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Lamb icteric carcasses condemnation due to Anaplasma ovis is causing relevant economic losses. A comparative study was developed on the effects of different antibiotics to treat ovine anaplasmosis in fattening lambs. A total of 100 A. ovis naturally infected lambs were selected and randomly divided into four groups of 25 lambs: Group ID, treated with injectable doxycycline; Group OD, oral doxycycline; Group O, injectable oxytetracycline; and Group C, untreated animals for the control group. Clinical, haematological, and molecular analyses were performed before the treatment and 12 and 45 days after the beginning of the treatments, and carcass condemnation was followed after slaughter. The A. ovis bacterial load was high before the treatments in the four groups and decreased significantly 45 days after treatment in the ID and O Groups (p < 0.001). The parameters that were related to haemolysis showed similar results. At the abattoir, 15 out of the 47 examined carcasses were condemned; 7 of C Group, 6 of OD Group, 2 of O Group, and 0 of ID Group. It can be concluded that injectable doxycycline and oxytetracycline significantly reduce A. ovis bacterial load in blood and carcass condemnation at the abattoir. Further studies are needed in order to confirm these encouraging findings.

Ovine anaplasmosis is a vector-borne disease caused by Anaplasma ovis and mainly transmitted through tick bites. In Spain, the first outbreak of ovine anaplasmosis occurred in 2014. An epidemiological study in fifty-one farms was carried out associated with this outbreak in the affected geographical area. An epidemiological questionnaire was performed. In addition, whole blood samples were taken for molecular analysis in 47 of these farms to determine the prevalence of infection of Anaplasma ovis. A. ovis was present in 44 out of 47 PCR-analysed farms (93.6%). However, only 40.4% of the studied farms showed severe clinical signs. The clinical signs affected mainly young animals, which showed severe anaemia, weakness, anorexia, cachexia and epiphora. The early culling of young animals was more frequently reported by severely affected farms than the analysed farms without clinical signs (71.4% vs. 12.5%, p &lt, 0.001). The geographical area where the farm is located seems to be relevant for the presence of clinical signs of the disease. Ovine anaplasmosis is an emerging disease in Europe that spreads rapidly through tick bites and is capable of causing significant economic losses when it spreads in a naive area and causes an epidemic.

Delia Lacasta,1 Ramses Reina,2 Marta Ruiz de Arcaute,1 Luis Miguel Ferrer,1 Alfredo Angel Benito,3 Maria Teresa Tejedor,4 Irache Echeverria,2 Hector Ruiz,1 Silvia Martinez Cardenas,1 Peter Andrew Windsor5 1Animal Pathology Department, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Veterinary Faculty of Zaragoza, Zaragoza, 50013, Spain; 2Instituto de Agrobiotecnología (CSIC-Gobierno de Navarra), Mutilva, 31192, Navarra, Spain; 3EXOPOL S.L, San Mateo de Gállego, Zaragoza, Spain; 4Anatomy, Embryology and Animal Genetics Department, CIBER CV (Universidad de Zaragoza-IIS), Veterinary Faculty of Zaragoza, Zaragoza, 50013, Spain; 5Sydney School of Veterinary Science, The University of Sydney, Camden, NSW, 2570, AustraliaCorrespondence: Delia LacastaFacultad de Veterinaria de Zaragoza, C/Miguel Servet 177, Zaragoza, 50013, SpainTel +34 609676727Email dlacasta@gmail.comIntroduction: Orf is a highly contagious eruptive viral disease of the skin and mucosa of sheep and goats. Although vaccination with live or attenuated orf virus is the preferred option for disease control, the vaccine is unavailable in many countries. Treatment of orf lesions involves standard hygiene and in numerous cases, management of presumptive secondary infections with antibiotics, increasing risks of antimicrobial resistance (AMR). The wound dressing formulation Tri-Solfen® containing two local anaesthetics (lignocaine and bupivacaine), adrenaline and an antiseptic (cetrimide) in a gel formulation was developed for pain relief in sheep undergoing surgical husbandry procedures in Australia. Recently, TS therapy was found to reduce suffering and enhance recovery in cattle and buffalo with oral and skin lesions due to foot-and-mouth disease (FMD) virus infection. It was noted that TS has a low pH and is potentially viricidal, potentially aiding disease control.Methods: One-month-old lambs (n=14), naturally infected with orf, were recruited from a farm during a natural outbreak of the disease. The animals were selected at the early stages of the infection and randomly divided into two cohorts: Group A (n=11) treated with the topical wound gel formulation (TS); and Group B (n=3) an untreated control group. Swabs were obtained before treatment (T0) and on days one (T1), 3 (T2) and 5 (T3) post-treatment, then submitted to direct DNA extraction with real-time PCR quantification, plus incubation with primary tissue cultures from ovine skin fibroblasts (OSF) and T-immortalized goat embryonic fibroblasts (TIGEF).Results: Although no significant differences were found in the clinical progression of the lesions and PCR quantification (p=0.722) between these small cohorts, there was a significant difference (p< 0.05) in reduction in infective viral load between the groups when assessed in OSF cell cultures between T0 and T3.Conclusion: These preliminary findings suggest that treatment of early stage lesions with this TS may reduce the infective viral load present in orf lesions.Keywords: sheep, contagious ecthyma, wound formulation, local therapy

© 2021 by the authors., Small ruminant lentiviruses (SRLV) cause an incurable multiorganic disease widely spread in sheep and goats that disturbs animal welfare and production. In the absence of a vaccine, control measures have been traditionally based on early diagnosis and breeding with virus-inactivated colostrum with segregation of seropositive animals. However, antigenic heterogeneity, poor antibody production due to low viral load, and single strain design of most available ELISA, pose a threat to SRLV diagnosis. Genome-wide association studies have described TMEM154 E35K polymorphism as a good genetic marker for selection of resistant animals in some American and European breeds. In this study, a multitargeted serological and virological screening of more than 500 animals from four different breeds (latxa, raza Navarra, assaf, and churra) attending to SRLV infection status was performed. Then, animals were genotyped to characterize TMEM154 E35K polymorphism. ELISA procedures, individually considered, only identified a proportion of the seropositive animals, and PCR detected a fraction of seronegative animals, globally offering different animal classifications according to SRLV infection status. TMEM154 allele frequency differed substantially among breeds and a positive association between seroprevalence and TMEM154 genotype was found only in one breed. Selection based on TMEM154 may be suitable for specific ovine breeds or SRLV strains, however generalization to the whole SRLV genetic spectrum, ovine breeds, or epidemiological situation may need further validation., This research was funded by Spanish Ministry of Science, Innovation, and Universities, grant number RTI2018-096172-B-C31. The APC was funded by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). I.E. was funded by Universidad Pública de Navarra. Hugo Ramírez was financially supported by the “Programa de apoyos para la superación del personal académico (PASPA)” scholarship from DGAPA-UNAM.

In spring and summer 2020, six outbreaks of condemnation of jaundiced lamb carcasses were diagnosed in different farms in Arag&oacute, n region, Spain. Anaplasma ovis was identified in all affected farms. Four hundred and ninety-two lambs from two affected farms were more closely examined. Clinical examination, haematologies, biochemistries, histopathology and microbiological and molecular analyses were performed. After slaughter, 34.84% of the lambs showed jaundiced carcasses and 79.64% presented splenomegaly at the abattoir. All tested lambs with icteric carcasses showed positive A. ovis PCR, although 72.72% of the unaffected lambs also tested positive. However, the bacterial load was significantly higher in the animals that showed jaundiced carcasses (Cq: 25.00 vs 26.16, p = 0.004). Moreover, all the tested lambs that showed severe anaemia were PCR positive. On the contrary, the PCR negative lambs did not show anaemia. Lambs that presented icteric carcasses displayed severe regenerative anaemia with significantly lower erythrocyte count (7.18 vs. 11.97), haematocrit (26.89 vs. 34.82) and haemoglobin (8.50 vs. 11.10) than unaffected lambs. Reticulocyte count (18.80 vs. 5.65) was also significantly increased in affected animals. This article describes a new disorder caused by Anaplasma ovis that is producing significant economic losses associated with the carcass condemnation of apparently healthy lamb.

Myxoma virus (MYXV) is the aetiological agent of myxomatosis, a systemic, mostly lethal disease that affects European rabbits. Vaccination against it, although widespread, has not been completely effective and disease outbreaks still take place on farms which carry out vaccination programmes. Since some of these cases have been attributed to airborne transmission or the spread of the virus via inanimate vectors, the aims of this study were to determine MYXV contamination levels and distribution in the environment of vaccinated farms and to ascertain whether the detected virus corresponded to field strains. For that, environmental samples from several areas, tools and employees from four (three infected and one uninfected) rabbitries were taken and analysed by qPCR. MYXV was detected in the environment of all the infected farms, whereas all the samples from the non-infected farm were negative. Furthermore, all the positive samples contained viral DNA compatible with field strains of the virus. These results lead us to believe that the administration of currently available commercial vaccines does not prevent infected animals from shedding the field virus. Moreover, viral DNA was also found in items that are not in direct contact with the animals, which could play a role in the transmission of the infection throughout the farm and to other farms. Therefore, this study proves that current vaccination schemes on their own are not sufficient to prevent this disease and should be accompanied by adequate biosecurity measures.

A total of 237 faecal specimens from diarrheic calves younger than two months were collected and submitted for diagnosis of enteropathogens over a two-year period (2017-2018) to a veterinary laboratory. Samples originated from 193 dairy and beef farms in 29 provinces distributed throughout Spain, and were tested for the occurrence of three target enteric pathogens by reverse transcription real-time PCR (RT-qPCR): bovine rotavirus A (RVA), Cryptosporidium parvum and bovine coronavirus (BCoV). RT-PCR and nucleotide sequencing analysis were used to determine the G (VP7 gene) and P (VP4 gene) genotypes of 26 specimens positive for RVA. A total of 188 specimens (79.3 %) were positive for at least one of the three target enteric pathogens, and 101 samples (42.6 %) harbored mixed infections. The individual prevalence was 57.8 %, 50.6 % and 23.6 % for C. parvum, RVA and BCoV, respectively. Molecular analysis of selected RVA strains revealed the presence of the G6, G10, G3, P[5] and P[11] genotypes, with the combinations G6P[5] and G6P[11] being the most prevalent. Alignments of nucleotide sequences of the VP7 and VP4 markers showed a high frequency of single nucleotide polymorphisms (SNPs), with up to 294 SNPs found in 869bp of sequence at the G6 genotype (0.338 SNPs/nt), which reveals the extensive genetic diversity of RVA strains. Phylogenetic analysis of the VP7 gene of the G6 strains revealed four distinct lineages, with most strains clustering in the G6-IV lineage. The discrepancies between the RVA genotypes circulating in the sampled cattle farms and the genotypes contained in commercial vaccines currently available in Spain are discussed. We believe that this is the first study on the molecular characterization of rotavirus infecting cattle in Spain.

Determination of multispectral specular reflectance is an important tool for ore identification in reflected light microscopy, and may be used for automated characterization of ores. However, reflectance values can be affected by compositional variations in a way that is seldom understood. The aim of the present work is to investigate this problem in chromite, an ore whose composition may show typically large natural variations as member of the spinel family, and whose relatively high reflectance variations are apparently unpredictable. For this research, eighteen samples of chromian spinel covering a large range of compositions in the base of the Hagerthy prism were selected for microprobe analysis and reflectance measure on polished sections. The samples belong to a variety of deposits and types (ultramafic massif, ophiolitic, and metamorphosed types: Ojen and Ronda Massifs, Spain; Mayari, Moa-Baracoa, Camaguey and Sagua de Tanamo, Cuba; Golyamo Kemenyane, Avren and Yakovitsa, Bulgaria). The specular reflectances are characterized as multispectral values, measured at thirteen intervals (50 nm each) in the VNIR region (Visible and Near-Infrared: 400–1000 nm), using the automated CAMEVA System. The relationship between compositional and reflectance values is studied by multivariate analysis and subsequently tested on independent samples. For this purpose, the samples have been grouped in two sets: a larger population of fifteen samples constitutes the initial data set for mathematical processing, while a selection of three samples of widely differing compositions is used to test the resulting functions, so as to gain a critical appraisal of their validity. The results obtained show that the specular reflectance of chromite depends on composition and can be used to estimate compositional parameters, as #Cr = Cr/(Cr + Al) or #Mg = Mg/(Mg + Fe2+), but this relationship is complex and does not allow simple direct determinations, due to the multiplicity of possible changes and coupled substitutions (e.g. Al–Cr–Fe3+, or Mg-Fe2+, Ni, Zn, Ti …) in the chromian spinel family. On the other hand, the relationship of chromite composition with deposit type is also detectable through the reflectance values, but with a higher uncertainty. Reflectance increases with increasing Cr and Fe3+ contents in all cases, but the relationship of reflectance with Mg seems to be specific of the deposit type: while reflectance increases with increasing #Mg in the Ojen chromites, it shows the opposite behaviour in podiform chromites. Although these results should be regarded as preliminary until further studies on larger sample populations can be achieved, they are suggestive of possible practical applications for exploration, e. g. to approach Cr-spinel compositions or chromite deposit typology, early in an exploration campaign, by inexpensive reflected light determination of specular reflectance in a few samples.

Digestive disorders are the main cause of economic damage to rabbit farms. This article provides a global and updated overview of the diverse etiological agents causing them, since 757 clinical cases were analyzed during 2018 and 2019&mdash, Ninety-five from young rabbits (&lt, 15 days old), 117 from preweaning rabbits (15&ndash, 35 days old), and 545 from growing rabbits. Etiological diagnosis was carried out by bacteriological culture and a set of real time polymerase chain reaction (qPCR) tests for the detection of enteropathogenic Escherichia coli (EPEC), Clostridium spiroforme, C. perfringens, rotavirus A, Bacteroides fragilis, and Eimeria spp. Also, 40 EPEC and 38 non EPEC isolates were investigated for the presence of other colonization factors (afr2, ral, liftA, and paa) by qPCR. EPEC is the most prevalent agent in young rabbits, and although different virulence profiles have been found among EPEC isolates, the liftA+, ral+, and paa+ profile is the most prevalent. C. spiroforme and EPEC are the more frequently detected pathogens in preweaning rabbits, but B. fragilis appears to be a new possible emergent pathogen. In growing rabbits, diverse co-infections between C. spiroforme, Eimeria spp., EPEC, and rotavirus are much more frequent than infections due to only one of them. Other pathogens detected in very few cases are Salmonella spp. and Enterococcus hirae.

In this article, we describe the work carried out for developing an accurate and fast numerical method that can efficiently integrate the mathematical model of natural gas flow in a pipeline under non-isothermal steady-state conditions. To do this, we transform the model equations in order to obtain a system of three explicit expressions for the spatial derivatives of gas velocity, pressure, and temperature, which can be easily integrated using any suitable numerical method. The proposed method enables us to determine the gas velocity, pressure, and temperature anywhere in the pipeline. Furthermore, we develop two procedures based on this method, one to calculate the flow rate and the other to experimentally determine the friction factor. We illustrate the performance of the proposed method using several numerical exercises and we compare the results with field measurements on a Spanish pipeline (provided by the company Enagas) and with those obtained using other methods.

Arquitecturas de la Memoria es una app de geolocalización para crear una cartografía interactiva de recuerdos de la comunidad, vinculados al espacio público como vertebrador de la vida en común, con el objetivo de favorecer el diálogo intergeneracional. Este proyecto propone un proceso de encuentro con los mayores de una comunidad y pone en valor la memoria colectiva como fuente de patrimonio inmaterial del territorio. Trata de generar un proceso de mediación y de acercamiento de estos contenidos a los más jóvenes a través de la tecnología. La esencia del proyecto es el encuentro con la comunidad para generar un proceso de carácter participativo con la ciudadanía. A través de entrevistas y dinámicas artísticas se crea un relato colectivo en primera persona, y se explora la identidad de un territorio en base a los recuerdos de sus vecinos. La tecnología aparece al final del proceso para captar el interés de los más jóvenes y facilitar el diálogo intergeneracional en un momento en el que ya no nos sentamos a escuchar las historias de nuestros mayores; en el que se han roto los lazos de oralidad frente al dominio de la imagen y las pantallas. Este proyecto crea un espacio para contarnos las historias de nuestras vidas, y regenerar ese lazo intergeneracional, tejiendo afectos que la vida contemporánea a veces nos hace creer olvidados. Arquitecturas de la memoria permite a los usuarios de la app recorrer las calles acompañados de las voces de sus habitantes.

Background: Ixodes ricinus, the predominant tick species in Europe, can transmit the causative agents of important human diseases such as Lyme borreliosis (LB), caused by Borrelia spirochetes. In northern Spain, LB is considered endemic; recently, a significant increase of the annual incidence of LB was reported in the northwestern (NW) region. Methods: In order to provide information on the prevalence of Borrelia spp., pooled and individually free-living I. ricinus from NW Spain were molecularly analyzed. Positive samples were characterized at the fla and Glpq genes and the rrfA-rrlB intergenic spacer region to identify Borrelia species/genospecies. Results: Borrelia burgdorferi (sensu lato) (s.l.) individual prevalence and MIR were significantly higher in adult females (32.3 and 16%) than in nymphs (18.8 and 6.2%) and adult males (15.6 and 8.4%). Five Borrelia genospecies belonging to the B. burgdorferi (s.l.) group were identified: B. garinii was predominant, followed by B. valaisiana, B. lusitaniae, B. afzelii and B. burgdorferi (sensu stricto) (s.s.). One species belonging to the tick-borne relapsing fever group (B. miyamotoi) was also found, showing low individual prevalence (1%), positive pool (0.7%) and MIR (0.1%) values. To our knowledge, this is the first citation of B. miyamotoi in free-living ticks from Spain. Conclusions: The significant prevalences of B. burgdorferi (s.l.) genospecies detected in questing ticks from NW Spain are similar to those detected in northern and central European countries and higher to those previously found in Spain. These results together with the high incidence of LB in humans and the high seroprevalence of B. burgdorferi (s.l.) in roe deer shown in other studies reveal that the northwest area is one of the most risky regions for acquiring LB in Spain This research was supported by a postdoctoral research grant (Banco de Santander, Spain) to PD and a predoctoral research grant (Xunta de Galicia, Spain) to SR and funds from the Program for consolidating and structuring competitive research groups (GRC2015/003, Xunta de Galicia, Spain) SI

Automated mineralogy, including quantitative compositional and textural information, is a requirement for an efficient ore processing, and is comprised as an important input for geometallurgical planning. Classical ore microscopy is seen by many potential users as an outdated, time consuming, tool. Thus, SEM-based systems are often the choice for those who can afford them, in spite of their evident limitations for some minerals (e.g. for iron oxide ores). However, automated and quantitative mineral characterisation of metallic ores is also possible with optical (reflected light) microscopes, attaining similar performance at a much lower price than SEM systems, as shown by the AMCO (Automated Microscopic Characterisation of Ores) prototype. This system relies on the measurement of multispectral specular reflectance, R, on polished ore sections, to achieve automated identification of the ore species (reflectance is computed from grey levels of digital images acquired by automated scanning of the sample). The performance of this approach, supported by a multispectral reflectance database covering the VNIR range (370–1000 nm) built with the AMCO System, is analysed in this paper, comparing the reliability of different classification methods to achieve ore identification. The work outlined in this article focuses on checking the actual behaviour of four classification techniques, based respectively on spectral angle mapper, euclidean distance, Mahalanobis distance and linear discriminant analysis. The tests carried out reveal that the last two techniques are powerful tools to determine to which mineral corresponds a pixel based on its reflectance spectrum. The obtained results prove that automated multispectral optical microscopy is a reliable tool for mineral characterisation of common/industrial ores, with few exceptions (distinction of cassiterite and chromite, or sphalerite and wolframite). For optimisation of its performance, the multispectral information may be complemented with some additional criteria, such as paragenesis or type of deposit (e.g. to differentiate cassiterite from chromite). The reflectance database can also be enriched with measures of local ores, to account for existing reflectance variations due to local conditions or to learn new ores. The performance is particularly good for iron oxide ores (hematite, magnetite, goethite), a very important commodity. In the tests carried out, they are successfully identified in more than 99 % of the cases.

Rex1/Zfp42 is a nuclear protein that is highly conserved in mammals, and widely used as an embryonic stem (ES) cell marker. Although Rex1 expression is associated with enhanced pluripotency, loss-of-function models recently described do not exhibit major phenotypes, and both preimplantation development and ES cell derivation appear normal in the absence of Rex1. To better understand the functional role of Rex1, we examined the expression and localization of Rex1 during preimplantation development. Our studies indicated that REX1 is expressed at all stages during mouse preimplantation development, with a mixed pattern of nuclear, perinuclear, and cytoplasmic localization. Chromatin association seemed to be altered in 8-cell embryos, and in the blastocyst, we found REX1 localized almost exclusively in the nucleus. A functional role for Rex1 in vivo was assessed by gain- and loss-of-function approaches. Embryos with attenuated levels of Rex1 after injection of zygotes with siRNAs did not exhibit defects in preimplantation development in vitro. In contrast, overexpression of Rex1 interfered with cleavage divisions and with proper blastocyst development, although we failed to detect alterations in the expression of lineage and pluripotency markers. Rex1 gain- and loss-of-function did alter the expression levels of Zscan4, an important regulator of preimplantation development and pluripotency. Our results suggest that Rex1 plays a role during preimplantation development. They are compatible with a role for Rex1 during acquisition of pluripotency in the blastocyst.

The services of natural ecosystems are clearly very important to our societies. In the last years, efforts to conserve and value ecosystem services have been fomented. By way of illustration, the Natural Capital Project integrates ecosystem services into everyday decision making around the world. This project has developed InVEST (a system for Integrated Valuation of Ecosystem Services and Tradeoffs). The InVEST model is a spatially integrated modelling tool that allows us to predict changes in ecosystem services, biodiversity conservation and commodity production levels. Here, InVEST model is applied to a stakeholder-defined scenario of land-use/land-cover change in a Mediterranean region basin (the Llobregat basin, Catalonia, Spain). Of all InVEST modules and sub-modules, only the behaviour of the water provisioning one is investigated in this article. The main novel aspect of this work is the sensitivity analysis (SA) carried out to the InVEST model in order to determine the variability of the model response when the values of three of its main coefficients: Z (seasonal precipitation distribution), prec (annual precipitation) and eto (annual evapotranspiration), change. The SA technique used here is a One-At-a-Time (OAT) screening method known as Morris method, applied over each one of the one hundred and fifty four sub-watersheds in which the Llobregat River basin is divided. As a result, this method provides three sensitivity indices for each one of the sub-watersheds under consideration, which are mapped to study how they are spatially distributed. From their analysis, the study shows that, in the case under consideration and between the limits considered for each factor, the effect of the Z coefficient on the model response is negligible, while the other two need to be accurately determined in order to obtain precise output variables. The results of this study will be applicable to the others watersheds assessed in the Consolider Scarce Project.

The relationship between the chemical composition and the multispectral reflectance values of chromite in the VNIR (Visible and Near-Infra-Red) realm is tested and mathematically analysed. Statistical tools as Pearson?s correlation coefficients, linear stepwise regression analysis and least-square adjustments are applied to two populations of data obtained from 14 selected samples of chromite: multielemental microprobe analysis and multispectral reflectance values (400-1 000 nm). Results show that both data sets correlate, and suggest that the VNIR reflectance spectra can be used as a tool to determine the chemical composition of chromites.

Rex-1/Zfp42 displays a remarkably restricted pattern of expression in preimplantation embryos, primary spermatocytes, and undifferentiated mouse embryonic stem (ES) cells and is frequently used as a marker gene for pluripotent stem cells. To understand the role of Rex-1 in selfrenewal and pluripotency, we used Rex-1 association as a measure to identify potential target genes, and carried out chromatin-immunoprecipitation assays in combination with gene specific primers to identify genomic targets Rex-1 associates with. We find association of Rex-1 to several genes described previously as bivalently marked regulators of differentiation and development, whose repression in mouse embryonic stem (ES) cells is Polycomb Group-mediated, and controlled directly by Ring1A/B. To substantiate the hypothesis that Rex-1 contributes to gene regulation by PcG, we demonstrate interactions of Rex-1 and YY2 (a close relative of YY1) with Ring1 proteins and the PcG-associated proteins RYBP and YAF2, in line with interactions reported previously for YY1. We also demonstrate the presence of Rex-1 protein in both trophectoderm and Inner Cell Mass of the mouse blastocyst and in both ES and in trophectoderm stem (TS) cells. In TS cells, we were unable to demonstrate association of Rex-1 to the genes it associates with in ES cells, suggesting that association may be cell-type specific. Rex-1 might fine-tune pluripotency in ES cells by modulating Polycomb-mediated gene regulation.

Ovine pulmonary adenocarcinoma (OPA) is a contagious disease caused by jaagsiekte sheep retrovirus (JSRV). In the three studies performed, we have obtained data of the importance of colostrum/milk (C/M) in the transmission of JSRV. In the first study, a group of sheep from a flock with a long history of OPA, samples from colostrum and peripheral blood leucocytes (PBLs) were collected. Two specific PCRs (U3-LTR and env of the JSRV) were carried out. Using U3PCR 8/34 sheep were positive in colostrum whereas with envPCR 7/34 were positive. From these animals only one was positive with U3PCR in the PBLs. Evidence of the transmission of JSRV infection by C/M was obtained in two more separate studies. In the second study, PBLs from five lambs from JSRV+ ewes and two from JSRV-ewes were tested by the U3PCR. They were fed C/M by their mothers during 3 months and slaughtered 7 months after birth. Three out of five lambs from the JSRV+ sheep become PBL positive at 3-4 months old and the other two were also positive at 4-6 months of age. One lamb of the JSRV-sheep became also PBL positive at an age of 3 months. In the third study, a group of lambs from JSRV negative mothers were fed with C/M from JSRV+ sheep and housed in separate unit. For comparison, another group of the same origin and maintained in another different unit, were fed with C/M containing a JSRV virus preparation. All lambs were blood sampled monthly and JSRV infection was detected as early as 15 days and several times onwards in both groups. Control groups fed with C/M from JSRV free flock and JSRV blood test negative sheep were always negative. Together these results indicate that suckling is an important natural transmission route for JSRV.