Molecular identification of Borrelia and SFG Rickettsia spp. in hard ticks parasitizing domestic and wild animals in southeastern Spain.

Lyme disease and the spotted fever group rickettsiosis, involve bacteria belonging to the genus Borrelia and Rickettsia, respectively. These infections are the most important tick-borne zoonotic diseases involving ticks as vectors. Descriptive and epidemiological studies are essential to determine the animal hosts involved in the maintenance of these diseases. In the present study, 94 tick pool samples from 15 different host species located in the Region of Murcia (southeastern, Spain) were analysed. Ticks were morphologically identified as: Dermacentor marginatus, Hyalomma lusitanicum, Ixodes Ricinus, and Rhipicephalus sanguineus. Our results showed that 5.3% of the tick pool samples carried Borrelia spp. DNA, and 20.2% carried SFG Rickettsia DNA. In every hard tick pool Spot Fever Group (SFG) Rickettsia spp. DNA were detected, except for H. lusitanicum. Likewise, D. marginatum was the only species in which Borrelia spp. DNA was not detected. Barbary sheep and wild boar were the host species in which tick pools showed DNA presence of both pathogens. This study increases the knowledge about the presence of Borrelia spp. DNA and SFG Rickettsia spp. DNA in different hard tick species from this geographical area.

Serological and molecular survey of canine distemper virus in red foxes (Vulpes vulpes): Exploring cut-off values and the use of protein A in ELISA tests.

The wide distribution and ecological plasticity of the red fox (Vulpes vulpes) make it a potential reservoir for many infectious diseases shared with domestic and wild carnivores. One of such diseases is canine distemper, which is caused by an RNA virus and its main domestic reservoir is the dog. However, other carnivores can also participate in its maintenance, as shown by the recent upsurge of reported cases in wildlife in many parts of the world, and by the fact that red foxes may act as true reservoirs for canine distemper virus (CDV). The lack of validated serological tests for wildlife or other non-target species may be a handicap for monitoring this virus. In this study, serological assays were compared in 147 red fox sera using a commercial ELISA validated for its use in dogs and a non-specific modified ELISA with Protein A peroxidase conjugate to detect bound antibodies. In addition, the presence of CDV RNA in brain, spleen, lung, and liver samples from 144 foxes was investigated by a RT-qPCR. Through the comparison of the results of both ELISAs and the use of a finite mixture model of the optical density values obtained by both techniques, we adjusted the cut-off point of the commercial ELISA to obtain the seroprevalence in foxes. The overall seroprevalence detected was 53.7% (79/147) and 57.1% (84/147) by the commercial and modified ELISA, respectively, with a moderate agreement according to Cohen's Kappa statistic (κ = 0.491, z = 5.97, p < 0.0001). CDV RNA was detected in 30 out of 144 foxes, which resulted in 20.8% of CDV-infected foxes. At individual level, the results obtained by relating the serological status and the presence/absence of RNA in different organs were explained in terms of the pathogenesis of the infection. Our results highlight the convenience of adjusting the cut-off point when using an ELISA assay developed in domestic dogs for its use in foxes. Moreover, Protein A is confirmed to be a good alternative to be used in red foxes, presenting a good reactivity towards its IgG.

Comparative analysis of short-term outcomes and oncological results between robotic-assisted and laparoscopic surgery for rectal cancer by multiple surgeon implementation: a propensity score-matched analysis.

Robotic-assisted surgery (RAS) is becoming increasingly common for the surgical treatment of rectal cancer. However, the use and implementation of robotic surgery remains controversial. This study aimed to compare the short-term outcomes of robotic surgery, focusing on pathological results and disease-free survival (DFS), in our cohort with initial robotic experience by multiple surgeon implementation. This retrospective study enrolled 571 patients diagnosed with rectal cancer, who were treated with chemoradiotherapy and surgery between January 2015 and December 2021. Surgical outcomes after RAS and laparoscopic surgery (LS) were compared using a propensity score-matching (PSM) analysis. After matching, 200 patients (100 in each group) were included. The median operative time was significantly longer in the RAS group than in the LS group (p < 0.001). The conversion and morbidity rates were similar between the groups. A significantly higher rate of complete mesorectal excision (92% vs. 72%; p = 0.001) and number of lymph nodes harvested (p = 0.009) was observed in the RAS group. There were no statistically significant differences between the groups regarding circumferential and distal resection margin involvement. The 3-year overall and disease-free survival rate was similar between the two groups (p = 0.849 and p = 0.582, respectively). Two patients in the LS group developed local recurrence and 27 patients (15.4%) developed metastatic disease. Multivariate analysis showed that tumor stage III was the only factor associated with disease-free survival (HR, 9.34; (95% CI 1.13-77.1), p = 0.038). RAS and LS showed similar outcomes in terms of perioperative, anatomopathological, and disease-free survival, after multiple surgeon implementations.

[Fungal infection by Cladophialophora bantiana and development of cerebral phaeohyphomycosis. A systematic review of 58 case reports]. / Infección micótica por Cladophialophora bantiana y desarrollo de feohifomicosis cerebral. Revisión sistemática de 58 informes de caso.

INTRODUCTION: Cladophialophora bantiana is a filamentous fungus, known as a dematiaceous fungus because of the presence of melanin. This fungus is of clinical importance because it is neurotropic and causes cerebral phaeohyphomycosis. MATERIAL AND METHODS: The available scientific information on the development of cerebral phaeohyphomycosis caused by Cladophialophora bantiana was analysed by selecting articles from the PubMed, Scopus and Google Scholar databases that describe case reports of fungal infection by C. bantiana in adults, taking into account the analysis of the patients' symptomatology, clinical history and neuroanatomical damage, in addition to considering the mortality of the condition. RESULTS: India and United States were the countries with most case reports, with 32 and 11 cases respectively. Moreover, in terms of neuroanatomical lesions, the majority of patients suffered mixed lesions (29%) and frontal lobe lesions (22%). In accordance with the patients' condition, the pathology has a mortality rate of 62%. CONCLUSIONS: It is concluded that cerebral phaeohyphomycosis has a high mortality rate, there is no standardised treatment and, in most cases, the fungal infection of the brain is mixed and affects several different parts of it. Furthermore, if not diagnosed and treated in time, it can lead to the patients' death.

TITLE: Infección micótica por Cladophialophora bantiana y desarrollo de feohifomicosis cerebral. Revisión sistemática de 58 informes de caso.Introducción. Cladophialophora bantiana es un hongo filamentoso, denominado hongo dematiáceo por la presencia de melanina. Este hongo tiene importancia clínica por ser neurotrópico y causar feohifomicosis cerebral. Material y métodos. Se analizó la información científica disponible sobre el desarrollo de feohifomicosis cerebral provocada por Cladophialophora bantiana, seleccionando artículos de las bases de PubMed, Scopus y Google Scholar, que describen informes de caso sobre infección micótica de C. bantiana en adultos, considerando el análisis de la sintomatología, el historial clínico y los daños neuroanatómicos de los pacientes, además de considerar la mortalidad de la patología. Resultados. La India y Estados Unidos fueron los países con más informes de caso, 32 y 11 casos, respectivamente. Asimismo, en cuanto a las lesiones neuroanatómicas, en su mayoría, los pacientes sufrieron lesiones mixtas (29%) y del lóbulo frontal (22%). De acuerdo con el estado de los pacientes, la patología tiene una mortalidad del 62%. Conclusiones. Se concluye que la feohifomicosis cerebral tiene una alta mortalidad, no existe un tratamiento estandarizado y, en la mayoría de los casos, la infección fúngica del cerebro es mixta y afecta a varias partes del cerebro; además, si no se diagnostica y trata a tiempo, puede ocasionar la muerte de los pacientes.

Infección micótica por Cladophialophora bantiana y desarrollo de feohifomicosis cerebral. Revisión sistemática de 58 informes de caso / Fungal infection by Cladophialophora bantiana and development of cerebral phaeohyphomycosis. A systematic review of 58 case reports

Introducción: Cladophialophora bantiana es un hongo filamentoso, denominado hongo dematiáceo por la presencia de melanina. Este hongo tiene importancia clínica por ser neurotrópico y causar feohifomicosis cerebral. Material y métodos. Se analizó la información científica disponible sobre el desarrollo de feohifomicosis cerebral provocada por Cladophialophora bantiana, seleccionando artículos de las bases de PubMed, Scopus y Google Scholar, que describen informes de caso sobre infección micótica de C. bantiana en adultos, considerando el análisis de la sintomatología, el historial clínico y los daños neuroanatómicos de los pacientes, además de considerar la mortalidad de la patología.ResultadosLa India y Estados Unidos fueron los países con más informes de caso, 32 y 11 casos, respectivamente. Asimismo, en cuanto a las lesiones neuroanatómicas, en su mayoría, los pacientes sufrieron lesiones mixtas (29%) y del lóbulo frontal (22%). De acuerdo con el estado de los pacientes, la patología tiene una mortalidad del 62%.ConclusionesSe concluye que la feohifomicosis cerebral tiene una alta mortalidad, no existe un tratamiento estandarizado y, en la mayoría de los casos, la infección fúngica del cerebro es mixta y afecta a varias partes del cerebro; además, si no se diagnostica y trata a tiempo, puede ocasionar la muerte de los pacientes. (AU)

INTRODUCTION: Cladophialophora bantiana is a filamentous fungus, known as a dematiaceous fungus because of the presence of melanin. This fungus is of clinical importance because it is neurotropic and causes cerebral phaeohyphomycosis. Material and methods. The available scientific information on the development of cerebral phaeohyphomycosis caused by Cladophialophora bantiana was analysed by selecting articles from the PubMed, Scopus and Google Scholar databases that describe case reports of fungal infection by C. bantiana in adults, taking into account the analysis of the patients’ symptomatology, clinical history and neuroanatomical damage, in addition to considering the mortality of the condition.RESULTSIndia and United States were the countries with most case reports, with 32 and 11 cases respectively. Moreover, in terms of neuroanatomical lesions, the majority of patients suffered mixed lesions (29%) and frontal lobe lesions (22%). In accordance with the patients’ condition, the pathology has a mortality rate of 62%.CONCLUSIONSIt is concluded that cerebral phaeohyphomycosis has a high mortality rate, there is no standardised treatment and, in most cases, the fungal infection of the brain is mixed and affects several different parts of it. Furthermore, if not diagnosed and treated in time, it can lead to the patients’ death. (AU)

Evaluation of a commercial double-recognition ELISA for caprine tuberculosis diagnosis: Sensitivity, specificity, and correlation to macroscopic and microscopic lesions.

Ante-mortem diagnosis of caprine tuberculosis, as in other ruminant species, is a complex process. Therefore, it is sometimes necessary to apply a combination of methods that increases the sensitivity of diagnosis while maintaining adequate specificity. In the present study, we analysed the use of ELISA based on a double-recognition methodology for the diagnosis of goat tuberculosis. Serum samples from animals with tuberculosis, confirmed by histopathological studies and presence of Ziehl-Neelsen-positive bacteria in the lesions, were used to assess sensitivity. Sera from flocks without tuberculosis were used to assess diagnostic specificity. The relationship between ELISA results and the type of tuberculous lesions, both macroscopic and microscopic, was analysed. The sensitivity and specificity of ELISA test were 69.9% and 97.9%, respectively. Sensitivity was higher in animals with macroscopic lesions, indicating more advanced forms of the disease. Similarly, a higher sensitivity was found in animals with microscopic lesions associated with active tuberculosis, such as cavitary lesions.

Oxidative stress and alterations in the expression of genes related to inflammation, DNA damage, and metal exposure in lung cells exposed to a hydroethanolic coal dust extract.

BACKGROUND: Open cast mining is well known as a concerning source of environmental and public health problems. This work aimed to obtain a hydroethanolic coal dust extract (≤ 38 µm) and to characterize its composition with particular regard to content of organic compounds by GC/MS, as well as describe its toxicity in vitro on Calu-1 after exposure to several concentrations (0-500 µg/mL). MATERIALS AND RESULTS: Cytotoxicity was measured with MTT assay and DCFH-DA probe was employed to estimate the amount of reactive oxygen species (ROS) in Calu-1 cells. RT-PCR was employed to quantify relative expression of genes associated with inflammation, oxidative stress, as well as metals, and lipid metabolism. Seventeen organic compounds were identified in the extract, highlighting undecane, dodecane, pentadecane and benzo[a]anthracene, 6,12-dimethyl-1,2,3,4-tetrahydro-. Cytotoxicity test showed a decrease trend in the cell viability after 24 h hours from the concentration of 62.5 µg/mL. Further, the extract raised intracellular ROS when compared with control. Expression levels of CYP1A1, IL-8, IL-6, MT1X, and NQO1 were up-regulated when cells were exposed to 125 µg/mL of coal dust, whereas PPAR-α was down-regulated, likely involving aryl hydrocarbon receptor regulation. CONCLUSIONS: In short, this study shows that despite hydroethanolic coal dust extract is not cytotoxic to Calu-1 cells, it produces an elevation of intracellular ROS and alters the expression in marker genes of oxidative stress, inflammation, metal transport, xenobiotic and lipid metabolism. These findings suggest that chemicals present in coal dust are biologically active and may interfere key biochemical process in the living organisms.

The burden of heat-related mortality attributable to recent human-induced climate change.

Climate change affects human health; however, there have been no large-scale, systematic efforts to quantify the heat-related human health impacts that have already occurred due to climate change. Here, we use empirical data from 732 locations in 43 countries to estimate the mortality burdens associated with the additional heat exposure that has resulted from recent human-induced warming, during the period 1991-2018. Across all study countries, we find that 37.0% (range 20.5-76.3%) of warm-season heat-related deaths can be attributed to anthropogenic climate change and that increased mortality is evident on every continent. Burdens varied geographically but were of the order of dozens to hundreds of deaths per year in many locations. Our findings support the urgent need for more ambitious mitigation and adaptation strategies to minimize the public health impacts of climate change.

Spanish Society of Allergology and Clinical Immunology (SEAIC) Vision of Drug Provocation Tests.

The controlled drug provocation test (DPT) is currently considered the gold standard for the diagnosis of drug allergy. Adverse drug reactions (ADRs) are an increasingly common presenting complaint in both primary and specialized care. In Spain, ADRs are usually assessed via the allergology department, which rules out immunological mechanisms in up to 90% of cases. An adequate approach to ADRs clearly impacts the costs and efficacy of the treatments prescribed by other specialists. Consequently, if we did not use DPTs, patients would require more expensive, more toxic, and less effective treatments in many cases. In recent years, many new drugs have been developed. This document is intended to be a practical guideline for the management of DPTs according to the vision of the Spanish Allergology Society. The diagnostic work-up begins with a detailed clinical history. Skin tests are only useful for some medications, and in most cases the diagnosis can only be confirmed by DPT. Although cross-reactivity is common, DPTs can confirm the diagnosis and help to find an alternative drug. Programmed individualized patient management based on the type of drug to be studied and the patient´s comorbidities usually enables a solution to be found in most cases.

Spanish Society of Allergology and Clinical Immunology (SEAIC) Vision of Drug Provocation Tests

The controlled drug provocation test (DPT) is currently considered the gold standard for the diagnosis of drug allergy. Adverse drug reactions (ADRs) are an increasingly common presenting complaint in both primary and specialized care. In Spain, ADRs are usually assessed via the allergology department, which rules out immunological mechanisms in up to 90% of cases. An adequate approach to ADRs clearly impacts the costs and efficacy of the treatments prescribed by other specialists. Consequently, if we did not use DPTs, patients would require more expensive, more toxic, and less effective treatments in many cases. In recent years, many new drugs have been developed. This document is intended to be a practical guideline for the management of DPTs according to the vision of the Spanish Allergology Society. The diagnostic work-up begins with a detailed clinical history. Skin tests are only useful for some medications, and in most cases the diagnosis can only be confirmed by DPT. Although cross-reactivity is common, DPTs can confirm the diagnosis and help to find an alternative drug. Programmed individualized patient management based on the type of drug to be studied and the patient's comorbidities usually enables a solution to be found in most cases (AU)

La prueba de exposición controlada a fármacos (DPT) se considera actualmente el estándar de oro para el diagnóstico de alergia amedicamentos. Las reacciones adversas inducidas por medicamentos (RAM) son un motivo creciente de consulta tanto en atención primariacomo especializada. Las consultas de Alergología en España son las que habitualmente estudian estas RAM y descartan mecanismosinmunológicos implicados hasta en el 90% de los casos consultados. Un abordaje adecuado de estos casos repercute de una maneraevidente en los costes y la eficacia de los tratamientos requeridos por otros especialistas, de modo que, si no empleáramos los DPT, lospacientes requerirían tratamientos más costosos, más tóxicos y menos eficaces en la mayoría de los casos.En los últimos años se han desarrollado un gran número de nuevos fármacos y este documento pretende ser una guía práctica en lagestión de las DPT con la visión de la Sociedad Española de Alergología. El trabajo de diagnóstico comienza con un historial detalladodel paciente. Las pruebas cutáneas solo son útiles en algunos medicamentos y, en la mayoría de los casos, el diagnóstico solo puedeconfirmarse mediante el DPT. Aunque suele haber reactividad cruzada, las DPT pueden confirmar el diagnóstico y también contribuir aencontrar un fármaco alternativo tolerable. El manejo individual de los pacientes de forma programada, teniendo en cuenta tanto eltipo de fármaco a estudiar como las comorbilidades del paciente, suele permitir encontrar una solución para la mayoría de los pacientes (AU)

Comparative Study of Conduction Mechanisms in Disodium Phthalocyanine-Based Organic Diodes for Flexible Electronics.

In the current work, flexible diodes with flat heterojunction and dispersed heterojunction architecture were manufactured with to study the behavior of thin films of disodium phthalocyanine (Na2Pc). The thin film devices, using the electronic acceptor tetracyano-π-quinodimethane (TCNQ), were fabricated by high-vacuum thermal evaporation with annealing post-treatment in order to optimize their behavior. Theoretical calculations based on density functional theory (DFT) with dispersion force analysis were carried out in order to simulate molecular interactions and to establish the nature of the weak interactions between the Na2Pc and TCNQ fragments. In the optimized structure of the coupled Na2Pc-TCNQ, the electronic relationship between phthalocyanine and TCNQ was observed to be through hydrogen bonds with bond lengths of 2.94 and 3.13 Å. Dispersed heterojunction device current density values were considerably larger than those of the flat heterojunction device. Barrier heights of 1.024 and 0.909 eV and charge mobilities of 10-10 and 10-9 m2/Vs for the flat heterojunction device and the dispersed heterojunction device, respectively, were observed. A small effect was observed on the electrical properties by thermal annealing on the flat heterojunction device. The threshold voltage decreased from 1.203 to 1.147 V and φb decreased by 0.001 eV.

Detection of a novel Chlamydia species in captive spur-thighed tortoises (Testudo graeca) in southeastern Spain and proposal of Candidatus Chlamydia testudinis.

The spur-thighed tortoise (Testudo graeca) is an endangered Mediterranean tortoise that lives in North Africa, Southern Europe and Southwest Asia. In the wake of recent legislation making their keeping as domestic animals illegal, many of these animals have been returned to wildlife recovery centers in Spain. In the present study, a population of such tortoises showing signs of ocular disease and nasal discharge was examined for the presence of Chlamydia spp. Cloacal, conjunctival and/or choanal swabs were collected from 58 animals. Using a real-time PCR specific for the family Chlamydiaceae, 57/58 animals tested positive in at least one sample. While only a few samples proved positive for C. pecorum, sequencing of the 16S rRNA gene revealed a sequence identical to previously published sequences from specimens of German and Polish tortoises. Whole-genome sequences obtained from two conjunctival swab samples, as well as ANIb, TETRA values and a scheme based on 9 taxonomic marker genes revealed that the strain present in the Spanish tortoises represented a new yet non-classified species, with C. pecorum being its closest relative. We propose to designate the new species Candidatus Chlamydia testudinis.

Statement of the Spanish Society of Allergology and Clinical Immunology on Provocation Tests With Aspirin/Nonsteroidal Anti-inflammatory Drugs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used throughout the world. They are frequently involved in hypersensitivity reactions, which range from local or mild reactions to systemic and severe reactions. Consequently, it is necessary to perform an exhaustive study of patients in order to make an accurate diagnosis, search for safe procedures in the case of severe reactions, and identify alternative treatment options. Various guidelines and protocols address the management of hypersensitivity to NSAIDs, although these vary widely from country to country. The Committees of Asthma, Rhinoconjunctivitis, and Drug Allergy of the Spanish Society of Allergy and Clinical Immunology (SEAIC) propose the present position statement on available options for provocation testing with aspirin/NSAIDs. This document is the fruit of an exhaustive review of current evidence and is based on recent publications addressing the diagnosis of patients with hypersensitivity to NSAIDs and on a consensus-oriented discussion among a group of experts from the SEAIC. The main objective was to draft an easy-toread, practical guideline for health care professionals in specialist areas who assess and manage patients with suspected hypersensitivity to NSAIDs. Furthermore, indications, contraindications, and procedures for oral, bronchial, and nasal provocation tests with aspirin/NSAIDs have been updated.

Statement of the Spanish Society of Allergology and Clinical Immunology on provocation tests with aspirin/nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used throughout the world. They are frequently involved in hypersensitivity reactions, which range from local or mild reactions to systemic and severe reactions. Consequently, it is necessary to perform an exhaustive study of patients in order to make an accurate diagnosis, search for safe procedures in the case of severe reactions, and identify alternative treatment options. Various guidelines and protocols address the management of hypersensitivity to NSAIDs, although these vary widely from country to country. The Committees of Asthma, Rhinoconjunctivitis, and Drug Allergy of the Spanish Society of Allergy and Clinical Immunology (SEAIC) propose the present position statement on available options for provocation testing with aspirin/NSAIDs. This document is the fruit of an exhaustive review of current evidence and is based on recent publications addressing the diagnosis of patients with hypersensitivity to NSAIDs and on a consensus-oriented discussion among a group of experts from the SEAIC. The main objective was to draft an easy-toread, practical guideline for health care professionals in specialist areas who assess and manage patients with suspected hypersensitivity to NSAIDs. Furthermore, indications, contraindications, and procedures for oral, bronchial, and nasal provocation tests with aspirin/NSAIDs have been updated

Los antiinflamatorios no esteroideos (AINE) son medicamentos ampliamente utilizados a nivel mundial y frecuentemente implicados en reacciones de hipersensibilidad que pueden comprender desde reacciones locales y/o leves a reacciones sistémicas y graves. La complejidad del diagnóstico ante la falta de pruebas cutáneas o de laboratorio estandarizadas y/o validadas, hace que en muchos casos debamos realizar pruebas de provocación de alto riesgo. Por ello, es necesario un exhaustivo estudio de estos pacientes en los que tienen gran importancia el correcto diagnóstico y la búsqueda de procedimientos más seguros ante pacientes con reacciones graves, así como también la búsqueda de opciones alternativas de tratamientos antiinflamatorios. Actualmente existen diversas guías y protocolos de actuación que describen el manejo de la hipersensibilidad a los AINE aunque con importante variabilidad entre diferentes países. Desde los distintos comités de Asma, Rinoconjuntivitis y Alergia a Fármacos de la Sociedad Española de Alergología e Inmunología Clínica (SEAIC) proponemos un documento de posicionamiento sobre las opciones en las pruebas de provocación con aspirina/ AINE. Este documento es el resultado de una revisión exhaustiva de la evidencia actual, basada en publicaciones recientes sobre el diagnóstico de pacientes con hipersensibilidad a AINE, y de la discusión consensuada de un grupo de expertos de la SEAIC. El objetivo fundamental ha sido elaborar una guía práctica de fácil lectura dirigida a profesionales sanitarios de atención especializada implicados en el estudio y manejo de pacientes con sospecha de hipersensibilidad a AINE. Además, se ha realizado una actualización sobre las indicaciones, contraindicaciones y procedimientos de las pruebas de provocación oral, bronquial y nasal con aspirina/AINE

Protocol for desensitization to trastuzumab in a patient with anaphylaxis and stage IV breast cancer: a case report

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Effect of female sex hormones on the developmental cycle of Chlamydia abortus compared to a penicillin-induced model of persistent infection.

BACKGROUND: Chlamydia abortus, an obligate intracellular pathogen with an affinity for placenta, causes reproductive failure. In non-pregnant animals, an initial latent infection is established until the next gestation, when the microorganism is reactivated, causing abortion. The precise mechanisms that trigger the awakening of C. abortus are still unknown. Sexual hormones such as estradiol and progesterone have been shown to affect the outcome of infection in other species of the family Chlamydiaceae, while estrogens increase chlamydial infection, progesterone has the opposite effect. To try to establish whether there is a relationship between these events and the latency/ reactivation of C. abortus in the reproductive tract of small ruminants, ovine endometrial (LE) and trophoblastic (AH-1) cells were treated with estradiol or progesterone prior to their infection with C. abortus. The results are compared with those obtained for treatment with penicillin prior to infection, which is a well-established model for studying persistent infection in other chlamydial species. Cells were examined by transmission electron microscopy, and an mRNA expression analysis of 16 genes related to the chlamydial developmental cycle was made. RESULTS: The changes observed in this study by the action of sex hormones seem to depend on the type of cell where the infection develops. In addition, while the changes are morphologically similar to those induced by treatment with penicillin, the patterns of gene expression are different. Gene expression patterns therefore, seem to depend on the persistence induced models of C. abortus used. Hormone treatments induced aberrant forms in infected endometrial cells but did not affect the chlamydial morphology in trophoblast cells. At the genetic level, hormones did not induce significant changes in the expression of the studied genes. CONCLUSIONS: The results suggest that penicillin induces a state of persistence in in vitro cultured C. abortus with characteristic morphological features and gene transcriptional patterns. However, the influence of hormones on the C. abortus developmental cycle is mediated by changes in the host cell environment. Furthermore, a persistent state in C. abortus cannot be characterised by a single profile of gene expression pattern, but may change depending on the model used to induce persistence.