Economics analysis of mitigation strategies for FMD introduction in highly concentrated animal feeding regions

Outbreaks of infectious animal diseases can lead to substantial losses as evidenced by 2003 US BSE (Bovine Spongiform Encephalopathy) event with consequent loss of export markets, and the 2001 UK FMD (Foot and Mouth Disease) outbreak that has cost estimates in the billions. In this paper we present a linked epidemiologic-economic modeling framework which is used to investigate several FMD mitigation strategies under the context of an FMD outbreak in a concentrated cattle feeding region in the US. In this study we extend the literature by investigating the economic effectiveness of some previously unaddressed strategies including early detection, enhanced vaccine availability, and enhanced surveillance under various combinations of slaughter, surveillance, and vaccination. We also consider different disease introduction points at a large feedlot, a backgrounder feedlot, a large grazing herd, and a backyard herd all in the Texas High Plains. In terms of disease mitigation strategies we evaluate the economic effectiveness of: 1. Speeding up initial detection by one week from day 14 to day 7 after initial infection; 2. Speeding up vaccine availability from one week post disease detection to the day of disease detection; 3.Doubling post event surveillance intensity. To examine the economic implications of these strategies we use a two component stochastic framework. The first component is the epidemiologic model that simulates the spread of FMD as affected by control policies and introduction scenarios. The second component is an economics module, which calculates an estimate of cattle industry losses plus the costs of implementing disease control. The results show that early detection of the disease is the most effective mechanism for minimizing the costs of outbreak. Under some circumstances enhanced surveillance also proved to be an effective strategy.Livestock Production/Industries,

Management factors associated with seropositivity to Lawsonia intracellularis in US swine herds.

abstract: This study was conducted to determine risk factors for Lawsonia intracellularis seropositivity in the breeding and grower-finisher units of US farrowing-to-finishing swine herds. Serum was collected from 15 breeding females and 15 grower-finisher pigs per herd in 184 farrow-to-finish herds, a subset of 405 herds in the National Animal Health Monitoring System (NAHMS) Swine 1995 Study that examined management, health and productivity in herds with at least 300 finisher pigs. Sera were tested by indirect fluorescent antibody test for L. intracellularis. Test results were linked with NAHMS questionnaire data and a logistic regression model of management factors associated with L. intracellularis serological status was developed. Separate models were used for breeding and grower-finisher units. Risk factors for seropositive breeding units were L intracellularis-seropositive status of the grower-finisher unit, use of a continuous system of management for the farrowing unit and a young parity structure (<75% multiparous sows). Risk factors for seropositive grower-finisher units were L. intracellularis-seropositive status of the breeding unit, the number of pigs entering the grower-finisher stage, raising pigs on concrete slats, and intensive management compared with raising pigs on outdoor lots. Use of all in-all out management in the farrowing house and an older parity structure in the sow herd were associated with a lower risk of L. intracellularis seropositivity in the breeding unit, and slatted concrete flooring in grower-finisher houses was associated with a greater risk. Alteration of these management factors might improve control of L. intracellularis infection in farrowing-to-finishing herds

The impact of seasonal variability in wildlife populations on the predicted spread of foot and mouth disease

Modeling potential disease spread in wildlife populations is important for predicting, responding to and recovering from a foreign animal disease incursion such as foot and mouth disease (FMD). We conducted a series of simulation experiments to determine how seasonal estimates of the spatial distribution of white-tailed deer impact the predicted magnitude and distribution of potential FMD outbreaks. Outbreaks were simulated in a study area comprising two distinct ecoregions in South Texas, USA, using a susceptible-latent-infectious-resistant geographic automata model (Sirca). Seasonal deer distributions were estimated by spatial autoregressive lag models and the normalized difference vegetation index. Significant (P < 0.0001) differences in both the median predicted number of deer infected and number of herds infected were found both between seasons and between ecoregions. Larger outbreaks occurred in winter within the higher deer-density ecoregion, whereas larger outbreaks occurred in summer and fall within the lower deer-density ecoregion. Results of this simulation study suggest that the outcome of an FMD incursion in a population of wildlife would depend on the density of the population infected and when during the year the incursion occurs. It is likely that such effects would be seen for FMD incursions in other regions and countries, and for other diseases, in cases in which a potential wildlife reservoir exists. Study findings indicate that the design of a mitigation strategy needs to take into account population and seasonal characteristics

Impact of treatment strategies on cephalosporin and tetracycline resistance gene quantities in the bovine fecal metagenome

The study objective was to determine the effects of two treatment regimens on quantities of ceftiofur and tetracycline resistance genes in feedlot cattle. The two regimens were ceftiofur crystalline-free acid (CCFA) administered to either one or all steers within a pen and subsequent feeding/not feeding of therapeutic doses of chlortetracycline. A 26-day randomized controlled field trial was conducted on 176 steers. Real-time PCR was used to quantify bla[subscript CMY-2], bla[subscript CTX-M], tet(A), tet(B), and 16S rRNA gene copies/gram of feces from community DNA. A significant increase in ceftiofur resistance and a decrease in tetracycline resistance elements were observed among the treatment groups in which all steers received CCFA treatment, expressed as gene copies/gram of feces. Subsequent chlortetracycline administration led to rapid expansion of both ceftiofur and tetracycline resistance gene copies/gram of feces. Our data suggest that chlortetracycline is contraindicated when attempting to avoid expansion of resistance to critically important third-generation cephalosporins

Economics analysis of mitigation strategies for FMD introduction in highly concentrated animal feeding regions

Outbreaks of infectious animal diseases can lead to substantial losses as evidenced by 2003 US BSE (Bovine Spongiform Encephalopathy) event with consequent loss of export markets, and the 2001 UK FMD (Foot and Mouth Disease) outbreak that has cost estimates in the billions. In this paper we present a linked epidemiologic-economic modeling framework which is used to investigate several FMD mitigation strategies under the context of an FMD outbreak in a concentrated cattle feeding region in the US. In this study we extend the literature by investigating the economic effectiveness of some previously unaddressed strategies including early detection, enhanced vaccine availability, and enhanced surveillance under various combinations of slaughter, surveillance, and vaccination. We also consider different disease introduction points at a large feedlot, a backgrounder feedlot, a large grazing herd, and a backyard herd all in the Texas High Plains. In terms of disease mitigation strategies we evaluate the economic effectiveness of: 1. Speeding up initial detection by one week from day 14 to day 7 after initial infection; 2. Speeding up vaccine availability from one week post disease detection to the day of disease detection; 3.Doubling post event surveillance intensity. To examine the economic implications of these strategies we use a two component stochastic framework. The first component is the epidemiologic model that simulates the spread of FMD as affected by control policies and introduction scenarios. The second component is an economics module, which calculates an estimate of cattle industry losses plus the costs of implementing disease control. The results show that early detection of the disease is the most effective mechanism for minimizing the costs of outbreak. Under some circumstances enhanced surveillance also proved to be an effective strategy

Economics Analysis of Mitigation Strategies for FMD Introduction in Highly Concentrated Animal Feeding Regions

In this article, we present a linked epidemiologic-economic modeling framework that is used to investigate several foot-and-mouth disease (FMD) mitigation strategies under the context of an FMD outbreak in a concentrated cattle-feeding region in the United States. We extend the literature by investigating the economic effectiveness of some previously unaddressed strategies. These include early detection, enhanced vaccine availability, and enhanced surveillance under various combinations of slaughter, surveillance, and vaccination. We also consider disease introduction points at a large feedlot, a backgrounder feedlot, a large grazing herd, and a backyard herd all in the Texas High Plains. To examine the economic implications of these strategies, we use a two-component stochastic framework. The first component is the epidemiologic model that simulates the spread of FMD as affected by control policies and introduction scenarios. The second component is an economic module, which calculates cattle industry losses and costs of disease control strategy implementation, and processes the results in a stochastic framework. The results show that early detection of the disease is the most effective mechanism for minimizing the costs of outbreak. Under some circumstances, enhanced surveillance also proved an effective strategy. Copyright 2009 Agricultural and Applied Economics Association

Thin film and bulk morphology of PI-PS-PMMA miktoarm star terpolymers with both weakly and strongly segregated arm pairs

A series of three homologous ABC miktoarm star terpolymers having a polyisoprene (PI), a polystyrene (PS) and a poly(methyl methacrylate) (PMMA) arm, is synthesized by living anionic polymerization. While the volume fraction of the PI and the PS blocks are kept equal and constant, the volume fraction of the PMMA block is varied. The room temperature bulk structure is characterized using small-angle X-ray scattering and transmission electron microscopy, while the structure of thin films is investigated using scanning electron microscopy, atomic force microscopy and X-ray reflectometry. For both bulk and thin films, it is found that the sample with the lowest volume fraction of PMMA has a morphology distinctly different from the two samples with larger PMMA volume fraction. All data for both bulk and thin film samples are consistent with an alternating lamellar structure for the lowest PMMA volume fraction sample. The two higher PMMA volume fraction samples show standing rod structure, however the details of the packing in the PMMA matrix differ depending on sample thickness. Overall, a structure with PI domains screened from interacting with PMMA by a PS shell is seen for both samples. In bulk, core-shell cylinders pack hexagonally, while a 100 nm thin film of the sample with the largest volume fraction of PMMA shows a square-lattice packing. The structuring is driven by two factors: i) the strong segregation of the PI-PMMA arm pair together with the weak segregation of the two arm pairs with a PS block and ii) the geometrical constraints resulting from the star architecture. No wetting layers are observed for any of the thin film samples, neither at the air-polymner surface or at the polymer-substrate interface.</p

Clostridium difficile in pork and retail meat in Texas

The incidence and severity of disease associated with toxigenic Clostridium difficile (Cd) have increased in hospitals in North America from the emergence of newer, more virulent strains of Cd. Toxigenic Cd has been isolated from food and animals and retail meat with potential implications of transfer to humans.</p

Comparison of antimicrobial susceptibility among Clostridium difficile isolated from an integrated human and swine population in Texas

Clostridium difficile can be a major problem in hospitals because the bacterium primarily affects individuals with an altered intestinal flora; this largely occurs through prolonged antibiotic use. Proposed sources of increased community-acquired infections are food animals and retail meats. The objective of this study was to compare the antimicrobial resistance patterns of C. difficile isolated from a closed, integrated population of humans and swine to increase understanding of the bacterium in these populations. Swine fecal samples were collected from a vertically flowing swine population consisting of farrowing, nursery, breeding, and grower/finisher production groups. Human wastewater samples were collected from swine worker and non-worker occupational group cohorts. Antimicrobial susceptibility testing was performed on 523 C. difficile strains from the population using commercially available agar diffusion Epsilometer test (Etest®) for 11 different antimicrobials. All of the swine and human strains were susceptible to amoxicillin/clavulanic acid, piperacillin/tazobactam, and vancomycin. In addition, all the human strains were susceptible to chloramphenicol. The majority of the human and swine strains were resistant to cefoxitin and ciprofloxacin. Statistically significant differences in antimicrobial susceptibility were found among the swine production groups for ciprofloxacin, tetracycline, amoxicillin/clavulanic acid, and clindamycin. No significant differences in antimicrobial susceptibility were found across human occupational group cohorts. We found that 8.3% of the swine strains and 13.3% of the human strains exhibited resistance to metronidazole. The finding of differences in susceptibility patterns between human and swine strains of C. difficile, provides evidence that transmission between host species in this integrated population is unlikely