Inflammatory responses to Opisthorchis viverrini infection in animal models: A comparison between susceptible and nonsusceptible hosts in different anatomical locations.

Background: Inflammation caused by Opisthorchis viverrini infection increases the risk of cholangitis, cholecystitis, and leads to bile duct cancer (cholangiocarcinoma or CCA). However, only certain infected individuals are susceptible to CCA, suggesting the involvement of host factors in cancer development. In addition, there are reports indicating differences in the locations of CCA. Aim: This study aims to investigate cellular inflammatory responses in the common bile duct (CB), intrahepatic bile duct (IHB), and gallbladder (GB) in susceptible and non-susceptible hosts following O. viverrini infection. Methods: Thirty Syrian golden hamsters (a susceptible host) and 30 BALB/c mice (a non-susceptible host) infected with O. viverrini were studied at six time points (five animals per group). Histopathological evaluations were conducted on samples from the IHB, CB, and GB. Inflammatory cell infiltration was quantitatively assessed and compared between groups and time points. Statistical analysis was performed using one-way ANOVA, with a significance level of p < 0.05. Results: Inflammation was significantly more pronounced in the IHB compared to the other two biliary locations. In comparison between susceptible and non-susceptible hosts, the intensity of inflammation was higher in the OV+H group than in the OV+M group (p < 0.05). Conclusion: This study highlights the association between host response to inflammation, tissue location, and host susceptibility, with the IHB showing particular susceptibility to inflammation and pathological changes. These findings contribute to our understanding of the increased risk of CCA in susceptible hosts.

BCG and BCGΔBCG1419c transiently protect hypersusceptible I/St mice and induce different influx of macrophages and neutrophils during pulmonary tuberculosis.

Background. Host genetic factors influence both susceptibility to Mycobacterium tuberculosis infection and immune responses generated by vaccination. Genetically susceptible mice help to study mechanisms of immune protection which may differ from those operating in more resistant models.Methods. In this work, we compared the efficacy of protection conferred by subcutaneous vaccination of hypersusceptible I/St mice with BCG and the first-generation, hygromycin resistant version of the vaccine candidate BCGΔBCG1419c, against tuberculosis (TB), measured as survival, weight loss and replication in lungs. We further characterized the relative presence of immune cells in lungs.Results. We found that in I/St mice, vaccination with BCG or BCGΔBCG1419c provided similar level of protection against TB-driven weight loss and M. tuberculosis replication in lungs, while prolonging median survival time compared with unvaccinated controls. Despite affording similar protection to parental BCG, BCGΔBCG1419c led to a reduced presence of macrophages in lungs during early TB and to an increased neutrophil recruitment to the lungs during chronic TB.Conclusions. BCGΔBCG1419c protects I/St mice in a different manner than wild-type BCG against pulmonary TB by promoting different influx of macrophages and neutrophils at distinct times post-infection. These findings prompt us to suggest that preclinical evaluation of novel TB vaccine candidates should include evaluation of efficacy not only in commonly used resistant inbred mice, but also in susceptible hosts, to further determine their potential application to populations varying in their genetic. This would likely impact their intended use depending on host resistance or susceptibility to TB.

Oral health's inextricable connection to systemic health: Special populations bring to bear multimodal relationships and factors connecting periodontal disease to systemic diseases and conditions.

The landscape in dentistry is changing as emerging studies continue to reveal that periodontal health impacts systemic health, and vice versa. Population studies, clinical studies, and in vitro animal studies underscore the critical importance of oral health to systemic health. These inextricable relationships come to the forefront as oral diseases, such as periodontal disease, take root. Special populations bring to bear the multimodal relationships between oral and systemic health. Specifically, periodontal disease has been associated with diabetes, metabolic syndrome, obesity, eating disorders, liver disease, cardiovascular disease, Alzheimer disease, rheumatoid arthritis, adverse pregnancy outcomes, and cancer. Although bidirectional relationships are recognized, the potential for multiple comorbidities, relationships, and connections (multimodal relationships) also exists. Proposed mechanisms that mediate this connection between oral and systemic health include predisposing and precipitating factors, such as genetic factors (gene polymorphisms), environmental factors (stress, habits-such as smoking and high-fat diets/consumption of highly processed foods), medications, microbial dysbiosis and bacteremias/viremias/microbemias, and an altered host immune response. Thus, in a susceptible host, these predisposing and precipitating factors trigger the onset of periodontal disease and systemic disease/conditions. Further, high-throughput sequencing technologies are shedding light on the dark matter that comprises the oral microbiome. This has resulted in better characterization of the oral microbial dysbiosis, including putative bacterial periodontopathogens and shifts in oral virome composition during disease. Multiple laboratory and clinical studies have illustrated that both eukaryotic and prokaryotic viruses within subgingival plaque and periodontal tissues affect periodontal inflammation, putative periodontopathogens, and the host immune response. Although the association between herpesviruses and periodontitis and the degree to which these viruses directly aggravate periodontal tissue damage remain unclear, the benefits to periodontal health found from prolonged administration of antivirals in immunocompromised or immunodeficient individuals demonstrates that specific populations are possibly more susceptible to viral periodontopathogens. Thus, it may be important to further examine the implications of viral pathogen involvement in periodontitis and perhaps it is time to embrace the viral dark matter within the periodontal environment to fully comprehend the pathogenesis and systemic implications of periodontitis. Emerging data from the coronavirus disease 2019 pandemic further underscores the inextricable connection between oral and systemic health, with high levels of the severe acute respiratory syndrome coronavirus 2 angiotensin-converting enzyme 2 receptor noted on oral tissues (tongue) and an allostatic load or overload paradigm of chronic stress likely contributing to rapid breakdown of oral/dental, periodontal, and peri-implant tissues. These associations exist within a framework of viremias/bacteremias/microbemias, systemic inflammation, and/or disturbances of the immune system in a susceptible host. A thorough review of systemic and oral diseases and conditions and their mechanistic, predisposing, and precipitating factors are paramount to better addressing the oral and systemic health and needs of our patients.

Comparative response of Metarhizium brunneum to the cuticles of susceptible and resistant hosts.

Earlier studies demonstrated that Metarhizium brunneum, usually a broad-host pathogen of arthropods, is unable to complete its pathogenic life cycle when inoculated on the fungus-resistant tick, Hyalomma excavatum engorged females. While the fungus penetrates the cuticle of fungus-susceptible tick, Rhipicephalus annulatus females, it is unable to penetrate the cuticle of fungus-resistant tick, and even perishes on its surface. This is probably due to high concentration of antifungal fatty acids and probably also due to a hypersensitive-like response of the tick. To understand the metabolic pathways occurring in the fungal hyphae upon encountering the cuticles, we compared the response of the fungus to cuticle from susceptible and resistant tick cuticles by 2D-gels. The intracellular proteomes of M. brunneum Mb7 exposed to cuticle of the fungus-susceptible tick, R. annulatus, and to the fungus-resistant tick, H. excavatum engorged females were compared after exposure to either cuticles. By means of liquid chromatography-mass spectrometry/mass spectrometry we identified in both proteomes common proteins involved in biological processes as well as unique proteins identified only in the proteome of fungus exposed to fungus-resistant tick cuticle. These proteins were identified in high probability as heat shock proteins, four key enzymes of the glyoxylate cycle, and proteins associated with hypoxia, and exposure to antifungal drugs. These findings are discussed within the M. brunneum-tick pathosystem in relation to tick resistance and host resistance in general.

Biocontrol of the Major Plant Pathogen Ralstonia solanacearum in Irrigation Water and Host Plants by Novel Waterborne Lytic Bacteriophages.

Three new lytic bacteriophages were found to effectively control the pathogen Ralstonia solanacearum, a quarantine bacterium in many countries, and causative agent of bacterial wilt, one of the most important vascular plant diseases. Bacterial wilt management has been carried out with fluctuating effects, suggesting the need to find alternative treatments. In this work, three lytic phages were isolated from environmental water from geographically distant regions in Spain. They proved to specifically infect a collection of R. solanacearum strains, and some of the closely related pathogenic species Ralstonia pseudosolanacearum, without affecting non-target environmental bacteria, and were able to lyze the pathogen populations within a wide range of conditions comprising environmental values of water temperatures, pH, salinity, and lack of aeration found in storage tanks. The three bacteriophages displayed high efficiency in controlling R. solanacearum, with reductions of the bacterial populations of several orders of magnitude in just a few hours, and proved to be able to survive in freshwater for months at environmental temperatures keeping activity on R. solanacearum, pointing out their suitability for field application through irrigation. Concerning their biocontrol potential, they were effective in reducing high populations of the pathogen in environmental water, and bacterial wilt incidence in planta by watering with either one phage or their combinations in assays with more than 300 plants. This is the first report on effective R. solanacearum biocontrol by applying single or combined bacteriophages through irrigation water in conditions mimicking those of the natural settings. The three phages belong to the Podoviridae family and are members of the T7likevirus genus. They are the first isolated phages from river water with activity against R. solanacearum, showing the longest persistence in natural water reported until now for phages with biocontrol potential, and consistently being able to control the disease in the host plant under environmental conditions. Consequently, the use of these bacteriophages for the prevention and/or biocontrol of the bacterial wilt disease caused by R. solanacearum has been patented. Evidence provided reveals the suitability of these waterborne phages to be effectively considered as a valuable strategy within the frame of sustainable integrated management programs.

Transcriptome analysis provides insights into molecular immune mechanisms of rabbitfish, Siganus oramin against Cryptocaryon irritans infection.

The rabbitfish Siganus oramin is resistant to the ciliate parasite Cryptocaryon irritans. L-amino acid oxidase (LAAO) protein from rabbitfish can kill C. irritans in vitro, however, other immune defence mechanisms against C. irritans remains unknown. Here, we generated transcriptomes of rabbitfish skin at 12 h post infection (PI) by C. irritans. The transcriptomes contained 238, 504, 124 clean reads were obtained and then assembled into 258,869 unigenes with an average length of 621 bp and an N50 of 833 bp. Among them, we obtained 418 differentially expressed genes (DEGs) in the skin of rabbitfish under C. irritans infection and control conditions, including 336 significantly up-regulated genes and 82 significantly down-regulated genes. Seven immune-related categories with 32 differentially expressed immune genes were obtained using Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. DEGs included innate immune molecules, such as LAAO, antimicrobial peptide, lysozyme g, as well as complement components, chemokines and chemokine receptors, NOD-like receptor/Toll-like receptor signaling pathway molecules, antigen processing and T/B cell activation and proliferation molecules. We further validated the expression results of nine immune-related DEGs using quantitative real-time PCR. This study provides new insights into the early immune response of a host that is resistant to C. irritans.

The development of Cryptocaryon irritans in a less susceptible host rabbitfish, Siganus oramin.

Cryptocaryon irritans is a ciliated protozoan parasite infecting the gills and skin of almost all marine teleosts, resulting in severe disease. Notably, C. irritans is unable to cause significant pathogenesis in rabbitfish, Siganus oramin, a well-known less susceptible host. However, little is known about the development of C. irritans in rabbitfish. Thus, in the present study, rabbitfish were artificially infected with C. irritans at a 1/2 maximal tolerance dose (MTD), using the susceptible host, large yellow croaker, Larimichthys crocea, as a control. The daily food consumption (DFC), survival, and relative infection intensity (RII) of the fish were observed, and the relative number of tomonts (RNT), reproductive rate, and characteristics of C. irritans tomonts were measured. The lethal concentration 50 (LC50) of C. irritans on rabbitfish and large yellow croaker was 2236, and 264 theronts/g fish, respectively. The DFC of rabbitfish decreased by 14.6% at day 1 post-C. irritans infection (PI), but immediately returned to normal DFC levels by day 2 PI, and was not affected by secondary infection. However, large yellow croaker stopped feeding at day 3 PI, and all fish died following secondary infection with C. irritans. The RII of rabbitfish exhibited a significant downward trend at 6 h PI, and the reproductive rate of C. irritans was 8%; in contrast, the RII of large yellow croaker was not significantly different from 0 to 72 h PI, and the reproductive rate of C. irritans reached to 59.05-fold. Over the same time frame, the diameter of tomonts from rabbitfish was smaller compared with those from large yellow croaker. These results indicated that the rabbitfish were somehow able to limit the development of C. irritans, such that most trophonts left the host during early developmental stages, whereas those that survive could only develop into small tomonts.

Interacting effects of land use and climate on rodent-borne pathogens in central Kenya.

Understanding the effects of anthropogenic disturbance on zoonotic disease risk is both a critical conservation objective and a public health priority. Here, we evaluate the effects of multiple forms of anthropogenic disturbance across a precipitation gradient on the abundance of pathogen-infected small mammal hosts in a multi-host, multi-pathogen system in central Kenya. Our results suggest that conversion to cropland and wildlife loss alone drive systematic increases in rodent-borne pathogen prevalence, but that pastoral conversion has no such systematic effects. The effects are most likely explained both by changes in total small mammal abundance, and by changes in relative abundance of a few high-competence species, although changes in vector assemblages may also be involved. Several pathogens responded to interactions between disturbance type and climatic conditions, suggesting the potential for synergistic effects of anthropogenic disturbance and climate change on the distribution of disease risk. Overall, these results indicate that conservation can be an effective tool for reducing abundance of rodent-borne pathogens in some contexts (e.g. wildlife loss alone); however, given the strong variation in effects across disturbance types, pathogen taxa and environmental conditions, the use of conservation as public health interventions will need to be carefully tailored to specific pathogens and human contexts.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.

Leptospirosis humana: un abordaje epidemiológico desde los factores ambientales / Human leptospirosis: an epidemiologic approach from environmental factors

Introducción: la leptospirosis es una enfermedad infecciosa zoonótica. La vía por la que el hombre puede enfermar está relacionada con el medio natural y su calidad. Objetivo: describir aspectos epidemiológicos de la leptospirosis y la influencia de los factores ambientales en la incidencia de la enfermedad. Métodos: se realizó una revisión bibliográfica relacionada con las formas clínicas de la enfermedad, diagnóstico y tratamiento preventivo, así como la influencia de los factores ambientales en la incidencia de la enfermedad. Conclusiones: la leptospirosis es una enfermedad en la que el médico de la atención primaria ejerce un papel fundamental al tener un pensamiento epidemiológico y poder realizar un diagnóstico oportuno ante la sospecha de un paciente con síntomas clínicos; y la identificación de grupos riesgo; para orientar las medidas de prevención relacionadas con la enfermedad, debido a que el agente causal utiliza el medio ambiente natural o creado por el hombre con condiciones favorables para sobrevivir y pasar al huésped susceptible(AU)

Introduction: Leptospirosis is an infectious zoonotic disease. The way the human being can become sick is related to the natural environment and its quality. Objective: To describe epidemiological aspects of leptospirosis and the influence of environmental factors on the disease incidence. Methods: A bibliographic review was carried out considering the disease's clinical forms, diagnosis and preventive treatment, as well as the influence of environmental factors on the disease incidence. Conclusions: Leptospirosis is a disease in which the primary care physician plays a fundamental role in having an epidemiological approach and being able to make a timely diagnosis when a patient is suspected with clinical symptoms, and the identification of risk groups, to guide the prevention measures related to the disease, because the causal agent uses the natural or man-made environment with favorable conditions to survive and pass to the susceptible host(AU)

Leptospirosis humana: un abordaje epidemiológico desde los factores ambientales / Human leptospirosis: an epidemiologic approach from environmental factors

Introducción: la leptospirosis es una enfermedad infecciosa zoonótica. La vía por la que el hombre puede enfermar está relacionada con el medio natural y su calidad. Objetivo: describir aspectos epidemiológicos de la leptospirosis y la influencia de los factores ambientales en la incidencia de la enfermedad. Métodos: se realizó una revisión bibliográfica relacionada con las formas clínicas de la enfermedad, diagnóstico y tratamiento preventivo, así como la influencia de los factores ambientales en la incidencia de la enfermedad. Conclusiones: la leptospirosis es una enfermedad en la que el médico de la atención primaria ejerce un papel fundamental al tener un pensamiento epidemiológico y poder realizar un diagnóstico oportuno ante la sospecha de un paciente con síntomas clínicos; y la identificación de grupos riesgo; para orientar las medidas de prevención relacionadas con la enfermedad, debido a que el agente causal utiliza el medio ambiente natural o creado por el hombre con condiciones favorables para sobrevivir y pasar al huésped susceptible(AU)

Introduction: Leptospirosis is an infectious zoonotic disease. The way the human being can become sick is related to the natural environment and its quality. Objective: To describe epidemiological aspects of leptospirosis and the influence of environmental factors on the disease incidence. Methods: A bibliographic review was carried out considering the disease's clinical forms, diagnosis and preventive treatment, as well as the influence of environmental factors on the disease incidence. Conclusions: Leptospirosis is a disease in which the primary care physician plays a fundamental role in having an epidemiological approach and being able to make a timely diagnosis when a patient is suspected with clinical symptoms, and the identification of risk groups, to guide the prevention measures related to the disease, because the causal agent uses the natural or man-made environment with favorable conditions to survive and pass to the susceptible host(AU)

Detection of macrophages infected with Mycobacterium avium subspecies paratuberculosis in a cow with clinical stage IV of Johne's disease. A case report / Detección de macrófagos infectados con Mycobacterium avium subspecies paratuberculosis en una vaca en fase clínica IV de la enfermedad de Johne. Reporte de un caso / Detecção de macrófagos infectados com Mycobacterium avium paratuberculosis subespécie em uma vaca com uma fase clínica IV da doença de Johne. Um relato de caso

Anamnesis: a six-year-old milking Holstein cow (Bos taurus taurus) was diagnosed with stage IV Johne's Disease (JD). Clinical and Laboratory findings: the cow suffered intermittent diarrhea during 6 months with no response to antibiotic treatment. Consequently, the cow was subjected to euthanasia. Treatment approach: antemortem milk and peripheral blood samples and postmortem colon, mediastinic, mesenteric lymph nodes, and spleen samples were processed for macrophages isolation. Total DNA was extracted from macrophages and used to diagnose IS900 of Mycobacterium avium paratuberculosis (MAP) through real time PCR. The MAP IS900 segment was successfully amplified from cells of all samples, indicating that these cells were MAP-infected macrophages. Conclusion: macrophages of cows suffering from JD can be used for amplification of the MAP IS900 segment.

Anamnesis: una vaca Holstein de 6 años de edad (Bos taurus taurus) presentó sintomatología de la fase IV de la enfermedad de Johne. Hallazgos clínicos y de laboratorio: la vaca presentó diarrea intermitente durante 6 meses sin respuesta al tratamiento con antibióticos. En consecuencia, la vaca fue sometida a eutanasia. Esquema de tratamiento: muestras de leche y de sangre periférica se tomaron ante-mortem; muestras de la mucosa del intestino, bazo y linfonodos mediastínico y mesentérico, se tomaron post-mortem, todas para aislamiento de macrófagos. El ADN total de los macrófagos fue usado para la amplificación del segmento IS900 de Mycobacterium avium paratuberculosis (MAP) por PCR en tiempo real. Conclusión: los macrófagos de vacas con la enfermedad de Johne pueden ser usados para la amplificación del segmento IS900 de MAP.

Anamnese: uma vaca Holstein com 6 anos de idade (Bos taurus taurus) apresentou os sintomas da fase IV da doença de Johne. Achados clínicos e laboratoriais: a vaca teve diarreia intermitente por seis meses sem resposta ao tratamento com antibióticos. Por conseguinte, a vaca foi submetida à eutanásia. Abordagem de tratamento: amostras de leite e de sangue periférico foram retiradas ante-mortem, enquanto as amostras da mucosa intestinal, baço e linfonodos mesentéricos e mediastinais foram tomadas todas post-mortem para o isolamento de macrófagos. O ADN total de macrófagos foi utilizado para amplificação do segmento IS900 do Mycobacterium avium paratuberculosis (MAP) por PCR em tempo real. Conclusão: macrófagos isolados a partir de vacas com doença de Johne podem ser utilizados para a amplificação da segmento IS900 do MAP.

Role of the Shrub Tamarix nilotica in Dissemination of Fusarium oxysporum f. sp. radicis-lycopersici.

The saltcedar shrub Tamarix nilotica grows as a weed in the Arava region of Israel. This weed is commonly found in cultivated fields naturally infested with Fusarium oxysporum f. sp. radicis-lycopersici, the causal agent of tomato crown and root rot. Young bushes, 20 to 40 cm tall, were randomly uprooted from different fields. The roots were cut into segments which were placed on Fusarium-selective medium. Although the plants did not show any symptoms of disease, the roots of the shrub were colonized by the pathogen. The incidence of infected saltcedar plants and level of root colonization by F. oxysporum f. sp. radicis-lycopersici decreased with increasing distance of the sampling location from a tomato field infected with crown and root rot. F. oxysporum f. sp. radicis-lycopersici was also isolated from chaff of inflorescence samples taken from mature T. nilotica shrubs. Identity of the pathogen isolates obtained from T. nilotica roots and chaff samples was verified by pathogenicity and vegetative compatibility tests. Roots of T. nilotica plants sown under greenhouse conditions in soil naturally infested with F. oxysporum f. sp. radicis-lycopersici became colonized by the pathogen. Uprooting and removing saltcedar plants throughout the season from fields not cultivated with tomatoes lowered the inoculum density of F. oxysporum f. sp. radicis-lycopersici in the soil from 611 to 6 and from 176 to 10 CFU/g of soil in the 1998-99 and 1999-2000 growing seasons, respectively. These results demonstrate that T. nilotica may contribute to the buildup of the pathogen populations in the absence of a susceptible host. Colonization of saltcedar by F. oxysporum f. sp. radicis-lycopersici is an additional mechanism for survival of this pathogen in the fields and for dissemination through the spread of infested seed or chaff of T. nilotica.

Damage Potential and Reproduction of Belonolaimus longicaudatus and Hoplolaimus galeatus on Alyceclover.

Alyceclover (Alysicarpus spp.) is an annual, high-quality leguminous forage, suitable for production under tropical and subtropical climates where the husbandry of conventional leguminous forages, Trifolium spp., is uneconomical. The damage potential and reproduction of Belonolairaus longicaudatus and Hoplolaimus galeatus on alyceclover were studied under greenhouse conditions, using sand and sandy clay loam soil materials, respectively. Both nematode species reproduced on alyceclover, but only B. longicaudatus was pathogenic. Symptoms of B. longicaudatus damage were suppression of shoot yield, limited root system, stunting, incipient wilting, and occasional seedling mortality. In one experiment, the threshold-damage density was three nematodes/100 cm(3) sand, whereas in the other experiment it was zero nematodes.