Efecto de la poda en plantaciones de pino radiata afectadas por Fusarium circinatum

Fusarium circinatum Nirenberg and O’Donnell (1998) is the causal agent of Pitch Canker Disease (PCD) in Pinus species, producing damage to the main trunk and lateral branches as well as causing branch dieback. The disease has been detected recently in northern Spain in Pinus spp. seedlings at nurseries and in Pinus radiata D. Don adult trees in plantations. Fusarium circinatum seems to require a wound to enter the tree, not only that as caused by insects but also that resulting from damage by humans, i.e. mechanical wounds. However, the effects of pruning on the infection process have yet to be studied. The aim of the present study was to know how the presence of mechanical damage caused by pruning affects PCD occurrence and severity in P. radiata plantations. Fifty P. radiata plots (pruned and unpruned) distributed throughout 16 sites affected by F. circinatum in the Cantabria region (northern Spain) were studied. Symptoms of PCD presence, such as dieback, oozing cankers and trunk deformation were evaluated in 25 trees per plot and related to pruning effect. A significant relationship between pruning and the number of cankers per tree was observed, concluding that wounds caused by pruning increase the chance of pathogen infection. Other trunk symptoms, such as the presence of resin outside the cankers, were also higher in pruned plots. These results should be taken into account for future management of Monterrey Pine plantations.Fusarium circinatum Nirenberg and O’Donnell (1998) es el agente causante de la enfermedad del chancro resinoso del pino, que afecta a especies del género Pinus y provoca la aparición de chancros resinosos en el tronco y en ramas gruesas, además de puntisecado en la guía terminal. Esta enfermedad fue detectada recientemente en el norte de España asociada a plántulas de coníferas en vivero y a plantaciones de Pinus radiata D. Don. Fusarium circinatum suele requerir una herida en el árbol para poder infectarlo. Estas heridas pueden estar causadas por insectos o ser de origen antrópico, como las heridas mecánicas. Con la finalidad de conocer cómo las heridas producidas durante la poda afectan a la severidad de la enfermedad del chancro resinoso del pino, se estudiaron 50 parcelas de P. radiata (podadas y no podadas) distribuidas a lo largo de la provincia de Cantabria. En cada una de las parcelas fueron evaluados 25 árboles, en los que se estudiaron los síntomas más característicos de la enfermedad, como son puntisecado, presencia de chancros resinosos y deformación del tronco, relacionándolos con la presencia de poda. Se observó una relación significativa entre la poda y el número de chancros presentes en el árbol, lo que indica que la herida producida en este tratamiento selvícola es susceptible de infección por parte del patógeno. Otros síntomas también presentes en el tronco, como los exudados de resina fuera del chancro, aparecieron más frecuentemente en las parcelas podadas. Estos resultados son de gran trascendencia para el futuro manejo de las plantaciones de P. radiata afectadas por el chancro resinoso del pino

The pine shoot beetle Tomicus piniperda as a plausible vector of Fusarium circinatum in northern Spain

International audienceAbstractKey messageThe pine shoot beetle, Tomicus piniperda, is a potential vector of the pitch canker disease pathogen. The insect could transmit the pathogenic fungus during its maturation or regeneration feeding on the shoots of healthy pine crowns.ContextFusarium circinatum, the causal agent of pitch canker disease, currently affects Pinus radiata in northern Spain, causing pitch-soaked cankers and tree death. Although several species of the family Scolytinae have been reported as vectors of this pathogen, the role of the pine shoot beetle T. piniperda remains unclear.AimsThe general objective of this study was to determine whether T. piniperda is a vector for the pitch canker pathogen F. circinatum. For this purpose, Leach’s postulates (1) an association between T. piniperda and trees affected by pitch canker disease; (2) regular visits by T. piniperda to healthy P. radiata trees; (3) presence of the pathogen on the insect in nature; and (4) transmission of the pathogen to disease-free host material under controlled conditions.MethodsFresh green shoots with feeding galleries were collected from the ground, breeding galleries were collected from diseased trunks and insects were collected during their dispersion flights. A laboratory experiment was conducted in which specimens of T. piniperda were inoculated with the pathogen prior to feeding on shoots.ResultsIn the field, T. piniperda was found to be associated with both diseased and healthy P. radiata trees, and F. circinatum was found to be present, at low rates, on the exoskeleton of T. piniperda. In the laboratory experiment, evidence of the ability of T. piniperda to transfer the pathogen to healthy shoots was found.ConclusionsThe study findings indicate T. piniperda as a plausible vector of this pathogen. We postulate for the first time a potential relationship between the life cycles of T. piniperda and F. circinatum

Factors affecting the performance of P22 ELISA for the diagnosis of caprine tuberculosis in milk samples

Caprine tuberculosis (TB) is a zoonosis caused by members of the Mycobacterium tuberculosis complex (MTBC). Caprine TB eradication programmes are based mainly on intradermal tuberculin tests and slaughterhouse surveillance. However, the use of serological test has been extended as a potential diagnostic tool in goats through the use of serum, plasma, or even milk samples. Milk production and the antibodies (Ab) present in milk can vary depending on several circumstances. In the present study, different factors that may affect the performance of humoral TB diagnosis were analysed using goat milk samples: 1) lactation stage, 2) a recent previous skin test (booster effect) and 3) the effect of freeze-thaw cycles on milk samples preserved with azidiol. TB-infected animals (n = 44) were selected to evaluate the evolution of the Ab levels during the 6-month lactation period, along with its potential effect on the P22 ELISA results. In general, no significant changes (p = 0.079) were observed throughout the study as regards Ab levels in milk samples between consecutive analysis although the reactivity to P22 ELISA decreased when samplings were performed at the last two months of the lactation. Regarding the booster effect, the quantitative results showed a significant variation (p < 0.001) for both milk and serum samples when serological tests were carried out 15 days after the skin test. Finally, there were no significant differences (p = 0.99) in the P22 ELISA results when using milk samples preserved with azidiol that had undergone freeze-thaw cycles.This study was funded by the Spanish Ministry of Science and Innovation through the project “Análisis del proceso de erradicación de la tuberculosis caprina a largo plazo y desarrollo de pruebas de diagnóstico y medidas de control para su mejora (GoaTBfree-UCM, reference PID2019-105155RB-C31) and the Spanish Ministry of Agriculture, Fisheries and Food. JO was supported by an FPU (Formación de Profesorado Universitario) contract-fellowship provided by the Spanish Ministerio de Ciencia, Innovación y Universidades (FPU18/05197).S

Effect of the topical administration of corticosteroids and tuberculin pre-sensitisation on the diagnosis of tuberculosis in goats

Background: Caprine tuberculosis (TB) is a zoonosis caused by members of the Mycobacterium tuberculosis complex (MTBC). Caprine TB control and eradication programmes have traditionally been based on intradermal tuberculin tests and slaughterhouse surveillance. However, this strategy has limitations in terms of sensitivity and specificity. Different factors may affect the performance of the TB diagnostic tests used in goats and, subsequently, the detection of TB-infected animals. In the present study, the effect of two of the factors that may affect the performance of the techniques used to diagnose TB in goats, the topical administration of corticosteroids and a recent pre-sensitisation with tuberculin, was analysed. Methods: The animals (n = 151) were distributed into three groups: (1) a group topically treated with corticosteroids 48 h after intradermal tuberculin tests (n = 53); (2) a group pre-sensitised with bovine and avian purified protein derivatives (PPDs) 3 days before the intradermal tuberculin test used for TB diagnosis (n = 48); and (3) a control group (n = 50). All the animals were tested using single and comparative intradermal tuberculin (SIT and CIT, respectively) tests, an interferon-gamma release assay (IGRA) and a P22 ELISA. Results: The number of SIT test reactors was significantly lower in the group treated with corticosteroids when compared to the pre-sensitised (p 0.05). No significant effect was observed on IGRA and P22 ELISA due to corticosteroids administration. Nevertheless, a previous PPD injection affected the IGRA performance in some groups. Conclusions: The application of topical corticosteroid 24 h before reading the SIT and CIT tests can reduce the increase in skin fold thickness and subsequently significantly decrease the number of positive reactors. Corticosteroids used can be detected in hair samples. A previous pre-sensitisation with bovine and avian PPDs does not lead to a significant reduction in the number of intradermal tests reactors. These results are valuable in order to improve diagnosis of caprine TB and detect fraudulent activities in the context of eradication programs.This study was funded by the “Analysis of the long-term caprine tuberculosis eradication process and development of diagnostic tests and control measures for its improvement (GoaTBfree-UCM)” Project (PID2019-105155RB-C31, Ministry of Science and Innovation of Spain) and the Ministry of Agriculture, Fisheries and Food of Spain. JO was supported by an FPU contract-fellowship (Formación de Profesorado Universitario) from the Spanish Ministerio de Ciencia, Innovación y Universidades (FPU18/05197).S

Tuberculin skin testing boosts interferon gamma responses to DIVA reagents in Mycobacterium bovis-Infected cattle

ABSTRACT Mycobacterium bovis BCG vaccination sensitizes cattle to bovine tuberculin, which compromises the use of the current bovine tuberculosis (TB) surveillance tests. Although the performance of a blood test (that utilizes antigens expressed by Mycobacterium bovis but not by BCG) capable of discriminating infected from vaccinated animals (DIVA interferon gamma test [DIT]) has been evaluated in naturally infected TB field reactors, there is a need to perform similar analysis in a BCG-vaccinated M. bovis -infected population. Furthermore, we explored different scenarios under which a DIT may be implemented alongside BCG vaccination: (i) serial testing to resolve potential false-positive skin test results or (ii) a standalone test to replace the single intradermal comparative cervical tuberculin (SICCT) skin test. Our results demonstrated significantly better relative test sensitivity when the DIT was evaluated in a serial test scenario. Direct comparison of pre- and post-skin test blood samples revealed that the SICCT test induced significant boosting of the gamma interferon response in M. bovis -infected animals to both the ESAT-6–CFP-10 and Rv3615c peptide cocktails that comprise the DIT, which persisted for the ESAT-6–CFP-10 reagent for at least 14 days. Importantly, no similar boosting effects were observed in noninfected BCG vaccinates, suggesting that DIVA blood testing after a recent skin test would have minimal impact on test specificity. </jats:p

Specificity of serological test for detection of tuberculosis in cattle, goats, sheep and pigs under different epidemiological situations

[EN] Background: Serum antibody detection has potential as a complementary diagnostic tool in animal tuberculosis (TB) control, particularly in multi-host systems. The objective of the present study was to assess the specificity (Sp) of an enzyme-linked immunosorbent assay (ELISA) based on the new multiprotein complex P22 for the detection of specific antibodies against the Mycobacterium tuberculosis complex (MTC) in the four most relevant domestic animals acting as MTC hosts: cattle, goat, sheep and pig. We used sera from an officially TB-free (OTF) country, Norway, and from a non-OTF one, Spain. The samples included sera from goats that had been vaccinated against M. avium subsp. paratuberculosis (MAP) and sheep from a herd in which Corynebacterium pseudotuberculosis had been isolated. Results: In cattle, the Sp ranged from 92.5 (IC95% 90.7-94) to 99.4% (IC95% 98.3-99.8) depending on the cut-off used and the origin of the samples (Spain or Norway). Sp in cattle (cut-off point 100) was significantly higher (P < 0.05) for Norwegian samples. By contrast, Sp in goats was consistently low at the 100 cut-off [30.9 (CI95%23.4-39.5)-78% (CI95% 68.9-85)]. A higher cut-off of 150 improved Sp in Norwegian goats [97% (CI95% 91.6-99)], but still yielded a poor Sp of 56.1% (CI95% 47.3-64.6) in Spanish goats. In Norway at the 100 cut-off the Sp was 58.3 (CI95% 42.2-72.9) and 90.6% (CI95% 81-95.6) in MAP vaccinated and non-vaccinated goats, respectively, indicating interference due to MAP vaccination. Sp in sheep was between 94.4 (CI95% 91.7-96.3) and 100% (CI95% 96.3-100) depending on the cut-off and country, and no diagnostic interference due to infection with C. pseudotuberculosis was recorded. Sp in pigs was 100%, regardless the cut-off point applied, and no significant differences were observed between pigs from Norway and from Spain. Conclusions: Due to its excellent Sp in pigs and acceptable Sp in cattle and sheep, this ELISA may constitute a suitable option for TB screening at herd level, particularly in OTF-countriesSIJose Antonio Infantes-Lorenzo was supported by an FPU contract-fellowship (Formación de Profesorado Universitario) from the Ministerio de Educación, Cultura y Deporte of the Spanish Government (FPU2013/6000). Alvaro Roy is the recipient of an Industrial Doctorate contract (DI-15-08110) funded by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and the European Social Fund. Javier Bezos is recipient of a Juan de la Cierva Incorporación research contract (IJCI-2015-24805) funded by the MINECO. This work was supported by the Spanish Ministry of Agriculture, Fisheries and Food and the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria of Spain (RTA2015–00043-C02–02). This is a contribution to Plan Nacional de I + D + i grant CGL2017–89866 WILD-DRIVER. The funding body was solely involved in funding and had no role in the design of the study, the collection, analysis, and interpretation of the data, or in writing the manuscrip

Onboard Guidance for Reusable Rockets: Aerodynamic Descent and Powered Landing

This paper describes a novel general on-board guidance strategy which can be applied toboth the aerodynamically-controlled descent and the powered landing phase of reusable rockets.The proposed guidance method is based on sequential convex optimization applied to a Cartesianrepresentation of the equations of motion. The contributions are an exploitation of convexand non-convex contributions, which are processed separately to maximize the computationalefficiency of the approach, the inclusion of highly nonlinear terms represented by aerodynamicaccelerations, a complete reformulation of the problem based on the use of Euler angle rates ascontrol means, an improved transcription based on the use of a generalized hp pseudospectralmethod, and a dedicated formulation of the aerodynamic guidance problem for reusable rockets.The problem is solved for a 40 kN-class reusable rocket. Results show that the proposedtechnique is a very effective methodology able to satisfy all the constraints acting on the system,and can be potentially employed online to solve the entire descent phase of reusable rockets inreal-time

Differences in skin test reactions to official and defined antigens in guinea pigs exposed to non-tuberculous and tuberculous bacteria

The single and comparative intradermal tuberculin tests (SITT and CITT) are official in vivo tests for bovine tuberculosis (TB) diagnosis using bovine and avian purified protein derivatives (PPD-B and PPD-A). Infection with bacteria other than Mycobacterium tuberculosis complex (MTC) can result in nonspecific reactions to these tests. We evaluated the performance of the skin test with PPDs and new defined antigens in the guinea pig model. A standard dose (SD) of Rhodococcus equi, Nocardia sp., M. nonchromogenicum, M. monacense, M. intracellulare, M. avium subsp. paratuberculosis, M. avium subsp. avium, M. avium subsp. hominissuis, M. scrofulaceum, M. persicum, M. microti, M. caprae and M. bovis, and a higher dose (HD) of M. nonchromogenicum, M. monacense, M. intracellulare, M. avium subsp. paratuberculosis were tested using PPD-B, PPD-A, P22, ESAT-6-CFP-10-Rv3615c peptide cocktail long (PCL) and fusion protein (FP). The SD of R. equi, Nocardia sp., M. nonchromogenicum, M. monacense, M. intracellulare and M. avium subsp. paratuberculosis did not cause any reactions. The HD of M. nonchromogenicum, M. monacense, M. intracellulare, and M. avium subsp. paratuberculosis and the SD of M. avium subsp. hominissuis, M. scrofulaceum and M. persicum, caused nonspecific reactions (SIT). A CITT interpretation would have considered M. avium complex and M. scrofulaceum groups negative, but not all individuals from M. nonchromogenicum HD, M. monacense HD and M. persicum SD groups. Only animals exposed to M. bovis and M. caprae reacted to PCL and FP. These results support the advantage of complementing or replacing PPD-B to improve specificity without losing sensitivity.info:eu-repo/semantics/publishedVersio

Development and Evaluation of a Serological Assay for the Diagnosis of Tuberculosis in Alpacas and Llamas

South American camelids are susceptible to tuberculosis, caused mainly by Mycobacterium bovis and M. microti. Despite the tuberculin skin test being the official test for tuberculosis, it has a very low sensitivity in these species (14–20%). Serological tests present the advantages of being rapid, easy to perform and facilitate analysis of large numbers of samples in a short period of time. Novel antigen discovery and evaluation would provide enhanced detection of specific antibodies against members of M. tuberculosis complex. Here, we describe the development and evaluation of an ELISA-type immunoassays to use in the diagnosis of tuberculosis in llamas and alpacas based on P22, a multiprotein complex obtained by affinity chromatography from bovine Purified Protein Derivative (bPPD), that showed high sensitivity and specificity in mice, cattle and goats. This work was performed in two stages. First, a preliminary panel of samples collected from tuberculosis-free (n = 396) and M. bovis-infected herds (n = 56) was assayed, obtaining high specificity (100%) and sensitivity ranging from 63 to 96%. Subsequently, the use of the serological assay was tested using samples from two herds suffering from clinical M. bovis (n = 88) and M. microti (n = 25) infection to evaluate the ability of the ELISA to detect infected animals. 11 out of 88 alpacas were positive to the ELISA in a M. bovis outbreak and 7 out of 25 in a M. microti outbreak. The P22 ELISA potentially provides a sensitive and specific platform for improved tuberculosis surveillance in camelids