RESUMEN
This study analysed sera from 390 llamas (Lama glama) from nine farms located in three different Argentine provinces: Buenos Aires, Cordoba and Jujuy. The samples were tested for antibodies against 8 virus known to infect cattle: bovine herpesvirus type 1 (BHV-1), bovine viral diarrhea virus (BVDV), bovine adenovirus (BAdV III), bovine enterovirus (BEV), bovine rotavirus (BRV), bluetongue virus (BTV), bovine leukaemia virus (BLV), and foot-and-mouth virus (FMDV) by conventional methods such as seroneutralization, immunoperoxidase staining, and agar gel immunodiffusion. The antibody prevalences detected in llamas were: BHV-1 in 0.77% (3/390), BVDV in 2.05% (8/390), BAdV III in 5.13% (20/390), BEV in 4.10% (16/390), BRV in 87.69% (342/390). No antibodies against BTV, BLV and VIAA (FMDV infection associated antigen) were detected.
Asunto(s)
Anticuerpos Antivirales/sangre , Camélidos del Nuevo Mundo/inmunología , Virosis/veterinaria , Animales , Argentina , Camélidos del Nuevo Mundo/sangre , Bovinos , Enfermedades de los Bovinos/virología , Línea Celular , Pruebas Serológicas , Virosis/diagnóstico , Virosis/inmunología , Virus/crecimiento & desarrollo , Virus/inmunología , Virus/aislamiento & purificaciónRESUMEN
An experimental trial was conducted to evaluate the ability of foot-and-mouth-disease (FMD) virus (serotypes A79, C3, O1) to infect susceptible llamas exposed either directly to affected livestock, or indirectly to llamas that had been directly exposed to affected livestock. In addition, susceptible livestock species (cattle, pigs, goats, and sheep) were exposed to those llamas that had been both directly and indirectly exposed to the FMD virus to further look at potential transmission possibilities. Of 30 llamas directly exposed to the FMD virus, only three (3/30) showed evidence of infection, and of those, only two (2/30) had mild clinical signs. No FMD virus was isolated from either oesophageal-pharyngeal (OP) fluid or blood samples collected from the infected llamas beyond 14 days post-exposure. There was no evidence of virus transmission between the directly exposed and indirectly exposed llamas or between both groups of llamas and susceptible domestic livestock, as determined by the lack of clinical signs, by virus isolation, and by serology results. These results provide further evidence that llamas are resistant to FMD infection, and that they play a minor role, if any, in transmitting the virus to domestic livestock.
Asunto(s)
Aphthovirus/fisiología , Camélidos del Nuevo Mundo , Fiebre Aftosa/epidemiología , Animales , Aphthovirus/aislamiento & purificación , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/transmisión , Enfermedades de los Bovinos/virología , Susceptibilidad a Enfermedades , Fiebre Aftosa/transmisión , Fiebre Aftosa/virología , Enfermedades de las Cabras/epidemiología , Enfermedades de las Cabras/transmisión , Enfermedades de las Cabras/virología , Cabras , Incidencia , Ovinos , Enfermedades de las Ovejas/epidemiología , Enfermedades de las Ovejas/transmisión , Enfermedades de las Ovejas/virología , Porcinos , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/transmisión , Enfermedades de los Porcinos/virologíaRESUMEN
Bovine spongiform encephalopathy (BSE) is a new disease of cattle first described in the United Kingdom in November 1986. BSE belongs to the scrapie-related group of diseases. The epidemiological studies performed in the United Kingdom demonstrate that the BSE epidemic was caused by feeding cattle with ruminant-derived protein contaminated by a scrapie-like agent. Until June 1994, the disease had been detected in indigenous cattle in Ireland, Switzerland and France. Three cases reported in Germany, two in the Sultanate of Oman, and single cases in the Falkland Islands (Islas Malvinas), Denmark, Portugal and Canada occurred in animals imported from the United Kingdom. Several countries have implemented surveillance programmes analysing the risk factors involved in the epidemic. An analysis of risk factors conducted in Argentina shows that it is highly unlikely that BSE or scrapie exist in the country, or will arise via feed in the future. As a continuation of the analysis of risk factors, a surveillance programme was implemented in the field and in abattoirs. Specialised personnel were trained in the clinical, histopathological and biochemical detection of the disease through a network of laboratories which covered 85% of the total cattle population and 100% of the high-risk group (dairy cows over five years of age). By using a statistical procedure with reference to the bovine population in nine provinces, 1,019 brains from animals belonging to the high-risk group were selected and studied by histopathological and biochemical analyses for BSE detection. The results were negative in all cases. It can be concluded from this analysis (with a sensitivity of detection of 2.95 per 1,000, and 95% statistical confidence) that Argentina may be regarded as BSE-free, and that the importation of infected animals or by-products may represent the sole potential source of introduction of BSE infection into the country in the future.
Asunto(s)
Encefalopatía Espongiforme Bovina/epidemiología , Mataderos , Animales , Argentina/epidemiología , Encéfalo/patología , Bovinos , Femenino , Masculino , Factores de RiesgoRESUMEN
Bovine fetuses chronically catheterized in utero during the last month of gestation were used to study the relationships of maternal-fetal calcium and phosphate levels. Calcium infusion into the pregnant cows induced a rapid and marked increase in maternal plasma calcium but no change in fetal plasma calcium concentrations. Oral administration of Solanum glaucophyllum to the mother for 6 days raised the plasma concentrations of calcium and phosphate in both the mother and the fetus.
Asunto(s)
Calcio/metabolismo , Feto/metabolismo , Intercambio Materno-Fetal , Alcaloides Solanáceos/metabolismo , Animales , Calcio/sangre , Bovinos , Femenino , Infusiones Parenterales , Fosfatos/sangre , Plantas , EmbarazoRESUMEN
White Leghorn eggs were injected on the 15th day of incubation with various doses of an acqueous extract of Solanum malacoxylon (SME). Most of the embryos died after the injection of 0.2 ml but the dose of 0.1 ml was well tolerated. The concentration of calcium in the sera from 15-day embryos injected with 0.1 ml SME was determined. Three hr after the injection the concentration of calcium had increased significantly; this increase lasted for at least 3 hr more but had disappeared 12 hr after the injection. It is suggested that this hypercalcemia may be produced by a water-soluble analog of 1,25-(OH)2D3 the presence of which has been demonstrated in the SME by other authors. It is also assumed that the mortality produced by the higher doses may be related to the hypercalcemia.
Asunto(s)
Embrión de Pollo/efectos de los fármacos , Dihidroxicolecalciferoles , Hidroxicolecalciferoles , Hipercalcemia/inducido químicamente , Extractos Vegetales , Animales , Calcio/metabolismo , Vitamina D/metabolismoRESUMEN
Sheep treated with a single dose of an extract of the dried leaves of Solanum malacoxylon (SM) at the rate of 0-2 g of leaves per kg liveweight produced a pronounced hypercalcaemia (49 per cent, P less than 0-005) after 24 h, which persisted for at least six days. The ultra-filtrable fraction of the serum calcium rose to approximately the same extent as the protein-bound calcium. This finding is consistent with osteosclerosis and parathyroid atrophy found to occur in cases of experimental SM intoxication. At the dose level given serum inorganic phosphorus was not significantly increased and packed cell volume, serum proteins and ceruloplasmin concentrations remained constant.