BSE infectivity in jejunum, ileum and ileocaecal junction of incubating cattle

ABSTRACT: To establish bovine spongiform encephalopathy (BSE) public health protection measures it is important to precisely define the cattle tissues considered as specified risk materials (SRM). To date, in pre-clinical BSE infected cattle, no evidence of the BSE agent had been found in the gut outside of the ileal Peyer's Patches. This study was undertaken to determine when and where the pathological prion protein (PrPSc) and/or BSE infectivity can be found in the small intestine of cattle 4 to 6 months of age, orally challenged with BSE. Samples of the jejunum, the ileum and the ileocaecal junction from 46 BSE infected cattle, culled from 1 up to 44 months post infection (mpi) were examined by immunohistochemistry. Samples from cattle 8 mpi to 20 mpi were additionally studied by PTA Western blot, rapid tests, and by mouse (TgbovXV) bioassay. In doing so nearly all of the cattle, from 4 up to 44 mpi, had detectable amounts of PrPSc and/or infectivity in the distal ileum. In the distal ileum clear time-dependent variations were visible concerning the amount of PrPSc, the tissue structures affected, and the cells involved. BSE infectivity was found not only in the ileum and ileocaecal junction but also in the jejunum. The systematic approach of this study provides new data for qualitative and quantitative risk assessments and allows defining bovine SRM more precisely.     

Predicting fadeout versus persistence of paratuberculosis in a dairy cattle herd for management and control purposes: a modelling study

ABSTRACT: Epidemiological models enable to better understand the dynamics of infectious diseases and to assess ex-ante control strategies. For Mycobacterium avium subsp. paratuberculosis (Map), possible transmission routes have been described, but Map spread in a herd and the relative importance of the routes are currently insufficiently understood to prioritize control measures. We aim to predict early after Map introduction in a dairy cattle herd whether infection is likely to fade out or persist, when no control measures are implemented, using a modelling approach. Both vertical transmission and horizontal transmission via the ingestion of colostrum, milk, or faeces present in the contaminated environment were modelled. Calf-to-calf indirect transmission was possible. Six health states were represented: susceptible, transiently infectious, latently infected, subclinically infected, clinically affected, and resistant. The model was partially validated by comparing the simulated prevalence with field data. Housing facilities and contacts between animals were specifically considered for calves and heifers. After the introduction of one infected animal in a naive herd, fadeout occurred in 66% of the runs. When Map persisted, the prevalence of infected animals increased to 88% in 25 years. The two main transmission routes were via the farm's environment and in utero transmission. Calf-to-calf transmission was minor. Fadeout versus Map persistence could be differentiated with the number of clinically affected animals, which was rarely above one when fadeout occurred. Therefore, early detection of affected animals is crucial in preventing Map persistence in dairy herds.     

Screening species of <Emphasis Type="Italic">Pilocarpus</Emphasis> (Rutaceae) as sources of pilocarpine and other imidazole alkaloids

Plants of the Pilocarpus genus (Rutaceae) are popularly known as jaborandi and are the only source of pilocarpine, an imidazole alkaloid used in eye-drops for the treatment of glaucoma as well as for the stimulation of sweat and lachrymal glands. Alkaloid extracts from leaf samples of seven species of Pilocarpus, from the states of São Paulo and Maranhão in Brazil, were analyzed using HPLC–ESI–MS/MS. The samples contained between 0.88 ± 0.04 and 1.00 ± 0.14% of alkaloids in relation to the dry weight of their leaves, with significant differences in results (P ≤ 0.05) found only between Pilocarpus microphyllus planted in the state of Maranhão and Pilocarpus spicatus, Pilocarpus trachyllophus, Pilocarpus pennatifolius and Pilocarpus jaborandi; as well as between Pilocarpus spicatus and Pilocarpus racemosus. Pilocarpine was not found in P. spicatus, whereas in the other species it ranged from 2.6 ± 0.1 to 70.8 ± 1.2% of total alkaloids. P. microphyllus planted in the state of Maranhão for pilocarpine extraction had the highest total alkaloid content, but it had only 35% of pilocarpine in relation to total alkaloids. Three other species contained more pilocarpine in relation to total alkaloids: P. jaborandi (70.8%), P. racemosus (45.6%) and P. trachyllophus (38.7%); and could be candidates for pilocarpine extraction. Differences in alkaloid content were significant for all these samples (P ≤ 0.05). Imidazole alkaloids were observed and partially characterized based on their retention times and high resolution mass. The seven species analyzed had different imidazole alkaloid profiles, but only one did not present quantifiable pilocarpine contents in its leaves. The Pilocarpus genus shows potential for the prospection of novel alkaloids.     

Guidelines for zoo and aquarium veterinary medical programs and veterinary hospitals

These guidelines for veterinary medical care and veterinary hospitals are written to conform with the requirements of the Animal Welfare Act, which states that programs of disease prevention and parasite control, euthanasia, and adequate veterinary care shall be established and maintained under the supervision of a veterinarian. Ideally the zoo and aquarium should be providing the best possible veterinary medical care for the animals in their collections. Many of these animals are rare and endangered and the institutions should endeavor both to provide for the long term health and well being of these animals and to advance the field of non-domestic animal medicine. It is hoped that this publication will aid in this process.     

Estimating Aboveground Net Primary Production in Grasslands: A Comparison of Nondestructive Methods

Aboveground net primary production (ANPP) is an important ecosystem property that is affected by environmental variability. ANPP in grasslands is typically measured by clipping peak live plant material. However, this method is time intensive (and therefore expensive), making it difficult to capture spatial and temporal variability. Additionally, it is impractical to use a destructive method to estimate ANPP in long-term, permanent plots. Thus, many double-sampling techniques have been developed to reduce costs and increase sample size. The objective of our study was to assess the accuracy and precision of nondestructive techniques to estimate ANPP as supplements to the traditional method of peak biomass harvest at two grassland sites. We harvested biomass and compared estimates from the same plots to 1) canopy interception using a point frame, 2) green cover estimates derived from a digital camera, and 3) reflectance measurements using a handheld radiometer. We calculated the optimum allocation of sampling effort to direct and indirect methods to minimize sampling cost yet achieve a desired precision. We found that the point frame technique explained the highest proportion of the variability in biomass at both sites (R² = 0.91, 0.90). However, our cost-optimization analysis revealed that the radiometer technique, although less accurate (R² = 0.38, 0.51), could achieve a desired precision for lower labor costs than the point frame. The radiometer and point frame methods will be a useful tool for grassland ecologists and rangeland managers who desire fast, nondestructive estimates of ANPP.     

Zoonotic pathogens isolated from wild animals and environmental samples at two California wildlife hospitals

During 2010, 48 states and Puerto Rico reported 6,154 rabid animals and 2 human rabies cases to the CDC, representing an 8% decrease from the 6,690 rabid animals and 4 human cases reported in 2009. Hawaii and Mississippi did not report any laboratory-confirmed rabid animals during 2010. Approximately 92% of reported rabid animals were wildlife. Relative contributions by the major animal groups were as follows: 2,246 raccoons (36.5%), 1,448 skunks (23.5%), 1,430 bats (23.2%), 429 foxes (6.9%), 303 cats (4.9%), 71 cattle (1.1 %), and 69 dogs (1.1 %). Compared with 2009, number of reported rabid animals decreased across all animal types with the exception of a 1 % increase in the number of reported rabid cats. Two cases of rabies involving humans were reported from Louisiana and Wisconsin in 2010. Louisiana reported an imported human rabies case involving a 19-year-old male migrant farm worker who had a history of a vampire bat (Desmodus rotundus) bite received while in Mexico. This represents the first human rabies case reported in the United States confirmed to have been caused by a vampire bat rabies virus variant. Wisconsin reported a human rabies case involving a 70-year-old male that was confirmed to have been caused by a rabies virus variant associated with tri-colored bats (Perimyotis subflavus).