Infectious Disease Virus Research Articles

Diagnosis of viral infectious diseases through sensitive detection of human serum antibodies using a modified label-free electrochemical biosensor.

Rapid virus identification is crucial for preventing outbreaks. The COVID-19 pandemic has highlighted the critical nature of rapid virus detection. Here, we designed a label-free electrochemical biosensor modified with gold nanoparticles (AuNPs) to detect IgG antibodies from human serum, enabling rapid point-of-care diagnostics. AuNPs were synthesized and characterized. A multivariate optimization was carried out to determine the optimal condition for functionalizing AuNPs with anti-IgG. Subsequently, using a glassy carbon electrode (GCE), a modified AuNPs/GCE electrochemical biosensor was developed for IgG detection. The results indicated thatAuNPs displayed a spherical morphology with a size distribution of 19.54nm. Additionally, the zeta potential was recorded at -7.84mV. Central composite design (CCD) analysis determined the optimal conditions for functionalizing AuNPs to be an anti-IgG concentration of 320µgmL-1, atemperature of 25°C, and pH of 7.4. The characterization study confirmed the successful synthesis and functionalization of AuNPs. Through electrochemical impedance spectroscopy measurement, the biosensor demonstrated a limit of detection (LOD) of 0.2ngmL-1 and limit of quantification (LOQ) of 0.8ngmL-1. Furthermore, tests in real samples showed the interaction between IgG antibodies in serum samples and AuNPs/GCE, confirming the biosensor's ability to detect and quantify IgG in clinical samples.

Emerging Trends in Applying Artificial Intelligence to Monkeypox Disease: A Bibliometric Analysis

Monkeypox is a rather rare viral infectious disease that initially did not receive much attention but has recently become a subject of concern from the point of view of public health. Artificial intelligence (AI) techniques are considered beneficial when it comes to diagnosis and identification of Monkeypox through the medical big data, including medical imaging and other details from patients’ information systems. Therefore, this work performs a bibliometric analysis to incorporate the fields of AI and bibliometrics to discuss trends and future research opportunities in Monkeypox. A search over various databases was performed and the title and abstracts of the articles were reviewed, resulting in a total of 251 articles. After eliminating duplicates and irrelevant papers, 108 articles were found to be suitable for the study. In reviewing these studies, attention was given on who contributed on the topics or fields, what new topics appeared over time, and what papers were most notable. The main added value of this work is to outline to the reader the process of how to conduct a correct comprehensive bibliometric analysis by examining a real case study related to Monkeypox disease. As a result, the study shows that AI has a great potential to improve diagnostics, treatment, and public health recommendations connected with Monkeypox. Possibly, the application of AI to Monkeypox study can enhance the public health responses and outcomes since it can hasten the identification of effective interventions.

Common Childhood Viral Infectious Diseases with Oral Symptoms

Common Childhood Viral Infectious Diseases with Oral Symptoms

Changes in the Distribution of Pathogens Causing Meningoencephalitis Before and During the COVID-19 Pandemic.

Infectious meningoencephalitis (ME) is a major global health concern. Viruses are the most frequently implicated etiologies, whereas bacterial causes, although life-threatening, constitute a lesser proportion of ME cases, together with other pathogens. The strict implementation of COVID-19 mitigation measures led to the decreased viral and non-viral infectious diseases. Therefore, this study aimed to investigate the effect of these mea-sures on ME-causing pathogens by age groups. This retrospective study aimed to determine and compare the rates of pathogen-positive ME cases during the pre-pandemic (P-1) and pandemic (P-2) periods. Molecular diagnostic methods using the cerebrospinal fluid of patients from all age groups were included. The positivity rate difference of the ME-causing pathogens between the two study periods was compared and the distribution pattern of the pathogens among the age groups was determined. The overall positivity rate for at least one ME-causing pathogen during P-1 was 22.0% (503/2,284), which significantly declined to 7.3% (83/1,141) during P-2 (p < 0.001). Particularly, a statistically significant decline in the pathogen positivity was observed in the groups 4 - 6 (≥ 3 years) (p < 0.001, p < 0.001, and p = 0.041, respectively). Specifically, the enterovirus cases decreased significantly, whereas the varicella zoster virus and herpes simplex virus-2 cases increased. Among bacterial causes, the S. agalactiae, S. pneumoniae, and E. coli K1 ME cases significantly increased. Men and women had no significant differences in the positivity rate during either study period. COVID-19 mitigation measures significantly impacted the positivity rates and the distribution of ME-causing agents, especially in the age groups ≥ 3 years, although not uniformly.

Atherosclerosis and Cardiovascular Complications in People Living with HIV: A Focused Review.

The intersection of Human Immunodeficiency Virus (HIV) infection and cardiovascular disease (CVD) represents a significant area of concern; advancements in antiretroviral therapy (ART) have notably extended the life expectancy of people living with HIV (PLWH), concurrently elevating the prevalence of chronic conditions such as CVD. This paper explores the multifaceted relationship between HIV infection, ART, and cardiovascular health, focusing on the mechanisms by which HIV and ART contribute to increased cardiovascular risk, including the promotion of endothelial dysfunction, inflammation, immune activation, and metabolic disturbances. We highlight the critical roles of HIV-associated proteins-Tat, Nef, and gp120-in accelerating atherosclerosis through direct and indirect pathways that exacerbate endothelial damage and inflammation. Additionally, we address the persistent challenge of chronic inflammation and immune activation in PLWH, factors that are strongly predictive of non-AIDS-related diseases, including CVD, even in the context of effective viral suppression. The impact of ART on cardiovascular risk is examined, with particular attention to the metabolic implications of specific ART regimens, which can influence lipid profiles and body composition, thereby modifying CVD risk. The therapeutic potential of statins, aspirin, and emerging treatments such as PCSK9 inhibitors in mitigating cardiovascular morbidity and mortality among PLWH is discussed, alongside considerations for their use in conjunction with ART. Our review underscores the necessity for a comprehensive, multidisciplinary approach to cardiovascular care in PLWH, which integrates vigilant cardiovascular risk assessment and management with HIV treatment. As we navigate the evolving landscape of HIV care, the goal remains to optimize treatment outcomes while minimizing cardiovascular risk, ensuring that the gains in longevity afforded by ART translate into improved overall health and quality of life for PLWH.

In Vivo Study of Inoculation Approaches and Pathogenicity in African Swine Fever.

African swine fever is an extremely infectious viral disease that can cause nearly 100% mortality in domestic pigs. In this study, we isolated an ASFV strain HB31A and characterized it using hemadsorption assay, immunofluorescence assay, and electron microscopy. We then performed animal experiments on 20-day-old pigs through intramuscular and oronasal inoculations with HB31A. Pigs in the intramuscular group exhibited more consistent clinical disease, with an incubation period of 4.33 ± 0.47 days and a 100% mortality rate within 6.67 (±0.47) days post-inoculation (dpi). In contrast, the oronasal group experienced a longer course of disease, with an incubation period of 6.00 ± 0.82 days. Two out of three pigs in the oronasal group died at 8 and 10 dpi, while the surviving pig exhibited chronic disease and persistent infection, intermittently excreting ASFV through the oral, nasal, and rectal pathways. Virus DNA was found in oral, nasal, and rectal swabs at 1-3 dpi in the intramuscular group and at 3-5 dpi in the oronasal group. In summary, HB31A is highly lethal to domestic pigs, and field-infected pigs have the potential to develop non-lethal, chronic disease and persistent infection, with intermittent viral shedding, even when infected with a highly virulent strain. These findings offer a valuable understanding of the viral dynamics and pathogenicity of ASFV and highlight the difficulties in diagnosing, preventing, and controlling African swine fever.

Factors Contributing to Emergence of infectious viral diseases in India: Issues and Challenges after COVID-19 Pandemic

Emerging and re-emerging viral infections are major cause of morbidity and mortality in humans and animals. India had experienced numerous infectious disease outbreaks and epidemics in past years. However, tremendous strides have been achieved in the past in the fight against serious epidemic diseases. It has been found that a wide range of complex factors, such as pathogen evolution, human invasion, commerce in wild animals, microbial adaptation, changes in the environment and dynamic interactions between humans and animals influence the emergence and transmission of infectious viral diseases. As the COVID-19 pandemic demonstrated, India's secondary and tertiary health-care system is quite advanced. The study of infectious diseases, in particular their pathogenesis, genetic profile and diagnosis has fundamentally changed with the advent of genome sequencing and nucleic acid detection technology. Additionally, advance therapy and vaccination led to best possible patient management and care. Further scientific investigations and research are needed to discover neglected diseases that have the potential to cause epidemics as well as to develop updated vaccines, modern treatment strategy and diagnostics at molecular level. This evaluation will aid for policymakers, academics and researchers to redesign the course of action to combat the deadly emerging pathogenic viruses and also preserve the ecosystem.

Ascorbic Acid and α-Tocopherol in the Inactivated SARS-CoV-2 Vaccine Formulation: Induction of the Th1 Pattern in Aged Mice.

Aging is physiologically associated with a decline in the function of the immune system and subsequent susceptibility to infections. Interferon-gamma (IFN-γ), a key element in the activation of cellular immunity, plays an important role in defense against virus infections. Decreased levels of IFN-γ in the elderly may explain their increased risk for viral infectious diseases such as COVID-19. There is accumulating evidence that ascorbic acid (vitamin C [VitC]) and α-tocopherol together help improve the function of the immune system in the elderly, control infections, and decrease the treatment duration. A SARS-CoV-2 strain was isolated from a patient and then cultured in the Vero cell line. The isolated and propagated virus was then inactivated using formalin and purified by the column chromatography. The inactivated SARS-CoV-2 was formulated in the Alum adjuvant combined with VitC or α-tocopherol and/or both of them. The vaccines were injected twice to young and aged C57BL/6 mice. Two weeks later, IFN-γ, IL-4, and IL-2 cytokines were assessed using ELISA Kits. Specific IgG and IgG1/IgG2a were assessed by an in-house ELISA. In addition, the expression of PD1 and TERT genes in the spleen tissue of the mice was measured using real-time PCR. IL-4 and IFN-γ cytokines showed a significant increase in both aged and young mice compared with the Alum-based vaccine. In addition, our results exhibited a significant decrease and increase in specific total IgG and the IgG2a/IgG1 ratio, respectively. Furthermore, the vaccine formulated in α-tocopherol + VitC led to decreased PD1 and increased TERT gene expression levels. In conclusion, our results demonstrated that α-tocopherol + VitC formulated in the inactivated SARS-CoV-2 vaccine led to a shift toward Th1, which may be due to their effect on the physiology of cells, especially aged ones and changing their phenotype toward young cells.

Hematological and biochemical studies of lumpy skin disease virus infection in cattle

Hematological and biochemical studies of lumpy skin disease virus infection in cattle

Experimental Velogenic Viscerotropic Newcastle Disease Virus Infection in Chickens Immunologically Impaired by Treatment with Cyclophosphamide

This study investigated whether lymphocytic depletion following chemical bursectomy influenced the severity of infection and development of lesions in chickens challenged with velogenic viscerotropic Newcastle disease virus (vvNDV). Cockerel chickens treated with cyclophosphamide on days 2, 3 and 4 post-hatch showed loss of weight, atrophy and lymphocytic depletion in the bursa of Fabricius and spleen. At 6 weeks of age, the chickens were assigned to four groups- Bursectomized intramuscularly vvNDV inoculated (BI), bursectomized uninfected (BU), non-bursectomized infected (NBI) and non-bursectomized uninfected (NBU) chickens. The BI and NBI chickens showed significant (P &amp;lt; .05) loss of weight than their uninfected controls. Depression, anorexia, greenish diarrhea, listlessness, tremor, and oculo-nasal discharges were observed in both infected groups, but were more severe and frequent in the NBI than in the BI chickens. Total mortalities were 100% and 95.5% for the NBI and BI chickens, respectively (P &amp;gt; .05). Lesions in both infected groups included atrophy of the bursa, spleen and thymus. Hemorrhages in the proventricular mucosa, intestines and cecal tonsils, as well as congestion and enlargement of the kidneys were significantly (P &amp;lt; .05) more severe and frequent in NBI than BI chickens. Histopathology showed necrosis and depletion of lymphocytes in the three lymphoid organs in both infected groups with more severity in the NBI than BI chickens. These results show that depletion of lymphocytes by treatment with cyclophosphamide may influence the severity of infection and development of lesions in vvNDV infection in cockerel chickens.

Integration and validation of host transcript signatures, including a novel 3-transcript tuberculosis signature, to enable one-step multiclass diagnosis of childhood febrile disease

BackgroundWhole blood host transcript signatures show great potential for diagnosis of infectious and inflammatory illness, with most published signatures performing binary classification tasks. Barriers to clinical implementation include validation studies, and development of strategies that enable simultaneous, multiclass diagnosis of febrile illness based on gene expression.MethodsWe validated five distinct diagnostic signatures for paediatric infectious diseases in parallel using a single NanoString nCounter® experiment. We included a novel 3-transcript signature for childhood tuberculosis, and four published signatures which differentiate bacterial infection, viral infection, or Kawasaki disease from other febrile illnesses. Signature performance was assessed using receiver operating characteristic curve statistics. We also explored conceptual frameworks for multiclass diagnostic signatures, including additional transcripts found to be significantly differentially expressed in previous studies. Relaxed, regularised logistic regression models were used to derive two novel multiclass signatures: a mixed One-vs-All model (MOVA), running multiple binomial models in parallel, and a full-multiclass model. In-sample performance of these models was compared using radar-plots and confusion matrix statistics.ResultsSamples from 91 children were included in the study: 23 bacterial infections (DB), 20 viral infections (DV), 14 Kawasaki disease (KD), 18 tuberculosis disease (TB), and 16 healthy controls. The five signatures tested demonstrated cross-platform performance similar to their primary discovery-validation cohorts. The signatures could differentiate: KD from other diseases with area under ROC curve (AUC) of 0.897 [95% confidence interval: 0.822–0.972]; DB from DV with AUC of 0.825 [0.691–0.959] (signature-1) and 0.867 [0.753–0.982] (signature-2); TB from other diseases with AUC of 0.882 [0.787–0.977] (novel signature); TB from healthy children with AUC of 0.910 [0.808–1.000]. Application of signatures outside of their designed context reduced performance. In-sample error rates for the multiclass models were 13.3% for the MOVA model and 0.0% for the full-multiclass model. The MOVA model misclassified DB cases most frequently (18.7%) and TB cases least (2.7%).ConclusionsOur study demonstrates the feasibility of NanoString technology for cross-platform validation of multiple transcriptomic signatures in parallel. This external cohort validated performance of all five signatures, including a novel sparse TB signature. Two exploratory multi-class models showed high potential accuracy across four distinct diagnostic groups.

A Guideline Strategy for Identifying Genes/Proteins Regulating Antiviral Innate Immunity.

Antiviral innate immunity is a complicated system initiated by the induction of type I interferon (IFN-I) and downstream interferon-stimulated genes (ISGs) and is finely regulated by numerous positive and negative factors at different signaling adaptors. During this process, posttranslational modifications, especially ubiquitination, are the most common regulatory strategy used by the host to switch the antiviral innate signaling pathway and are mainly controlled by E3 ubiquitin ligases from different protein families. A comprehensive understanding of the regulatory mechanisms and a novel discovery of regulatory factors involved in the IFN-I signaling pathway are important for researchers to identify novel therapeutic targets against viral infectious diseases based on innate immunotherapy. In this section, we use the E3 ubiquitin ligase as an example to guide the identification of a protein belonging to the RING Finger (RNF) family that regulates the RIG-I-mediated IFN-I pathway through ubiquitination.

Case Report: Methimazole-Induced Parotitis - An Unusual Presentation

A 56-year-old female with a medical history of unspecified hyperthyroidism and a recent thyroid storm presented to the ED with tachycardia, hypertension, and bilateral enlarged parotid glands. During a previous hospitalization, she was diagnosed with unspecified hyperthyroidism and started on methimazole. During hospitalization, laboratory findings suggested Graves’ disease with an acute thyroid storm. The patient also complained of enlarged parotid glands bilaterally. CT tomography of the neck revealed no calculi of the parotid glands but showed extensive fatty replacement, possibly related to methimazole use. Treatment with propranolol and IV hydrocortisone improved thyroid function. Due to the suspicion of methimazole-induced parotitis, she was transitioned to a reduced methimazole dosage for treatment of Graves’ disease, which subsequently improved her parotitis. Methimazole, the standard initial treatment for Graves’ disease, is generally well-tolerated. It can cause adverse reactions; however, parotitis is very rare and has been documented in only a few case reports. Owing to the limited number of reports, its incidence is currently unknown. Here, we present a case of methimazole-induced parotitis as an unusual presentation of thyroid storm. Drug-induced reactions can only be considered once common causes of parotitis such as viral infection, obstruction, and autoimmune diseases are ruled out. Treatment involves dosage adjustments and supportive care. Methimazole-induced parotitis is often misdiagnosed and overlooked because of the lack of reported cases. This necessitates future research into the reaction mechanisms and optimal treatment.

An automated syringe-based PoC RT-LAMP LFB platform for infectious disease detection from saliva

Decentralized Point-of-Care (PoC) diagnostics hold momentous potential for rapid and accessible viral infection disease detection. Presented is a unique design application of an easy-to-use (plug-and-play) platform for viral detection. The platform leverages a simplified multiplex Reverse-Transcription Loop-mediated Isothermal Amplification (RT-LAMP) Lateral Flow Biosensor (LFB) assay with a lyophilized master mix, eliminating the need for RNA isolation or special reporting equipment. A user-friendly Saliva Measuring Tube (SMT) ensures accurate saliva volume self-collection, and a Syringe-based PoC (SPoC) platform automates sample treatment, reagent mixing, and temperature control using readily available components and consumables. The platform’s performance was evaluated by multiplexed detection of the SARS-CoV-2 N2 target gene and human ACTB gene from saliva samples. The SPoC platform achieved a detection limit of spiked 500 copies/mL for SARS-CoV-2 and consistent internal control readout. The presented PoC system offers a promising initial step for further development toward a decentralized solution for viral infection testing.

Computational exploration and molecular dynamic simulation for the discovery of antiviral agents targeting Newcastle disease virus

Newcastle disease virus (NDV) is a highly infectious viral disease that impacts birds globally, especially domestic poultry. NDV is a type of avian paramyxovirus which poses a major threat to the poultry industry due to its ability to inflict significant economic damage. The membrane protein, Hemagglutinin-Neuraminidase (HN) of NDV is an attractive therapeutic candidate. It contributes to pathogenicity through various functions, such as promoting fusion and preventing viral self-agglutination, which allows for viral spread. In this study, we used pharmacophore modeling to identify natural molecules that can inhibit the HN protein of NDV. Physicochemical characteristics and phylogenetic analysis were determined to elucidate structural information and phylogeny of target protein across different species as well as members of the virus family. For structural analysis, the missing residues of HN target protein were filled and the structure was evaluated by PROCHECK and VERIFY 3D. Moreover, shape and feature-based pharmacophore model was employed to screen natural compounds’ library through numerous scoring schemes. Top 48 hits with 0.8860 pharmacophore fit score were subjected towards structure-based molecular docking. Top 9 compounds were observed witihin the range of −8.9 to −7.5 kcal/mol binding score. Five best-fitting compounds in complex with HN receptor were subjected to predict biological activity and further analysis. Top two hits were selected for MD simulations to validate binding modes and structural stability. Finally, upon scrutinization, A1 (ZINC05223166) emerges as potential HN inhibitor to treat NDV, necessitating further validation via clinical trials.

Exploring antiviral effect and mechanism of Jinye Baidu granules（JYBD）against influenza A virus through network pharmacology and in vitro and invivo experiments

Ethnopharmacological relevanceJinye Baidu granules (JYBD) have been used to treat acute respiratory tract infections and demonstrated clinical efficacy for the treatment of emerging or epidemic respiratory viruses such as SARS-CoV-2 and influenza virus. Aim of the studyThis study is to investigate the antiviral effect of JYBD against influenza A viruses (IAV) in vitro and in vivo and elucidate its underlying mechanism. Materials and methodsUltra-high-performance liquid chromatography connected with Orbitrap mass spectrometer (UHPLC-Orbitrap MS) was employed to describe the chemical profile of JYBD. The potential pathways and targets involved in JYBD against IAV infection were predicted by network pharmacology. The efficacy and mechanism of JYBD were validated through both in vivo and in vitro experiments. Moreover, combination therapy with JYBD and the classic anti-influenza drugs was also investigated. ResultsA total of 126 compounds were identified by UHPLC-Orbitrap MS, of which 9 compounds were unambiguously confirmed with reference standards. JYBD could significantly inhibit the replication of multiple strains of IAV, especially oseltamivir-resistant strains. The results of qRT-PCR and WB demonstrated that JYBD could inhibit the excessive induction of pro-inflammatory cytokines induced by IAV infection and regulate inflammatory response through inhibiting JAK/STAT, NF-κB and MAPK pathways. Moreover, both JYBD monotherapy or in combination with oseltamivir could alleviate IAV-induced severe lung injury in mice. ConclusionsJYBD could inhibit IAV replication and mitigate virus-induced excessive inflammatory response. Combinations of JYBD and neuraminidase inhibitors conferred synergistic suppression of IAV both in vitro and in vivo. It might provide a scientific basis for clinical applications of JYBD against influenza virus infected diseases.

STRAP upregulates antiviral innate immunity against PRV by targeting TBK1

Serine/threonine kinase receptor-associated protein (STRAP) serves as a scaffold protein and is engaged in a variety of cellular activities, although its importance in antiviral innate immunity is unknown. We discovered that STRAP works as an interferon (IFN)-inducible positive regulator, facilitating type I IFN signaling during pseudorabies virus infection. Mechanistically, STRAP interacts with TBK1 to activate type I IFN signaling. Both the CT and WD40 7 − 6 domains contribute to the function of STRAP. Furthermore, TBK1 competes with PRV-UL50 for binding to STRAP, and STRAP impedes the degradation of TBK1 mediated by PRV-UL50, thereby increasing the interaction between STRAP and TBK1. Overall, these findings reveal a previously unrecognized role for STRAP in innate antiviral immune responses during PRV infection. STRAP could be a potential therapeutic target for viral infectious diseases.

Longitudinal seroepidemiological survey and risk factors for bluetongue virus infection in sheep in the state of Parana, Brazil, from 2014 to 2017.

The Bluetongue disease is an infectious and non-contagious viral disease mainly transmitted through hematophagous vector of the Culicoides genus, to domestic and wild ruminants. The aim of this study was to evaluate the antibodies occurrence, persistence and potential risk factors associated with bluetongue virus infection in sheep flocks in the state of Parana, Brazil. The competitive ELISA test was applied to evaluate 690 blood serum samples from 22 farms in eight mesoregions of Parana in 2014, and 270 sheep blood serum samples from 10 of the 22 previously studied farms in 2017. A questionnaire was applied to evaluate the risk factors associated with BTV infection. In 2014 and 2017, the numbers of seroreactive sheep were found to be 28.26% (195/690) and 41.11% (111/270), respectively, representing 95.45% (21/22) and 90% (9/10) of the flocks. The significant variables considered as risk factors were Culicoides presence (P < 0.0001; OR = 8.83 and 95% CI 4.28-18.22); genealogical record (P < 0.0001; OR = 0.23 and 95% CI 0.12-0.45) and use of sheepfold (P = 0.0208; OR = 0.36 and 95% CI 0.15-0 0.86). It was determined that BTV infection is endemic in Parana and persists in the mesoregions where the climate is favorable to vector proliferation.

Mechanistic exploration of COVlD-19 antiviral drug ritonavir on anaerobic digestion through experimental validation coupled with metagenomics analysis

Aggregation of antiviral drugs (ATVs) in waste activated sludge (WAS) poses considerable environmental risk, so it is crucial to understand the behavior of these agents during WAS treatment. This study investigated the effects of ritonavir (RIT), an ATV used to treat human immunodeficiency virus infection and coronavirus disease 2019, on anaerobic digestion (AD) of WAS to reveal the mechanisms by which it interferes with anaerobic flora. The dosage influence results showed that methane production in AD of WAS decreased by 46.56 % when RIT concentration was increased to 1000 μg/kg total suspended solids (TSS). The AD staging test revealed that RIT mainly stimulated microbial synthesis of the extracellular polymeric substance (EPS), limiting organic matter solubilization. At 500 μg/kg TSS, RIT decreased CHO and CHON levels in dissolved organic matter by 23.12 % and 56.68 %, respectively, significantly reducing substrate availability to microorganisms. Metagenomic analysis of microbial functional gene sets revealed that RIT had greater inhibitory effects on protein and amino acid metabolism than on carbohydrate metabolism. Under RIT stress, methanogens switched from hydrogenotrophic and acetotrophic methanogenesis to methylotrophic and acetotrophic methanogenesis.

Very virulent infectious bursal disease virus infection triggered microscopic changes, apoptosis, and inflammatory cytokines imbalance in chicken spleen and thymus

ABSTRACT Infectious bursal disease virus (IBDV) can cause a highly contagious disease, resulting in severe damage to the immune system that causes immunosuppression in young chickens. Both spleen and thymus are important immune organs, which play a key role in eliciting protective immune responses. However, the effects of very virulent IBDV (vvIBDV) strain LJ-5 infection on chicken spleen and thymus are still unknown. In the present study, 3-week-old specific pathogen-free chickens were infected with vvIBDV for 1–5 days. The vvIBDV infection significantly increased the spleen index and decreased the thymus index. Microscopic analysis indicated necrosis, depletion of the lymphoid cells, and complete loss of structural integrity in spleen and thymus. Ultrastructural analysis displayed mitochondrial and nuclear damage, including mitochondrial cristae breaks, and deformation of nuclear membrane in vvIBDV-infected spleen and thymus tissues. Cytokine levels increased in the spleen and thymus after IBDV infection, promoting inflammation and causing an inflammatory imbalance. Moreover, the mRNA expression of apoptosis-related genes was significantly upregulated in the vvIBDV-infected group compared to the control group. Meanwhile, the mRNA expression of mitochondrial dynamics was altered in the spleen and thymus of vvIBDV-infected chickens. These results suggested that vvIBDV infection triggers an imbalance of inflammatory cytokines, and apoptosis in the spleen and thymus, resulting in immune injury in chickens. This study provides basic data for the further study of vvIBDV pathogenesis.