Epidemiology of viral haemorrhagic disease and myxomatosis in a free-living population of wild rabbits     

Calvete C  Estrada R  Villafuerte R  Osácar JJ  Lucientes J 《The Veterinary record》2002,150(25):776-782

From January 1993 to June 1996, the epidemiology of myxomatosis and viral haemorrhagic disease (VHD) was studied in a free-living population of wild rabbits (Oryctolagus cuniculus) in Spain by means of serological surveys and radiotracking. Myxomatosis was endemic and associated with the breeding period. Its serological pattern was characterised by a 100 per cent prevalence of antibodies in adult rabbits and a rapid increase in antibodies in young rabbits in their first year. No mortality from myxomatosis was detected in adults, and mortality in young rabbits could not be estimated because of interference by predators and scavengers and the deaths of many radiotagged rabbits inside their burrows. VHD was also an endemic disease associated with the breeding period. Adults had a higher prevalence of antibodies against VHD than young rabbits, reaching values of 80 to 90 per cent. During the study, there was an increase in rabbit numbers as a result of a decrease in mortality from predation which was associated with an increase in mortality due to VHD and in the prevalence of antibodies to VHD. Mortality from VHD was lower in rabbits with VHD antibodies than in seronegative rabbits, but some mortality from the disease was also detected in seropositive rabbits. The annual mean mortality rate due to VHD in adult rabbits was estimated to be 21.8 per cent.  相似文献   

Short-term survival and dispersal of translocated European wild rabbits. Improving the release protocol   总被引：1，自引：0，他引：1  

Carlos Calvete  Rosa Estrada 《Biological conservation》2004,120(4):507-516

Translocation of European wild rabbit Oryctolagus cuniculus L. is one of the most frequent management tools to increase rabbit density in Spain, both as prey of several predators that are threatened with extinction and for sport hunting. Nevertheless the elevated short-term mortality by predation makes translocations unsuccessful and increases their biological cost. Information on the factors affecting the short-term survival and dispersal of translocated rabbits is required to improve release management and increase performance of translocated rabbits, and to avoid the use of non-selective lethal methods for predator control. In this study we tested electric fencing and night-shooting as alternative to traditional release protocols, and the effects of vegetation cover and warren fencing on short-term survival and dispersal of rabbits. Night shooting performed during the first nights after release increased significantly the survival of rabbits, by hindering the activity of carnivores in the release area. The use of an electric fence enclosure also increased the performance of rabbits, but was not efficient to constraint rabbit dispersal. Rabbits released in areas with low vegetation cover showed higher mortality and dispersal distances than rabbits released in high cover areas. Warren fencing decreased both the dispersal of rabbits and the adverse impact of predation in low cover areas, but had no effect in high cover areas. Selection of high cover areas or warren fencing in low cover areas seem to be the most advantageous release conditions to decrease the short-term predation impact, reducing the biological cost of rabbit translocations and the risks for endangered predators derived from the use of traditional predator control practices during translocations.  相似文献   

Seroprevalence of Neospora caninum in non-carnivorous wildlife from Spain     

Almería S  Vidal D  Ferrer D  Pabón M  Fernández-de-Mera MI  Ruiz-Fons F  Alzaga V  Marco I  Calvete C  Lavin S  Gortazar C  López-Gatius F  Dubey JP 《Veterinary parasitology》2007,143(1):21-28

Serum samples from 1034 non-carnivorous wildlife from Spain were tested for antibodies to Neospora caninum by competitive screening enzyme linked immunosorbent assay (ELISA) and confirmed by an indirect fluorescent antibody test (IFAT). High agreement was observed between results in both techniques (kappa value higher than 0.9). Prevalences of N. caninum antibodies positive by both techniques were 11.8% of 237 red deer (Cervus elaphus), 7.7% of 13 barbary sheep (Ammotragus lervia), 6.1% of 33 roe deer (Capreolus capreolus) and 0.3% of 298 wild boar (Sus scrofa). In one of 53 hares (Lepus granatensis), antibodies were found in the ELISA but could not be confirmed by IFAT due to lack of sample. Antibodies to N. caninum were not found in any of 251 wild rabbits (Oryctolagus cuniculus), 79 fallow deer (Dama dama), 27 mouflon (Ovis ammon), 40 chamois (Rupicapra pyrenaica) and three Spanish ibex (Capra pyrenaica). Statistically significant differences were observed between N. caninum seroprevalence in red deer and management of hunting estates (open versus fenced) with higher prevalence in fenced estates, and among sampling sites. Seroprevalence was particularly high in some areas (MO estate in South-Central Spain or some estates of Catalonia, North-East Spain), while no contact with N. caninum was observed in others. Results indicate that in certain areas of Spain, N. caninum is present in wildlife, especially in red deer. These results have important implications in both sylvatic cycles and may influence the prevalence of infection in cattle farms in those areas. To our knowledge, this is the first report of antibodies to N. caninum in wildlife from Spain and the first report of N. caninum antibodies in barbary sheep and wild boar.  相似文献   

Protein Composition of Seminal Plasma in Fractionated Stallion Ejaculates     

AM Kareskoski  MM Rivera del Alamo  K Güvenc  T Reilas  JJ Calvete  H Rodriguez‐Martinez  M Andersson  T Katila 《Reproduction in domestic animals》2011,46(1):e79-e84

Seminal plasma (SP) contains several types of compounds derived from the epididymides and accessory glands. The aim of this study was to examine the protein composition of different ejaculate fractions. Trial I: fractionated ejaculates were collected from two normal and two subfertile stallions. Samples containing pre‐sperm fluid and the first sperm‐rich jets (HIGH‐1), the main sperm‐rich portion (HIGH‐2), the jets with low sperm concentrations (LOW), and a combined whole‐ejaculate (WE) sample was centrifuged, and the SP was filtered and frozen. A part of each SP sample was stored (5°C, 24 h) with spermatozoa from HIGH‐2 and skim milk extender. Sperm motility was evaluated after storage in extender mixed with the stallion’s own SP or SP from one of the other stallions (sperm from a normal stallion stored in SP from a subfertile stallion and vice versa). Protein composition was analysed using reverse‐phase liquid chromatography (RP‐HPLC), N‐terminal sequencing and mass spectrometry. The area‐under‐the‐curve (AUC) was used for quantitative comparison of proteins within fractions. Trial II: semen samples were collected from seven stallions. Fractions with the highest (HIGH) and lowest (LOW) sperm concentrations and WE samples were examined using SDS‐PAGE and densitometry. No significant differences emerged between fractions in the AUC‐values of the Horse Seminal Protein‐1 (HSP‐1) and HSP‐2 peaks, or the peak containing HSP‐3 and HSP‐4 (HSP‐3/4). Levels of HSP‐1, HSP‐2 and HSP‐3/4 were not significantly correlated with total sperm motility, progressive sperm motility or average path velocity after storage. Significant differences between ejaculate fractions in the amount of different protein groups present in SP were not found in Trial I; but in Trial II, the proteins in the 60–70 kDa range were more abundant in LOW than in HIGH and WE, indicating that this band contained proteins derived mainly from the seminal vesicles, which produce most of the SP in LOW.  相似文献   

Absence reduction in entomological surveillance data to improve niche-based distribution models for Culicoides imicola     

Peters J  De Baets B  Van Doninck J  Calvete C  Lucientes J  De Clercq EM  Ducheyne E  Verhoest NE 《Preventive veterinary medicine》2011,100(1):79-28

Data-driven models for the prediction of bluetongue vector distributions are valuable tools for the identification of areas at risk for bluetongue outbreaks. Various models have been developed during the last decade, and the majority of them use linear discriminant analysis or logistic regression to infer vector-environment relationships. This study presents a performance assessment of two established models compared to a distribution model based on a promising ensemble learning technique called Random Forests. Additionally, the impact of false absences, i.e. data records of suitable vector habitat that are, for various reasons, incorrectly labelled as absent, on the model outcome was assessed using alternative calibration-validation schemes. Three reduction methods were applied to reduce the number of false absences in the calibration data, without loss of information on the environmental gradient of suitable vector habitat: random reduction and stratified reduction based on the distance between absence and presence records in geographical (Euclidean distance) or environmental space (Mahalanobis distance). The results indicated that the predicted vector distribution by the Random Forest model was significantly more accurate than the vector distributions predicted by the two established models (McNemar test, p<0.01) when the calibration data were not reduced with respect to false absences. The performance of the established models, however, increased considerably by application of stratified false absence reductions. Model validation revealed no significant difference between the performance of the three distinct Culicoides imicola distribution models for the majority of alternative stratified reduction schemes. The main conclusion of this study is that the application of Random Forests, or linear discriminant analysis and logistic regression on the condition that calibration data were first reduced on geographical or environmental information, potentially lead toward better vector distribution models.  相似文献   

The infectibility of cowpea mesophyll cells by tobacco necrosis virus     

J. Salinas Calvete  D. Hendrina Wieringa-Brants 《European journal of plant pathology / European Foundation for Plant Pathology》1981,87(6):211-216

The time required for infectious tobacco necrosis virus (TNV) to pass through the epidermis of cowpea leaves after mechanical inoculation, depended on plant age and environmental temperature. At 22°C the passage time was about 2 h but at 32°C it was only 10 min. Water stress seemed to play a role in the transport of infectious virus into the mesophyll. It was possible to infect cowpea mesophyll cells with TNV directly by using a fine brush without carborundum. Differences between tobacco and cowpea in the establishment of virus infection are discussed.Samenvatting De mogelijkheden om cowpea-mesofylcellen met TNV te infecteren, hetzij via de epidermis, hetzij rechtstreeks, werden onderzocht. De minimum tijd die infectieus virusmateriaal nodig heeft om de epidermis te passeren werd bepaald. De ouderdom van de zaailingen speelde daarbij een rol. Bij 20 dagen oude planten bedroeg de passagetijd meer dan 4 uur, in 10 dagen oude planten was meer dan 2 uur nodig voor passage. De temperatuur van de omgeving was een belangrijke factor. In cowpeabladeren, direct na inoculatie met TNV bij 32°C gezet, bleek de passgetijd slechts 10 minuten te zijn. Verduistering van de planten 24 uur voor inoculatie bekortte de passagetijd aanzienlijk. Ook speelde water-stress in het blad door hoge temperatuur na inoculatie een rol in de vroege infectiestadia. Het was mogelijk, cowpea-mesofyl direct te infecteren, indien cowpea-bladeren gebruikt werden van 9–12 dagen oude zaailingen die opgekweekt waren bij 22±3°C. De bladeren werden gedurende ±1 uur na afplukken op droog filtreerpapier gelegd, daarna werd de onderepidermis met een fijn pincet verwijderd. Inoculatie van het naakte mesofyl met TNV onmiddelljk na het strippen met een fijne penseel zonder carborundum resulteerde in eenzelfde aantal lesies als in de niet-gestripte helft, die geïnoculeerd was door wrijven met hetzelfde TNV-inoculum in aanwezzigheid van carborundum.Het schijnt dat de processen, die betrokken zijn bij het tot stand komen van een TNV-infectie in cowpea en tabak, van elkaar verschillen.  相似文献   

Proteomic identification of actin-derived oligopeptides in dry-cured ham     

Sentandreu MA  Armenteros M  Calvete JJ  Ouali A  Aristoy MC  Toldrá F 《Journal of agricultural and food chemistry》2007,55(9):3613-3619

An intense proteolysis of muscle proteins, mainly due to the action of endogenous proteolytic enzymes, has been reported to occur during the processing of dry-cured ham. This gives rise to an important generation of free amino acids and peptides of small size that contribute directly or indirectly to flavor characteristics of the final product. The nature and properties of the free amino acids generated during postmortem proteolysis have been well established. However, little is known about the identity of peptides generated during the processing of dry-cured ham. In the present paper, we describe the isolation (by ethanol precipitation followed by size exclusion and reverse phase chromatographies) and identification (by matrix-assisted laser desorption/ionization time-of-flight MS and collision-induced dissociation MS/MS) in a Spanish dry-cured ham of the following four oligopeptides: (A) TKQEYDEAGPSIVHR, (B) ITKQEYDEAGPSIVHRK, (C) DSGDGVTHNVPIYE, and (D) DSGDGVTHNVPIYEG. This is the first time that these peptide fragments have been reported in dry-cured ham at the end of processing. Sequence homology analysis revealed that the four peptides originated from muscle actin, indicating an extensive hydrolysis of this protein during dry-curing. Some of the cleavage sites corresponding to these fragments in actin were reproduced by other authors through the incubation of this myofibrillar protein in the presence of cathepsin D (EC 3.4.23.5), thus supporting a relevant action of this enzyme during the processing of dry-cured ham.  相似文献   

Widespread exposure to Sarcoptes scabiei in wild European rabbits (Oryctolagus cuniculus) in Spain     

Millán J  Casáis R  Delibes-Mateos M  Calvete C  Rouco C  Castro F  Colomar V  Casas-Díaz E  Ramírez E  Moreno S  Prieto JM  Villafuerte R 《Veterinary parasitology》2012,183(3-4):323-329

Sarcoptic mange was recently described in the wild European rabbit (Oryctolagus cuniculus) in north-eastern Mediterranean Spain, the first such infection reported in this species anywhere in the world. This finding has created concern in conservationists and game managers given that an outbreak of mange after a translocation would have catastrophic consequences for na?ve rabbit populations in other parts of Spain. A retrospective serosurvey using an 'in house' ELISA test based on the use of a recombinant antigen aimed at determining the rates of contact with Sarcoptes scabiei was carried out on sera from 966 rabbits collected between 1993 and 2010 in Spain. Antibodies were found in 13% of wild rabbits in 60% of the 53 areas surveyed, as well as in 16 of the 17 Spanish provinces and islands studied. Seropositive rabbits were found amongst the oldest samples analyzed and in all studied years. Antibodies were also detected in 36% of rabbits from the protected island of Dragonera, where rabbits have probably not been released since the 1970s. On Mallorca, where 89 rabbits were inspected for both lesions and antibodies, the prevalence of lesions (5.6%) was much lower than the seroprevalence (22.5%), indicating that rabbits often survive infection or that ELISA detects infected rabbits before they develop visible lesions. Seroprevalence was higher in areas with medium levels of rabbit abundance, no restocking and high rainfall. The results show that mange is widespread in rabbits and that the mite is not a recent introduction. Thus, sarcoptic mange could be considered as an enzootic disease in the wild rabbit and so prophylactic measures implemented during rabbit translocations are to be encouraged to avoid local outbreaks in na?ve populations.  相似文献   

Ecological correlates of bluetongue virus in Spain: predicted spatial occurrence and its relationship with the observed abundance of the potential Culicoides spp. vector     

Calvete C  Estrada R  Miranda MA  Borrás D  Calvo JH  Lucientes J 《Veterinary journal (London, England : 1997)》2009,182(2):235-243

Using data from bluetongue (BT) outbreaks caused by viral serotype 4 (BTV-4) in Spain during 2004–2005, a predictive model for BTV-4 occurrence in peninsular Spain was developed. An autologistic regression model was employed to estimate the relationships between BTV-4 presence and bioclimatic-related and host-availability-related variables. In addition, the observed abundances of the main potential Culicoides vectors during 2004–2005, namely Culicoides imicola, Culicoides obsoletus group, and species of the Culicoides pulicaris group, were compared between BTV-4 presence/absence areas predicted by the model.BTV-4 occurrence was mainly explained by bioclimatic variables, although a consideration of host-availability variables led to improved fit of the model. The area of BTV-4 presence predicted by the model largely resembled the core distribution area of C. imicola, and this species was the most abundant Culicoides spp. in predicted BTV-4 presence areas. The results suggest that the spatial expansion of BTV-4 took place only as far as those areas in which C. imicola populations efficiently transmitted the virus.  相似文献   

Habitat factors related to wild rabbit conservation in an agricultural landscape   总被引：5，自引：0，他引：5  

Calvete  C.  Estrada  R.  Angulo  E.  Cabezas-Ruiz  S. 《Landscape Ecology》2004,19(5):531-542

Populations of European wild rabbit (Oryctolagus cuniculus) have been decreasing since the 1950s. Changes in agricultural practices have been suggested as reasons for their decline in Mediterranean landscapes. We evaluated the environmental variables affecting rabbit distribution in a semiarid agricultural landscape of Northeastern Spain. Sampling was performed in 147 sites randomly distributed across Zaragoza province. At each site, data were recorded in five 100 m segments along a 1 km transect, following ecotones between crops and natural-vegetation areas. A rabbit abundance index was estimated from latrine count, pellet density and number of plots with pellets. In addition to environmental variables that have been shown to be related to rabbit abundance in other habitats, as climate, soil hardness and topography of the site, we measured landscape components related to agricultural use, such as structure of natural vegetation in remaining areas non-devoted to agricultural use and distances to different types of crops and to ecotone between crop and natural vegetation. Our results showed that rabbit abundance was positively correlated to yearly mean temperature, February and May mean rainfall, and negatively correlated to September and November mean rainfall, hardness of soil, and site topography. In relation to agricultural use, rabbit abundance was positively correlated to the scrub structure of natural-vegetation areas and negatively correlated to distance to edge between cultivated unirrigated cereal crops (wheat or barley) and yearly resting cereal crops. Rabbit abundance increased only when the edge between alternate cereal crops was less than 50 m from the ecotone between crops and natural vegetation.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献