Dynamics of porcine circovirus type 2 infection in a herd of pigs with postweaning multisystemic wasting syndrome   总被引：6，自引：0，他引：6  

Rodríguez-Arrioja GM  Segalés J  Calsamiglia M  Resendes AR  Balasch M  Plana-Duran J  Casal J  Domingo M 《American journal of veterinary research》2002,63(3):354-357

OBJECTIVE: To determine the pattern of infection for porcine circovirus type 2 (PCV2) in a herd of pigs with postweaning multisystemic wasting syndrome (PMWS). ANIMALS: 29 sows and 250 pigs. PROCEDURE: Blood samples were collected from all 3-, 7-, and 12-week old pigs and 59 pigs at 28 weeks of age. Pigs that died during the study were necropsied. Porcine parvovirus and PCV2 antibodies were assayed. A polymerase chain reaction (PCR) was used to detect PCV2 genome in serum of selected pigs. RESULTS: The PMWS started when pigs were 8 weeks old, with a prevalence of 30% in 8- to 10-week-old pigs. Eighty-three pigs died during the period between 3 and 12 weeks of age. Microscopic lesions consistent with PMWS were observed, and PCV2 nucleic acid was detected (50 of 68 pigs). Antibodies to PCV2 decreased from 3 to 7 weeks of age, increased at 12 weeks of age, and were maintained until 28 weeks of age. One sow had a positive result for PCR of serum. Nine, 37 and 8 pigs had PCV2 genome in serum obtained at 7, 12, and 28 weeks of age, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Infection with PCV2 coincided with severe clinical signs; however, infected 28-week-old pigs did not have evidence of disease. Immunity declined over time in young pigs. A long duration of PCV2 viremia was apparent in a high percentage of infected pigs, which may affect transmission and persistence of the virus in a herd.  相似文献   

Facet joint geometry and intervertebral disk degeneration in the L5-S1 region of the vertebral column in German Shepherd dogs     

Seiler GS  Häni H  Busato AR  Lang J 《American journal of veterinary research》2002,63(1):86-90

OBJECTIVE: To evaluate the possible association between facet joint geometry and intervertebral disk degeneration in German Shepherd Dogs. ANIMALS: 25 German Shepherd Dogs and 11 control dogs of similar body weight and condition. PROCEDURE: Facet joint angles in the caudal portion of the lumbar region of the vertebral column (L5-S1) were measured by use of computed tomography, and the intervertebral discs were evaluated microscopically. The relationship between facet joint geometry and disk degeneration was evaluated by use of statistical methods. RESULTS: German Shepherd Dogs had significantly more facet joint tropism than control dogs, but an association with disk degeneration was not found. However, German Shepherd Dogs had a different facet joint conformation, with more sagittally oriented facet joints at L5-L6 and L6-L7 and a larger angle difference between the lumbar and lumbosacral facet joints, compared with control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: A large difference between facet joint angles at L6-L7 and L7-S1 in German Shepherd Dogs may be associated with the frequent occurrence of lumbosacral disk degeneration in this breed.  相似文献   

Tick salivary gland extract-activated transmission of Borrelia afzelii spirochaetes     

Pechová J  Stĕpánová G  Kovár L  Kopecký J 《Folia parasitologica》2002,49(2):153-159

Saliva-activated transmission of Borrelia afzelii Canica, Nato, du Merle, Mazie, Baranton et Postic, 1993 was demonstrated using salivary gland extract (SGE) from Ixodes ricinus (L., 1758) ticks and C3H mice. Injection of Borrelia spirochaetes together with SGE increased the level of bacteraemia and accelerated the appearance of bacteria in the urinary bladder, compared with the injection of spirochaetes alone. More I. ricinus nymphs became infected when feeding on mice inoculated with B. afzelii plus SGE. Analysis of cytokines produced by cells of draining lymph nodes from SGE-treated mice showed a suppression of proinflammatory cytokines IFN-gamma, IL-6 and GM-CSF following a transient upregulation in comparison with the control mice infected without SGE.  相似文献   

Poisoning of horses by bamboo, Bambusa vulgaris     

Jos Diomedes Barbosa  Carlos Magno C. de Oliveira  Marcos Dutra Duarte  Gabriela Riet-Correa  Paulo Vargas Peixoto  Carlos Hubinger Tokarnia 《Journal of Equine Veterinary Science》2006,26(9):393-398

The clinical and pathological aspects of a neurological disease observed in 16 horses in Pará, Amazonia, Brazil, are presented. The symptoms were mainly motor incoordination, paresis of the tongue, somnolence, difficulties in apprehension, chewing and swallowing of food, as well as instability and standing with abducted members. The clinical course was subacute or chronic and in most cases was not fatal. Postmortem examination performed in one already very sick, euthanized animal, did not show significant macroscopic lesions; histopathological examination revealed slight edema and degenerative alterations of a few axons, mainly in the medulla oblongata. In all pastures where horses were affected, plenty of bamboo had been eaten, probably because of scarcity of pasture. By feeding large amounts of fresh bamboo leaves of this region, in different growing stages, to three horses (horse 1, 47 g/kg/d for 30 days; horse 2, 10 g/kg/d for 60 days; horse 3, 18 g/kg on the first day, and 31 g/kg/d for 6 more days)—the animals ate the leaves unassisted—it was possible to reproduce nervous symptoms essentially identical to those observed in the natural disease 24 to 72 hours after the first feeding of the plant. In spite of continuous administration of the plant, intensity of the clinical signs did not increase. Based on field observations and comparison of the clinical and pathological pictures seen in the natural and experimental disease, the described illness can be concluded to be caused by the ingestion of large amounts of the leaves of Bambusa vulgaris f. vulgaris.  相似文献   

Improvements in somatic embryogenesis protocol in Feijoa (Acca sellowiana (Berg) Burret): Induction,conversion and synthetic seeds     

Gabriela Claudia Cangahuala-Inocente  Lírio Luiz Dal Vesco  Douglas Steinmacher  Antonio Carlos Torres  Miguel Pedro Guerra 《Scientia Horticulturae》2007

Pineapple guava (Acca sellowiana) syn. Feijoa sellowiana, a Brazilian indigenous Myrtaceae is under domestication in South Brazil. Previous works showed that this species is responsive to somatic embryogenesis and recalcitrant to conventional methods of clonal propagation. In the present work it was evaluated the role of components of culture medium in the induction and development of somatic embryos. The technology of synthetic seeds was also evaluated. Zygotic embryos were inoculated in LPm medium supplemented with 8 mM glutamic acid and 8 mM l-glutamine, 2,4-dichlophenoxiacetic acid (20 μM) and myo-inositol. For conversion of somatic embryos and synthetic seeds it was tested the effect of 6-benzylaminopurine and gibberellic acid combined or not with activated charcoal. The highest values for embryogenetic induction (100%) and number of somatic embryos/explant (113) were observed in the LPm medium supplemented with Glu (8 mM), and 2,4-D. The culture medium supplemented with BA (0.5 μM) and GA₃ (1 μM) and activated charcoal (1.5 g L⁻¹) enhanced the conversion of somatic embryos to plantlets. Pre-germinated somatic embryos encapsulated in sodium alginate with BA (0.5 μM) and GA₃ (1 μM) developed radicles. The use of synthetic seed was a requisite for the survival of plantlets.  相似文献   

Untersuchungen zum Einfluß von Sonnenlicht auf das Schwärmverhalten von Borkenkäfern     

Dr. Gabriela Lobinger  Prof. Dr. U. Skatulla 《Journal of pest science》1996,69(8):183-185

Zusammenfassung Mit Hilfe elektronischer Meßmethoden sowie durch verschiedene weitere Versuchsanordnungen konnte gezeigt werden, daß der Buchdrucker in seinem Anflugverhalten an Pheromonquellen maßgeblich durch die jeweils herrschenden Lichtverhältnisse beeinflußt wird. Es bestand eine deutliche Präferenz von besonnten Standorten. In sonnigen Zeitabschnitten, auch innerhalb von nur wenigen Minuten, waren signifikant höhere Anflugzahlen zu vereichnen als in Phasen mit Bewölkung. Für den Kupferstecher gilt dies nur in eingeschränktem Maße.Diese Zusammenhänge konnten auch anhand von nord-bzw. südexponierten Fallen aufgezeigt werden. Die besonnte Fallenseite fing 4,2mal mehr Buchdrucker als die der Sonne abgewandte Seite. Beim Kupferstecher betrug der Faktor nur 1,66. Die beschriebenen Ergebnisse fanden ihre Bestätigung auch in der Befallssituation im Kalamitätsgebiet. Bei beginnendem Stehendbefall wurden vom Buchdrucker zunächst südexponierte Bestandesränder und hier die zur tageszeitlichen Hauptschwärmzeit besonnten Stämme besetzt.

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Influencing the flight behaviour of bark beetles by light conditions

With the aid of eletronic registration equipment and other experimental methods, it could be shown that the flight behaviour of spruce bark beetles to pheromone sources is strongly influenced by the prevailing light conditions. There is a definite preference for sunny conditions. Even during sunny periods of only a few minutes, significantly more beetles were flying than during overcast periods.A similar pattern of behaviour was observed for P.chalcographus, but there was no statistical evidence. This preference was also seen when pheromone baited traps were set up in a northerly direction with low sunlight levels and a southerly direction with strong sunlight. In the traps facing south 4,2 times more lps typographus were caught than in the north facing traps. P. chalcographus preferred the sunnier traps at a radio of 1,66.These results confirm the fact that at the beginning of an infestation of forest the southerly regions were first to be attacked by spruce bark beetles. Even there trees were first affected where they were exposed to sun during the daily main period of flight activity.

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Mit 2 Abbildungen und 1 Table.  相似文献   

Changes in understory species diversity during theNothofagus pumilio forest management cycle     

Pastur  Guillermo Martínez  Peri  Pablo Luis  Fernández  María Cecilia  Staffieri  Gabriela  Lencinas  Mará Vanessa 《Journal of Forest Research》2002,7(3):165-174

Human commercial activities must be compatible with sustainable management to achieve species conservation in the natural environment. After harvesting, diversity and abundance of understory species differ substantially from the pre-harvest situation. Have knowledge of the changes that logging produces in all components of the system allows us to develop management alternatives with reduced impacts. The objective of this work was to evaluate changes in density, biomass and diversity of understory species along a forest shelterwood cut system management cycle in aNothofagus pumilio forest. Six forest management situations (postharvesting stands and different phases of forest development) were sampled in a pureN. pumilio forest of Tierra del Fuego (Argentina) of middle-high site class (fromclass I toIII). Species number, density and biomass were modified substantially after a shelterwood cut. These were being greatest after cutting and falling substantially when the forest canopy closes during theinitial growth phase, returning to values similar to this virgin forest when themature phase was reached. The impact of the forest management on understory species diversity is analyzed and discussed. The silvicultural practices applied toN. pumilio forest in Tierra del Fuego permit the introduction of alien flora to the system, and produce great changes during the forest management cycle. To Celina Matteri, Itatí Ferraro, and Rosa Kofalt for their aid in taxonomical identification. To Juan Manuel Cellini, Ricardo Vukasovic and Gregorio Martínez Pastur for their participation in the field work; and to the sawmillLos Castores, Universidad Nacional de la Patagonia Austral, Centro Austral de Investigaciones Científicas and Instituto Nacional de Tecnología Agropecuaria for the institutional and financial support.  相似文献   

Die Lufttemperatur als limitierender Faktor für die Schwärmaktivität zweier rindenbrütender Fichtenborkenkäferarten,lps typographus L. undPityogenes chalcographus L. (Col., Scolytidae)     

Dr. Gabriela Lobinger 《Journal of pest science》1994,67(1):14-17

Single catches of bark beetles in pheromone baited traps were registered by the aid of a new instrument. It consists of an electronical weather station in connection with a pheromone trap with infrared sensors as additional equipment. So it was possible also to register weather data at the moment of every catching event. It could be shown that the flight behaviour of both species of bark beetles was influenced by air temperature.I. typographus did not fly beneath a minimum temperature of 16.5°C. There was also an upper limit of 30°C for flight activity of this species.P. chalcographus has a threshold of temperatures about 16.8–17°C, for activity. No upper limit of temperature could be observed up to 35°C. Both of them,I.typ. andP. chalc., reacted very sensitive and spontaneous to these temperature thresholds.  相似文献   

Different drought-adaptive capacity of a native Patagonian tree species (Nothofagus pumilio) resulting from local adaptation     

Soliani  Carolina  Mattera  Ma. Gabriela  Marchelli  Paula  Azpilicueta  Ma. Marta  Dalla-Salda  Guillermina 《European Journal of Forest Research》2021,140(5):1147-1161

European Journal of Forest Research - The resistance of different genotypes to abiotic stress may be due to genetic effects and/or to phenotypic plasticity allowing them to acclimate to variable...  相似文献   

Effect of a size-based selection program on blood metabolites and immune response of Litopenaeus vannamei juveniles fed different dietary carbohydrate levels     

Cristina Pascual  Leticia Arena  Gerard Cuzon  Gabriela Gaxiola  Gabriel Taboada  Manuel Valenzuela  Carlos Rosas   《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):405-416

Blood metabolites in wild and seventh-generation cultivated shrimp were measured to determine how size-based selection could alter the nutritional and immunological conditions of Litopenaeus vannamei. Wild L. vannamei juveniles and a sample of seventh-generation cultured shrimp were acclimated under identical conditions. During 55 days, shrimp were fed a high (HCHO: 44%) or a low (LCHO: 3%) carbohydrate diet for 55 days. Wild shrimp showed a direct relation between dietary CHO and lactate, protein and hemocyte levels indicating that dietary CHO was used for protein synthesis via transamination pathways. In seventh-generation cultured shrimp these parameters were inversely proportional to dietary CHO level, indicating the capacity to synthesize protein from dietary CHO was repressed in cultured shrimp. Farmed shrimp showed a limited capacity to respond to LCHO diets demonstrating high protein dependence in their metabolism and immune response. These results demonstrate that during size-based breeding programs other metabolic process than CHO catabolism can be selected. The incapacity of shrimp to use dietary CHO could limit protein reduction of diets and limit the efforts of the shrimp industry to be ecologically and environmentally profitable.  相似文献