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  • Author or Editor: D. L. Forster x
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Epidemiologic modeling of the likely herd-to-herd transmission of pseudorabies virus (prv) was developed to assess the progress and potential for the prv-eradication program in the United States. The herd-to-herd transmission of prv over a 20-year period (1993 to 2012) in the United States was simulated under various scenarios, which included variable program-funding levels and variable prevalences. A transition model (Markov process model) was used to predict yearly changes in herd prevalence of prv infection. Five mutually exclusive states of nature for herds were assumed: uninfected and not vaccinated; uninfected and vaccinated; known to be infected and not vaccinated; known to be infected and vaccinated; and infected, but not known to be infected. Three prevalences for states in the United States were assumed: higher prevalence, moderate prevalence, and lower prevalence. Three funding levels were assumed: no eradication program, continued funding at the current level, and increased funding of 25%. Estimates made by an expert panel for determining probabilities in the state-transition matrices were used. A model also was developed, and was considered to be the most optimistic scenario likely under increased funding of 25%. The most optimistic estimates of the probabilities that still lay within the range of estimates made by the expert panel were used for this model. Only the optimistic transmission matrices allowed for total eradication of prv. Using the optimistic matrices, all states in the United States of America had moved into the moderate- or low-level risk status by the year 2000. The longest time taken to achieve eradication was for the state of Iowa, where eradication was not achieved until 2012.

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in American Journal of Veterinary Research


Productivity and economic effects of pseudorabies were estimated for a mean-size, farrow-tofinish swine enterprise. A Delphi technique was used to elicit productivity effects from an expert panel. Enterprise budgets for pseudorabies-infected and noninfected herds were constructed by use of these productivity estimates, as well as by use of economic data from secondary sources. Data examined to determine effects on productivity included preweaning, nursery, and growing/ finishing pig mortality; breeding hog mortality; feed conversion; labor; and veterinary services and medication expenses. Results indicated that profitability was lowered in infected herds by approximately $6/cwt of swine produced.

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in Journal of the American Veterinary Medical Association


Case Description—A 4-year-old Hanoverian gelding was evaluated because of a mobile worm-like structure in the right eye.

Clinical Findings—Ophthalmologic examination of the right eye revealed a white, thin, coiled, mobile parasite, which was presumed to be a nematode, located in the ventral portion of the anterior chamber of the eye; there also were vitreal strands located temporally and inferiorly near the margin of the pupil. Results of ophthalmologic examination of the left eye were unremarkable.

Treatment and Outcome—The horse was treated with a neomycin-polymyxin B-dexamethasone ophthalmic solution applied topically (1 drop, q 8 h) to the right eye and penicillin V potassium (22,000 U/kg [10,000 U/lb], IV, q 6 h). The horse was anesthetized. A stab incision was made in the cornea, and a viscoelastic agent was infused around the parasite. The parasite was extracted via the incision by use of an iris hook and tying forceps. The horse had an uncomplicated recovery from the procedure and retained vision in the right eye. Gross and microscopic examination was used to identify the parasite as an adult metastrongyloid nematode consistent with a fully developed male Parelaphostrongylus tenuis.

Clinical Relevance—To the authors' knowledge, this is the first report of intraocular parelaphostrongylosis in a horse. This report provided evidence that vision could be retained after treatment for intraocular P tenuis infection in a horse.

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in Journal of the American Veterinary Medical Association