Retroviral association with ovarian adenocarcinoma in laying hens.

The laying hen has been used as a model for ovarian adenocarcinoma (OAC) in women. Previous work has shown an association between expression of endogenous retroviral proteins and elevated envelope mRNA and occurrence of OAC in humans, but causality has not been demonstrated. The objective of this study was to determine whether there is a similar association between retrovirus presence and OAC in a commercial laying hen flock at the University of Illinois Poultry Research facility with a history of a high OAC prevalence in older hens. Laying hens of three age strata were randomly selected for a cross-sectional study. Blood samples were collected, and serum was tested for antigens of endogenous or exogenous avian leukosis virus (ALV) by ELISA. Birds were humanely euthanized, and spleens, ovaries, and any tissues with gross lesions were sampled. Ovaries and gross lesions were examined histologically and spleens were used for RT-PCR to detect endogenous ALV via ALV-E env mRNA expression. Overall, hens with OAC were 5.2 times more likely to be ALV positive than hens without OAC (95% C.I. 2.06-13.14). Controlled for age, OAC positive hens were 3.6 times more likely to be positive for ALV via antigen-capture ELISA (95% C.I. 1.08-11.96). Endogenous ALV-E in hens may be analogous to human endogenous retroviruses, which have also been associated with OAC in women. Further studies to establish causation are warranted to better understand the potential for laying hens to serve as a laboratory model for viral-induced ovarian tumours in humans. RESEARCH HIGHLIGHTSOAC in hens was associated with age, seropositivity for ALV, and endogenous ALV mRNA expression.Older hens with OAC were more likely to be ALV seropositive by ELISA and ALV-E mRNA-positive.Associations between OAC, age, and endogenous retrovirus expression have been reported in humans.These findings support the use of hens as models for OAC in humans.

Determination of enrofloxacin stability and in vitro efficacy against Staphylococcus pseudintermedius and Pseudomonas aeruginosa in four ear cleaner solutions over a 28 day period.

Chemical stability and in vitro bactericidal efficacy of 0.9% enrofloxacin-compounded solutions were evaluated following storage at room temperature for 28 days. Chemical stability of enrofloxacin was determined by high-performance liquid chromatography (HPLC) in five compounded solutions, including sterile water. Bactericidal efficacy was determined by spiral plating serial 10-fold dilutions of bacteria and solutions followed by colony counts. Tris-EDTA [TrizEDTA(®) (TE)], Tris-EDTA and 0.15% chlorhexidine [TrizChlor(®) (TC)], 2.5% lactic acid, 0.1% salicylic acid and 0.1% parachlorometaxylenol [Epi-Otic (EO)], and 0.1% free salicylic acid, 0.1% parachlorometaxylenol and 0.5% EDTA [Epi-Otic Advanced (EA)] were used. High-performance liquid chromatography was carried out with one-step liquid/liquid extraction to detect and quantify enrofloxacin stability. Mean recoveries for compounded samples run in triplicate at 28 days were 97.7% (TE), 99.9% (TC), 98.1% (EO) and 97.8% (EA). Kruskal-Wallis analysis showed no significant difference in the percentage recovery (H=0.0539, df=3, P=0.9967). American Type Culture Collection strains of Staphylococcus pseudintermedius and Pseudomonas aeruginosa were used to evaluate in vitro efficacy following 30 min incubation on days 0, 14 and 28. Consistent in vitro bactericidal efficacy of all compounded solutions, indicated by killing >2.3×10(7) colony-forming units/mL, was seen; however, bactericidal efficacy decreased for compounded TC on day 14. Pseudomonas aeruginosa was more sensitive to the ear cleaners and enrofloxacin than S. pseudintermedius. The HPLC and in vitro data suggest that 0.9% enrofloxacin compounded with sterile water, TE, EO and EA maintains chemical stability and bactericidal efficacy for 28 days.

A public-policy practicum to address current issues in human, animal, and ecosystem health.

There are recognized needs for cross-training health professionals in human, animal, and ecosystem health and for public health policy to be informed by experts from medical, science, and social science disciplines. Faculty members of the Community Health and Preventive Medicine Section at the University of Illinois at Urbana-Champaign, College of Veterinary Medicine, and the Institute of Government and Public Affairs, University of Illinois at Urbana-Champaign, have offered a public-policy course designed to meet those needs. The course was designed as a practicum to teach students the policy-making process through the development of policy proposals and to instruct students on how to effectively present accurate scientific, demographic, and statistical information to policy makers and to the public. All students substantially met the learning objectives of the course. This course represents another model that can be implemented to help students learn about complex, multifactorial issues that affect the health of humans, animals, and ecosystems, while promoting participation in public health policy development.

West Nile virus seroconversion in penguins after vaccination with a killed virus vaccine or a DNA vaccine.

To investigate the serologic response of penguins to West Nile virus (WNV) vaccines, four species of exclusively indoor-housed penguins, negative for WNV by serology, were evaluated: Humboldt (Spheniscus humboldti), Magellanic (Spheniscus magellanicus), Gentoo (Pygoscelis papua), and Rockhopper (Eudyptes chrysoscome) penguins. Birds were inoculated with either a killed virus vaccine or a plasmid-mediated DNA WNV vaccine, and postinoculation serology was evaluated. Both vaccines induced seroconversion in all four species, and no adverse reactions were noted. Postvaccination serology results varied across species and vaccine types. However, in all four species, the killed virus vaccine resulted in a greater seroconversion rate than the DNA vaccine and in a significantly shorter time period. Additionally, the duration of the seropositive titer was significantly longer in those birds vaccinated with the killed virus vaccine compared with those vaccinated with the DNA vaccine. A subset of unvaccinated penguins serving as negative controls remained negative throughout the duration of the study despite the presence of WNV in the geographic locations of the study, suggesting that indoor housing may minimize exposure to the virus and may be an additional means of preventing WNV infection in penguins.

Potential uses for geographic information system-based planning and decision support technology in intensive food animal production.

Although geographic information systems (GIS) have been used in many disciplines, the available technology in planning and decision support has only recently begun to be used in intensive animal production, in areas such as confined animal feeding operations. GIS-based planning and decision support systems have the potential to enhance many aspects of intensive animal production, such as disease monitoring and prevention, emergency management and nutrient waste disposal. Current uses of GIS in animal production are reviewed. Potential uses are illustrated using the example of the poultry industry on the Delmarva Peninsula, USA.

A survey of biosecurity practices as risk factors affecting broiler performance on the Delmarva Peninsula.

A 10-page questionnaire on biosecurity practices was mailed to 187 growers on the Delmarva Peninsula in October 2000. The growers were selected by three broiler integrators on the basis of flock performance and were classified as cases (bottom 10% performers) and controls (top 10% performers). After two mailings, 71 growers (38%) responded to the survey, of which 47 (66.2%) represented good performers and 24 (33.8%) represented poor performers. Univariate and multivariate statistical analyses revealed that increased frequency of sanitizing water lines was statistically significantly associated with good flock performance (P = 0.0449). The presence of wild birds inside poultry houses during grow-out showed a slightly statistically significant association with poor flock performance (P = 0.0633).

The development and validation of a geographic information system database for the poultry industry on the Delmarva Peninsula.

A geographic information system (GIS) database of the poultry industry on the Delmarva Peninsula was developed through a cooperative agreement between the Delmarva Poultry Industry, Inc., and the Virginia-Maryland Regional College of Veterinary Medicine. The purpose of this database was to facilitate disease surveillance and assist in managing the response to outbreaks and other emergencies. Two methods of data collection were employed and are described in this paper. The first method was to visit each poultry farm and collect the latitude and longitude coordinates with a handheld global positioning system unit. The second method used property ownership information, aerial photographs, and a GIS to determine the latitude and longitude of each poultry farm. There was no significant difference between the two methods in the accuracy of the results, but there was a large difference in the amount of time and money necessary to obtain the data. These findings indicate that whereas there are many ways to obtain accurate data for a GIS database, other factors may influence which method is chosen. A subset of farms contained within the database was visited to assess the accuracy of the locations contained within the database. Of the 240 farms visited for validation, 212 showed evidence of a functioning or previously functioning poultry operation. The corresponding error rate was 11%. This demonstrates the need to assure that the database is kept up to date to ensure that attrition among poultry growers is recorded. Several potential factors that might contribute to sources of error are discussed.

Economic implications of bovine leukemia virus infection in mid-Atlantic dairy herds.

OBJECTIVE: To determine the baseline costs of bovine leukemia virus (BLV) infection, including costs of clinical disease and subclinical infection, in a dairy herd representative of the mid-Atlantic region and compare these costs with the cost of a test-and-manage BLV control program. DESIGN: Stochastic spreadsheet model. SAMPLE POPULATION: A commercial Holstein dairy herd with 100 milking cows. PROCEDURES: A spreadsheet model was developed. The overall cost of infection included the cost of clinical disease (ie, lymphosarcoma [LS]) and the effects of subclinical infection on milk production and premature culling. Model input values and distributions were designed to reflect economic conditions in the mid-Atlantic region. Relative costs of infection and control were calculated for infection prevalences of 20, 50, and 80%. RESULTS: Estimated mean cost to the producer per case of LS was 412 dollars; for a herd with a 50% prevalence of BLV infection, annual incidence of LS was 0.66. Mean annual cost of subclinical infection at a 50% prevalence of infection was 6,406 dollars. Mean annual cost of a test-and-manage control program was 1,765 dollars. The cost of clinical disease and subclinical infection varied substantially with the prevalence of infection, whereas the cost of control varied with herd size. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a basic BLV control program may be economically beneficial in herds in which the prevalence of BLV infection is > or = 12.5%. Farm-specific considerations may factor prominently when weighing the costs and benefits of an individual BLV control program.

Comparison of culling rates among dairy cows grouped on the basis of serologic status for bovine leukemia virus.

OBJECTIVE: To determine the association between serologic status for bovine leukemia virus (BLV) and culling rates by use of survival times in a commercial Holstein dairy herd. DESIGN: Longitudinal study. ANIMALS: 593 milking cows. PROCEDURE: Cattle were tested for antibodies against BLV by use of agar gel immunodiffusion or ELISA 4 times each year from 1989 to 1993 and then annually through 1999. Dates of birth, first calving, and culling or death were obtained from Dairy Herd Improvement Association records. Most cows were enrolled in the study on the date of first calving. Survival times were compared among seropositive, seronegative, and seroconverted cows with the Kaplan-Meier method and a Cox regression model stratified on the basis of year of birth. RESULTS: Complete records were available for 593 of 685 (87%) cattle in the dairy herd during the study period. Median survival time for all cows was 31.7 months. Survival times, which correspond to cull rates, did not differ significantly between seropositive and seronegative cattle, whereas cattle that seroconverted during the study had a significantly longer survival time. Year of birth was positively and significantly associated with survival time. CONCLUSIONS AND CLINICAL RELEVANCE: BLV serologic status was not associated with cull rate as measured by survival time in this dairy herd. This finding is in contrast to results of studies that used survival analysis techniques; our results may influence management decisions concerning BLV.

Temporal and spatial distribution of blastomycosis cases among humans and dogs in Illinois (2001-2007).

OBJECTIVE: To compare the temporal and spatial distribution of cases of blastomycosis among humans and dogs in Illinois. DESIGN: Retrospective cross-sectional survey. SAMPLE: Human and canine populations in Illinois from 2001 through 2007. PROCEDURES: For each year, human population data were obtained from the US Census Bureau, and the total number of dogs was estimated by use of a human population-based formula. Data regarding infections with Blastomyces dermatitidis in humans were accessed from the Illinois Department of Public Health. Data regarding B dermatitidis infections in dogs were acquired through a survey of a random sample of the 747 veterinary medical practices in Illinois. Statistical analyses of human and canine data were performed by use of t tests, ANOVA, odds ratio assessment, and regression modeling. RESULTS: Estimated annual incidence of human cases of blastomycosis in Illinois increased from 3.8 to 10.7 cases/1 million persons/y from 2001 through 2007. Analysis of data from 221 veterinary practices revealed that the mean estimated annual incidence of canine cases of blastomycosis was 8.3 times the mean estimated annual incidence of human cases, with a similar pattern of change and regional distributions. Thirty-eight counties reported either human or canine cases but not both. CONCLUSIONS AND CLINICAL RELEVANCE: The estimated annual incidence of blastomycosis in humans and dogs in Illinois increased during the period of interest. Veterinarians, physicians, and public health agencies should be encouraged to communicate with each other regarding diagnoses of blastomycosis in either species to facilitate early diagnosis and treatment.

Considerations when using discriminant function analysis of antimicrobial resistance profiles to identify sources of fecal contamination of surface water in Michigan.

The goals of this study were to (i) identify issues that affect the ability of discriminant function analysis (DA) of antimicrobial resistance profiles to differentiate sources of fecal contamination, (ii) test the accuracy of DA from a known-source library of fecal Escherichia coli isolates with isolates from environmental samples, and (iii) apply this DA to classify E. coli from surface water. A repeated cross-sectional study was used to collect fecal and environmental samples from Michigan livestock, wild geese, and surface water for bacterial isolation, identification, and antimicrobial susceptibility testing using disk diffusion for 12 agents chosen for their importance in treating E. coli infections or for their use as animal feed additives. Nonparametric DA was used to classify E. coli by source species individually and by groups according to antimicrobial exposure. A modified backwards model-building approach was applied to create the best decision rules for isolate differentiation with the smallest number of antimicrobial agents. Decision rules were generated from fecal isolates and applied to environmental isolates to determine the effectiveness of DA for identifying sources of contamination. Principal component analysis was applied to describe differences in resistance patterns between species groups. The average rate of correct classification by DA was improved by reducing the numbers of species classifications and antimicrobial agents. DA was able to correctly classify environmental isolates when fewer than four classifications were used. Water sample isolates were classified by livestock type. An evaluation of the performance of DA must take into consideration relative contributions of random chance and the true discriminatory power of the decision rules.