 negatively correlated with oocyst output. In the spleen, chTLR15 and chTLR21 positively correlated with oocyst output, while chTLR5 uniquely and negatively correlated with lesion scores. These findings identify both proinflammatory and potentially protective TLR pathways in subclinical coccidiosis.

Giardia duodenalis, Cryptosporidium spp., Blastocystis sp., and Enterocytozoon bieneusi are prevalent zoonotic intestinal parasitic protozoans that cause diseases in humans and various animals. In this study, a total of 319 fresh fecal samples from domestic and wild animals collected from the Qinghai-Tibetan Plateau Area (QTPA), China, were examined. The results showed that the overall prevalence of these four protozoa in this region was 6.6% (21/319). Specifically, the infection prevalence of G. duodenalis, Cryptosporidium spp., Blastocystis sp., and E. bieneusi was 3.4% (11/319), 1.3% (4/319), 1.9% (6/319), and 0% (0/319), respectively. Three G. duodenalis assemblages, A (n = 1), E (n = 4) and F (n = 1), and two zoonotic Cryptosporidium spp., C. ubiquitum and C. alticolis, were identified. Regarding Blastocystis sp., only one subtype (ST1) was identified in root vole (Microtus oeconomus), a potentially zoonotic subtype. PCR amplification at the internal transcribed spacer (ITS) locus did not detect E. bieneusi in any of the samples. This study provides fundamental data on these four pathogens in M. oeconomus and other domestic animals in the QTPA, China. Although the prevalence of the four parasites was relatively low, the zoonotic species C. ubiquitum and G. duodenalis assemblage A were identified, indicating that wild animals and domestic animals might act as potential reservoirs in the transmission between humans and animals. Further studies are needed to better understand the epidemiology of parasites in wild animals in the QTPA and their potential public health implications.

Natural products with dual immunomodulatory and antimicrobial functions offer promising strategies to reduce antibiotic use in livestock. Glycyrrhizic acid (GA), the principal bioactive component of licorice, has demonstrated anti-inflammatory and antiviral properties, yet its translational potential in swine health remains underexplored. This study evaluated the efficacy of GA in weaned piglets under commercial nursery conditions as an antibiotic alternative. A total of 225 weaned piglets were assigned to five groups: negative control (CON, basal diet), farm routine (FA, conventional antibiotics), and three GA-supplemented groups (GLL, 0.65 g/kg; GLM, 1.3 g/kg; GLH, 2.6 g/kg). The result showed that dietary GA supplementation (2.6 g/kg) numerically improved growth performance and reduced cough scores, although not statistically significant. GA significantly decreased the diarrhea index and improved skin scores. GA also significantly increased serum IgG and IgM levels in piglets and showed a trend toward higher IgA levels. Furthermore, GA exhibited a trend toward lowering serum IL‑1β levels while upregulating IFN‑γ and IL‑10 levels. Regarding antioxidant parameters, GA significantly upregulated T‑SOD, GSH‑PX, and CAT activities and downregulated LDH activity. Metagenomic analysis revealed that high‑dose glycyrrhizic acid (GA) significantly increased the abundance of Alloprevotella, while decreasing the abundances of Moraxella pluranimalium and 11 other pathogenic species associated with respiratory diseases and lung injury, including Glaesserella parasuis, Mesomycoplasma hyorhinis, Mesomycoplasma hyopneumoniae, Streptococcus suis, among others, thereby reshaping the upper respiratory tract microbiota of pigs. Collectively, these findings support GA as a viable non-antibiotic strategy for improving immune function, antioxidant capacity, and respiratory health in weaned piglets.

Anaplasma phagocytophilum is an obligate intracellular, tick-borne bacterial pathogen capable of causing disease and even mortality in various mammals, including humans. Non-coding RNAs play important regulatory roles in multicellular organisms, including innate and adaptive immune pathways, which control bacterial, parasitic, and viral infections. However, the global transcriptomic landscape encompassing both ncRNAs and mRNAs in HL-60 cells invaded by A. phagocytophilum remains unexplored. Cell apoptosis was evaluated by flow cytometry at multiple time points after HL-60 cell infection with A. phagocytophilum. Total RNA was extracted and analyzed by RNA sequencing (RNA-seq) to delineate expression alterations of long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) at 24 h post-infection (hpi). Bioinformatics methods were employed for gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses to elucidate the potential functions of these differentially expressed genes. Furthermore, an integrated bioinformatics approach was applied to systematically construct a competing endogenous RNA (ceRNA) network involving lncRNAs, miRNAs, and mRNAs. A. phagocytophilum infection accelerated HL-60 cell apoptosis at multiple time points, with the most significant effect observed at 24 hpi. Transcriptome profiling at 24 hpi identified substantial differential expression, including 487 lncRNAs, 550 mRNAs, and 22 miRNAs with statistically significant changes in expression. Then, expression patterns of eight lncRNAs, eight mRNAs, and seven miRNAs were experimentally validated through reverse transcription quantitative polymerase chain reaction (RT-qPCR), demonstrating strong correlation with RNA-seq results. Bioinformatics analyses revealed significant enrichment of differentially expressed mRNAs in three key pathways: the PI3K/Akt signaling pathway, the actin cytoskeleton regulation pathway and the p53 signaling pathway. Differentially expressed lncRNAs were largely related to the phospholipase D signaling pathway and pathways related to cortisol and aldosterone synthesis/secretion. The altered miRNAs showed predominant enrichment in Rap1 and NF-κB signaling pathways. Notably, computational reconstruction of the lncRNA–miRNA–mRNA ceRNA network identified hsa–miR–4518 and hsa–miR–3609 as central regulatory nodes. This comprehensive transcriptome study elucidates complex gene regulatory networks activated in HL-60 cells after A. phagocytophilum invasion, with particular emphasis on pathogen-modulated miRNA signatures that coordinate critical pathways governing host immune responses and microbial survival strategies. These findings elucidate previously uncharacterized molecular mechanisms underlying A. phagocytophilum pathogenesis and may provide actionable targets for novel therapeutics.

Nipah virus (NiV) infection is a highly fatal zoonotic disease and remains a major public health concern in Bangladesh. This narrative review comprehensively examines the epidemiology, outbreak pattern, transmission dynamics, clinical manifestations, ecological drivers, public health interventions, surveillance systems, therapeutic progress, and vaccine development related to NiV infection in Bangladesh. The review was conducted through a comprehensive analysis of published literature and relevant reports from 2001 to February 2026, retrieved from PubMed, Scopus, and Google Scholar. During this period, Bangladesh reported 348 confirmed NiV cases across 35 districts, with 250 deaths and an overall case fatality rate of 71.84%. Outbreaks were concentrated mainly in the central and northwestern regions, commonly referred to as the “Nipah belt.” The principal route of transmission was consumption of raw date palm sap contaminated by greater Indian fruit bat (Pteropus medius), while person-to-person transmission through close contact with infected individuals also played an important role. Clinical features were dominated by fever, unconsciousness, respiratory distress, headache, vomiting, and other neurological symptoms. Seasonal outbreaks were strongly associated with winter sap collection, bat feeding behavior, environmental conditions, and cultural practices. Although bamboo skirts, awareness campaigns, boiling of sap, and hospital-based surveillance have contributed to prevention efforts, sustained community adoption remains limited. Bangladesh still lacks approved vaccines, specific antiviral therapy, rapid point-of-care diagnostics, and advanced biosafety infrastructure. Expanding surveillance, improving early diagnosis, implementing ecological interventions, and advancing vaccine and therapeutic research are essential to reduce future spillover and human-to-human transmission.

The zoonotic protozoans Cryptosporidium and Giardia are major drivers of the global gastrointestinal disease burden, circulating through complex human-animal-environment interfaces. This review synthesizes global epidemiological data to evaluate the role of fish and shellfish as reservoirs and potential conduits for zoonotic transmission. The pooled prevalence of Cryptosporidium spp. was 8.7% (858/9878) in fish and 16.5% (1459/8820) in shellfish. Likewise, the pooled prevalence of Giardia spp. in fish and shellfish were approximately 8.3% (30/361) and 6.2% (332/5392), respectively. Zoonotic Cryptosporidium species in fish included C. parvum, C. hominis, C. ubiquitum, C. scrofarum, and C. xiaoi. In shellfish, there were C. parvum, C. hominis, and C. meleagridis, with C. parvum dominant in both hosts. Zoonotic G. duodenalis assemblages A and B were detected in both fish and shellfish, with G. duodenalis assemblage A dominant in shellfish. These findings highlight that fish and shellfish, acting as either biological hosts or mechanical concentrators of environmental contamination, facilitate the dissemination of (oo)cysts through the aquatic food web. The presence of human-pathogenic genotypes in edible tissues poses significant food and water safety risks, exacerbated by anthropogenic pressures such as inadequate wastewater management and urbanization. This review emphasizes the necessity of a One Health framework to bridge the gap between environmental monitoring and public health surveillance. We advocate for integrated preventive measures, including enhanced molecular diagnostics and cross-sectoral management of aquatic ecosystems, to mitigate the transmission of foodborne and waterborne cryptosporidiosis and giardiasis.

Cattle and sheep farming play a pivotal role in agricultural economies, yet parasitic diseases significantly impede industry development. Traditional manual diagnostic methods suffer from low efficiency and subjectivity. While art ificial intelligence (AI) based detection shows promise, its advancement is constrained by limited data availability. This study aims to integrate microscopic images, morphological characteristics and genomic data of bovine and sheep parasites, and establish a multimodal biometric database of bovine and sheep parasites. Standardized protocols were implemented to collect blood, fecal, and ectoparasite samples. Expert teams conducted cross-validated annotations following unified protocols to ensure data integrity. The database system, developed based on MySQL, comprises a structural design, a user front-end module, and an administrator backend module. This database provides comprehensive data support for AI model development and validation, promising enhanced efficiency and accuracy in parasitic disease detection, which facilitates the healthy development of the animal husbandry industry.

Giardia duodenalis is a zoonotic protozoan parasite that causes giardiasis in humans and other mammals. Early diagnosis remains challenging because current diagnostic methods, including microscopy and enzyme-linked immunosorbent assays (ELISAs), primarily detect established infections. Consequently, a critical diagnostic gap exists during the early stage of infection within the first 2-48 h following exposure. To address this limitation, we characterized the proteins released by in vitro-cultured G. duodenalis trophozoites under serum-free conditions and evaluated their potential as early diagnostic biomarkers. Proteomic analysis of culture supernatants collected during early trophozoite incubation identified 31,773 peptides corresponding to 2504 quantifiable proteins. Temporal profiling showed distinct secretion patterns, including proteins that peaked during the early stage, progressively accumulated over time, or remained persistently abundant throughout the incubation period. Based on their secretion characteristics and predicted immunogenic properties, five candidate biomarkers were selected for further evaluation. Polyclonal antibodies raised against selected candidates successfully detected the corresponding proteins in serum-free culture supernatants, providing preliminary evidence for their potential utility as early-stage diagnostic targets. These findings identify stage-associated candidate proteins that may serve as a resource for future early giardiasis diagnostic development, provide a valuable resource for investigating host-parasite interactions, and establish a foundation for future diagnostic assay development. However, further validation in clinical and biological samples is required to confirm their diagnostic applicability. SIGNIFICANCE: Giardiasis, caused by Giardia duodenalis, is a major diarrheal disease worldwide. Although enzyme-linked immunosorbent assays (ELISAs) provide rapid detection, their diagnostic utility is limited by the lack of biomarkers capable of identifying infection during its earliest stages, creating a critical gap in the detection of active infection within 2-48 h following exposure. Using data-independent acquisition proteomics, this study provides a time-resolved characterization of proteins released by G. duodenalis trophozoites into serum-free culture supernatants. Our findings reveal temporal secretion dynamics of protein secretion and identify candidate biomarkers with potential utility for the development of early-stage diagnostic assays pending rigorous biological and clinical validation. In addition, this proteomic resource provides a foundation for investigating host-parasite interactions and may facilitate the development of future point-of-care diagnostic strategies.

Cryptosporidium is an important avian pathogen. It can also be transmitted to humans through water sources contaminated with avian faeces or through direct avian-human contact. We conducted a meta-analysis to evaluate the global prevalence of Cryptosporidium in chicken. A total of 74 datasets from 21 countries/regions were used for the quantitative analysis. The prevalence of Cryptosporidium infection in chicken varied from 0.0% to 37.7%, with a summary estimate of 15.7% (3402/25,627; 95% confidence interval 14.0-17.4%). Nine Cryptosporidium species/genotypes were detected in chicken globally. Among the zoonotic Cryptosporidium species, Cryptosporidium meleagridis was the dominant species, followed by Cryptosporidium parvum. The isolates included 3 genotypes of C. meleagridis (IIIb, IIIe, IIIg), the proportion of subgenotype family IIIb of C. meleagridis was 45.6% (110/241). The results indicated that Cryptosporidium baileyi is the dominant species in Asia, while C. meleagridis is the dominant species in South America, with higher rates of Cryptosporidium noted in South America. Given that chicken has a substantial role in the global C. meleagridis zoonoses, and the need for further study of the prevalence, transmission, and control of this pathogen. This study assessed the global distribution of Cryptosporidium spp. in chicken, highlighting its zoonotic implications. It serves as a key resource for researchers, veterinarians and public health officials for future studies and control strategies.

Giardia duodenalis is a protozoan parasite responsible for waterborne diarrheal diseases in humans and animals worldwide. TLR4 is a key pattern recognition receptor of the innate immune system, and MHC-II bridges innate and adaptive responses, while role of these receptors in the activation of macrophages by G. duodenalis still needs further investigation. This study confirmed knockdown efficiency using RT-qPCR and western blotting then employed multiple molecular and cellular assays to investigate the functions of TLR4 and MHC-II in RAW264.7 macrophages during defense against G. duodenalis. Results showed that the significant upregulation of proinflammatory cytokines (e.g., 5.18-fold increase in IL6 expression) and marked activation of NF-kappa B pathways (marked enhancement of p65 fluorescence in the cell nucleus) in macrophages following G. duodenalis infection were dependent on TLR4, as demonstrated by their attenuation after TLR4 knockdown. Interestingly, we also observed that the knockdown of MHC-II produced similar results, and the elevated expression of MHC-II in macrophages induced by G. duodenalis was inhibited by the interference of class II transactivating factor (CIITA). Overall, CIITA/MHC-II/NF-kappa B pathway is critical for full activation of TLR4mediated innate immune response in macrophage initiated by G. duodenalis, which elaborated the innate immune network in the interaction between G. duodenalis and macrophages, holds significant implications for the immunotherapeutic strategies targeting Giardiasis.

Tick dissection is fundamental for isolating internal organs for histological, developmental, cell culture, microbiome, functional, and epidemiological studies. However, comparative anatomical details and methodological guidance for identification, and aseptic isolation of internal organs remain limited. The purpose of this study is to demonstrate the internal anatomy of hard ticks using Haemaphysalis longicornis Neumann, H. flava Neumann, and Amblyomma testudinarium Koch as the dissection materials and identify optimal dissection approaches for obtaining intact and contamination-free organs. Six groups of ticks, categorized by species, sex, life stage, and engorgement level, were dissected in aseptic conditions under a stereomicroscope. Internal morphoanatomical features were compared across groups, with particular emphasis on salivary glands, Malpighian tubules, gonads, tracheae, and associated organs. Given the risk of cross-organ contamination, the ease of tick handling, organ-specific separation techniques, difficulties, and immediate troubleshooting are documented. Dissection feasibility was found to vary by sexes, developmental stages, and engorgement states. A dense tracheal network was consistently observed across all groups, regardless of maturity. Organ isolation was most efficient in adult males owing to their simpler internal anatomy, reduced midgut blood volume, and less extensive tracheae. Engorgement level and tracheal complexity remained key limiting factors influencing the efficiency of dissection and ability to retrieve desired organs without cross-organ contamination, particularly due to fragmented tissues and midgut contents. Partly engorged, mid-sized adult ticks provide optimal conditions to master dissection techniques. This integrated approach has transformed the descriptive tick dissection into pictorial methodological guidance and offers comparative anatomical insights for tick dissection.

Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) is a major immunosuppressive pathogen involved in the porcine respiratory disease complex. Licorice extract (LE) has anti-inflammatory, immune-regulating, and growth-promoting effects. In this study, the use of LE as a novel feed additive in PRRSV-infected nursery pigs was evaluated, and the effects of dietary supplementation and drinking water were compared. A total of 264 weaned piglets were allocated into 8 groups: three dietary supplementation groups (low, medium, and high doses: BLL, BLM, and BLH), three drinking water supplementation groups (low, medium, and high doses: WLL, WLM, and WLH), a farm control group (Farm), and a negative control group (CON). Compared with the CON group, dietary LE supplementation in the BLL and BLM groups significantly increased the average daily gain (ADG) by 1.02-fold and 1.18-fold (P < 0.001) and reduced the feed-to-gain ratio (F/G) by 3.58% and 5.35% (P < 0.05), respectively, compared with their drinking water counterparts, with the effects in the BLM group being the most pronounced. Additionally, compared with CON, LE administration via either route alleviated coughing, with significant downregulated (P < 0.001) of cough scores in the BLH, WLL, and WLH groups during weeks 3–4. Furthermore, compared with the CON group, the BLM group exhibited increased tracheal cilia integrity (P < 0.1) and significantly decreased (P < 0.05) lung injury scores. While LE did not alter PRRSV-specific antigen or antibody levels (P=0.065), it significantly modulated immune responses by downregulating IL-1β and IL-6 (P < 0.05), upregulating IL-10 (P < 0.05), and increasing IgA, IgG, and IgM levels (P < 0.05). Gut metagenomic analysis revealed that LE notably increased the abundance of multiple beneficial bacteria and reshaped the structure of the gut microbiota. Specifically, LE upregulated Anaeromassilibacillus sp. An172 and reversed the antibiotic-induced decrease in the abundance of Bacteroides bouchesdurhonensis and Bacteroides sp. OF04‑15BH. These findings demonstrate that dietary LE, at an optimal dose of 2.6 g/kg, is a promising feed additive for PRRSV-infected pigs, with benefits mediated through immune modulation and gut microbiota remodeling.

ABSTRACT Meat, as an important source of animal protein, has attracted widespread attention in recent years because of its quality and safety issues. Therefore, it is particularly important to assess potential impact risks and identify improvement strategies. This review comprehensively discusses the main factors influencing the meat quality, including genetic and environment factors. Furthermore, this review focuses on the application of nutritional and feed‐based strategies for improving the meat quality, including feed additives such as probiotics, prebiotics, plant extracts, antioxidants, and functional amino acids, which can markedly enhance the physicochemical properties, nutritional quality, and taste of meat by modulating the intestinal microecological balance, strengthening antioxidant defense mechanisms, and optimizing nutrient metabolism. These insights will help lay the foundation for promoting the high‐quality development of the lamb industry and implementing the One Health concept.

Membrane transporters play a vital role in the obligate intracellular parasite Toxoplasma gondii, mediating the acquisition of nutrients from host cells, the regulation of ion gradients, and the maintenance of metabolic homeostasis. Despite their central importance for parasite survival, pathogenesis, and drug resistance, the majority of T. gondii transporters remain poorly characterized. Key unresolved questions include the mechanisms underlying purine nucleotide transport across the plasma membrane and the import/export of metabolites for core pathways in the apicoplast (e.g., thiamine, isopentenyl diphosphate[IPP]/dimethylallyl diphosphate [DMAPP], and coproporphyrinogen III) and mitochondria (e.g., amino acids and cofactors). Recent advances in bioinformatics and CRISPR-based phenotypic screening have enabled systematic identification of transporter candidates. This review summarizes current knowledge of T. gondii transporters localized to the plasma membrane, apicoplast, mitochondria, endoplasmic reticulum, and Golgi apparatus, highlighting their roles in nutrient acquisition, metabolic crosstalk, and organellar function. Furthermore, we propose a screening strategy integrating transmembrane domain prediction, CRISPR phenotyping, and hyperLOPIT-based protein localization to prioritize uncharacterized transporters for functional study. These insights underscore the potential of transporters as therapeutic targets and provide a roadmap for future research into the physiology of T. gondii.

Ticks and tick-borne pathogens pose significant threats to livestock and public health. While tick occurrences have been reported in China, systematic assessments of pathogen risk factors across diverse hosts and regions remain limited. This study investigated tick distribution, prevalence, and associated pathogen infections across seven sampling sites in China, analyzing 521 ticks collected from cattle, goats, sheep, dogs, and wild boars. Molecular identification revealed five tick species, with Haemaphysalis longicornis (58.93%, 307/521) and Rhipicephalus microplus (24.18%, 126/521) being the most prevalent, exhibiting distinct host and geographic preferences. Pathogen screening detected Anaplasma bovis (10.94%, 57/521), Anaplasma ovis (6.91%, 36/521), Anaplasma phagocytophilum (3.84%, 20/521), and Piroplasmida (1.34%, 7/521). Pathogen carriage rates varied significantly among regions (p < 0.05), with the highest in Haikou (45.83%, 44/96). Significant differences in pathogen carriage were observed among tick species (p < 0.05), with the highest rate in H. hystricis (37.14%, 13/35). The overall co-infection rate was 3.65% (19/521), predominantly driven by concurrent A. ovis and A. bovis infections (2.30%, 12/521), which may complicate diagnosis and exacerbate disease outcomes. Together, these findings highlight the complex interactions among tick vectors, vertebrate hosts, and pathogen communities across diverse regions of China, revealing host- and region-specific distribution patterns that provide critical evidence to strengthen integrated public health and veterinary surveillance and mitigate zoonotic threats at the human-animal-environment interface.

Coccidiosis is a global disease caused by protozoans, typically including Eimeria spp., which pose a significant threat to the normal growth and development of young animals. Coccidiosis affects mainly the gut, where parasite proliferation occurs. The intestinal barrier, which consists of chemical, mechanical, biological, and immune defences, plays a crucial role in protecting the host against pathogens, xenobiotics, and toxins present in the gastrointestinal tract. When animals ingest sporulated Eimeria spp. oocysts, these parasites primarily reproduce in the intestinal tract, causing damage to the structure and function of the intestine. This disruption of intestinal homeostasis adversely affects animal health. Numerous studies have also revealed that Eimeria-infected animals experience slower bone growth rates, inferior meat quality, reduced egg production and quality, as well as impaired growth and development. Therefore, the purpose of this review is to examine the underlying mechanisms through which Eimeria spp. regulate intestinal damage and disturb the balance of the internal environment. Specifically, this review will focus on their effects on the structural basis of the host intestine’s chemical, mechanical, biological and immune barriers. This understanding is crucial for the development of effective drugs to prevent the invasion of Eimeria spp. into the intestine, which is of paramount importance for maintaining host health.